QO100 DATV reception finally

Well, that made quite a difference! I removed the POTY from the QO100 dish today and replaced it with a ‘Bullseye 10kHz’ LNB sourced from Amazon and advertised as a ‘QO-100 Bullseye TCXO LNB’. It’s just clamped in place with no attention to position or skew. Winterhill plugged in and instantly I see pictures.

The LNB behind the POTY only managed negative values in the MER and D fields, this one seems too work rather well. No idea what happened to the old LNB but these things happen I guess. It’s dry and had a waterproof housing. I’ve used the existing CT125 cable and connectors. Now to put the Winterhill box in a better location than just sitting on a ladder tied on with a bit of wire!!

The above photo shows the Winterhill viewer and console on the left and the Quick Tune on the right, all working nicely.

QO100 next steps…

As I said before I want to use an actual transceiver for QO100 work rather than the Pluto. A precursor to that is a 2400MHz transmit capability and so I now have a nice new (used, new to me) SG Labs 13cm transverter, complete with the PCB log periodic antenna. It is already set up for the correct frequency range and seems fine… so, the next step is move the dish, clear the loft in that area, and get the kit up there. The transverter claims to put out 2W so I can use the existing AMSAT UK PA via an attenuator (max input is 200mW) which should get me 4 to 5W to the dish and has been adequate in the past when using the Pluto. I will first try with just the ‘raw’ 2W and see if I can get into the satellite. The eventual aim is to use an 80W PA I have ready so I can use DATV as well as SSB or digimodes – that also takes 200mW input – but as yet I don’t have a suitable PSU.

QO100 DATV attempt

Well this got off to a bad start! Ahead of my plan to move the QO100 disk so I can get the electronics in the loft rather than the garage I wanted to test out the Winterhill box to see if I could pick up any DATV on the wideband transponder.

The Winterhill box generates the 18V necessary for the LNB so in theory it was just a matter of pulling the coax feed from the bias-tee in the garage and putting that into the Winterhill. That done, I could see the occasional signal but never a picture.

Now, I had noticed that the NB beacon strength had dropped a while ago so today I decided to adjust the dish in case it had been knocked. That snowballed! I needed a laptop so I could see the signal strength while at the dish (remember the dish is on the garage wall currently at about 6 foot, so easy reach). Of my two laptops one is a Mac and had no SDR software, the other a Samsung Netbook running Ubuntu and terribly slow. I tried setting up several SDR packages on the Netbook and failed miserably. At this stage I need to state that after a lifetime working in IT and solving problems I now have no time or patience to solve my own, so if something fails it goes to the bin!

So, the Mac. CubicSDR refused to even think about installing. I found SdrDX which works with the USB Funcube dongle amongst other, mainly networked things. This worked just fine.

Mac out on a lab stool in the shade, SdrDX and the Funcube running, the bias-tee in the garage powered up, a cable fed out the garage back to the dish and into the Funcube… fortunately it didn’t all fall over and actually worked. So I adjusted the dish but only gained a couple of dBm more than before no matter what I tried. Oh well…

Back inside and plug the Winterhill in. Back upstairs to the Windows PC and now I see locked signals but just not enough signal strength for a picture.

I wonder if the LNB is full of spiders…

Anyway, now the QO100 kit in the garage is in bits I can’t transmit so it can all stay as it is. My next plan is to remove the POTY and install an LNB and see if that gets me any DATV pictures, otherwise I am a bit stuck. The 1.2M offset dish has a clear view of the sky and should be ideal – it worked just fine for SSB on the NB transponder. I never got round to sorting out a GPSDO input for the Pluto but I am about to get a SG Labs 3cm transverter and plan to use an actual transceiver for tx once the dish is moved.

Fiddling with APRS

I’ve been fiddling recently with trying to receive satellites but without all the going outside and waving yagi antennas around… I’ve heard a few QSOs on DIWATA 2 and there is a very good pass in a day or so where I may be able to get a call in. This is using the Trio TR-9130 as receiver as it has a horizontal dipole connected, and the FTM100DE as transmitter, though so far without success on transmit.

Anyway, I remembered the FTM100 has APRS built in and the ISS often sends and receives this in 145.825 and so I’ve been leaving the radio switched on. Today I noticed it did indeed receive packets from the ISS.

I also downloaded UISS by ON6MU which seems to ‘just work’ – nice that, I downloaded it and ran it and it found the sound card and returned an APRS message on a later ISS pass. Oddly, the FTM100D did not decode that message (the squelch is set to 0). It comes with a module called SoundModem by UZ7HO which seems pretty comprehensive. Another package to play with…



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