6m Antenna Upgrade Part 3 – microHam Antenna Control System

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:

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

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 choose 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 as well as 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

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

Next, we updated the firmware in the new Control Boxes and 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

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 which 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

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.

Antenna Switching Matrix

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

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

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

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

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

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

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

Learn About Radio Propagation

February 2021 Tech Night – Understanding and Using Propagation to Work The World

Anita, AB1QB, recently did a Tech Night Program on Radio Propagation as part of the Nashua Area Radio Society’s Tech Night program. I wanted to share the presentation and video from this Tech Night so that our readers might learn a little more about propagation and how to use it to facilitate contacts.

Anita, AB1QB provides a comprehensive overview of HF and VHF/UHF propagation and how to use it to Work the World. Topics include the many online tools to help one determine and measure propagation conditions. VHF+ modes such as Meteor Scatter, Tropo, EME, and Satellite paths are also covered.

You can view the Tech Night presentation by clicking on the video above. Here’s a link to the presentation that goes with the video. You can learn more about the Nashua Area Radio Society’s Tech Night program here.

Fred, AB1OC

Tech Night – EME II: Station Construction and Operation

EME II - Station Construction and Operation

EME II Tech Night – Station Construction and Operation

We recently did a second Tech Night Program on EME as part of the Nashua Area Radio Society’s Tech Night program. I wanted to share the presentation and video from this Tech Night so that our readers might learn a little more about how to build and operate an EME station for the 2m band.

January 2021 Tech Night – EME II: Station Construction and Operation

You can view the Tech Night presentation by clicking on the video above. Here’s a link to the presentation that goes with the video. You can learn more about the Nashua Area Radio Society’s Tech Night program here. There is a demonstration of an actual live EME contact on the 2m band at 57:57 in the video.

The first Tech Night in the EME Series was about Getting Started in EME Communications. You can view that Tech Night here.

We are in the process of upgrading our EME station to include adaptive polarity. you can read more about that project here.

Fred, AB1OC

EME Station 2.0 Part 12 – Station Software

EME Operating Position

EME Operating Position

Software is a big part of most current EME stations. The JT65 Protocol, which was created by Joe Taylor, K1JT, has revolutionized EME operations. It has made it possible for modest single and two yagi stations to have lots of fun with EME.

Phase 1 of our 2m EME station software and hardware uses manual switching/selection of receive polarity. This Phase is about integrating all of the station components together and sorting out operational issues. After some experimentation, we have settled on a dual-decoder architecture for the First Phase of our 2m EME Station.

You can learn more about the Phase 1 EME hardware setup at our station here.

EME Software Environment

EME Station Block Diagram - Phase 1

EME Station Block Diagram – Phase 1

The diagram above shows the current configuration of our 2m EME station. As explained in a previous article in this series, we are using a FUNCube Pro+ Dongle with the MAP65 application as our primary JT65b decoder and we are using our IC-9700 Transceiver along with WSJT-X as a secondary, averaging decoder. Using multiple decoders has proven to be a significant advantage. It is quite common for one of the two applications to decode a weak signal that the other does not.

We use two custom applications (WSJTBridge and Flex-Bridge) to capture the Moon Azimuth and Elevation data generated by the MAP65 application and use it to control the rotators for our EME Antenna Array.

We have been experimenting with Linrad as a front-end to MAP65 and WSJT-X. At present, we are using the NB/NR functions in MAP65 and in our IC-9700 as an alternative to Linrad. We expect the add Linrad into our setup when we add Adaptive Polarity capabilities in Phase 2.

EME Software Operating Environment

EME Software Operating Environment (click for a larger view)

We use the DXLab Suite for logging and QSL’ing our contacts along with several web apps to find potential EME contacts and to determine the level of EME Degradation on any given day.

The screenshot above shows most of these apps running during a 2m EME operating session.

MAP65 Application – Primary Decoder and Operating Application

MAP65 Software

MAP65 Software

We are using MAP65 as our primary decoder. It also controls our IC-9700 Transceiver when transmitting JT65b messages. MAP65 used the I/Q data from our FUNCube Pro+ Dongle to detect and decode all of the signals in the 2m EME sub-band. A waterfall window displays all of the signals on the band as well as a zoomed-in view of the spectrum around the current QSO frequency. MAP65 also generates heading data for our rotators as well as estimates for the doppler shift between stations. The MAP65 application also provides windows that list all of the stations on the band as well as the messages that they are sending.

