6m Antenna Upgrade Part 3 – microHam Antenna Control System

September 16, 2022 by fkemmerer

6m Antennas choices on the Station Master Deluxe

6m Antenna choices on the Station Master Deluxe

The next step in our project is to configure our microHam station management system to support the new antennas and other components in our 6m antenna project. Each radio in our station (we have five that are 6m capable) has a microHam Station Master Deluxe antenna controller that is used to select and control all of our antennas. These units use the band selection and frequency data from their associated Transceivers to present a set of antenna choices and associated rotator, LNA, amplifier, and other controls to the user.

We are adding the following components to our 6m antenna farm that will need to be controlled by our microHam system:

A 7-element LFA Antenna on our main tower
Three stacks of 3-Element LFAs on our main tower
A microHam remote TEN SWITCH antenna switch to select one of the above antennas
Two Premamp Housings – one shared unit between the antennas above on our main tower and a second housing that will be added to our existing 7-element antenna on our VHF tower

Any of these antennas and their associated Preamp Housings can be used by any of the six Transceivers in our station. There are also two Elecraft KPA-1500 1500w amplifiers (one is shared) that operate on 6m and can be used by three of the five Transceivers in our setup. In this article, I will cover the configuration of our microHam system to support all of the new elements.

Remote Antenna Switching

microHam TEN SWITCH

I choose a microHam TEN SWITCH to handle switching between the new 7-Element LFA and the 6m Antenna Stacks that we will be installing. This switch is can be mounted outdoors on our tower and has good SWR, power handling, and loss performance at 50 MHz. I also chose the option to have N-connectors installed on our TEN SWITCH.

Control Interface Installation

microHam Control Boxes - Relay 10 (Remote Ant. Switch) & Relay 6 (Preamp Housings)

microHam Control Boxes – Relay 10 (Ant. Switch) & Relay 6 (Preamp Housings)

The first step in this part of our project was to install two new microHam Control Boxes to control the new remote antenna switch and the two 6m Preamp Housings. These control boxes are connected to a control bus which allows the Station Master Deluxe antenna controllers associated with our transceivers to control all of our equipment and antennas. The microHam TEN SWITCH that we are using requires ten 12 Vdc control lines to select one of its ten antenna inputs. Each of the two 6m Preamp Housings requires a combination of two 28 Vdc control lines to manage its relays and a 13.8 Vdc line to power its LNA. The microHam Relay 10 Control Box is a good choice for controlling the antenna switch, and a single microHam Relay 6 Control Box can be configured to control the two Preamp Housings. I installed the two new control boxes and a DIN Rail Terminal Block for ground fan out on an existing section of DIN rail in our shack. Finally, I extended the microHam control bus to the new units and connected the control boxes to the 13.8 Vdc and 28 Vdc power systems in our shack, and set the addresses of the two new control boxes.

Relay 10 (Ant. Switch) and Relay 6 (Preamp Housing) Control Box Configuration

Next, we updated the firmware in the new Control Boxes. We configured their relays into groups for interfacing to the remote microHam TEN SWITCH and the components in the 6m Preamp Housings.

New Antenna and Remote Switch Configuration

microHam Ten Switch on Tower

The next step was to define “RF Boxes” in the microHam program for the 7-Element LFA, three fixed-direction 3-Element LFA Antenna Stacks, and the two 6m Preamp Housings that we are going to be installing on our towers.

With this done, we created an additional RF box for the microHam TEN SWITCH that will be located on our main tower. The image above shows how the switch is configured in the microHAM system. We also needed to associate the Relay 10 control box with the switch to enable the microHam system to control it.

6m Preamp Housing Configuration

6m Shared Preamp Housing.jpg

The next step was to configure our 6m Preamp Housings. The image above shows the configuration of the shared housing installed on our main tower behind the microHAM TEN SWITCH.

Station Antenna Switching Matrix

The shared Preamp housing will be connected to one of the inputs on our antenna switching matrix shown above.

This arrangement allows us to use the 6m LNA in the housing with any of the 3-Element LFA antenna stacks or the 7-Element LFA antenna we are installing on this tower. One of the features of the microHam system is that it can understand and correctly sequence shared devices like LNAs, amplifiers, and other active RF components.

LNA Controls

Preamp Housing LNA Control

The image above shows the configuration for the LNA control button that will appear on our SMDs. The configuration above creates a button and display to turn the LNA on or off when an associated button on one SMDs is pressed. This control will appear on the SMDs for any radio using one of the associated 6m antennas.

LNA and PTT Sequencing

Preamp Housing Sequencer

We also need to configure a sequencing element for each of our 6m Preamp Housings. This ensures that the Push To Talk (PTT) lines and transceiver inhibit lines are properly sequenced for the transceivers, amplifiers, and relays in the Preamp Housing that is part of a path to a selected antenna. The microHam system automatically applies the appropriate timing and sequencing rules to all of the RF elements in the path based on the sequencer settings shown above. Configuring the sequencer also involved associating the appropriate relay control units on the newly installed Relay 6 Control Box with the elements in the sequencer timing diagram above. One item to note here is the 20 – 30 ms tail on the sequencing of the Preamp Housing relays when going from Transmit to Receive. This is done to allow extra time for any stored RF energy in the feedlines during high-power Tx to dissipate before bringing the LNA back into the feedline system.

We also added our second 6m Preamp Housing to the RF path for our existing 7-Element M2 Antenna on our VHF Tower and configured it similarly.

Virtual Rotator for Fixed Antenna Stacks

6m Antenna Stacks – microHam Virtual Rotator

The microHam system has a Virtual Rotator feature which is a great way to control selecting between fixed stacks of antennas of the type we are installing. The image above shows the Virtual Rotator we configured for our 3-Element LFA stacks. The Virtual Rotator becomes an additional antenna choice that accepts a direction in the same way that a conventional rotator does. The microHam system figures out which of the available stacks would best match any heading selected and automatically switches the antenna path to the stack that best matches the chosen heading. This capability will be a great tool in VHF contests when we are working multiplier grids on 6m.

microHam Control App – 7-Element LFA, shared LNA, and Rotator Controls

Final Testing

With all the configuration work done, I downloaded the final microHam program to all of our Control Boxes and SMDs and did some more testing. I connected one of our 6m Preamp Housings to the newly installed Relay 6 Control Box and tested the operation with our Transceivers. Everything worked as expected.

I also used the microHam Control App (shown above) to test the various combinations of 6m antenna selections and configured options. The image above shows the selection of the new 7-Element LFA we are adding. Note the availability of controls for the LNA in the shared Preamp Housing and the controls for pointing the antenna via the associated rotator.

Virtual Rotator for 6m Stacks

The image above shows the selections and controls for the 6m Antenna Stacks. The Virtual Rotator choice (STK-VR) is selected in this example. Each SMD has a control knob that can be turned to any heading. When the heading for the STK-VR antenna choice is changed, the system automatically chooses the stack that most closely matches the chosen direction. Choices are also available to choose any of the three stacks directly (ex. EU-STK for the LFA stack facing Europe).

microHam Control App – 6m Split Tx and Rx Antennas

Another nice feature of the microHam system is its ability to use different antennas for Transmit and Receive. The example above shows a setup that uses two different antennas for Tx and Tx.

As you can probably tell, the microHam Station Master Deluxe (SMD) system provides many features for controlling complex antenna arrangements and shared equipment. You can learn more about the microHam SMD system and what it can do here. You can learn more about the programming and operation of the SMD components via the SMD manual.

Next Steps

We’ll continue to post more articles in this series as our project proceeds. Here are some links to other articles in our series about our 6m Antenna Upgrade Project:

Our new LFA antennas and supporting equipment have arrived. The next step in our project will be assembling them and creating an adjustable mounting system for the 3-Element LFA antennas in our stacks.

