I get quite a few emails from readers of my blog asking how my QO-100 satellite station is put together and so, I thought perhaps now is a good time to put together an article detailing the complete build.

My QO-100 satellite ground station is built around my little Icom IC-705 QRP transceiver, it’s a great little rig and is ideal for the purpose of driving a 2.4Ghz transverter/up-converter.

Of course all the software used for the project is Opensource and freely available on the internet.

The station comprises of the following building blocks:

• Icom IC-705 Transceiver
• DXPatrol 28/144/433Mhz to 2.4Ghz Up-Converter
• DXPatrol GPSDO Reference Oscillator
• DXPatrol 2.4Ghz 5/12w Amplifier
• Nolle Engineering 2.2 turn 2.4Ghz IceCone Helix Antenna
• 1.1m (110cm) Off-set Dish
• Bullseye 10Ghz LNB
• Bias-T to feed 12v to LNB
• NooElec SmartSDR Receiver
• PC Running Kubuntu Linux Operating System
• GQRX SDR Opensource Software
• Griffin Powermate USB VFO Knob
• QO-100 Ground Station Dashboard developed using Node-RED
• LMR400-UF/RG58 Coax Cable

To get a good clear view of the QO-100 satellite I have the dish mount 3.2m above the ground. This keeps it well clear of anyone walking past in the garden and beams the signal up at an angle of 26.2 degrees keeping well clear of neighbouring gardens.

The waterproof enclosure below the dish houses all the 2.4Ghz equipment so that the distance between the feed point and the amplifier are kept to a minimum.

The DXPatrol amplifier is spec’d to run at 28v/12w or 12v/5w, I found that running it at 28v produced too much output for the satellite and would cause the LEILA alarm on the satellite to trip constantly. Running the amp at 12v with a maximum of 5w output (average 2.5-3.5w) is more than enough for me to have a 5/9+10 signal on the transponder.

The large 1.1m dish gives me quite an advantage on receive enabling me to hear the very weak stations with ease compared to other stations.

The photo above shows the 2.4Ghz equipment mounted in the waterproof enclosure below the dish. This photo was taken during the initial build phase before I rewired it so, the amplifier is shown connected to the 28v feed. To rewire the amp to 12v was just a matter of removing the 28v converter and connecting the amp directly to the 12v feed instead. This reduced the output from a maximum of 12w down to a maximum of 5w giving a much better (considerate) level on the satellite.

It’s important to keep all interconnects as short as possible as at 2.4Ghz it is very easy to build up a lot of loss between devices.

For the connection from the IC-705 to the 2.4Ghz Up-Converter I used a 7m run of
LMR-400 coax cable. The IC-705 is set to put out just 300mW on 144Mhz up to the 2.4Ghz converter and so it’s important to use a good quality coax cable.

Once again the output from the 2.4Ghz amplifier uses 1.5m of LMR-400-UF coax cable to feed up to the 2.2 turn Icecone Helix Antenna mounted on the dish. This keeps loss to a minimum and is well worth the investment.

The receive path starts with a Bullseye LNB, this is a high gain LNB that is probably one of the best you could use for QO-100 operations. It’s fairly stable frequency wise but, does drift a little in the summer months with the high temperature changes but, overall it really is a very good LNB.

The 12v feed to the LNB is via the coax and is injected by the Bias-T device that is in the radio shack. This 12v feed powers the LNA and associated electronics in the LNB to provide a gain of 50-60dB.

From the Bias-T the coax comes down to the NooElec SmartSDR receiver. This is a really cheap SDR device (<£35 on Amazon) based on the RTL-SDR device but, it works incredibly well. I originally used a Funcube Dongle Pro+ for the receive side however, it really didn’t handle large signals very well and there was a lot of signal ghosting so, I swapped it out for the NooElec SDR and haven’t looked back since.

The NooElec SmartSDR is controlled via the excellent Opensource software GQRX SDR. I’ve been using GQRX SDR for some years now and it’s proven itself to be extremely stable and reliable with support for a good number of SDR devices.

To enhance the operation of the SDR device I have added a Griffin Powermate VFO knob to the build. This is an old USB device that I originally purchased to control my Flex3000 transceiver but, since I sold that many moons ago I decided to use it as a VFO knob in my QO-100 ground station. Details on how I got it working with the station are detailed in this blog article.