EME QSOs via MAP65

EME QSOs via MAP65

The screenshot above shows the main MAP65 window during a QSO with HB9Q. Round trip delay (DT) and signal strength information (dB) is shown for each message that is decoded. The MAP65 application along with a manual that explains how to set up and use the program for 2m EME can be downloaded here.

Moon Tracking and Rotator Control

Custom Rotator Control Apps

Custom Rotator Control Apps (WSJT-Bridge and FlexBridge)

We developed an application we call FlexBridge some time back as part of our ongoing project to remote our Satellite Ground Station using our Flex-6700 based SDR Remote Operating Gateway. This application includes functionality to operate Az/El rotator controllers based upon UDP messages which contain tracking data. We wrote a second application that we call WSJT-Bridge which reads the Moon heading data that either MAP65 or WSJT-X and generates and sends UDP messages that enable FlexBridge to track the moon. The combination enables MAP65 to control tracking the moon in our setup.

Both of these applications are at an alpha stage and we will probably separate the rotator control functionality from FlexBridge and make it into a dedicated application.

Antennas On The Moon

Antennas On The Moon

One of the first steps in the integration process was to carefully calibrate our rotators to point precisely at the moon. We got the azimuth calibration close using the K1FO Beacon in CT. With this done, we made final adjustments visually until our antennas were centered on the moon on a clear night.

EME Tower Camera at Night

EME Tower Camera at Night

We recently installed an additional IP camera which gives us a view of our EME tower. This is a useful capability as it enables us to confirm the operation of our rotator from our shack.

WSJT-X – Secondary Decoder

WSJT-X Software

WSJT-X Software

We also run WSJT-X as a second decoder using the receive audio stream from our IC-9700 Transceiver. WSJT-X has some more advanced decoding functions and can average several sequences of JT65b 50-second transmissions to improve decoding sensitivity. It only works on one specific frequency at a time so we use it to complement the broadband decoding capability that MAP65 provides.

We can also transmit using WSJT-X which enables us to use its Echo Test functionality to confirm that we can receive our own signals off the moon.

The WSJT-X application along with a manual that explains how to set up and use the program for EME can be downloaded here.

Finding Contacts and Logging

Finding QSOs and Logging

Finding Contacts and Logging

We use the DXLab Suite for logging and QSL’ing our contacts. DXLab’s Commander application provides the interface between WSJT-X and our IC-9700 Transceiver. This enables the DXLab Suite to determine the current QSO frequency and mode for logging purposes.

MAP65 Software

MAP65 Software and DXKeeper’s Capture Window

We keep DXKeeper’s Capture Window open on the screen where we run MAP65 so we can easily transfer QSO information to our log as we make contacts.

We also use several web apps to find potential EME contacts and to get an estimate of the level of EME Degradation on any given day:

We are working on interfacing our instance of MAP65 to LiveCQ so that we can contribute spots when we are operating. More on this to come in a future article in this series.

Next Steps

We have a dual-channel coherent SDR receiver from Afedri in hand which will allow us to do Adaptive Polarity using MAP65. We will be upgrading our station hardware and software to support Adaptive Polarity in the near future.

We are planning some enhancements to our H-Frame to enable better alignment of our antennas along with improved reliability and stability when rotator our antennas. We will cover these enhancements in the next article in this series.

You can read more about our EME station project via the links that follow:

If you’d like to learn more about How To Get Started in EME, check out the Nashua Area Radio Society Tech Night on this topic. You can find the EME Tech Night here.

Fred, AB1OC

6m VUCC In A Day – ARRL June VHF Contest

6M VUCC Operating Award

6M VUCC Operating Award

The 6m Band is one of my favorite bands. The combination of its unpredictability and the amazing openings that it can produce certainly makes 6m The Magic Band for me!