Fred, AB1OC

An 80m Broadband Matching System

January 28, 2018 by fkemmerer

Our Tower with 75m Loop

We installed a 75m loop for SSB operation on our tower when we built it. The loop is full size and is diamond shaped so that our lower SteppIR DB36 yagi can rotate inside of it. The loop is fed at the bottom corner about 20 ft up from the ground. It works great for SSB operation on 75m, but we have often wished we could use it across the entire 80m Band. This goal led to a project to create a matching system for the antenna. The idea was to use a set of loading coils in series at the feed point to create a good match in all segments of the 80m band.

EZ-NEC Model for 75m Loop

The first step in designing our 80m matching system was to build a model of our current loop using EZ-NEC. The model was then used to determine the correct values of a set of series loading inductors to match different segments of the 80m band.

Matching System Design Analysis

We also considered how likely different segments of the 80m band were to be used by profiling historical spotting data from DXSummit. All of this analysis led to the creation of a final design which is captured in the spreadsheet shown above. The final design requires our current 75m loop to be shortened to work well at the very top of the 80m Band.

Modeled Loading Coil Inductance Values

A set of 5 different inductor pairs can be used in series with the loop’s feed point to create a good match across the 80m band. The modeled values for the series-matching inductors are shown above.

Matching System Modeled SWR

Our microHAM control system can easily implement the switching of the various inductance values based on the frequency that a radio using the antenna is tuned to. The resulting modeled SWR for the final 80m loop and match combination is shown above. The design should achieve an SWR < 1.5:1 across the entire 80m Band except for the very top, where the SWR remains < 2:1. Also, the design optimizes the system’s SWR in the important CW DX, SSB DX, and Digital windows on the 80m band.

The layout of Components in Enclosure

With the design completed, we chose an enclosure and all components. Here are the details of what we used:

Barker and Williamson 2404TL 32 uH Airdux coil stock cut in half (3″ dia, 4 TPI)
Array Solutions RF-15 15/20 kW RF Relays
Balun Designs 1.5:1 Balun with eyelets
V22ZA2P Varistors (MOVs), 0.1 uF Capacitors, 1N4001 Diodes make up the 12Vdc relay control circuits
Outdoor NEMA Box Approx. 16″x12″x6.5″
DX Engineering Saddle Clamps to fit our tower

The first step in the construction was to lay out all of the components in the enclosure. Attention was paid to keeping the two series inductors at right angles to avoid coupling and to keep RF connections as short as possible. The relays were arranged to keep the leads connecting to the coils of roughly equal length. Finally, the control circuitry was kept as far removed from the RF leads as possible.

Enclosure Mounting Ears and Clamps

The matching system attaches to a tower leg via saddle clamps. We fabricated a set of mounting ears and spacer blocks to position the enclosure far enough away from the tower so that the antenna connections do not interact with the tower.

80m Matching System Construction

A summary of the completed matching system construction is shown above. The design uses a set of four double-pole double-throw relays to switch in different coil taps, which selects the loading inductance provided by the matching system.

We did a set of calculations and found that our relays would be subjected to a worst-case peak-peak voltage of about 2.1 KVp-p at the coil tap points.

The relays are arranged such that two sets of contacts have to be traversed to select any given coil tap. The relays we are using have a third pole which we are not using. We disassembled each relay and removed the internal contact wiring for the center pole, which improves both the coil-to-contact voltage rating and the isolation values of the relays.

These steps combine to improve the voltage rating of the system. This is an important design element given that the match will operate at legal limit power.

Completed RF Deck

The completed RF deck and control circuitry is shown above. The enclosure we chose came with a removable plastic plate that made mounting and wiring all of the components simple.

Loading Coil Mounting and Taps

The loading inductors are mounted using nylon hardware with the ends connected to the two antenna terminals on the sides of the enclosure. The coils use movable tap clips to allow us to fine-tune the match once the system is installed with the antenna on our tower. The initial clip locations are set to create the inductance values modeled during the design phase.

Relay Control Circuit Connections

The relay control leads use twisted pair wiring to minimize RF pickup. The control leads are routed away from the RF connections to minimize potential RF coupling.

Relay Control Circuit Details

The control circuits for each relay use a combination of a Diode, a Varistor (MOV), and a filter capacitor in parallel to avoid relay coil switching interference and to suppress control line noise.

1.5 to 1 Matching Balun

The matching system is designed to operate at 75 ohms which is close to the resonant impedance of our 75m loop. The current antenna uses a 1.5:1 Balun to match the loop to our 50-ohm coax feedline. We disassembled an identical matching balun (actually a 75-ohm balun plus a 1.5:1 unun) and used it without its enclosure to create a final 50-ohm match.

MicroHAM Setup to Control 80m Matching System

The final step in constructing our matching system was to program our microHAM antenna switching system to properly configure the relays in our matching system. This was quite simple to do using microHAM’s frequency-dependent antenna control capabilities. The microHAM system automatically operates the appropriate relays to create the best possible match as the radio which is using the matching system is tuned across the 80m band.

Unfortunately, we are in the middle of winter here in New England, so I will have to wait for warmer weather to install our new matching system on the tower and make the final adjustments. I am planning another article here when the final integration steps are done to cover the performance of the completed project.

Fred, AB1OC

Plans for 2017 Station Upgrades – Radio, Shared Amplifier, and Remote Op Enhancements

October 9, 2017 by fkemmerer

Current Flex-6700 Remote Operating Gateway and Icom IC-7600 Transceiver

We have several station upgrades planned for this fall. Our planned upgrades include the following:

Enhancing our FlexRadio 6700-based Remote Operating Setup to include additional remote control client options, better networking via the Internet, and better integration with our microHAM system – you can read about this completed project here.
Upgrading the second radio in Anita’s (AB1QB) operating position from the current Icom IC-7600 to a new Icom IC-7610 SDR-Based Transceiver
Adding a new shared Elecraft KPA1500 Solid State Amplifier to our station. The KPA1500 will be shared between the Icom IC-7610 and our FlexRadio 6700-based Remote Operating Gateway.

We always begin our station projects by updating our station design documents.

Updated Remote Operating Gateway Architecture

Our Remote Operating enhancements will include the following:

Updating our FlexRadio SmartSDR Software to V2, which provides operation of the radio over the Internet
Using the SmartSDR CAT Cable features to create a direct interface between the FlexRadio 6700 and the microHAM Station Master Deluxe associated with the SDR
The addition of a Maestro Control Console to our set of PC-based remote operating clients

The figure above shows an updated architecture for our Remote Operating Gateway, including these enhancements. The planned Elecraft KPA1500 solid-state amplifier will simplify the software associated with remotely controlling and monitoring the amplifier, tuner, and wattmeter components in our previous remote operating setup.

Icom IC-7610 SDR-Based Transceiver

We have been quite impressed with the performance of our Icom IC-7300’s radio receiver. As a result, we have decided to upgrade the second radio in Anita’s operating position to an Icom IC-7610. We expect the IC-7610’s receiver performance to be as good as or better than the IC-7300.

Icom IC-7610 External Display

The Icom IC-7610 also provides a nice external display capability, allowing us to take advantage of the radio’s pan adapter. We believe that the IC-7610 will integrate easily into our microHAM system. It should be a “drop-in” replacement for our current IC-7600. We hope to see the IC-7610 shipping before the end of this year.

Elecraft KPA1500 Legal Limit Solid State Amplifier

Our final upgrade will be to add an Elecraft KPA1500 Solid State Amplifier. This amplifier provides 1500 watts on all bands 160m – 6m. The new amplifier will bring up the Icom IC-7610 and our FlexRadio SDR-Based Remote Operating Gateway to full legal limit power. This will be especially helpful on the 6m band where both the IC-7610’s and the FlexRadio 6700’s excellent receiver performance will help us to take the best advantage of the extra power for Meteor Scatter and other weak signal work on 6m.

microHAM KPA1500 Shared Amplifier Design

Our microHAM Station Automation System can accommodate shared amplifiers. We will utilize this capability when integrating the Elecraft KPA1500 into our station. The shared amplifier setup will also allow us to eliminate one of our bandpass filters. The KPA1500 amplifier integrates autotuner and wattmeter functions into the amplifier and provides a direct Ethernet interface for remote control and management. These enhancements should eliminate the need for several remote control server software applications we are currently running on a PC in our shack. Also, we can manage all of these functions from a single client application on a remote client PC. These simplifications will make our remote operating gateway setup more reliable and easier to use.

