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OFF-LINE due to ADALM PLUTO FAILIURE - Awaiting new DX Patrol Transverter delivery

QO-100 Ground Station

My QO-100 Station is based around the ADALM Pluto, SG-Labs 20w PA, Bullseye LNB, POTY and SDR Console, as are many others.

Using SSTV, FT4 & FT8, 300 baud Packet and SSB, I have had a number of contacts which has been very enjoyable. I am collecting grid squares for ARRL Sat VUCC,QO-100 DX Club awards and entities for ARRL Satellite DXCC.

QO-100 DX Club Bronze Award - 50 Entities (Oct 2023)

The operators on QO-100 have been very helpful and courteous, some sending me received SSTV pictures for analysis, and SSB QSO's are always an interesting discussion on the station builds and related radio subjects. With a less congested band, there is always time for a qso !

First QSO's per mode on QO-100

I look forward to iterating my station build as time progresses. With my current basic station, I am on the air but would like to add capability and added performance as I get more stations in my log. 

Station Schematic diagram

External Station Set-up - Aug 2023 (Mid Build) - Triax TDS 80 Dish with POTY Antenna and Bullseye LNB, with external TX Cabinet in the background.

Inside External Enclosure - Aug 2023 - TX Cabinet with the ADALM Pluto Rev D, AD CN-417 and SG-Labs PA, along with various power boards, GPSDO and cables. 

Station Update Notes

The station has been built as a basic design, to enable operation on QO-100, but further work is needed to improve performance and capability. These include further work on the POTY and Dish mounting, and replacement of the Uplink Co-ax with something less lossy than I have now. A general list of further items follows ;

• DL6YCL YATT (Yet Another Two-Turn) Helix Antenna Project
• POTY to LNB Clamp - 3D Printed - https://www.thingiverse.com/thing:5427881
• POTY Rain Cover - 3D Printed - Re-mix of the rear clamp part above
• TX Cabinet base with cooling ducting- 3D Printed - Own Design
• Replacement POTY Lens for testing- 3D Printed - http://www.hybridpretender.nl
  
  
• Arduino / Node-Red monitoring / cooling - In progress
• Dedicated Sat PC for Station control - In progress
  
  

Digital Modes Set-up

SDR Console
WSJT-X or JTDX
MMSSTV
UZ7HO SoundModem

SSB Set-up

SDR Console
Audio-Technica AT-804 Dynamic Microphone or Audio-Technica BPHS-1 Headset into a Behringer X1002USB Mixer

CW Set-up

FTDI - Serial adapter - Homebrew - See HERE
Morse Keyer 4.3 Software
SDR Console
Begali Sculpture Paddle Key

Theoretical Link Budgets - Work In progress

* = Station is running with an SDR Console TX level of 70, and PA voltage of 24v, instead of 28v until testing has completed.

# = Uplink Co-ax to be replaced with M&P Ultraflex 10 - Loss of 0.35 dB, resulting in 830 mW output, or 13.9W Max.

1 = Measured with Nano VNA

2 = Measured with Spectran 6000

Building a QO-100 Ground station

Having a background in SatComs, I'm not really sure why it has taken me so long to look at QO-100 operation. I already have the Dish and some prior knowledge of the technologies involved. This page will chart the progress of the build and installation of a QO-100 Ground Station, firstly for Rx and then to Tx for Voice and Digital modes.

Building the Station

Whilst I have a 1.2m Channel master dish for DX TV, this station is based on a 80cm Triax dish, as a separate install. The 1.2m could be used for Wideband at a later date, but the station is being prepared for NB operation. Starting as a RX station, the following products were purchased from Passion Radio ;

• Bullseye TXCO LNB
• POTY Kit
• Bias-T
• F-type to SMA convertor

Dry-Fit POTY, Bullseye LNB and Bias-T

A 80cm Triax Off-set Dish from CPC, along with Compression F-type connectors. I already have RG6U in stock from the BevFlex-4X project, and a configured SDR Console install on both Shack PC and the Test machine. I have an ADALM Pluto Rev. B for a general SDR, but will need to get a Rev. D for the external clocking as I do not want to modify my current device.

Installation

With the 80cm Dish assembled, LNB plugged in and the SDR configured, the Bias voltage was applied and the Receive station sprang into life. After a bit of searching of the waterfall, the signals were located and I scanned over some QSO's and found the PSK beacon, which decoded nicely on AO40Rcv. The one issue is with the 2.8Khz spaced interference, on the waterfall. SDR Console easily can notch the interference off the signals, but I want a cleaner waterfall. With some research another amateur had the same issue and fixed it with an LTE filter, therefore one has been purchased from Amazon, and await it's arrival to see if that makes a difference.

Initial Install - Note Interference

Post-LTE Filter - Clean Waterfall

Soldered POTY and G4EML 3D Printed LNB Cap (By M0LRV)

Finally, I found some time to tune the POTY, wire up the components and test resulting in two afternoons of frustration. Before that however, the dish was re-peaked onto the satellite now that a POTY had been installed onto the Bullseye LNB, and I satisfyingly got a 9 +20 signal from the beacon, equalling the raw LNB value. I then set-about getting the POTY checked on a NanoVNA to check the SWR/LogMag had not shifted, but all was good. Next, the troubles ...

In the end, there were two issues that I had to work through. One being that the 28v board, purchased via eBay had both a constant Voltage and Current limiter, with the Current limit too low for the SG Labs PA, so it was not kicking in. I also had to sort out my battery in my Multi-meter which failed at just the moment I was setting things up. interestingly, it was measuring high.

My First FT8 QSO was with YL2GC and SSB, was DL9RAN, Norbert on Friday 7th April, 2023.

PSK Reporter after first session on QO-100

Parts List

Project Total : £ 687.00