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.

Our initial experience with operating our new 2m EME station will be covered 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

EME Station 2.0 Part 11 – Station Hardware In Shack

EME Station Hardware Components

EME and Satellite Ground Station Hardware Components

Now that our 2m EME Antenna Array is fully installed, we have turned our attention to the setup of the equipment in our Shack. Our plan is to do a mix of JT65 Digital and CW operation with our 2m EME Station.

The image above shows the equipment that is dedicated to EME and Satellite operations in our station. We built some shelves to make room for all of the equipment as well as to create some space to move our Satellite Ground Station 4.0 to this same area. The components in our 2m EME station include (left to right):

We’ll explain each of these components as well as the supporting shack infrastructure that we are using for EME below.

Phase 1 Station Architecture

EME Station Block Diagram - Phase 1

EME Station Block Diagram – Phase 1 (Manual Rx Polarity Selection)

Unfortunately, the LinkRF Receiver and Sound Card to enable a full MAP65 Adaptive Polarity installation are not currently available. As a result, we’ve created a Phase I Architecture that uses an SDR Dongle and manual selection of Receive Polarity via a switch. We also added a receive splitter and a Transmit/Receive relay in front of an Icom IC-9700 Transceiver which is dedicated to our EME setup to enable both the MAP65 and one of either the WSJT10 or WSJT-X Software Decoders to operate simultaneously.

This approach has some significant advantages when conditions are poor as one of either MAP65 or WSJT10/WSJT-X will often decode a marginal signal when the other will not. More on this in the next article in this series which will explain the software we are using more.

Transceiver, SDR Receiver, and Sequencing

IC-9700 Transceiver and Sequencer

IC-9700 Transceiver and Sequencer

A combination of an Icom IC-9700 Transceiver and M2 Antennas S2 Sequencer handle the Transmit side of our EME Station including the associated sequencing of the preamplifiers and Transmit/Receive Switching which is part of our Antenna System. The IC-9700’s receiver is also used with the WSJT10 Decoder in our setup.

GDSO Injection Board Installed in IC-9700

Reference Injection Board Installed in IC-9700 (Leo Bodnar Website)

To ensure good frequency stability in our setup, we installed a Reference Injection Board from Leo Bodnar in our IC-9700.  The Reference Injection Board uses Leo Bodnar’s Mini Precision GPS Reference Clock (the small device on top of our IC-9700 in the photo above) to lock the IC-9700 to a highly accurate GPS sourced clock. The installation and configuration of the Reference Injection Board in our IC-9700 were simple and Leo Bodnar’s website covers the installation and setup procedure for these components. FUNcube Dongle Pro+

FUNcube Dongle Pro+

We used a FUNcube Dongle Pro+ as a second Software Defined Radio (SDR) Receiver in our setup and as an I/Q source to drive the MAP65 Software. Good information on configuring the MAP65 software to work with this dongle can be found here.

EME Station RF Paths and Sequencing

EME Station RF Paths and Sequencing

The diagram above shows the RF Paths and associated sequencing in our Version 1 EME Station. A Manual Antenna Switch is used to select either Horizontal or Vertical polarity when in receive mode. The S2 Sequencer handles polarity selection during transmit. A splitter divides the Rx signal between the FUNcube Pro+ Dongle for MAP65 and a Transmit/Receive Switching Circuit in front of our IC-9700 Transceiver. The relay enables the IC-9700 to provide Transmit signals for both the MAP65 and WSJT10/WSJT-X Software applications. The IC-9700 drives a 1.2 Kw Amplifier during Transmit and the final Tx output is metered using a WaveNode WN-2 Wattmeter.

Completed T/R Relay Assembly

Completed T/R Relay Assembly

To enable both the receivers in our IC-9700 and the FUNcube Dongle to function simultaneously, we built a circuit using a CX800N DPDT RF Relay and a Mini-Circuits 2-Way RF Splitter. We also built a simple driver circuit for the relay using a Darlington Power Transistor and some protection diodes. The circuit enabled our S2 Sequencer to control the relay along with the rest of the sequencing required when changing our EME Station from Receive to Transmit and back.