FlexRadio Maestro Control Console

We plan to share more on these projects in future posts here on our Blog. The FlexRadio Maestro and all the other components we need for Remote Operating Gateway enhancements have arrived. We will complete this part of our project in the very near future and post more here.

Also, the local control interface to the new Elecraft KPA1500 amplifier appears nearly identical to that used by our current Elecraft KPA500 Amplifier. This means that we can begin our shared amplifier upgrades using the KPA500. We do not have a firm date for the IC-7610 to ship, and that portion of our upgrade plans is likely to be our last step in the project.

Special thanks to Dave, K1DLM, who has helped us with ideas for several aspects of this project.

Fred, AB1OC

A Portable Satellite Station Part 4 – 2.0 Station First Contacts!

March 3, 2017 by fkemmerer

Station Packed and Ready for Transport

With our new 2.0 Satellite station built, tested, and packed; we were ready to try it in a portable environment. Fortunately, the Nashua Area Radio Club had a Technician License class coming up and we thought that the new station test would be a great way for our students to learn about Amateur Radio Satellites.

Satellite Status from AMSAT Website

Final preparations included checking the operational status of potential satellites on the AMSAT website. The page shown above is like a spotting cluster for LEO Satellites – it shows satellite activity reported by HAM satellite operators. Using this information, we configured MacDoppler to track the active satellites.

Satellite Pass Predictions

Next, we used MacDoppler to generate pass predictions for the weekend of our Technical Class. We assembled this data for all of the potential satellites and color-coded the available passes to identify those which had the best chance of producing contacts.

With this done, we loaded our portable tower, antennas, and all of the rest of the gear into our pickup truck and transported it to the class site.

Satellite Antennas Setup Portable

The first step at the class site was to unload all of our gear and move the portable tower to a suitable location. We used a compass to orient the tower to true north and leveled it. We used the weight bags that we made up to anchor the tower securely and then installed the antennas, rotator loops, and control cables. The antenna system worked out very well in the portable environment and was easy to set up.

Satellite Antenna Details

Here’s a closer look at the LMR-400 UF coax cables which connect the antennas to the rest of the system. The loops just behind the antennas are necessary to keep the coax from affecting the pattern of the antennas. The coax cables shown were made long enough to allow the antennas to be rotated through their full travel in the azimuth and elevation directions without binding.

Satellite Station Portable – Radio and Supporting Equipment

The final step in the portable setup was to put the IC-9100 Transceiver and Supporting Equipment together in the building and check everything out. We heard an ON4 station through FO-29 near the end of a low-angle pass as soon as we got everything hooked up and working. A very good sign!

We took some time to fine-tune the calibration of our rotators and to check the operation of the computer controls – everything checked out fine. The video above shows MacDoppler controlling the Azimuth/Elevation rotator and the IC-9100 Transceiver during the testing.

First Contact using New 2.0 Station (AO-85)

First Contact using New 2.0 Station (via AO-85)

With all the setup done, it was time to try to make our first contact. Fortunately, we did not have long to wait. We caught a medium-angle pass of AO-85, a U/V Mode FM Easy Sat. With MacDoppler setup and tacking, we immediately heard contacts being made through AO-85. I gave a whistle and adjusted my uplink VFO until I heard my signal coming back through AO-85. I gave a quick CQ call and immediately got a response from Jonathan, NS4L in Virginia, USA! It took a few seconds to exchange call signs and grid squares, and our first contract with our new station was in the log.

Explaining Satellite System to License Class

Our Technician License Class students were very interested in the station. We spent some time explaining the setup and demonstrating how it worked. We made more contacts between our class sessions using AO-85 and FO-29 (a V/U Mode Linear Transponder Satellite). Our most interesting contact was with Burt, FG8OJ, in Guadeloupe through FO-29. Working DX using the new station the first time we used it was great.

We learned several things during our first use of the new station. First, while the 35 ft. maximum separation allowed between the antenna system and the rest of the station is adequate in many applications, the antenna system’s close proximity to the building we were in blocked passes to the west of us with this separation. We have subsequently made up an additional set of feed lines using a pair of 100 ft. long 7/8″ hardline coax cables to allow for a greater separation in portable deployments such as this one.

We were glad we had the Heil Pro 7 Headset with us, and we used it for most of our contacts. The separate speaker allowed our students to hear the contacts well, and the boom microphone on the Pro 7 Headset eliminated feedback due to our voice coming back through the satellites. We improvised a mono-to-stereo converter cable to connect the Heil Pro 7 Headset to one of the two speaker outputs on the IC-9100 Transceiver. This allowed the radio to drive the separate speaker and the headphones at the same time.

We were glad to have the low-noise preamps available. These were especially useful during low-angle satellite passes, and our sequencing setup worked well.

All in all, the first test of our new 2.0 Portable Satellite station was a success. Our license classes students enjoyed learning about Amateur Satellites and had fun, along with us making contacts through a few of them. Our next goal will be to get packet modes and APRS working with our setup. We plan to do another article in this series when this part of our project is completed. Other articles in this series include:

We plan to add larger antennas and switchable polarity to our portable satellite station soon. This will enable us to make contacts using Satellites and the ISS in more difficult conditions.

You may also be interested in the satellite station at our home QTH. You can read more about that here.

Fred, AB1OC

Fall Antenna Projects – A New Low-Band Receive Antenna System

November 27, 2016 by fkemmerer

NCC-1 Receive Antenna System Control Unit and Filters

Anita and I like to take advantage of the mild fall weather to do antenna projects at our QTH. We have completed two such projects this fall – the installation of a Two-Element Phased Receive System and a rebuild of the control cable interconnect system at the base of our tower.

NCC-1 Receive Antenna System Components

Our first project was the installation of a DXEngineering NCC-1 Receive Antenna System. This system uses two receive-only active vertical antennas to create a steerable receive antenna system. The combination can work on any band from 160m up to 10m. We set ours up for operation on the 80m and 160m bands.

NCC-1 Receive System Antenna Pattern

The NCC-1 System can be used to peak or null a specific incoming signal. It can also be applied to a noise source to null it out. The direction that it peaks or nulls in is determined by changing the phase relationship between the two Active Antenna Elements via the NCC-1 Controller.

NCC-1 Filter Installation

The first step in the project was to open the NCC-1 Control Unit to install a set of 80m and 160m bandpass filter boards. These filters prevent strong out-of-band signals (such as local AM radio stations) from overloading the NCC-1. The internal switches were also set to configure the NCC-1 to provide power from an external source to the receive antenna elements through the connecting coax cables.

Installed Active Receive Antenna Element

The next step in the project was to select a suitable location for installing the Receive Antenna Elements. We choose a spot on a ridge that allowed the two Antenna Elements to be separated by 135 ft (for operation on 160m/80m) and which provided a favorable orientation toward both Europe and Japan. The antenna elements use active circuitry to provide uniform phase performance between each element’s 8 1/2-foot whip antenna and the rest of the system. The antenna elements should be separated by a 1/2 wavelength or more on the lowest band of operation from any towers or transmit antennas to enable the best possible noise rejection performance.