Fred’s (AB1QB) First Place Finish in NH – 2013 ARRL June VHF Contest

Fred’s New Hampshire First Place Finish in the ARRL June VHF Contest

I haven’t had the chance to work the ARRL June VHF Contest from our home station for several years. A combination of Nashua Area Radio Society activities and preparations for ARRL Field Day have taken a higher priority. ARRL June VHF is a great contest and I was looking forward to working it this year. A few days before the contest Anita and I were talking about the contest and she suggested that I do a 6m Digital Entry. E-skip has been pretty good on 6m this year and we wanted to sort out how we’d do digital and 6m for our upcoming 2020 Field Day Operation from our home so I decided to take Anita’s advice and focus on 6m Digital for June VHF. I entered the contest in the Low-Power Category.

June VHF Operating Setup

6m VUCC

AB1OC Operating in 2020 June VHF

We built a Remote Operating Gateway that allows our station to be operated both over the Internet and from any room in our home via our Home Network. I decided to set up a 6m Digital Station upstairs in our dining room so I could be with Anita more during the contest. The setup consisted of a laptop PC with an outboard monitor and a Flex Maestro as the client for the Flex 6700 SDR in our shack.

Completed Antenna Stack On New Tower

Completed Antenna Stack on our VHF Tower

We have three antennas for 6m – one on our VHF Tower and two via the SteppIR DB36 yagis with 6m kits on our main tower.

Delta Loop On Tower

SteppIR DB36 Yagis on our Main Tower

The three antennas can be pointed in different directions and selected instantly via the computer. This provided to be an advantage during the contest. I kept one on Europe, one point due West, and the third pointed at the Tip of Florida and the Caribean during the contest.

6m VUCC

Operating Setup – N1MM+ and WSJT-X

Having two monitors (the Laptop and an outboard one) allow me to arrange all of the N1MM+ Logger and WSJT-X windows for efficient operating. The image above shows a snapshot of the screen layout during the contest. N1MM+ has some nice features that integrated with WSJT-X to make it easy to spot new grids (Multipliers) and stations that have not yet been worked. The windows on the very right side allowed me to control antenna switching and monitor power and SWR while operating. I use the PSTRotator application (lower-left center to turn my antennas.

6m Band Conditions

6m VUCC

6m PSK Reporter On Sunday Evening

Band conditions on 6m were amazing from here in New England almost the entire contest period! The band was open right at the start of the contest on Saturday and remained open to 11 pm local time on Saturday evening. I was up early on Sunday and was working folks in the Northeastern Region right from the start. After being open all day on Sunday, the band shut down around 5 pm local time and I was afraid that the fun on 6m might be over. I ate some dinner and took a 45-minute nap and got back to my station at around 6:30 pm. About 15 minutes after I resumed, 6m opened again to most of the United States and I was able to work DM and DN grid squares in the Western States! The band stayed open right until the end of the contest at 11 pm local time.

What About the VUCC…

6m VUCC

100 Grids Worked on 6m

Conditions on 6m were so good on Saturday that I almost worked a 6m VUCC by 11 pm on Saturday evening when the band closed. I had 93 grids worked on 6m in just 8 hours! The band opened again early on Sunday morning and I worked my 100th grid square before 10 am – working a 6m VUCC in less than 18 hours!

6m VUCC

Final 6m Grids Worked

By the end of the contest, I had worked a total of 162 Grids! They ranged from the West Coast of the US to Western Europe and from Southern Canada to Northern South America.

6m VUCC

6m Grids Worked During 2020 June VHF

The image above shows most of the 6m grids that I worked plotted on a world map (the EU grids are not shown).

6m VUCC

Final Claimed Score

I was able to make a total of 402 unique contacts on 6m by the end of the contest with a final Claimed Score that was a bit over 65K. All of my 6m contacts during the contest were made using a combination of FT8 and FT4 modes on 6m.

New Ones on 6m for AB1OC

6m VUCC

AB1OC Worldwide 6m Grid Map

I was hoping to work some all-time new Grids and June VHF did not disappoint. I worked a total of 11 new Grids and one new DXCC (Dominica) on 6m during the contest. The image above shows my worldwide grid coverage including the new ones worked during June VHF (my grids in Argentina and Uruguay are not shown above). I now have worked 432 grids on 6m and have confirmed 408 of them with 63 DXCC’s worked and 62 confirmed on the Magic Band.