Having the need for full duplex operation on the satellite this complicates things when it comes to VFO tracking and general control of the two radios involved in the solution and so I set about creating a QO-100 Dashboard using the great Node-RED graphical programming environment to create a web app that simplifies the management of the entire setup.

The QO-100 Dashboard synchronises the transmit and receive VFO’s, enables split operation so that you can transmit and receive on different frequencies at the same time and a whole host of other things using very little code. Most of the functionality is created using standard Node-RED nodes. More info on Node-RED can be found on the Opensource.radio Wiki or from the menu’s above.

I’ll be publishing an article all about the QO-100 Dashboard in the very near future along with a downloadable flow file.

I’m extremely pleased with how well the ground station works and have had well in excess of 500 QSO’s on the QO-100 satellite over the last last year.

More soon …

What’s your idea of the perfect tuner? Here’s my wish list:

• Easy to operate
• Finds and remembers settings
• Covers 160-6 meters
• Matches just about anything you can throw at it
• Automatic operation

There are some good candidates out there, like the FlexRadio Tuner Genius XL. It will convince your radio that it’s connected to a 50-ohm antenna system—or close to it.

This review is based on the Tuner Genius XL (TGXL) 1×3 model, but there’s also an SO2R version.

Both are identical except for the antenna interface. Two transceivers and two antennas can be connected simultaneously on the SO2R model. The 1×3 version accommodates one transceiver and up to three connected antennas. During operation, one of three antennas is selected.

On both models, switching is done via remote control by LAN, serial interface, or individual signals from the transceiver.

FlexRadio Tuner Genius XL Features

The Tuner Genius XL is the first self-contained SO2R (single operator, two radio) tuner in the amateur market. This tuner covers 1.8 MHz to 54 MHz with the ability to tune up to 10:1 SWR. All functions can be controlled either from the front panel of the tuner or by using a Windows computer software application. This allows the Tuner Genius XL to be moved off the desktop to a more convenient location, while still maintaining full control by computer.

Handling up to 2,000W ICAS of power, the Tuner Genius XL has considerable headroom above the 1,500W legal limit. Accurate peak responding RF power and SWR meter displays are also provided, so you really don’t need a separate watt/SWR meter in your shack. The easy-to-read 4.5-inch color display is centered on the front panel.

Electrically, the TGXL is a pi network tuner with three changeable elements, a series inductor with two capacitors to ground—one at the input and the other at the output. A pi network is a good choice for matching the relatively low 50-ohm impedance of a transmitter and relatively high and unknown impedances of an antenna system. The combination of discrete L or C components determines each network element’s value—one of 255 possible values. This provides 255³ (16,581,375) possible matching combinations. Because the matching circuit also forms a low pass filter, it also provides additional harmonic suppression.

All of this is enclosed in a sturdy metal case, resembling the FlexRadio Power Genius XL companion amplifier. The Tuner Genius XL provides three operational modes: standby, operate, and bypass selected by two front panel buttons.

Plays Well with Others

The Tuner Genius XL easily integrates with the Power Genius XL RF amplifier and all FLEX-6000 series HF transceivers. These station components communicate with each other using a LAN connection via ethernet or Wi-Fi. When used in conjunction with a Power Genius XL amp and a FLEX-6600 or FLEX-6700 transceiver, you can have a fully functional SO2R station.

You may enjoy this review on the FlexRadio Power Genius XL Amplifier too.

In addition, the TGXL supports frequency detection from other brands of HF radios at the inputs and automatically chooses the appropriate setting for tuning. This band-switching mode may require double-keying before the first transmission for non-Flex radios before it tunes. You still need to set up a PTT or the TGXL will not go into TX mode. RF Sense is for frequency detection. Alternatively, you can use data from your radio.

TGXL PTT lines are opto-isolated, but they won’t tolerate high voltages or an AC voltage. Be aware of this if you use an older transceiver. Incoming PTT line specs should be checked before you connect. Some operators may want to use a keying buffer in all cases as insurance to prevent any possible damage to the exciter or tuner due to possible transient voltage spikes or RF ingress.