Received Antenna Element Closeup

The two Antenna Elements were assembled and installed on 5 ft rods which were driven into the ground. To ensure a good ground for the elements and to improve their sensitivity, we opted to install 4 radials on each antenna (the black wires coming from the bottom of the unit in the picture above). The Antenna Elements are powered through 75-ohm flooded coax cables which connect them to the NCC-1 Control Unit in our shack. The coax cable connections in our setup are quite long – the longer coax of the pair being approximately 500 ft. The use of flooded coax cable allows the cables to be run underground or buried. Should the outer jacket become nicked, the flooding glue inside the cable will seal the damage and keep water out of the cable.

Receive RF Choke

It is also important to isolate the connecting coax cables from picking up strong signals from nearby AM Radio stations, etc. To help with this, we installed Receive RF Chokes in each of the two coax cables which connect the Antenna Elements to the NCC-1. These chokes need to be installed on ground rods near the Antenna Elements for the best performance.

Underground Cable Conduit In Our Yard

We ran the coax cables underground inside cable conduits for a good portion of the run between the antenna elements and our shack. The conduits were installed in our yard when we built our tower a few years back so getting the coax cables to our shack was relatively easy.

Receive Antenna Coax Ground System

The last step in the outdoor part of this project was to install a pair of 75-ohm coax surge protectors near the entry to our shack. An additional ground rod was driven for this purpose and was bonded to the rest of our station’s ground system. We routed both of the 75-ohm coax cables from the two Antenna Elements through surge protectors and into our shack. Alpha-Delta makes the copper ground rod bracket shown in the picture for mounting the surge protectors on the ground rod.

Antenna Equipment Shelf In Our Shack (The NCC-1 Control Unit Is At The Bottom)

The installation work in our shack began with the construction of a larger shelf to hold all of our antenna control equipment and to make space for the NCC-1. The two incoming coax cables from the Antenna Elements were connected to the NCC-1.

microHAM Station Master Deluxe Antenna Controller

Antenna switching and control in our station is handled by a microHAM System. Each radio has a dedicated microHAM Station Master Deluxe Antenna Controller which can be used to select separate transmit and receive antenna for the associated radio. The microHAM system allows our new Receive Antenna System to be shared between the 5 radios in our station.

Antenna Switching Matrix

The first step in integrating the Receive Antenna System was to connect the output of the NCC-1 to the Antenna Switching Matrix outside our shack. We added a low-noise pre-amp (shown in the upper left of the picture above) to increase the sensitivity of the Antenna System. The blue device in the picture is a 75-ohm to 50-ohm matching transformer which matches the NCC-1’s 75-ohm output to our 50-ohm radios. The other two pre-amps and transformers in the picture are part of our previously installed 8-Circle Receive Antenna System.

Multi-Radio Sequencer

The Antenna Elements must be protected from overload and damage from strong nearly RF fields from our transmit antennas. In a single radio station, this can be handled via a simple sequencer unit associated with one’s radio. In a multi-op station such as ours, it is possible for a different radio than the one which is using the Receive Antenna System to be transmitting on a band that would damage the Receive Antenna System. To solve this problem, we built a multi-radio sequencer using one of the microHAM control boxes in our station. The 062 Relay Unit shown above has one relay associated with each of the five radios in our station. The power to the Receive Antenna System is routed through all 5 of these relays. When any radio transmits on a band that could damage the Antenna Elements, the associated relay is automatically opened 25 mS before the radio is allowed to key up which ensures that the system’s Antenna Elements are safely powered down and grounded.

Updated microHam Antenna System Diagram

With all of the coax and control connections complete, I was able to update the microHam system design information for our station and add the new receive antenna system to our setup. You can find more about the programming of our microHam system here.

NCC-1 Controls

So how well does the system work? To test it, we adjusted the NCC-1 to peak and then null a weak CW signal on 80m. This is done by first adjusting the Balance and Attenuator controls on the NCC-1 so that the incoming signal is heard at the same level by both Antenna Elements. Next, the B Phase switch is set to Rev to cause the system to operate in a signal-nulling configuration, and the Phase control is adjusted to maximize the nulling effect on the target signal. One can go back and forth a few times between the Balance and Phase controls to get the best possible null. Finally, the incoming signal is peaked by setting the B Phase switch to Norm.

Peaked And Null’ed CW Signal

The picture above shows the display of the target CW signal on the radio using the NCC-1 Antenna System. If you look closely at the lower display in the figure (nulled signal) you can still see the faint CW trace on the pan adapter. The difference between the peak and the null is about 3 S-units or 18 dB.

NCC-1 Used For Noise Cancellation

The NCC-1 can also be used to reduce (null out) background noise. The picture above shows the result of doing this for an incoming SSB signal on 75m. The system display at the top shows an S5 SSB signal in the presence of S4 – S5 noise (the lower display in the picture). Note how clean the noise floor for the received SSB signal becomes when the unit is set to null the noise source which comes from a different direction than the received SSB signal.

We are very pleased with the performance of our new Receive Antenna System. It should make a great tool for DX’ing on the low bands. It is a good complement to our 8-circle steerable receive system which we use for contesting on 160m and 80m.

Tower Control Cable Interconnects (Bottom Two Gray Boxes)

Our other antenna project was a maintenance one. We have quite a number of control leads going to our tower. When we built our station, we placed surge protectors at the base of our tower and routed all of our control leads through exposed connections on these units. Over time, we found that surge protection was not necessary and we also became concerned about the effects that sunlight and weather were having on the exposed connections. To clean all of this up, we installed two DXEngineering Interconnect Enclosures on our tower and moved all the control cable connections inside them.

Inside View Of Interconnect Enclosures

We began with a pair of enclosures from DXEngineering and we mounted screw terminal barrier strips on the aluminum mounting plates in each enclosure. The aluminum plates are grounded via copper strap material to our tower.

Closer Look At One Of The Interconnect Enclosures

The picture above shows one of the interconnection boxes. This one is used to connect our two SteppIR DB36 Yagi Antennas and some of the supporting equipment. The barrier strips form a convenient set of test points for troubleshooting any problems with our equipment on the tower. There are almost 100 control leads passing through the two enclosures and this arrangement keeps everything organized and protected from the weather.

With all of our antenna projects complete, we are looking forward to a fun winter of contesting and low-band DX’ing.

73,

Fred, AB1OC

Software Defined Radio/Remote Operating Gateway Part 3 – On The Air Remote!

November 29, 2015 by fkemmerer

Remote Operating Setup In Our Home Office

In the previous articles in this series, we explained how we integrated a FlexRadio-6700 Software Defined Radio (SDR) into our station and how we used it as a platform to build the Remote Operating Gateway for our station. The project has turned out to be somewhat involved so we will be providing a series of articles to explain what we did:

With all of the hardware and software installed and the integration steps complete, we will show some examples of using our remote operating setup on the air in this article. The first set of operating examples was made using the Remote Operating Client PC in our Home Office. This system is shown in the picture above.

Working The VK9WA DXpedition – Left Monitor

We were able to make several contacts with the VK9WA DXpedition to Willis Island using our remote operating setup. The picture above provides a closer look at how we set up our Remote Client PC to work VK9WA (you can click on the pictures here to see a larger view). We just completed a CW contact with the VK9WA DXpedition on 40m and you can see that we have the QSO logged in DXLab’s DXKeeper. We used CW Skimmer to help determine where the operator was listening (more on this in a bit). We also used our Elecraft KPA500 Amplifier to make it a little easier to break through the pileup.

Working The VK9WA DXpedition – Right Monitor

The picture above shows a better view of the second monitor on our Remote Client PC. SmartSDR is running to control our FlexRadio-6700 SDR and it is set up for split operation in CW mode on the 40m band. We also have DXLab’s DXView running and we used it to point our antennas to the short path heading for the VK9WA DXpedition. Finally, we used DXLab’s WinWarbler to remotely key the Winkeyer connected to our SDR in the shack to make the actual contact.

VK9WA DXpedition 30m Pileup Viewed From CW Skimmer

The video above shows the VK9WA DXpedition operating split in CW mode on the 30m band. Note how CW Skimmer allows us to see exactly where the operator is listening (the VK9WA operator’s signal is the green bar at the bottom and the stations being worked can be seen sending a “599” near the top). You can see many of the folks trying to work the VK9WA DXpedition move near the last station that is worked in the pileup video.