Summing It All Up…

I must say that I had as much fun working 6m during June VHF this year as I have ever had in any contest! The band openings on 6m were really good and I was busy making new contacts for the entire time that I operated. The combination of the 6m Band and the contest certainly made some Magic for me!

Fred, AB1OC

Perspectives on a 6m DX Opening

6m DX Opening to Europe - PSK Reporter

6m DX Opening to Europe – PSKReporter

I’ve had a chance to operate on the 6m Band this past week. We are approaching the prime time for the summer Es (E-Skip) season here in the Northeastern United States. As a result, I wanted to see how propagation on the 6m band might be unfolding during this spring Es season. I was fortunate to catch a typical limited DX opening on the 6m band between our location here in New England and Europe. I thought that it might be helpful for those who are relatively new to the 6m band to see what this was like.

DX Opening Begins - JTDX Software View

A 6m DX Band Opening Begins – JTDX Software View

I spent some time on and off yesterday calling CQ and monitoring the 6m band using the JTDX software and FT8 mode. FT8 now dominates most of the activity on the 6m band. This is a result of a combination of FT8’s weak-signal performance and available reverse beacon tools such as PSKReporter. As you can see from the JTDX screenshot above, the 6m band was basically only open to the United States here until about 16:58z. At that point, I weakly decoded CT1ILT. This station faded almost immediately and I was unable to make a contact.

Approximately 4 minutes later, the 6m band opened solidly to Spain and France and quite a few stations in this area of Europe appeared with relatively strong signals.

6m DX Opening to Europe - Spotlight Area Propagation

6m DX Opening to Europe – Spotlight Area Propagation (PSKReporter)

As you can see from the PSKReporter screenshot above (taken near the end of the band opening), the probation on 6m was quite strong but limited to a very specific area and heading in Europe. This is typical of limited double-hop Es propagation. We most likely had two Es clouds aligning in such a way that a narrow path of propagation had been created on the 6m band.

A 6m DX Band Opening In Full Swing - JTDX Software View

A 6m DX Band Opening In Full Swing – JTDX Software View

The view above shows the 6m band opening in full-swing. I was hearing 5-6 strong stations from France, Spain, and Italy almost immediately. These stations are all on a relatively narrow range of headings center at about 65 degrees from my QTH. I am scrambling to work the stations that represented new grid squares for me. I am using JTAlert as a bridge to my logger (DXLab Suite) and it is telling me that 2-3 of the station in the mix are in grid square that I have not yet worked on the 6m band.

A 6m DX Band Opening Comes to an End - JTDX Software View

A 6m DX Band Opening Comes to an End – JTDX Software View

Like all good things, the 6m DX opening had to come to an end. As you can see above, the 6m band closed as rapidly as it opened, leaving me calling CQ with no takers to work in Europe.

Contacts Made During the 6m DX Opening

Contacts Made During the 6m DX Opening

The total duration of this opening was about 20 minutes. The contacts that I made during this period are shown above. During the brief opening, I was able to make a total of 11 contacts with a limited set of grid squares in Europe. Most of the signals were quite strong (see the Sent and Rcvd columns in my log above). During the opening, I worked 5 new grid squares that were centered around the border between France and Spain.

AB1OC 6m Grids Worked and Confirmed

AB1OC 6m Grids Worked and Confirmed

By this morning, three of the five new grids that I worked had already confirmed on LoTW. Just for fun, I plotted my 6m grid progress on the Gridmapper website. I keep a copy of the Gridmapper view of my log by my operating area as a reference that I use in conjunction with PSK Reporter to help me identify 6m band openings that might provide opportunities to work new grids.

I hope that this article gives you some idea of the nature of 6m DX openings. The opening described here is pretty typical in that:

  • The band open (and closed) suddenly without much warning
  • The propagation was very good with many strong signals being decoded and worked at once
  • The opening was of short duration lasting only about 20 minutes
  • The band closed as rapidly as it opened
Monitoring the 6m Band at AB1OC

Monitoring the 6m Band at AB1OC

In order to work 6m DX, this experience emphasizes the need to monitor the 6m band for DX openings on a regular basis. This is most easily done using PSKReporter. The pattern of DX openings on 6m to Europe from here in New England is such that EU DX openings typically begin south of us and progress northward. I use our Remote Operating Gateway, a Flex-6700 SDR based setup, to monitor the 6m band for DX openings while I work here in my office. You can see the 6m FT8 setup here in my office running in the monitor-mode above.