Finally, we configured a 30mS transmit delay in our IC-9700 to ensure that the S2 Sequencer had some time to do its job as the station transitions from Receive to Transmit. This delay coupled with the Transmit delays built into the MAP65 and WSJT10 software ensures that we will not hot switch the MAP65 Preamp System on our tower. One must be very careful to ensure that RF power is not applied before the sequencer can complete its transition to the Transmit state or damage to the Preamplifiers and/or relays at the tower will occur.

Amplifier and Rotator Controls

EME Station Hardware Components

EME and Satellite Ground Station Hardware Components

The Elevation Rotator from our Antenna System was added to the Green Heron RT-21 Az/El Rotator Controller previously installed in our shack and both the Azimuth and Elevation Rotators were roughly calibrated. Our EME station requires quite a few USB connections to our Windows 10 Computer so we added a powered USB hub to our setup. Chokes were added to the USB cables which run to our IC-9700 Transceiver and our FUNcube Dongle to minimize digital noise from getting into our receivers.

Our planned OM Power 2002+ Amplifier is not yet available so we temporarily moved our M2 Antennas 2M-1K2 Amplifier from our Terrestrial Weak Signal setup to our EME station. The 2M-1K2 can produce about 1KW of power on 2m when operating in JT65 mode and this should be enough power for our planned EME work until the OM Power Amplifier is available. Our S2 Sequencer also controls the keying of our Amplifier as part of the T/R changeover sequence in our EME station.

WaveNode WN-2 Wattmeter

WaveNode WN-2 Wattmeter

We added a 2m high power sensor to the output of our Amplifier and connected it to a free port on one of the WaveNode WN-2 Wattmeters in our station to provide output and SWR monitoring of the Transmit output of our EME station.

Supporting Station Infrastructure

VHF+ Antenna Switching Console

VHF+ Antenna Switching Console

We had some work to do to configure the antenna, grounding, and DC power infrastructure in our station. We redid the manual switching in our VHF/UHF Antenna Switching consoles to accommodate our new EME Antenna System as well as to prepare for our Satellite Station to be moved into our shack in the near future. The console on the right provides Grounding of the Transmit and Receive sides of our EME Antenna System as well as the selection of the Antenna’s Horizontal or Vertical polarity for decoding.

We also expanded our station grounding system to provide a ground point directly behind all of our EME equipment. Our DC power system was also expanded to accommodate our EME equipment.

GPS NTP Server

GPS NTP Server

Our station already has a GPS Controlled NTP Time Server installed and we’ll use it to ensure that the clock on the PC which will run the MAP65 and WSJT10 software will have very accurate clocks for JT65 decoding.

EME Tower CAM

EME Tower CAM

We already have cameras that cover our Main and Satellite Towers. We’ve added a third camera to allow us to view our EME Tower’s operation from our shack. This ensures that we can visually confirm the operation of our antennas and detect any problems should they occur.

Next Steps

All of the new EME equipment has to be integrated and tested with the software components which provide digital operation, tracking of the moon, logging, and other functions in our station. The software setup as well as our initial experience with operating our new EME station will be covered 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

EME Station 2.0 Part 10 – Antennas On The Tower

Completed 2m EME Antenna System

After a year’s worth of planning and 10 months of construction, we have our new 2m EME Antenna System installed on our EME Tower and working! This stage of our project took about a week and included a lot of help from Matt and Andrew at XX Towers.

Final Preparations

Antenna Ground Test

The first step was to arrange the four 2MXP28 Yagis that we built on saw horses near our EME Tower and check each antenna’s vertical and horizontal SWR. Performing SWR measurements with the antennas close to the ground like this does not produce very accurate measurements. Doing this does allow one to spot potential problems if some of the measured SWR fail to show a resonance or are wildly different than the other antennas in the group. All of our antennas checked out as expected.

50 Ft Boom Lift, H-Frame Cross Boom Assembly On The Ground

We also rented a 50-ft Boom Lift and set it up near our EME Tower. A tool like this is almost essential to safely assemble and adjust a large, complex antenna system involving an H-Frame. It also speeds up the assembly and adjustment process considerably.

Elevation Rotator and H-Frame

Elevation Rotator Installation on Mast

Elevation Rotator Installation on Mast

The first step was to install the MT-3000A Elevation Rotator on the mast. We pre-installed the control cable for the elevation rotator before installing it on the tower. This enabled us to get it temporarily hooked up to the Rotator Controller in our shack so that we could adjust the elevation of the H-Frame and Antennas as we installed them.