VK9WA DXpedition 30m Pileup Viewed From SmartSDR

The next video shows the VK9WA pileup in the SmartSDR application which controls the radio. This video provides a closer look at how SmartSDR is set up for split operation. Can you find the station that the VK9WA operator worked? It is not quite in Slice Receiver B’s passband.

Laptop Remote Operating Client

We also configured our Laptop PC to be a Remote Operating Client for our station. Our Bose SoundLink Bluetooth Headset is used as both a wireless microphone and headphones with this system. Our Laptop Client PC can be used from any location on our property via the WiFi Wireless extension of our Home Network.

Window Arrangement For remote Operating From Laptop

Since our Laptop PC has limited screen space, we created a configuration of overlapping windows to provide access to SmartSDR, key elements of the DXLab Suite, and the applications which control/monitor our KPA500 Amplifier and Antennas. Each window is arranged so that a portion of it is always visible so that we can click on any required window to bring it forward when we need to use it.

Operating From Our Remote Laptop Client – A 20m SSB QSO

The video above shows a QSO that we made with AD0PY, David, and his friend Daniel in Missouri, USA. We used the FlexRadio-6700 SDR/SmartSDR combination in VOX mode to make transmit keying simpler. At the beginning of the QSO, we turned our antennas to point to AD0PY. Also, note the operation of the KPA500 Amplifier when we transmit in the video. The QSO is logged in DXLab’s DXKeeper at the end of the contact in the usual way. It’s fun to make casual contacts this way!

As you can see from this post, there is very little difference when we operate our station remotely or from our shack. This was an important goal that shaped the design of our Remote Operating Gateway and Client PC setup. Future posts will provide some details on how we set up the CW Skimmer and Digital Mode (RTTY, PSK, and JT65/JT9) software to work on our Remote PC Clients.

– Fred, AB1OC

Software Defined Radio/Remote Operating Gateway Part 2 – Client/Server Setup And Software

November 29, 2015 by fkemmerer

Remote Operating Gateway Client/Server Architecture

The next step in our Software Defined Radio/Remote Operating Project was to build a Remote Operating Gateway System in our shack and set up Client PCs to operate our station remotely. In a previous article, we explained how we integrated a FlexRadio 6700 Software Defined Radio (SDR) into our station to create a platform to build our remote operating project around. This project has turned out to be somewhat involved, so we will be providing a series of articles to explain what we did:

Part 1 – System Design and Hardware Installation
Part 2 – Client/Server Setup and Software (Shack Equipment, Computers, and Software Enabling Remote Operation – this post)
Part 3 – On The Air Remote!
Part 4 – Remote Operating Enhancements
Satellite Station 4.0 Part 7 – Flex SDR Satellite Transceiver to Enable Remote Satellite Operation
PTT Switch for Remote Operation

In this article, we will explain the additional hardware and software we used to enable remote operating and some other equipment we added to our Client PCs that we use to run our station remotely. The reader may want to refer to the picture above as you browse this article to better understand how the parts in our remote operating setup fit together. You can click on any of the pictures on our blog to see a larger, easier-to-read version.

SmartSDR Software Operating With A FlexRadio 6700 SDR

FlexRadio’s SmartSDR Software handles operating the SDR remotely. At the present state of maturity, SmartSDR can operate over a wired or wireless Ethernet LAN connection. SmartSDR and the FlexRadio-6xxx hardware must function properly on the same sub-network. FlexRadio has indicated they plan to enable SmartSDR operation over wide-area broadband internet connections. The design we chose for our Remote Operating Gateway and Client PCs will allow the operation of our entire station over the internet when SmartSDR can fully support this. SmartSDR handles remoting of audio (microphone and speakers/headphones), CW keying over our Home Network (more on this later), and control of the radio. With these essential functions taken care of, we also need to remotely control the following functions of our station to fully support remote operation:

Control of the power to all of the remote equipment (FlexRadio-6700 SDR, microHAM Station Master Deluxe, W2 Wattmeter, and other Accessories)
Selection and control of our antennas and rotators via a microHAM Station Master Deluxe Antenna Controller
Monitoring and control of our Elecraft KPA500 Amplifier, KAT500 Auto-tuner, and W2 Power/SWR Meter

Remote control of equipment power is particularly important to provide a means to reset/restart equipment remotely and shut down the Transmitter remotely.

Remote GW Control Stack - Antenna, Power and Monitoring

Remote Gateway Control Stack – Antenna, Power, and Monitoring

Remote control of power for the components in our Remote Operating Setup is handled by a RIGRunner 4005i power control device. This unit provides remote power control over a network for up to 5 separate groups of devices. It also provides voltage/current monitoring and solid-state over-current protection.

RIGRunner Remote Power Control Setup

The figure above shows how we set up our RIGRunner 4005i. The device is controlled over our Home Network via a standard Web Browser. As you can see from the picture above, this device lets us remotely control power to all of the devices in our Remote Operating Setup.

Remote Control Relay Unit

The FlexRadio-6700 SDR requires some additional power control handling. Simply removing and applying power to the FlexRadio-6700 SDR will reset the radio and leave it in a power-off state. The FlexRadio-6700 SDR does have a remote power control input which can be controlled via a relay closure. We used a microbit Webswitch 1216H device to provide a remotely controlled relay closure to control the power off/on for the FlexRadio-6700 SDR.

Flex-6700 On/Off Control Via microbit Webswitch

The microbit Webswitch 1216H relay unit is also controlled over our Home Network via a standard Web Browser.

SmartSDR Setup - Tx Keying, Tx Interlock and Remote Power Control

SmartSDR Setup – Remote On/Off Control

The FlexRadio-6700 SDR is configured for remote on/off operation via the Radio Setup dialog in SmartSDR, as shown above. A cable is run between the remote power on/off port on the FlexRadio-6700 SDR and the microbit Webswitch 1216H relay unit to complete this part of our Remote Control System.

Beams On Our Tower

It is also important to have full remote control of our Antennas and Rotators to effectively use our station outside our shack. Control of our Rotators is accomplished by software that remotes serial COM ports over our Home Network.

Network Serial Port Kit

We used Fabulatech’s Network Serial Port Kit package to remote the serial COM ports used to control the microHAM Station Master Deluxe Antenna Controller, the associated antenna Rotators, and the WinKeyer associated with our FlexRadio-6700 SDR. This software runs on both the local Server computer in our shack which hosts the Remote Operating Setup, and any Client PCs which are used to operate our station remotely.

microHAM Station Master Deluxe Antenna Control via Teamviewer and Development App

microHAM Station Master Deluxe Development Application Via TeamViewer

There is not currently a production software tool to enable remote control of the microHAM Station Master Deluxe Antenna Controllers we use in our shack. I plan to develop my own application to do this in the future. The folks at microHAM have been so kind as to provide me with the interface specifications needed to control the Station Master Deluxe Antenna Controller remotely along with a Developer Only test application (shown above) which can be used to understand the microHAM Device Protocol. In the interim, I have been using the microHAM Developer Only application along with the TeamViewer Remote Control Software to remotely control antenna selection and monitor the position of the currently selected rotators.

Shack Remote Operating Gateway Server PC Applications

The remaining software required for remote control of our station is provided by the Elecraft applications, which control the KPA500 Amplifier, KAT500 Auto-Tuner, and W2 Wattmeter, which are used in our Remote Operating Gateway setup. All of these applications, along with the microHAM Developer Only Application for Station Master Deluxe control and the DDUtil Program, which inter-works the FlexRadio-6700 SDR CAT interface with the Station Master Deluxe (see the previous article in this series) are shown above running on our Shack Server PC. This PC is on at all times and is protected by an Uninterruptible Power System (UPS) to ensure that it runs trouble-free.