FlexRadio Maestro Console

FlexRadio Maestro Console

I use the Maestro here in my office as my SDR client.

I hope that this information has been useful to our readers. As you can see from this example, the 6m Band is called the Magic Band for good reason. It is very exciting to be able to catch and work a good DX opening on 6m. The FT8 mode has both increased the level of activity on the 6m band and made 6m available to many stations with simple antennas and 100W transceivers. You can learn more about how to get started with FT8 on 6m here.

As I sit here writing this, the 6m band just opened to Austria and Hungry! Have to go work some DX on the 6m band…

Fred, AB1OC

Winter Field Day 2020 Final Station Test

Source: Winter Field Day 2020 Final Station Test – Nashua Area Radio Society

Winter Field Day 2020 is almost here! A few weekends ago, several of us got our QTH to complete the final station test for our planned 5O operation in Winter Field Day (WFD). Activities including setup and testing of a new, Portable Networking Pod and three of our five planned Winter Field Day stations. We are planning to use the N1MM+ Logger in a networked configuration this year…

This article covers equipment and networking aspects of the Nashua Area Radio Society’s planned 5O setup for Winter Field Day 2020. All of our stations will use the N1MM+ Logger to support SSB Voice, CW, and Digital modes.

Fred, AB1OC

December 2019 ISS SSTV Event

Source: December 2019 ISS SSTV Event – Nashua Area Radio Society

Slow-Scan TV from the International Space Station (ISS) was on the air again late in December 2019.  The ISS SSTV event was in memory of cosmonaut Alexei Leonov. We had our satellite station running to track the ISS and capture the SSTV images during the event. It’s pretty easy to receive these images – it can be done with an HT, hand-held antenna, and a laptop…

This article includes a gallery of the images that we received during the December 2019 ISS SSTV event and some how-to information that you can use to receive SSTV images from the ISS with just an HT and a handheld antenna.

Anita, AB1QB and Fred, AB1OC

Satellite Station 4.0 Part 10 – Adding 23 cm To Our Satellite SDR

Satellite SDR

DEM L24TX Tx Converter

We’ve recently received our L24TX Transmit Converter from Down East Microwave. The unit is compact, simple, and produces up to 25W output in the satellite section of the 23 cm band (1260 MHz – 1270 MHz, actually 24 cm). The L24TX is a transmit-only device that is intended to enable L-band uplinks for Satellite use. This article is about our most recent project which involved integrating the L24TX into our Flex SDR Satellite System.

Satellite SDR

24 cm Tx Converter Rear Panel

Connecting the unit is straightforward. The unit requires an IF input, a 10 MHz reference oscillator, DC power, and a transmit keyline. The later two inputs are provided via a 7-pin connector and a DEM supplied cable. We ordered our unit with the following configuration options:

  • IF 28 Mhz = 1260 MHz output
  • Max IF Drive Level – +10 dBm
  • Fan and Case configured for mounting in the shack

Fortunately, our feedlines for the 23/24 cm band are hardline-based and relatively short. The unit is also available in a configuration that would enable it to be remotely mounted in an enclosure on a tower.

Satellite SDR

24 cm Tx Converter Installation in our Remote Gateway SDR Rack

The unit fits nicely into our Remote Gateway SDR Rack. The L24TX does not include a power output display so we used a 23/24 cm sensor and our WaveNode WN-2 Wattmeter to monitor output power from the unit. The unit does have leads that output a voltage that is proportional to output power. This could be used to build a power output bar display or meter. the front panel indicates display a power-on indication, lock to the 10 MHz clock input, and Tx when the unit is transmitting.

Satellite SDR

Overall Satellite SDR System Design

Integration into our Satellite SDR System was straightforward. Our system already included splitters for the 10 MHz GPSDO and the 28 MHz Transverter outputs from our Flex 6700 SDR. I had hoped to use one of the leads from the SmartSDR BITS cable we are using to key our 70 cm Transverter but the BITS cable did not have an adequate drive level to key the L24TX.