H-Frame Assembly on Tower

H-Frame Assembly on Tower

Next, Matt and Andrew installed the H-Frame Crossboom and Truss assembly on the Elevation Rotator. The assembled Vertical Risers went on next to complete the H-frame. The time spent pre-assembling these components and marking centers to enable accurate final assembly saved a great deal of time.

Antenna Installation

Upper Antenna Installation

Upper Antenna Installation

With the H-Frame in place, we installed the upper 2MXP28 Yagi Antennas next. The image above shows the rigging of the boom trusses which was done on the Tower.

Lower Antenna Installation and Adjustments

Lower Antenna Installation and Adjustments

Next came the lower 2MXP28 Yagis. We spent considerable time leveling and aligning all of the Antennas and H-Frame components at this stage.

Feedlines, Electronics, and Balancing

T-Braces and Feedlines

T-Braces and Feedlines

The T-Brace assemblies and Antenna Phasing Lines were installed next. Each Antenna requires two LMR-400 Phasing Lines and these coax cables add considerable weight to the backs of the Antennas. The T-Braces support these cables and help to align the Antennas on the H-Frame.

We replaced the Vertical H-Frame Boom Truss Pipe with a heavy section of Mast Pipe to act as a counter-weight and balance the final H-Frame and Antenna assembly. This step is critical to ensuring a long life for the Elevation Rotator’s drive system and chain.

Phasing Lines, Power Dividers, and Feedline Connections on Crossboom

Phasing Lines, Power Dividers, and Feedline Connections on Crossboom

The photo above shows the final installation of the Power Dividers, Antenna Phasing Lines (there are 8 in total), the MAP65 Preamp Housing, and the Feed and Control Cables that run down the Tower. We took the time to carefully make SWR measurements on each Antenna and check all of the connections to the MAP65 Housing at this stage.

Antenna Integration Details

Rotator Loop

Rotator Loop

The Rotator Loop contains the following cables and Coax Feedline connections from the H-Frame/Antenna assembly:

  • Vertical and Horizontal Rx Feedlines
  • Tx Feedline
  • Elevation Rotator Control Cable
  • MAP65 Housing Control Cable

All of these cables are bundled and securely fastened to the H-Frame Cross Boom and to the Tower. Andrew is a master at this sort of rigging!

Control Cable Connections at Tower Base

Control Cable Connections at Tower Base

I took some time to finalize the Control Cable connections at the base of our tower. Time was spent with a voltmeter doing checks to ensure that everything was connected correctly and working. This effort resulted in the discovery and correction of some wiring errors and a faulty relay in the MAP65 housing. Had I not done these steps, we would have surely destroyed the Preamps in the MAP65 Housing when we transmitted for the first time.

Testing Our New Antenna System

Vertical Polarity Tx SWR at Shack

Vertical Polarity Tx SWR at Shack

A series of SWR measurements were taken before sealing the coax cable connections on the tower. SWR measurements were checked and recorded for future reference at the following points in the feedline system:

  • At the ends of the phasing lines associated with each antenna
  • At the output of the two Power Dividers on the tower
  • At the shack entry ground block

Measurements were taken separately for both the Vertical and Horizontal elements of the final Antenna System. The image above shows a typical SWR measurement for our final Antenna System.

I did many final checks and adjustments while the Boom Lift was still here. These steps included:

  • Checking the oil level in the elevation rotator
  • Re-lubing the elevation rotator chain
  • Adjusting the limit switch stops on the Elevation Rotator to allow enough over-travel for future adjustments and maintenance
  • Checking all hardware for tightness
  • Sealing all coax cable connectors with Coax Wrap and Electrical Tape
  • Making some final adjustments to align the four 2MXP28 Antennas with each other and the H-Frame

Next Steps

The next step in our project will be the integration of our new 2m EME Antenna System into our shack. This step will include the final setup, configuration, and testing of the Rotator Controller, Interim SDR Receiver, Transmitter, Amplifier, and the MAP65 and Moon Tracking Software.