Setup: TGXL User Interface

For Flex radios, you start the Tuner Genius XL Windows Utility program on a Windows-based computer. It will find your Tuner Genius XL tuner automatically and direct you to the copy of the front panel display.

The configuration has five separate tabs: network settings, CAT/CI-V information, FlexRadio settings, Antenna Genius (a remote switchbox option), and other, which is a collection of miscellaneous settings. These allow you to customize radio, antenna, and other settings for your particular station.

The user interface has all the same functions available on the front panel. All you need to do is point and click.

Tuning Process for the FlexRadio Tuner Genius XL

There are two modes of tuner operation: manual and automatic. In automatic mode (default), you start a tune operation to better match the transmitter and the antenna system. If one is found, the match solution (L/C/L values and frequency) is stored in memory and automatically used when the frequency of the transmit slice is within the match frequency range, with the same antenna selected.

Go through each antenna on each band once, then the tuner will use the tuning values closest to your operating frequency for the antenna you’re currently using. There are 10 memories per band, and up to four tunings per band can be saved. Once set up, TGXL will remember individual settings for each frequency change.

Band configuration settings let you select ranges of frequencies that the tuner will selectively ignore for resonant antennas. For example, suppose your 80M dipole is resonant at 3750 kHz. In that case, frequencies near this value can be bypassed by selecting the Enable Bypass check box in the 80M row, then entering the range of the bypass in the Bypass Start and Bypass Stop columns.

Manual tuning is also possible to tweak a current or saved setting. Three front panel controls allow manual tuning by turning one of three knobs found along the bottom edge of the front panel or clicking on them in the TGXL control app on your computer. The first and third knobs select the capacitance with the second adjusting inductance values.

Once you have tuned a frequency, the solution is saved. When you change bands on the radio, the tuner senses your new frequency and is ready almost instantly. It uses relays rather than servo-controlled inductors and capacitors.

TGXL on the Air

I have several HF antennas at my location, so I chose an inverted L (160/80m) and a rotatable 40m D-40 dipole. These would require tuning somewhere within the range of their coverage. In addition, I used a triband Yagi on 20/15m to test the abilities of a non-Flex radio (Icom IC-7610).

The FLEX-6400M and an Icom 7610 were both connected through a Power Genius XL to the tuner. The Flex used the LAN for PTT and frequency tracking. The 7610 used a CI-V and conventional PTT line consisting of a shielded cable with RCA connectors on the A inputs. Internal tuners on both radios were bypassed.

Starting with the potentially challenging 160M band on the Flex, I checked for matches on five frequencies across the band. All read 1.26:1 or less using the onboard TGXL SWR meter. The seek time for 160 meters was under 10 seconds. For 80 and 40 meters it took less than five seconds to arrive at an initial tuning solution. Once stored, the memory settings are applied within milliseconds. When returning to a previously memorized band segment, the TGXL makes one relay click noise and it’s tuned in a fraction of a second.

With the IC-7610, the frequency tracking followed the radio. The front panel tune button was used to set up the memory locations, requiring a carrier from the 7610. I also found that the TGXL control software would duplicate the tune button function on the front panel for the Icom. Tuning setup can be done from any radio that produces band data for the TGXL.

Finally, I changed the 80m settings to add a bypass start/stop. Since the measured antenna resonance was 3780 kHz, I set the bypass to 3730 kHz through 3830 kHz (50 kHz each side of resonance.) The tuner ignored the range set to be bypassed and continued to access memory settings for the other portions of the band.

Overall Impressions of the FlexRadio Tuner Genius XL

Whether you’re currently a Flex owner or not, this is a tuner you should consider. It works well in the SmartSDR ecosystem and is built like a tank. At the time of writing this review, I know of no tuner that accommodates two radios simultaneously.

It’s a perfect match for the PGXL amp, which also has SO2R capabilities. It’s also compatible with the Antenna Genius 8×2, a smart matrix antenna switch that supports eight antennas and two radios while operating on your existing LAN/WAN.

If you have a PGXL or other solid-state amp, the TGXL is a must, since the tuning is precise and repeatable. You’ll also be protecting those expensive transistor finals. Once you have set up the TGXL with tuning solutions for your antennas, you are good to go. Because the TGXL quickly follows the radio’s frequency as I tune my 6400M and IC-7610, a tuning solution is ready to go even before I transmit.