Satellite SDR

Remote SDR Gateway Tx Band Settings

Fortunately, the Flex 6700 has configurable TX1-TX3 outputs for keying devices like Transverters. The use of the TX2 output to key the L24TX was easily configured in the SmartSDR’s TX Band Settings.

Satellite SDR

23 cm Tx Converter Setup in SmartSDR

It is necessary to configure SmartSDR for the L24TX. The required settings are in the XVTR options tab. In addition to configuring the mapping between the Flex 6700’s XVTR IF frequency and the unit’s output Frequency, one needs to set the IF drive levels. We used the default drive level of 6.0 dBm and adjusted the IF Gain Control on the L24TX until the full output of 25W was reached while transmitting a tone. The correct adjustment is apparent when further gain increases do not provide a proportional increase in output power. The proper setting of the RF drive and gain will keep the L24TX’s output in its linear range of operation.

Satellite SDR

Final Power Distribution Design

The L24TX is powered via the power distribution system in our Satellite SDR Rack. Control and current limiting for the 2m LPDA, 70 cm Transverter, and the L24TX are individually controlled via a RigRunner 4005i IP Power Controller.

Satellite SDR

SDR Satellite System Remote Power Control via a RigRunner 4005i

The RigRunner is remotely accessible over the Internet and our network via a password-protected web interface. This enables us to easily power down or power cycle individual components in the Satellite SDR System remotely.

MacDoppler Tracking AO-91

MacDoppler Tracking AO-91

With all of the hardware installation and calibration steps complete, we are turning our attention to the software side of the setup. We will be using MacDoppler for satellite tracking and VFO control of our Satellite SDR System. This creates a need to connect the MacDoppler program which runs on a Mac to SmartSDR and the Flex 6700 which is a Windows-based system. Fortunately, MacDoppler provides a UDP broadcast mode that transmits az/el antenna position information as well as data to control radio VFOs to adjust for Doppler shift.

Satellite SDR

FlexBridge Software Beta

We are working on a custom windows application called FlexBridge to enable MacDoppler to run our Flex SDR-based Satellite System. FlexBridge runs on a Windows PC. It receives and parses the UDP broadcast messages from MacDoppler and uses the FlexLib API to properly configure and control the Flex SDR’s VFOs.

Satellite SDR

SmartSDR Operating With AO-92 in L-V Mode

At present, FlexBridge can configure and control SmartSDR (or a Maestro Client) that is operating our SDR Satellite System. The screenshot above shows the MacDoppler, FlexBridge, SmartSDR combination operating with AO-92 in L/V mode. This software is still an in-progress development and we plan to add the ability for FlexBridge to connect to the radio via SmartLink as well as support for the Green Heron RT-21 Az/El Rotator Controller that we are using. We’ll be sharing more about FlexBridge here as the software development progresses.

The next step in our Satellite Station 4.0 Remote Gateway project will be to move our satellite antenna controls and feedlines into the shack and begin testing the complete setup using local control. Once this step is complete, we’ll focus on the final steps to enable remote operation of our satellite station via the Internet.

Here are links to some additional posts about our Satellite Station 4.0 Projects:

Fred, AB1OC

A Raspberry Pi Video Player for Ham Expo Displays

Dave, K1DLM recently prototyped a simple Raspberry Pi Video Player for use in our Ham Exposition Displays. We’ve built a number of these players to play video content at our upcoming Ham Expo Display at HamXposition at Boxboro in September. The article below shares information on the hardware and software we used to put these players together. The information should provide a useful start for many other Raspberry Pi projects.

Source: A Raspberry Pi Video Player for Expo Displays – Nashua Area Radio Society

Simple Raspberry Pi Computers have many useful applications in Amateur Radio. They can also be used to create a nice general purpose computing platform for many applications.

The hardest part of using the Raspberry Pi is getting the basic hardware and software components together to create a working system. This article explains these basic steps for a simple video player application that we use as part of our Ham Radio Expo Displays. I hope that this information is useful to others who might want to use the Raspberry Pi.

Fred, AB1OC