Remote Operating PC Client Software Applications

In addition to FlexRadio SmartSDR, each server-side PC application has a corresponding Client Side application used on the Remote Operating Client PC. The three Elecraft Client applications for Amplifier, Auto-Tuner, and Wattmeter control and monitoring are shown above. The client-side Network Serial Port Kit application replicates the WinKeyer, microHAM Station Master Deluxe, and Rotator Control COM ports are also shown.

Heil Microphone And USBQ Adapter

The PC in our home office will be our station’s primary remote operating location. Audio quality is important to us, and we wanted to ensure that our audio quality was just as good operating remotely as it is when we operate from our Shack. To accomplish this, we installed a Heil PR781 Microphone, PL2T Boom, and USBQ Adapter/Pre-Amp on our home office PC. The Heil USBQ is a USB sound card and microphone pre-amplifier which connects directly to the PR781 microphone to create a high-quality phone audio source that can be used with the FlexRadio-6700 SDR when operating remotely.

Bose SoundLink Bluetooth Headset

The speakers on my home office PC are quite good, but sometimes a set of headphones is needed to hear weak signals. We choose a quality Bluetooth Headset from Bose for this purpose. The Bose SoundLink Headset is lightweight, wireless, has excellent fidelity, and includes a very good microphone which can be used as an alternative to the Heil PR781. This headset is also very useful when operating from our Laptop Client PC from noisy locations outside our home (more on this in a future article).

SmartSDR DAX Control Panel

The last pieces of the remote operating system are provided by two applications that are part of the SmartSDR software package. The SmartSDR’s DAX Control panel provides remote audio connections for Digital Mode Software and the CW Skimmer decoder. Audio is provided by software “audio cables” for each FlexRadio SDR’s Slice Receiver and the active Tx Slice. SmartSDR DAX Audio IQ interfaces are also provided for each of the SDR’s Panadapters which permits software like CW Skimmer to monitor and decode a wide range of frequencies simultaneously.

SmartSDR CAT

The SmartSDR CAT application provides CAT interfaces on both our Client and Server PCs for applications that need to control or monitor what the FlexRadio-6700 SDR is doing. Many loggers and other applications are beginning to implement direct IP interfaces to the CAT channel of the FlexRadio 6xxx Series SDRs. This approach simplifies interworking between the software and the radio and appears to be more reliable than virtual COM-based CAT interfaces.

Client PC Running SmartSDR And The DXLab Suite (Home Office)

With all of the above elements in place, any client PC that can access our Home Network can be used to operate our station. The picture above shows SmartSDR and the DXLab Suite running on our Home Office PC. The remote emulations of the Rotator, CAT, and Winkeyer interfaces are such that DXLab’s applications can fully operate our station as if they were running in our shack.

Client PC Running SmartSDR And The DXLab Suite – Right Monitor

The picture above shows a closer view of my Home Office PC’s Right monitor (click on the picture to enlarge it). SmartSDR is running the upper left corner, and I am listening to folks operate in the 2015 CQ WW DX CW Contest. The SDR is set on the 20m band, and I have the CW Keyer built into SmartSDR running. The DAX Control Panel is running on the lower right corner of the screen, and it’s set up for use with the CW Skimmer decoder. DXLab’s WinWarbler is running (top-center), enabling me to use the WinKeyer in the shack to send CW via the remote COM port associated with the WinKeyer. Below WinWarbler is the microHAM Developer Only application (accessed remotely via a TeamViewer connection to the Shack Server PC) which shows that I have both of our SteppIR DB36 Yagis selected as a stack and pointed towards Europe. DXLab’s DXView Rotator Control application is running in the center bottom of the screen so that we can turn our Yagis towards other parts of the world (rotators are controlled via another remote COM port). Finally, the client KPA500 Amplifier control application is running in the lower left corner to control the amplifier and to monitor the power out and SWR seen by the amplifier being used to operate remotely.

Client PC Running SmartSDR And The DXLab Suite – Left Monitor

The picture above shows a closer view of the left monitor. DXLab’s logger, DXKeeper, is running at the top/center of the screen. Below is DXLab’s SpotCollector application which monitors spots of the many CW stations worldwide operating in the contest. DXLab’s Commander applications are running in the lower-right corner of the screen and are monitoring the FlexRadio-6700 SDR’s slice Tx/Rx frequency and providing a control interface of the SDR to the rest of the DXLab Suite (via SmartSDR CAT). The Elecraft W2 Wattmeter client control application is just above commander. The W2 Wattmeter client application provides higher resolution power out and SWR monitoring for the remote setup. Bottom-center is DXLab’s Launcher application, and just to the left of that is the KAT500 Auto-Tuner Client Control application. Finally, CW Skimmer is running on the left side of the screen.

CW Skimmer Operating Remotely

As you can see, CW Skimmer decodes a wide range of frequencies in the 20m CW sub-band. It receives its audio in IQ format via the SmartSDR DAX application. It is great fun to operate CW this way, and I am finding myself making a lot more CW contacts now that I have the remote operating setup in my office.

The next post will provide some samples of remote operation in the form of videos. I will also share some information on setting up a Remote Operating Client on a laptop where screen space is more limited. We plan to take a trip outside our house to operate our station over the Internet and share information on how that is done. We will also provide future articles on how to set up CW Skimmer and Digital Modes (RTTY, PSK, and JT65/JT9) on the HF Bands and use them remotely.

For now, we are really enjoying the freedom to operate our station remotely!

Fred, AB1OC

Software Defined Radio/Remote Operating Gateway Part 1 – System Design And Hardware Installation

November 23, 2015 by fkemmerer

Flex-6700 Software Defined Radio And Remote Operating Gateway

We’ve been planning to add a remote operating capability to our station for some time now. We also did some previous work with a FlexRadio Software Defined Radio (SDR) in our station, and we felt that an SDR would be a good platform to build a remote operating project around. We decided to combine our remote operating goals with a next-generation SDR upgrade (a FlexRadio-6700) for our station. This project has turned out to be somewhat involved, so we will be providing a series of articles to explain what we did:

Part 1 – System Design and Hardware Installation (this post)
Part 2 – Client/Server Setup and Software (Shack Equipment, Computers, and Software Enabling Remote Operation)
Part 3 – On The Air Remote!
Part 4 – Remote Operating Enhancements
Satellite Station 4.0 Part 7 – Flex SDR Satellite Transceiver to Enable Remote Satellite Operation
PTT Switch for Remote Operation
Operating FT8 Remote on the 6m band

We will tackle our goals of building a Remote Operating Gateway (GW) in two stages. Stage 1 will focus on operating our station from other rooms in our house (our Home Offices are prime locations for this). Stage 2 will involve operating our station “On The Go” from anywhere in the world that has sufficient Internet Access is available. We also want to enable full control of our station when operating remotely, including:

Use of our Amplifier
Antenna Selection
Rotator Control
Equipment Power Monitoring and Management

We also use a microHAM station control system and contesting equipment as part of our remote operating gateway, and we want to fully integrate our new Flex-6700 SDR with this gear. Our Flex-6700 uses a dedicated Microphone to avoid audio integration issues that we encountered between the Flex-6700 and the microHAM MK2R+ that we use in our station.

Flex-6700 SDR/Remote Operating Gateway Architecture

The first step in this project was to develop a system design (pictured above). We opted for an architecture that uses the Flex SDR as a third radio in Anita’s Operating Position. Her position is now an SO2R setup with a Yaesu FTdx5000 as the primary radio and a choice of an Icom IC-7600 or the Flex-6700 SDR as the second active radio.