The post Ham Radio Product Review—FlexRadio Tuner Genius XL appeared first on OnAllBands.

Solid-state amplifiers have become mainstream as vacuum tubes have become more difficult to find and solid-state power capabilities have increased.

Now it is commercially feasible for amateur radio amplifier manufacturers to provide maximum legal output power, plus headroom, using the new generation of solid-state devices. Though comparable tube amplifiers are currently less expensive, it’s likely that the price point on solid-state amps will continue to drop.

If you are searching for a high-performing solid-state linear amplifier, the Power Genius XL (PGXL) amplifier is exactly what you need. It’s the only amplifier on the market that allows fully integrated single-operator, two-radio (SO2R) operation using a single amplifier. It also works equally well in single-operator mode.

The Power Genius XL transforms your FlexRadio FLEX-6000 series radio (or any other brand radio) into a legal-limit powerhouse with headroom to spare.

The PGXL delivers 1,500 watts thanks to the pair of NXP MRF1K50H LDMOS transistors, each rated at 1.5 kW dissipation. That’s 1,500 watts at full ICAS duty cycle using any amateur mode. Also unique to the PGXL is a technology called MEffA (Maximum Efficiency Algorithm). It controls the DC voltage and bias levels on the PA to yield high efficiency and low intermodulation distortion.

This amplifier is built to broadcast industry standards, incorporating low pass and high pass band switched RF output filter networks. All signal harmonic energy is directed into an internal resistor load, eliminating the reflection of this harmonic energy back into the amplifier.

This feature improves amplifier stability, distortion, and efficiency.

PGXL Amplifier Features

Up front is a color touch screen with power and SWR readings shown as horizontal bar graphs.  Temperature and voltage readings are displayed numerically. The A and B input/outputs show amplifier class settings, band information, and keying method. Rounding out the display is the local IP address and software version.

You can also communicate with the amplifier using Power Genius XL Utility software (downloadable from the FlexRadio website), which mirrors the display settings on your computer screen.

To the left of the display is a horizontal bar. I originally thought this was just part of the front panel design.

Actually, it’s a handle built into the PGXL that makes carrying the amp easy, compared to holding it like a box. Behind the handle, you’ll find an open space for airflow, populated with LED lighting indicating the operating state. Yellow is standby, green is operate mode, red is transmit, and purple is firmware update.

Band switching is automatic, controlled via a transceiver interface, LAN for Flex radios or by sensing the RF input signal. The PGXL operates at full power with an antenna system SWR up to about 2:1. Output power folds back between 2:1 and 3:1. Above 3:1, the amplifier stops transmitting.

The unit does not include an antenna tuner, but a companion Tuner Genius XL is available at DXEngineering.com.

The Power Genius XL features a predistortion sampler output for transceivers that can use this signal for predistortion processing to reduce transmitted intermodulation distortion. There are separate predistortion samplers for the A/B transceiver inputs.

Separate bias settings can be used for linear modes and nonlinear modes to increase efficiency when possible. Class AAB (more linear, less efficient) is intended for AM, SSB, and PSK modes. Class AB (less linear, more efficient) is intended for FM, CW, RTTY, and other digital modes. Bias selection is automatic when the amplifier is paired with a FLEX-6000 series transceiver. It can also be selected manually from the front panel or by using the PGXL Utility software.

Easy Peasy

Adding a PGXL to a FlexRadio FLEX-6000 series transceiver is a simple five-step process:

• Plug the PGXL into 240 VAC power
• Insert an ethernet LAN cable
• Connect the coax from the radio(s)
• Connect ANT 1 and ANT 2 to the respective inputs of the amplifier and connect the antennas to the two outputs of the PGXL
• Install the desktop software on your PC and configure the PGXL to your radio

Only have 120 VAC outlets? The internal power supply will automatically sense the input voltage. Maximum power output is limited to 700W, and the power meter scales adjust to reflect this. Drive power is also attenuated to minimize the possibility of overdriving the amplifier

The Flex PGXL can also be easily configured to work with any radio from other manufacturers because it supports CAT, CI-V, BCD band decode, and RF sensing. Detailed information appears in the operating manual.

