More QO100 work

I finally mounted the dish. It’s been cluttering up the workshop for months now. My original plan was to mount it on a pole by the workshop which would have needed a concrete base and regular trimming of the apple tree and hedge. So, it’s mounted on the garage wall with a TK bracket.

Aligning it wasn’t too bad except I managed first to find the Astra satellite at 19.2 degrees thinking it was the one at 28.2. After I found the second one it was not too difficult to find a satellite carrying Qatar TV using the GTMedia V8. With bolts tightened a bit and after rigging all the gubbins up I found the beacon via an SDRPlay SDR and SDRUno but the levels were well down. The Pluto and SDR Console did a far better job so there will be some setting I overlooked. I copied a couple of QSOs but working outside on a Sunday with the whole estate doing gardening made it rather hard, even with headphones! Anyway, the Pluto is the one that will be used so good to see the whole RX chain working. I have some decent WF100 cable for the LNB feed but will need to make something up for the GPSDO feed.

Next step is to mount the Pluto, bias tee and PSUs inside the garage and use Ethernet back to the shack. There is a convenient air brick next to the ironmongery.

The POTY is back inside for now and I’ll need to make a rain cover too, but it feels like progress finally.

Ethernetting the Pluto

This was awkward. I found some info on the Web where someone had used a USB to Ethernet adapter and a Y-splitter cable to connect their Pluto to their LAN. So I got the exact same bits off eBay. Nope, no go. I resorted to asking on the very helpful Facebook group and tried all the advice, for example powering it via the separate USB power socket, but still no go. So, a process of elimination – the USB adapter worked fine on the Mac so no issues there, nor with the CAT5 cabling in use. But I did not have a separate mini-USB to USB socket cable, only the splitter cable. Back to eBay…

A cable arrived today and the Pluto appears on the LAN just fine. So it’s the Y-splitter cable that is at fault. Not tested it yet but it’s only a couple of quid so no biggie. Serves me right for not keeping things simple and using a splitter.

Anyway, one step closer to my QO100 project! All I need now is a decent way to get Ethernet out to the workshop. I do need a LAN out there anyway, not just the house wifi, so either a cable or a wireless bridge.

More Pluto fun

Been having fun with the Pluto today. It has been working fine, though not used very often with SDR Console on my acquire Windows 10 laptop but today I needed an SSB source to find a fault on the TR-9130 which had gone deaf on SSB. The Pluto made an ideal source and helped me to find out I’d got the gain and RIT controls mixed up and so had turned the gain right down! D’oh. So, after putting the TR back on the shelf it gave me the opportunity to finally fiddle with the Pluto.

First off, when transmitting on SDR Console the transmission breaks at a regular short interval. Googling (well, actually these days DuckDuckGo’ing – does that work?) found some info which I tried but to no avail. Someone mentioned that it worked fine in SDR Angel so I downloaded this and after watching YouTube I managed to get a decent output. Not sure what I’ve done wrong with SDR Console but that will wait for now.

But I really wanted to use the Pluto on the Linux box. Some time ago I had a go at installing the Gnu Radio software along with the modules that make the Pluto work. Ages back I tried but I could never get it to compile but since then I have upgraded Ubuntu to 18.04. This time it all seemed to go in but the software cannot see the Pluto. There is something obvious that I am missing here.

Anyway, I installed SDR Angel on the Linux box via snapd and it loads fine but it cannot see the Pluto. Probably no surprise because Gnu Radio can’t either and I had forgotten of course!

As an intermediate step here I have ordered a USB to Ethernet adapter as someone posted information about this and he can access his Pluto that way. That doesn’t mean I will carry on trying to crack why the Pluto is invisible to Gnu Radio and SDR Angel but it will help once I finally get the dish set up for QO100 as the Pluto will be out in the workshop as close to the dish as possible while still under cover, and I will want to drive it over the wires. More on that later as I still need a decent galvanised pole and some concrete and we’re still locked down here.

For completeness on the Pluto issues, iio_info -s finds the Pluto fine, and avahi-resolve —name pluto.local tells me it is on as expected. But neither iio_info -n pluto.local or iio_info -n will work, both stating ‘Unable to create IIO context: Connection timed out’.

Update: Typical. Reading what I have written got me thinking that this is simply a routing issue. When plugged in the Pluto appears as a USB Ethernet device and fails because it is not on the same subnet. Closing that and running ifconfig by hand I updated the Ethernet device Pluto ‘becomes’ by giving it the IP address and the netmask and now I can see the Pluto – I can ping it and iio_info -n finds it. and running gnuradio-conpanion (NB I already compiled this with the relevant libraries for the Pluto) it can see the device.

QO100 dish

My current issue with receiving QO100 (not got round to transmitting yet, baby steps!) is where to put the 1.2m dish. I don’t really want it on the wall or at the front of the house as it’s grey and huge. It can’t go at the front of the workshop due to an apple tree and if it goes anywhere on the garden we’ll fall over it. I’m currently thinking that the bit of land we have at the back of the garage will do and I can easily run the cables into the workshop from there, or even put all the RF side of things in the garage. But with no cable route from the garage to the shack (aka the little bedroom) it seems I will need the SDR co-mounted with the RF bits and run it via Ethernet or Wifi. Of course, there is also the wall outside the little bedroom but then we’d see it every time we gaze over at the moors…

Update 11/April/20 I’ve worked it out. There is room at the front of the workshop to the side of the apple tree where the dish will see the sky if it’s up maybe 4 foot. The mount I have is 3 foot so my ‘plan A’ is to get a 4 foot 2″ pole and an extender clamp, set some concrete (whenever we’re out of lockdown) and get the dish up. This makes it a doddle to feed the cables into the workshop.

QO100 experiments

Finally I had time and reasonable weather to have a go at receiving QO100 today. I know I can receive the satellite because I’ve used my GT Media V8 and managed to resolve the TV channels. No home for the dish yet so it lives in the workshop between fiddles.

Anyway, today was a bit of a comedy of errors but did result in success. First off, dish out, LNB in and aligned to the satellite. All good. I replaced the LNB with the POTY and got absolutely nothing on the V8. So I remembered I need the external 25MHz source so grabbed my Leo Bodnar GPSDO and the Windows laptop to make sure it was set up. Success, I can see the TV again.

Next was to set up the bias tee, PSU and cabling, the SDRPlay RSP2 and the SDR on the PC. After a bit of fiddling I did manage to see traces but I have yet to investigate the SDR software on Windows so it was off back indoors for the MacBook. Note to self: remember to learn how to use software before you need to actually use it!

The MacBook and CubicSDR proved the setup. I managed to decode a couple of SSB transmissions and decode the morse on the band edge beacon: “HI DE QO100 QRA DK0SB”.

Anyway, here is the lash-up. The signals were quite weak and clearly I need to do some adjustments yet but that really needs to wait until I fix the dish somewhere.