Elecraft KPA500 Amplifier and KAT500 Auto Tuner

Elecraft W2 Watt Meter

FilterMax IV Automated Band Pass Filter

The Flex-6700 SDR has an associated Elecraft KPA-500W Amplifier/KAT500 Auto Tuner combination, an Elecraft W2 Wattmeter, an automated bandpass filtering via an Array Solutions FilterMax IV, and a dedicated microHAM Station Master Deluxe (SMD) Antenna Controller. The Elecraft components are good choices for our remote operating project because they all have applications that enable them to be controlled and monitored over a network (more on this later in this series of articles).

Out Station’s Antenna System

The additional microHAM SMD allows the Flex-6700 SDR to access and control our antenna system and associated rotators.

K1EL WinKeyer

Our setup also includes a K1EL WinKeyer to enable computer-controlled CW keying of the Flex-6700 SDR. This device is relatively inexpensive in kit form and was fun to put together. We have a Bencher Iambic Paddle connected to the WinKeyer for in-shack CW operation.

SDR microHAM Integration

The diagram above shows the details of the device interconnections which make up the SDR Radio System. The microHAM SMD Antenna Controller requires a serial CAT interface to its host Flex-6700 SDR to determine what band and frequency the SDR is on. The Flex-6700 SDR does not provide such an interface directly but creates CAT control virtual ports on a host Personal Computer (PC).

DDUtil Setup – SDR Virtual CAT Access

DDUtil Setup – Bridging Physical Serial Port To SMD

To solve this problem, we used an application called DDUtil to bridge the derived CAT port associated with the SDR to a physical serial port on the PC. The PC’s physical port is then connected to the microHAM SMD associated with the Flex-6700 SDR. The pictures above show how DDUtil is set up to do this.

Station COM Port Configuration

The microHAM gear, WinKeyer, Rotators, Radio CAT Interfaces, Amplifier/Auto Tuner Interfaces, etc., all use serial or COM ports on a host PC for control. It’s also true that many loggers have trouble accessing serial ports above COM16. This requires a carefully developed COM port allocation plan for a complex station like ours. The figure above shows this part of our design.

A-B Switching Design For Radio Port 4

microHAM Bus Expansion and Antenna Switching Gear

The last part of the hardware puzzle required to integrate the SDR into our station was the installation of a second microHAM uLink Bus Hub, microHAM Relay 10 Control Box, and an A/B antenna switch controlled by the microHAM SMDs. This allows the 4th radio port on our antenna switching matrix to be shared between the Icom IC-7600 and the Flex-6700 SDR.

microHAM Configuration For SDR Station Master Deluxe

The last step in integrating the Flex-6700 SDR was configuring the microHAM system for the new equipment. This involves adding SMD #5 to the microHAM system and configuring it (and the rest of the system) to know about the Flex-6700 SDR, associated amplifier, and its interconnections to the rest of the system.

SmartSDR Software

The Flex-6700 SDR Hardware is controlled and operated over a network via FlexRadio’s SmartSDR Application. We have 1 Gbps wired and an 802.11 b/g/n Wireless Ethernet system in our home, and the SmartSDR/Flex-6700 SDR combination works well over either network. The software-based approach with most SDRs allows new features to be added to the radio via software upgrades.

SmartSDR Setup – Tx Keying And Interlock

It is very important to prevent the Flex-6700 SDR and the associated Amplifier from keying up when the antennas in our station are switched or tuned. The screenshot above shows the configuration of SmartSDR to enable the keying and interlock interfaces between the Flex-6700 SDR and its associated microHAM Station Master Deluxe Antenna Controller to implement these functions. This setup enables the Tx Keying and Tx Inhibit interfaces between the Flex-6700 SDR and the microHAM Station Master Deluxe to work properly to key all of the equipment in the setup (SDR, Amplifier, active Rx antennas, etc.) and to lock out keying when antennas are being switched or when one of our SteppIR antennas are tuning.

Flex-6700 SDR With CW Skimmer

We will cover additional software and integration steps to realize our Remote Operating goals. Check out the above video to see how the system performs. This video was recorded using our Flex-6700 SDR and CW Skimmer during the 2015 ARRL CW Sweepstakes Contest. We are really enjoying operating in CW mode with the new SDR setup!

Fred, AB1OC

ARRL Centennial Convention This Week – Come Join Us In Hartford!

July 16, 2014 by fkemmerer

ARRL Centennial

Anita (AB1QB) and I will be attending the ARRL Centennial Convention in Hartford Connecticut, USA this coming weekend. We are looking forward to seeing the vendor exhibits, Contest University and the many fine forum presentations which are scheduled.

Station Design Presentation

I will be doing a presentation on the design, construction and operation of our station at the ARRL Centennial event. My presentation is scheduled for Saturday, July 19th at 11 am in Room 27 at the Connecticut Convention Center. I will be presenting the complete story of our station from planning and design, through construction and finally how the station operates and performs. The presentation will include lots of high-resolution pictures and video including material on our shack, tower and antennas.

Updated Station Tour

The presentation will include lots of new material covering all of our recent projects as well as an updated virtual station tour.

Latest Antenna Projects

Some new topics will include our latest antenna projects and some information on our recently completed LEO Satellite System.

Station Automation Overview

The presentation will also include information on our recently installed Station Automation System from microHAM.

Current Station Performance

We plan to talk about how our station is performing against our original design goals and we’ll have some updated video too!

For those who are attending the ARRL Centennial Convention in Hartford Connecticut, I hope you stop by and say hello to Anita and me. We’re anxious to meet as many of our readers as we can at the event. For those who cannot make the trip, we will be taking lots of pictures and we plan to post a summary of what we saw here after the event.

– Fred (AB1OC)

Station Automation Part 3 – Antenna Cutover And Final Integration

April 3, 2014 by fkemmerer

AB1QB Operating Position

The final article in our microHAM installation series will be about our station’s cut-over, configuration, and integration testing. The first step was to bring the second radio in Anita’s (AB1QB) position into the microHAM system. We also added a PR 781 microphone and boom from Heil Sound to her setup at the same time.

AB1QB Position Design

Anita’s second radio is an Icom IC-7610, and its integration into the system went very smoothly. We also integrated the control of our Power Amplifiers (a combination of Icom PW-1s and an Elecraft KPA500) into the microHAM system. As you can see from the diagram above, the amplifiers are dedicated to specific radios and can be controlled directly by each radio’s Station Master Deluxe (SMD). We used microHAM-supplied amplifier control cables for the PW-1, and I built a custom control cable for the Elecraft KPA500 (this was not difficult – both microHAM and Elecraft provide good documentation for the interfaces involved).

Bandpass Filter Control

I also built custom cables to allow our SMDs to control and automate the switching of our Bandpass Filter Units from Array Solutions.

Bandpass Filter Configuration

With the cabling done, I configured the SMDs to correctly set the control leads to switch the Amplifier and Bandpass filter bands based on the Transmit (Tx) frequency of the associated transceiver. The picture above shows the configuration for the bandpass filters. The configuration for the amplifiers is similar.

Control Box Configuration

The next step in the process was to add some microHAM Control Boxes to the uLink bus and configure their addresses. The picture above shows the control interfaces in our system, including the four SMDs. The addressing convention we use in our station has 40-series control boxes that control our 4×10 antenna switching matrix, 50-series control boxes that control our Tx antennas, and 60-series control boxes that control our Receive (Rx) antennas and associated equipment. The picture above also illustrates some of the Units we’ve defined on our Control Boxes to create interfaces to amplifiers, filters, antenna switching, and other controls.

Palstar Dummy Load

The first step in the cutover of our antennas was to connect the antennas and devices, which did not require complex control. This included our OCF Dipole and our Palstar High-Power Dummy Load. As each antenna was connected, the associated path was configured in the system and tested to ensure everything worked as expected.

Dummy Load Modification

I modified the Dummy Load to allow its lamp to be switched on when one of the radios in the shack selects it. This involved adding a couple of binding posts to the device and running the lamp bulb circuit through the binding posts. The posts are connected to a RELAY6 control box, and the microHAM system is configured to close the associated relay whenever a radio selects the Dummy Load. This makes it easy to see that the Dummy Load is selected and extends the life of the bulb.