How Does it Perform in Everyday Operation?

The PGXL is a device you can forget about during operation. It can be left powered on in standby for minimal current draw and jumps to instant operation when you press operate. The standby/operate functions are fully integrated into SmartSDR Maestro and SmartSDR iOS. In fact, an entirely new set of meters can be selected in the amplifier app to monitor the PGXL power output, SWR, and temperature on your computer screen.

You can place the amp just about anywhere that your home network and sufficient AC voltage is available. For example, I’ve placed mine in another part of the shack, since my operation position is a bit crowded. If you use any of the FLEX-6000 series radios, Tuner Genius, or Antenna Genius, you’ll find that they communicate with each other on the network.

First Impressions of the Power Genius XL

Power Genius is a reasonably compact unit, especially for one that delivers 1,500W on 160 through 6 meters with about 50W of drive. The amplifier power switch is on the rear panel. I found this unusual, as most amps have them on the front panel. It’s not a deal breaker, but sometimes inconvenient.

I’ve had the Power Genius XL with the FLEX-6400M transceiver and the Tuner Genius automatic antenna tuner for a while. Setup is relatively simple—just configure the PGXL touch screen or computer app for the radio(s) you plan to use.

The FLEX-6600/6600M provides SO2R operation from one box, or you can choose any two transceivers. In my case, I don’t have an SO2R configuration. I use the A input/output for my Flex radio and the B input/output channel for my other radios—the best of both worlds. There’s 70dB of isolation between the A/B connections and only one can transmit at a time. It’s almost like having two amps.

On the Air

I’ve used the Power Genius XL on all bands from 160 through 6 meters, primarily on SSB. My antennas include a Yagi for 20 through 6 meters, inverted-L wire for 160 and 80 meters, rotatable dipole for 40 meters, and a Big IR vertical for 80-6 meters.

When the going got tough during poor band conditions or atmospheric noise on 160/80 meters, the PGXL made the difference between QSO and no QSO. I generally leave it in standby mode so it’s ready to go at a moment’s notice. 

When using the FLEX-6400M, the amplifier tracked the band using the ethernet connection to communicate. Using other rigs like the Icom IC-7610, the amplifier sensed the frequency and selected the proper band if I used the C-IV connection—in this case a standard 3.5mm male to male audio cable. The TGXL tuner adds additional versatility, something to be discussed in a future review.

Virtually any transceiver that provides a PTT output to control an amplifier will also work with the PGXL. The PTT control is optically isolated with very low voltage and current, so it will work with any transceiver. This requires a brief pulse of RF from the transceiver, then release of the PTT, VOX, or CW keyer. The amplifier then operates normally following a band change.

The PGXL keeps its cool with fans in the power supply unit, the RF deck, and the filter compartment. The firmware manages the fans independently based on information from sensors in each compartment. To help manage that, the PGXL offers three user-selectable fan profiles (standard mode, contest mode, and broadcast mode) in order of increasing fan speed.

In standby mode, the PGXL fan is quiet after it cools down. In operational mode and receiving, the fan is only moderately noisy. As with other solid-state legal-limit amplifiers, the fan gets louder after a long full-power transmission as it tracks the internal temperature and provides more cooling.

Remote operation is supported by Flex SmartSDR. This is very helpful for me since I often spend the winter months in warmer climates. I can pull out an iPad or iPhone, turn on the station remotely, and get on the air. You can bring the amp online or offline from your laptop, tablet, or smartphone and monitor. It also will let you monitor PGXL power output and SWR.

Currently there is no remote on/off control built into the amplifier—perhaps that may be added in the future. In the meantime, I use a homebrew remote relay switch. As for connecting to the PGXL utility, it can be done through a VPN connection and a Node Red program running on a PC or Raspberry Pi. There’s plenty of information on this, the relay switch, and other subjects on the FlexRadio community discussion board.

PGXL Amplifier Review Summary

The FlexRadio Power Genius XL is a great solid-state, maximum-legal-limit amplifier for 160 through 6 meters. It integrates seamlessly with FLEX-6000 series radios, but it also works well with other transceivers, with or without band data connections.