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

EME Station 2.0 Part 8 – Elevation Rotator Assembly and Sub-System Test

Elevation Rotator and MAP65 EME Preamp System Test

The next major component in our new EME station is the assembly of the Elevation Rotator. This step also involves pre-assembly and testing of the MAP65 Pre-amp Housing, Antenna Power Dividers, Transmit/Receive Sequencer, and the Rotator Controller. Here are the components involved in this part of our project:

We choose the MT-3000A Elevation Rotator for its heavy-duty construction. This will be important to handle the weight of our EME antenna array as well as the winter conditions that we encounter here in New England.

Elevation Rotator Assembly

MT-3000A Elevation Rotator Parts

MT-3000A Elevation Rotator Parts

The first step was to inventory all of the parts for the MT-3000A Elevation Rotator and carefully read the MT-3000A manual from M2 Antennas.

Assembled MT-3000A Elevation Rotator

Assembled MT-3000A Elevation Rotator

Assembly of the MT-3000A is pretty straight forward. It uses a chain-drive system to produce a very strong, high-torque elevation rotator system. It’s important to fill the gear-box with the supplied gear oil and to lube the chain with the proper lubricant prior to testing and installing the rotator. Spray style chain lubricants for motorcycle chains work well in this application.

Rotator Controller Integration and Testing

Green Heron RT-21 Az-El Rotator Controller

Green Heron RT-21 Az-El Rotator Controller

The next step was to make up a rotator and connect the MT-3000A to our Green Heron RT-21 Az/El Rotator Controller for a test. The RT-21 Az/El is a very flexible controller that is capable of controlling almost any popular antenna rotator. We’ve already tested this unit with the M2 Antennas OR2800G2 Azimuth Rotator that is installed on our EME tower.

RT-21 Configuration of the MT-3000A Elevation Rotator

RT-21 Configuration of the MT-3000A Elevation Rotator

The MT-3000A is a pulse-counter style rotator with 0.1-degree positioning resolution. It required a custom setup in the Green Heron RT-21 Az/El which was easily accomplished with Green Heron Engineering’s setup utility. One must determine the correct Divide Ratio setting by experimentation. When the correct value is found, a rotation of 90 degrees on the controller will result in exactly 90 degrees of actual movement by the MT-3000A. This calibration was much easier to do with the MT-3000A in our shop than it would have been once the unit was installed on our tower. We also set up the RT-21 Az/El Controller to allow for 5 degrees of rotation beyond the 0 and 90-degree points.

After some testing, I decided to use the 42Vdc tap setting in the RT-21 Elevation Controller with our MT-3000A. The specifications for the MT-3000A allow for up to 42 Vdc to be used to run its motor. To be safe, we set the Max Speed setting in the RT-21 Az/El to “8” which resulted in a maximum of 40 Vdc measured with a voltmeter at the output of the controller.

Assembly and Integration of MAP65 Housing and Cross Boom

Elevation Rotator and MAP65 Preamp Housing Assembly

Elevation Rotator and MAP65 Preamp Housing Assembly

The next step was to install the H-frame Main Boom center section and Truss Support Tubes in the MT-3000A. The MAP65 EME Preamp Housing is mounted on the horizontal Truss Support Tube as shown above.

MAP65 EME Preamp System Housing

MAP65 EME Preamp System Housing

A control cable for the MAP65 EME Preamp Housing was made up and connected to the terminal strip on the housing.

EME Sequencer Testing

S2 Sequencer

S2 Sequencer

The S2 EME Sequencer from M2 Antennas is designed to control the MAP65 Housing but its internal jumpers must be properly set to do this. We spent some time with the manual for the S2 Sequencer and for the MAP65 Housing carefully setting the S2 Sequencer’s jumpers and verifying proper voltages at both the output of the S2 Sequencer and the terminal strip in the MAP65 housing with a voltmeter. The manuals for the S2 EME Sequencer and the MAP65 EME Preamp Housing were clear on these steps.

Mounting Power Dividers

Power Divider Mounting Bracket

Power Divider Mounting Bracket

The next step in this part of our project was to mount the M2 Antennas 4-Port Power Dividers that are used to connect the MAP65 Pre-Amp housing to the four 2MXP28 Antennas. Two power dividers are required as each antenna has a separate feed point connection for their horizontal and vertical polarities. We made up some custom mounting brackets for the power dividers from 1-1/4″ aluminum angle material.

