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

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