Transmit Antenna Controls

The next step in the cutover process was to move all of our transmit antennas and rotators to the system one at a time and test them. This required constructing and testing some RS-232 serial cables to connect our three SteppIR Antennas and our Green Heron RT-21D Rotator Controllers to their associated DATA Control Boxes (top row in the picture above).

SteppIR DB36 Control

The picture above shows the configuration for one of our SteppIR Antennas – The Upper DB36 Yagi. This particular configuration step involved assigning the antenna to a DATA Control Box as well as telling the system the type of control protocol to use to control the antenna. The microHAM system “knows” about a wide array of serial and other controllable devices and implements the necessary protocols.

Receive Array Control And Sequencer

The integration of our 8-Circle Low-Band Receive Array involved some special steps at both the Hardware and Configuration levels. The connections on the RELAY10 control box above are used to “steer” the Rx array and enable or disable the shared Low-Noise pre-Amplifiers (LNAs). To protect this antenna from damage from nearby transmit antennas, power to the array must be removed a few milliseconds before transmission begins. This is normally done by a sequencer in a single radio station. Our station can have up to four radios transmitting on any of several different antennas on the low bands. To solve this problem, I used a RELAY6 control box to create a multi-radio sequencer. Each antenna that can transmit on the 160m – 60m bands has one of the relays on the RELAY6 shown above associated with it.

80m Delta Loop Sequencer

These relays are controlled via an optional SEQ control unit configured for each of the associated antennas. These relays are wired in series with the power lead for the 8-Circle Receive Array. Whenever any radio transmits on any band from 160m – 60m on one of the low-band Tx antennas, the associated relay is first opened (with appropriate delay) before Tx is enabled. This approach implements a multi-radio low-band sequencer across the four radios in our station. The control logic also powers down the array when it is not in use by any radio.

Virtual Rotator For 8-Circle Receive Array

The other “special” step involved in the integration of our 8-Circle Receive Array was the implementation of a “virtual rotator” for it. This involves creating a table in the system configuration which maps all possible headings to one of the eight available direction settings for this antenna. Once this is configured, the antenna behaves as if it had a conventional rotator associated with it. When it’s selected, loggers like the DXLab Suite and N1MM can automatically steer the antenna to the best possible direction selection to work a given station. The front panel rotator controls on the SMDs can also be used to turn the antenna just as if it had a “real” rotator.

Available Antenna Paths

With all of the antennas and other RF devices properly configured and interconnected in the configuration, the microHAM router software generates a list of available antenna paths, as shown above. The software automatically determines the path and associated control resource to connect a given antenna to a radio. Note that some of our antennas have multiple paths by which they can be reached. The software detects this and allows the alternative paths to be selected or, if configured as is the case with our 8-Circle Receive Array, be used by multiple radios at the same time. This table represents all of the possible antenna selections in our system.

Antenna Selection Configuration

The final step in the configuration process is to determine which antennas may be used by which radios on each of the available bands. The microHAM router software initially populates this table with all possible choices based on the “available antennas.” I edited the automatically generated configuration to remove a few choices which were not needed and to reorder the lists for each band so that the displays on the SMD would be the most logical for us to use. With these steps done, our configuration was complete.

Yagi Stack Control

The system is quite easy to use and provides easy-to-read and useful displays. The picture above shows the selection of our Stack of two SteppIR DB36 yagis on one of the radios. That radio (an Icom IC-7800) is currently on the 20m band tuned to 14.267 MHz for both transmit and receive. The two white squares show that both yagis are currently included in the stack. Options exist to use either antenna independently and to use them either in or out of phase in the stack. Both SteppIR DB36 antennas are pointed to 45 degrees (we can turn them independently), as can be determined from the numbers next to the white blocks and the direction of the arrow next to them. The row of buttons numbers 1 – 7 shows the available antenna selections for this radio on the 20m band.

80m Split Tx/Rx Antenna Selection

The picture above shows the SMD display for the same radio tuned to 3.658 MHz on the 80m band. Note that the antenna selections have changed to those available in our station for the 80m band. In this example, I am using different antennas for Tx (our 80m Delta Loop) and Rx (our 8-Circle Receive Array). The virtual rotator for the 8-Circle array is active, and you can see that this antenna is pointed toward 245 degrees (the virtual rotator input was 255 degrees, and the SMD picked the closed direction selection on the Rx antenna). Our 80m Delta Loop is vertically polarized and omnidirectional, which is indicated by the symbol next to it on the display.

Station Master Deluxe Keypad

In addition to the buttons and rotary controller on each of our SMDs, antennas can also be selected and steered via a keypad that is associated with each SMD. The keypads enable many functions, including direct entry of rotator headings, antenna selection, and setup for split Tx/Rx antenna operation.

MK2R+ Virtual COM Port Configuration

The microHAM platform (MK2R+ and SMDs) creates an interface to all our logging and control software on our PCs via a series of Virtual COM Ports. The ports for radio CAT interfaces, PTT and FSK (RTTY) keying, and control of the CW and Voice Keyers in the MK2R+ are created by the microHAM Router, as shown above. Each of the two radios at a given operating position has a unique set of ports for CAT and keying.

Station Master Deluxe Virtual COM Ports

In addition, the SMD associated with each radio creates additional virtual COM ports to allow software programs to control the rotator associated with the currently selected antenna(s) on that SMD. The control also includes any “virtual rotators” associated with antenna(s) that may be selected on a given SMD.

DXLab Radio Control

We use the DXLab Suite and the N1MM+ Logger at our station, which works well with the microHAM system. DXLab, including its Commander component (lower-right), is shown above, which provides the radio interface to the suite. If you look closely, you can see the Commander radio buttons, which select either of the two radios at this position. DXLab (and N1MM) know the microHAM control protocol and will automatically switch the associated MK2R+ to use the appropriate radio. This includes setting which radio is active to Tx, what audio is heard in the headphones/speakers, and what audio goes to the sound card for the associated MK2R+ and its radios. The appropriate routing of the shared microphone and CW paddles is also automatically configured.

DXLab and HRD Rotator Control

The picture above shows our rotator control software. We are using two programs here. In the upper left is DXLab’s DXView program, which will steer our antennas in the direction associated with the callsign currently entered into the logger. The other rotator controller is HRD Rotator (lower right) which displays a map of the world and a path. We can click on any location on HRD’s Rotator’s map, and the software will turn the currently selected antennas in that direction. The use of independent rotator control programs is made possible by the microHAM Router, which implements two separate Virtual COM Ports for the rotator(s) associated with each SMD’s selected antenna(s) for its associated radio.

As you can probably tell from the articles in this series, the microHAM system is very powerful and can handle most any station’s setup, including those which are much more complicated than ours. While the construction and configuration work described here may seem a little complex, it’s not that difficult to create a good plan for your system at the outset (see the first post in this series). The documentation for the microHAM system is very good, and Jozef (OM7ZZ) and Joe (W4TV) at microHAM were very good about answering my questions and steering me in the right direction as I built and configured my system. There is also a good Yahoo! group for the microHAM system. You may want to look at the other articles in this series for more information as well:

I had the opportunity to use our new microHAM System as part of the 2014 CQ WPX SSB Contest this weekend, which helped me improve my score. For more on this, check out the article on the contest on this Blog.

We are considering the addition of legal limit solid-state amplifiers and high-power bandpass filters to our station, which will be integrated into the microHAM system when installed. I am also experimenting with the addition of a software-defined radio to the setup. I plan to provide additional articles here as those projects proceed.

– Fred, AB1OC

Our HAM Station

Notes on the construction and operation of a multi-op Amateur Radio Station

Category Archives: Station Automation

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Control Interface Installation

New Antenna and Remote Switch Configuration

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LNA Controls

LNA and PTT Sequencing

Virtual Rotator for Fixed Antenna Stacks

Final Testing

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