MAP65 EME Preamp Housing Connections

MAP65 EME Preamp Housing Connections

The MAP65 Preamp Housing connects to the outputs of the two Power Dividers that feed the H-polarity and V-polarity of the antenna array. The outputs from the MAP65 EME Housing connect to the H-polarity and V-polarity receive coax cables and the Transmit Hardline Coax Cable that runs from the tower to our shack.

Coax Interconnect Cables

Power Divider and Feedline Jumper Coax Cables

Power Divider and Feedline Jumper Coax Cables

The final step was to make up LMR-400 coax cables to connect the MAP65 Preamp Housing to the Power Dividers. We used right-angle male N connectors to make the connections to the 4-Port power drivers to avoid sharp bends in the cables.

We also made up three additional LMR-400uF coax cables to connect the MAP65 Preamp Housing to the coax Tx and Rx feedlines that are installed on our tower. It’s important to keep the H-Pol and V-Pol cables as close to identical in length as possible to minimize and phase differences between the associated receive feedline systems.

Next Steps

The next step in our project will be the final assembly and preparation of the H-frame which will be used to mount our four 2MXP28 Antennas. 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 Teach Night on this topic. You can find the EME Tech Night here.

Fred – AB1OC

Tech Night – VHF+ Weak Signal Stations Part 1 (Intro and 6 Meters)

Tech Night - VHF+ Weak Signal Stations Part 1 - Overview and 6 Meters

Tech Night – VHF+ Weak Signal Stations Part 1 – Overview and 6 Meters

We recently did a Tech Night on building and operating VHF+ stations as part of the Nashua Area Radio Society’s educational 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 get started and build their own VHF+ Weak Signal Station.

There is a lot to this topic so we’re going to cover it with two Tech Night presentations. The first one in the series is included here and it provides an Introduction to the VHF+ topic along with details on building and operating a station for the 6 Meter Band.

July 2020 Tech Night Video – VHF+ Weak Signal Stations Part 1 – Introduction and 6 Meters

You can view this Tech Night session via 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.

We have built a number of stations and antennas for the VHF+ Bands (6 Meters and above). Here are some links to articles about those projects and our operations on the VHF+ Bands here on our Blog:

Fred, AB1OC

Tech Night July 14 – Building and Operating a VHF+ Station

Completed Antenna Stack On New Tower

6m Yagi and 2m/70cm/23cm Satellite Antennas On A Tower

We will be hosting a Tech Night about Building and Operating a VHF+ Weak-Signal Station tonight, July 14th at 7 pm Eastern Time. The live, interactive video of our tech Night will be shared via a Zoom conference and all of our readers are welcome to join. I plan to cover the following topics during our session this evening:

  • Why do weak-signal work on 6 meters and above?
  • What can you work and what modes are used on these bands
  • How does propagation work at 50 Mhz and above and how can you measure it?
  • How does one operate using SSB, CW, and digital modes on these bands?
  • What equipment is needed and what are some possible ways that you can put together a VHF+ station?
  • Some demonstration of actual contacts

In addition to an overview of how to get on all of the bands above 50 MHz, we will focus on the 6 Meter (Magic) band. The session will include demonstrations of FT8 and Meteor Scatter contacts on 6 m. I will also briefly describe the 6 m station here at AB1OC-AB1QB and show how we use it to make contacts. A second Tech Night will cover stations and weak-signal operating on 2 m and above.

The Zoom information for our Tech Night Session follows. We suggest that you join early so that you have a chance to make sure that your computer, speakers, microphone, and camera are working.

July 14th, 7 pm Eastern – Nashua Area Radio Society Tech Night. Fred, AB1OC Setting up a VHF+ Station. Here’s an opportunity to learn how to add 6 m and above weak-signal modes to your station. Join Our Zoom Meeting

We hope to see many of our readers this evening!

Fred, AB1OC

Getting Started With Amateur Satellites (and Progressing to Linear Birds)

Get Started with Amateur Satellites

Get Started with Amateur Satellites

We get quite a few requests from folks to explain how to get started with Amateur Radio Satellites. Requests for information on how to build a computer-controlled ground station for Linear Satellites are also pretty common. I recently got such a request from our CWA class so I decided to put together a session on this topic.