As you might expect from an amplifier at this price point, it has outstanding performance. It produces 1,500W output on any band with about 50W drive and hardly breaks a sweat—something that cannot be said about just any amplifier. It will cruise along in any mode, including digital, at full throttle/full output all the time. Of course, the amp will fold back or shut down extremely fast if a fault is found, making the PGXL bulletproof.

But wait, there’s more. The FlexRadio Power Genius XL manual and other documentation is available from DX Engineering.com to give you the bigger picture.

The post Ham Radio Product Review: Power Genius XL Amplifier—Go on a Power Trip appeared first on OnAllBands.

I’ve been gradually building my QO-100 ground station over the last few months and have had the receive path working for some time now. One of the things I really miss with the Funcube Dongle Pro+ (FCD) SDR is a real VFO knob for changing frequency.

My QO-100 Node Red dashboard is configured so that I can have the FCD track the uplink frequency from the IC-705 but, sometimes I use the FCD without the IC-705 in the shack and so a physical VFO would be handy.

Many years ago when I lived in France (F5VKM) I had a Flexradio Flex-3000 SDR, a great radio in it’s time and one that gave me many hours of enjoyment. One addition I bought for that station was a Griffin Technology Powermate VFO knob. It worked extremely well with the PowerSDR software for the Flex-3000 and I used it for many years.

Many years later I’m back in the UK and much of my equipment is packed away in the attic, including the Griffin Technology Powermate VFO.

I decided to dig it out and see if I could get it working with GQRX SDR software. Sadly I couldn’t get it working with GQRX however, I did find a way of getting it working with Node Red and thus could add it to my QO-100 Node Red Dashboard and then control GQRX with it via a simple Node Red flow.

Plugging the Powermate VFO into my Kubuntu PC it wasn’t immediately recognised by the Linux O/S. After a little searching I found the driver on Github. I added the PPA to my aptitude sources and installed the driver using apt.

https://launchpad.net/~stefansundin/+archive/ubuntu/powermate

Once installed the default config for the Powermate device is to control the default audio device volume. To make the device available for use as a VFO knob you need to change the configuration so that the default setting is disabled. To do this is relatively easy, just edit the config file using your favourite command line editor (Vi/Vim in my case) and add the following entry.

vi /etc/powermate.toml

# Entry to control HDMI volume with Powermate
#sink_name = "alsa_output.pci-0000_01_00.1.hdmi-stereo"

# Set powermate not to work with volume control
sink_name = ""

As shown above, comment out the default “sink_name” entry (Yours may be different depending on audio device in your PC) and add in the Powermate “sink_name” entry that effectively assigns it to nothing.

Once this is done, save the file and exit your editor and then reboot the PC.

Next you’ll need to install a small program called evtest.

sudo apt install evtest

To check the evtest program has installed correctly, plugin your Powermate VFO to any available USB port and run the following command in a terminal.

evtest /dev/input/powermate

Turning the Powermate knob you should see output on the screen showing the input from the device. You should also see BTN events for each press of the Powermate device.

Input driver version is 1.0.1
Input device ID: bus 0x3 vendor 0x77d product 0x410 version 0x400
Input device name: "Griffin PowerMate"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 256 (BTN_0)
  Event type 2 (EV_REL)
    Event code 7 (REL_DIAL)
  Event type 4 (EV_MSC)
    Event code 1 (MSC_PULSELED)
Properties:
Testing ... (interrupt to exit)
Event: time 1685816662.086666, type 2 (EV_REL), code 7 (REL_DIAL), value -1
Event: time 1685816662.086666, -------------- SYN_REPORT ------------
Event: time 1685816662.318638, type 2 (EV_REL), code 7 (REL_DIAL), value -1
Event: time 1685816662.318638, -------------- SYN_REPORT ------------
Event: time 1685816662.574615, type 2 (EV_REL), code 7 (REL_DIAL), value -1
Event: time 1685816662.574615, -------------- SYN_REPORT ------------
Event: time 1685816663.670461, type 2 (EV_REL), code 7 (REL_DIAL), value 1
Event: time 1685816663.670461, -------------- SYN_REPORT ------------
Event: time 1685816664.030421, type 2 (EV_REL), code 7 (REL_DIAL), value 1
Event: time 1685816664.030421, -------------- SYN_REPORT ------------
Event: time 1685816664.334389, type 2 (EV_REL), code 7 (REL_DIAL), value 1
Event: time 1685816664.334389, -------------- SYN_REPORT ------------
Event: time 1685816665.334255, type 1 (EV_KEY), code 256 (BTN_0), value 1
Event: time 1685816665.334255, -------------- SYN_REPORT ------------
Event: time 1685816665.558230, type 1 (EV_KEY), code 256 (BTN_0), value 0
Event: time 1685816665.558230, -------------- SYN_REPORT ------------
Event: time 1685816666.030161, type 1 (EV_KEY), code 256 (BTN_0), value 1
Event: time 1685816666.030161, -------------- SYN_REPORT ------------
Event: time 1685816666.182151, type 1 (EV_KEY), code 256 (BTN_0), value 0
Event: time 1685816666.182151, -------------- SYN_REPORT ------------

