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.

Bagged a bag…

Yesterday was my second National Hamfest trip. I first went in 2018 having purchased a ticket and then going late so there was no queue anyway, then I purchased a ticket for the 2019 one and didn’t go. Then we had COVID and the event was cancelled. So this year I had some determination and wanted to get there for the opening time. It also gave the electric car a good run.

And so I bagged a bag – came with the RSGB Yearbook which I’ve been buying since I passed the Foundation. No bag back then as I was far too late, but I made it this time.

The car got there and back on one charge – it’s about 160 miles round trip from home. I’ll be back next year.

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.

FT817 first fiddle…

I now have a second Signalink USB complete with the Yaesu cable to go with the FT817. This is actually the third one to arrive here, the second was mis-advertised as having the radio cable – it didn’t so it is going back because the price is £20 more than a competitor, a little less than the cost of the radio cable. Serves me right for trying to save a couple of quid!

Anyway, FT817 and Signalink all cabled together and no antenna. Hmmm. Ok let’s try into a dummy load, should be good enough for across the shack with FT8 running on the Linux box. Nothing received.

Ah, it’s a Windows box and 1.5 seconds adrift. Sync the time. No change.

Ok. Set WSJT-X to 2m and use the front antenna which I have. Nope, nothing sent.

It is always a good idea to read the manual before fiddling! Let’s change the display to power. Ah. No power… Hmmm.

Ok, transmit from the Linux box and I can see that on WSJT-X via the FT817. So it receives fine.

Did I mention the manual?

Set radio to DIG. Works fine now! Funny, that.

To switch or patch…

I like to fiddle with stuff but getting antenna a to whatever-it-is b is complex and usually messy. Coax to the loft is all RG213 or Westflex 103 and tends to be a bit stiff and unwieldy so sits attached to whatever transceiver or transverter it was originally put in for. But mixing and matching is my aim.

Switches would be equally complex I think. So I am eyeing up a BNC patch panel I used to have in a Land Rover for antenna patching and which has been sitting for 20 or so years sulking in a box of tools.

It has 32 holes each designed to take a BNC-BNC through adapter which makes for an extra plug at the rear – maybe a BNC socket wired to whatever kit it is intended for rather than the rear socket would be a better idea. It is the wrong shape of course, better for 4 rows and less width as it makes for long patch leads but if I have all the antennas in the centre I can cut that down – sensible routing is a must.

I will still need at least one switch but I have a good one ready to go in. The FT450D is the only thing that needs the three transverters (4m, 2m and 70cm) so no sense in those having both input and output on the panel.

Now, where on earth do I fit this thing…

Mobile?

One thing I am not good at is actually getting on the bands and taking. I tend to dwell on FT8 due to rather naff hearing, but this POTA / SOTA thing has caught my eye now and so I wanted something other than an FM handheld. Enter a used FT817 – not the ND but hey. Yes it is yet another thing to learn but it came with a rechargeable battery and gives 2.5W out on 2m into a dummy load (very quick test, you know, new thing, gotta fiddle!) which the manual says it will set itself to when on battery. Unfortunately I got this a few days after our last excursion which would have been an ideal test. It also came with a cigar-lighter charge lead so it can be charged in the car on the way to somewhere. The rig is smaller than I had imagined, very luggable. It’s dwarfed by my SWR meter – I really need to get a smaller one for portable use. I reckon it will be very useful for when I eventually finish off my various microwave kits.

On order is a CAT / USB lead. It came with a Bluetooth CAT dongle, not tried that yet. Of course, now I want a TCXO-9 as a treat for it… do we treat rigs as pets?

Moving

I have been renting a dedicated server for a while now as I had a project on the go that needed a bit of oomph and it was killing the VPS I was using. That project is not going anywhere fast and so I have moved this blog over to a VPS. Hopefully nothing has broken!

Test gear expansion

I am (still) gathering microwave test gear and have now acquired a rather nice HP frequency counter, good to 18GHz (but apparently tested to 20GHz). This will help once I begin constructing the numerous kits waiting their turn, in particular a 10GHz transverter.

Microwaves have interested me since my school days, not because of school but because I remember being interested and being at school. Actually, the interest probably dates further back to me seeing various microwave towers around the place and my grandfather telling me what they were.

Anyway, having something means trying it out… so here it is with a HT keyed on 145.5, and more interestingly to me a 6cm FPV transmitter held close by (until I realised it was getting hot!). The meter had not even warmed up for the 6cm test – me being impatient!

Now, I just need a signal generator and a spectrum analyser…

Potential activities

I suddenly developed an interest in POTA and SOTA. Not sure why, I never seem to go anywhere other than the railway once a week, or shopping. But there you are. So far I have been active as a hunter and although I have only one confirmed QSO it’s still more than zero.

The QSO format seems to suit me too. I do prefer digital modes due to having naff hearing but this should get me onto the voice modes.

Testcards

I’ve been meaning to set up something to generate a testcard via composite video for a while and, as is typical of me the ideal solution was sitting there in a BATC magazine on my bookshelf. CQ-TV No 270 has the details of one such setup using a Raspberry Pi Zero. I don’t have one of those and Pi systems are hard to come by these days but surprisingly I had a 3B not doing anything. Software downloaded, 4-way jack to RCA plugged in and connected to a TV and, nothing. Well, a buzz. Checked the cable, all ok. Checked what the Pi wants…

…why does the Pi have to have the connections different from what appears to be a standard hi-fi 4-way to RCA lead? Or, rather, why does the hi-fi 4-way lead I have have to have different connections? Grumble.

Ok. I wanted to test this seeing I had it all sitting in one of the bedrooms attached to a TV. Stripping down a 4-way jack lead that I never needed and which was far too short to be of use I made a lead. It would last probably half a second in normal use but worked sufficiently well to prove the setup.

It is of course a waste of a ‘whole’ 3B, but until I get a Zero this at least lets me push a testcard out when I need one. The alternative has been to use the rather clunky Sandisk device that can present an SD card or other media to an a/v output, as used in my first 5.6GHz setup https://m0rvb.uk/index.php/2021/05/22/5-6ghz-experiments/ – this way is a whole lot neater!

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