We covered a number of topics and demonstrations during the session including:

  • How to put together a simple station and work FM EasySats with HTs and a handheld antenna
  • A recorded demonstration of some contacts using FM EasySats
  • How-to build a computer-controlled station and work Linear Transponder Satellites
  • Fixed and Portable Satellite Station Antenna options
  • A recorded demonstration of some contacts using Linear Satellites
  • How-to work digital (APRS digipeater) contacts
  • How-to receive SSTV Transmissions from the ISS

About 30 folks attended this session and there was some good Q&A throughout.

Getting Started With Amateur Satellites

The presentation was recorded and can be viewed above. Here’s a link to the associated Powerpoint Presentation.

There are lots of articles about building and operating Amateur Satellite Stations here on our blog. The following are links to several articles and series on this topic:

I hope that you find this information useful for your Amateur Satellite projects!

Fred, AB1OC

Tech Night – Getting Started In EME Communications

Tech Night – Getting Started in EME (Click to View The Presentation)

We recently did a Tech Night Program as part of the Nashua Area Radio Society’s educational 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 get started in EME or Moonbounce Communications.

April 2020 Tech Night Video – Getting Started in EME Communications

You can see the presentation via 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.

We are in the process of building a new 2m EME station that will have adaptive polarity. you can read more about that project here.

Fred, AB1OC

EME Station 2.0 Part 6 – Tower Grounding System

Tower Ground System

Tower Ground System

Now that spring is here, we’ve continued work on our EME station project. The most recent project was to build complete the ground system for our new EME tower. The proper way to ground a tower is shown above. Each leg of the tower is connected to an 8′ ground rod via a heavy-gauge ground cable. The cable is attached to the tower leg using stainless steel clamps meant for this purpose. The three ground rods associated with the tower legs are then bonded together using a heavy copper ground cable ring.

Ground Cable CAD Weld

Ground Cable CAD Weld

The ground cables are welded to the top of the ground rods using CAD weld on-shots. This creates a strong connection that will not corrode or fail. It is important that the ground rods be free of dirt, corrosion, oxidation, and burrs before performing the CAD welding. We used a combination of 3-wire and 4-wire one-shot CAD welds to build our ground system and connect it to the bonding system running from out tower to the entry to our shack.

Main Grounding System Bonding

Main Grounding System Bonding

The final step was to connect the bonding run from the tower to the perimeter grounding system around our house. This completed the tower grounding system and enabled us to complete our final permit inspection courtesy of our local building inspector.

Finished Tower Base

Finished Tower Base

With all of this work done and the inspection complete, we added a mulch bed around our new tower to make this area of our lawn easy to maintain.

The next step in our project is to begin building the antennas that will go on our EME tower. 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 Teach Night on this topic. You can find the EME Tech Night here.

Fred, AB1OC

EME Station 2.0 Part 5 – Control Cables and Rotator Controller

Control Cable Junction Box on EME Tower

Control Cable Junction Box on EME Tower

Snow is coming to New England this weekend so we wanted to get the control cables run to our new EME Tower before the ground is covered with snow. The project involved installing a Utility Enclosure on our tower and running three control cables to our shack for the following devices:

Az-El Rotor and Preamp Switching Control Connections

Az-El Rotator and Preamp Switching Control Connections

We began by install some barrier strips and a copper ground strap in the Utility Enclosure. The copper strap provides a good ground connection to the tower and associated grounding system. The enclosure is clamped to the tower using two stainless steel clamps.

We ran three new control cables through the conduits that we installed between the tower and our shack and terminated them in the utility enclosure. We only needed 6 leads for control of the planned MAP65 Switching and Preamp System which will go on our tower later so we doubled up some of the higher current connections using two wires in the 8-conductor cable.

Green Heron RT-21 Az-El Rotator Controller

Green Heron RT-21 Az-El Rotator Controller

The final step was to hook up our rotator cables to a Green Heron RT-21 Az/El Rotator Controller in our shack.  We do not yet have our elevation rotator so we tested the M2 Orion 2800 Azimuth Rotator that is installed in our tower. The azimuth rotator is configured so that the rotator’s dead spot faces north. This is a good configuration of our planned EME operation.

With all of our control cabling in place, we are ready to begin preparing our Antennas, Elevation Rotator, H-Frame, and MAP65 components to go on our EME Tower. We’re hoping that the weather will cooperate and enable us to get these steps completed during this winter.

Here are some links to other articles in our series about our EME Station 2.0 project:

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

Fred, AB1OC