My first QO-100 SOTA activation and s2s

I had seen that G0HIK and G4VLF had alerted for another QO-100 activation so jumped aboard with my own alert. I needed an excuse to carry radio kit to a summit.

Since QO-100 became operational in early 2019 I have been experimenting with various combinations of hardware to reliably access the satellite. First reception with a small dish and unmodified LNB and later a full GPS-disciplined frequency-locked RX/TX.

My main home system is based around a SG-Labs transverter which was originally going to be used as a portable system. However it has become my main home-station and refined so much that I didn’t want to remove it for portable use.

This leaves my secondary system based around an Adalm Pluto SDR transceiver for portable. I have been experimenting with various combinations of amplifiers and LNBs for 2.4GHz/10GHz using SDR Console as the software for RX and TX.

Walton Hill (G/CE-002) is my nearest summit to home and has a very easy quick walk to the top. It has plenty of open space to make sure I had lots of separation from any other people visiting the summit and a clear view of the sky in the direction of the satellite.

I had previously set-up at home the mixture of hardware I wished to use: a 45cm dish, POTY feed, unmodified LNB (relying on SDR Console to track drift) and a filter/pre-amp/PA combination for TX. Sat on my patio, this system worked sufficiently, albeit with some limitation on the receive side with weaker stations due to the size of the reflector. I was confident I could make contacts even though a test the night before showed the possible issue.

The weather forecast for Thursday (02/07/2020) had deteriorated during the week with intermittent showers for the morning tracking across the Midlands. This didn’t put me off. I arrived at the parking below the top of Walton Hill with plenty of time to climb set-up and test the system well before my alerted time. Dish was quickly aligned and a contact with LY2GC, in Lithuania, showed all was well except SDR Console struggled to keep up with the drift on the LNB.

My station with 45cm dish and brolly (for sun and rain protection) on Walton Hill (G/CE-002)

I started calling on the alerted, and then spotted, frequency just before 10:00utc and began making contacts, first with G4SJH followed by M0GAQ. I could keep the drift under control to some extent manually but each time the sun peaked out of the clouds, the LNB went off on a wander.

Next station was one of the reasons I had gone out. Andrew (G0HIK) called in for my first s2s via QO-100. Typically it was when the LNB was acting up and it took a short while to make sure all information was correctly received. DK1KQ was the filling in the summit to summit sandwich before Nick (G0HIK) called in. Again I was struggling on receive to ensure the contact was good.

After the main event of the two s2s was over, I was in two minds whether to pack things away and try to work out why my RX was playing up so much. Strangely the weather decided for me. I had made sure that even though my set-up was a bit of a “rats-nest” I could protect it if a shower came over: it was then that it rained. This shower had the effect of dropping the temperature and thus stopping the LNB drifting faster than the software could track, so I hunkered down and called CQ satellite to easily finish the activation with four more in the log: DF2ET, 3B8FA, DG3YGB and finally G4CXQ. That made 10 contacts in all for a successful first activation for me via QO-100.

Adalm Pluto, Amsat-UK filter and preamp, DXPatrol PA (with 28V PSU and LiFe battery) and bias-T

Reasonably pleased with myself I packed away the bits and pieces as the sun came out again. Sat quietly enjoying the summit and the views down to the Malvern Hills, I decided to make a few calls on 70cm with the hand-held I had carried to the summit. I hadn’t really intended to use any other bands but why not? I had nowhere important to go.

I worked 4 stations; G3LVP, M6DOO, M3EMO and G8ADD. I was reminded that Vicky (M6BWA) and Rod (M0JLA) were due on a summit using 70cm, so I settled down to wait for them to pop up. 30 minutes later they were in my log along with G0LGS and 2E0MDJ to finish off.

Thank you to Andrew and Nick for getting me back on a hill!


The 45cm dish was a little bit on the small size, this combined with an unmodified LNB makes resolving weak signals a bit of a challenge if it’s drifting badly even with the beacon tracking on SDR Console.

Using a lap-top is a pain when used in bright sunshine.

I need to put everything in a box.

Carolyn (G6WRW)


Thanks for the report Carolyn, it’s good to see how someone else goes about setting up a QO-100 portable station.
I struggle to do the mental maths of the LNB offset from where it should be (about 43KHz in my case) and the 13cm to 3cm shift, but on a hill with wind and rain it sure gets harder.
Lots of whistling and knob twiddling till you hear your own signal.
Andrew has a nice Arduino box to do that for him.

I’m hopping to get out again next week maybe around Thursday.

Nick G0HIK

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You need a NoteBook Tent like:

For the number of times I’m likely to take a lap top to a summit I can find other solutions to the display issue.

So I will give this a miss