At this point you’re ready to stop evtest (CTRL-C) and then create the following little BASH shell script that Node Red will run to collect the O/P from the Powermate USB device.

#!/bin/bash

###############################################
# Griffin Technology Powermate control script #
# for Node Red.                               #
#                                             #
# 04/06/23 - M0AWS - v0.1                     #
#                                             #
###############################################

VAL="1"
echo "STEP-1Hz"

/usr/bin/evtest /dev/input/powermate | while read LINE 
do
   case $LINE in

      *"(REL_DIAL), value 1") echo "$VAL"
           ;;

      *"(REL_DIAL), value -1") echo "-$VAL"
           ;;

      *"(BTN_0), value 1") case $VAL in

                              "1") VAL="10"
                                   echo "STEP-10Hz"
                                      ;;

                             "10") VAL="100"
                                   echo "STEP-100Hz"
                                      ;;

                             "100") VAL="1000"
                                    echo "STEP-1Khz"
                                       ;;

                             "1000") VAL="10000"
                                     echo "STEP-10Khz"
                                         ;;

                             "10000") VAL="1"
                                       echo "STEP-1Hz"
                                          ;;
                              esac
                                 ;;
        esac
done

Once the BASH script is copied and pasted into a file called powermate.sh you need to make it executable by using the following command.

chmod 700 ./powermate.sh

If you now run the shell script in a terminal you’ll see a similar output to that shown below from the device when used.

./powermate.sh 
STEP-1Hz
-1
-1
-1
1
1
1
STEP-10Hz
10
10
10
-10
-10
-10
STEP-100Hz
100
-100
-100
STEP-1Khz
1000
STEP-10Khz
STEP-1Hz
1
1
STEP-10Hz

As you can see above the shell script outputs a positive or negative number for VFO tuning and changes the VFO step size each time the Powermate is depressed.

Getting this output from the BASH shell script into Node Red is really simple to achieve using just 3 or 4 nodes.

In the Node Red development UI create the following nodes.

The first node in the flow is a simple inject node, here I called it trigger. This sends a timestamp into the next node in the flow at startup to set the flow running.

The Griffin Powermate node is a simple exec node that runs the script we created above.

Configure the node as shown above and connect it to the inject node that’s used as a trigger. Note: Change “user” in the Command field shown above to that of your username on your Linux PC)

Once done create the third node in the flow, a simple switch node and configure as shown below.

The switch node has two outputs, the top one is a text output that is fed into a text field to show the current step size of the Powermate device and the lower output is the numeric output that must be fed into your VFO control flow so that the VFO value is incremented/decremented by the amount output by the Powermate device.

I’ve found the Griffin Technology Powermate USB device works extremely well with Node Red and GQRX that I use for controlling the FCD SDR radio and it’s now part of my QO-100 ground station build.

As shown above you can see the Powermate Step size at the bottom of the dashboard, this text changes each time the Powermate device is depressed and will set a step size of 1Hz, 10Hz, 100Hz, 1Khz, 10Khz in a round-robin fashion.

The next stage of the build is the 2.4Ghz transmit path. I now have all the necessary hardware and so this part of the build can finally commence.

More soon …