RB-DATV from GI-G
Posted: Fri Apr 20, 2018 12:00 pm
I'm pleased to report my first RB-DATV two way contact on 146MHz yesterday morning with Tony G4CBW at 283km, which is also my first ATV contact.
For this test we were to try DATV on 2m and 3cm if workable along with the 6cm FPV setup. My location was /p at the car park for Scrabo Hill IO74DN38 with Tony IO83UB93.
3cm wasn't as good as a previous site I've spoken to Tony from so we didn't progress beyond a quick SSB contact. The 6cm TX test didn't work out either not unsurprisingly.
We had an easy contact on 2m FM with me using down to 2.5w from an FT-290 with a portable Elk log periodic.
With that result I tried a 333KS/s TX test from my Portsdown on 146.5 with 8w, and some additional loss from a little too low LPF, and to my surprise Tony copied fine! Of course it worked right at the start of a conversation with an interested passer by so I didn't noticed his message for a good while. I switched from the Portsdown test card to the Pi camera for a while which also worked fine. A few captures from his .TS recording:
Tony them moved on to transmit but despite the good signals I wasn't expecting it to work at all given I was using a compromise antenna, no BPF or preamp but the car park site itself is somewhat protected from the local nasty transmitters by the rest of the hill. To make things worse the laptop didn't hold much of a charge and the inverter I'd taken along that hadn't seen daylight for 10 years didn't work...
I did however take a Windows tablet and USB OTG connector I had tried MiniTioune on previously but had decided it wasn't usable due to the screen size. But on this occasion it saved the day and I received Tony, the cutoff edge is down to the tablet issues but it's whole on the .ts file I captured while messing things up with the tiny touch screen over and over. Happy days
Next tests will be using a better antenna, a not so lossy at 2m LPF and I will have a BPF/preamp setup sorted out for the receive side. Looking forward to more contacts with others this year.
Thanks Tony for the guidance and doing most of the antenna work on this one!
John - GI7UGV
For this test we were to try DATV on 2m and 3cm if workable along with the 6cm FPV setup. My location was /p at the car park for Scrabo Hill IO74DN38 with Tony IO83UB93.
3cm wasn't as good as a previous site I've spoken to Tony from so we didn't progress beyond a quick SSB contact. The 6cm TX test didn't work out either not unsurprisingly.
We had an easy contact on 2m FM with me using down to 2.5w from an FT-290 with a portable Elk log periodic.
With that result I tried a 333KS/s TX test from my Portsdown on 146.5 with 8w, and some additional loss from a little too low LPF, and to my surprise Tony copied fine! Of course it worked right at the start of a conversation with an interested passer by so I didn't noticed his message for a good while. I switched from the Portsdown test card to the Pi camera for a while which also worked fine. A few captures from his .TS recording:
Tony them moved on to transmit but despite the good signals I wasn't expecting it to work at all given I was using a compromise antenna, no BPF or preamp but the car park site itself is somewhat protected from the local nasty transmitters by the rest of the hill. To make things worse the laptop didn't hold much of a charge and the inverter I'd taken along that hadn't seen daylight for 10 years didn't work...
I did however take a Windows tablet and USB OTG connector I had tried MiniTioune on previously but had decided it wasn't usable due to the screen size. But on this occasion it saved the day and I received Tony, the cutoff edge is down to the tablet issues but it's whole on the .ts file I captured while messing things up with the tiny touch screen over and over. Happy days
Next tests will be using a better antenna, a not so lossy at 2m LPF and I will have a BPF/preamp setup sorted out for the receive side. Looking forward to more contacts with others this year.
Thanks Tony for the guidance and doing most of the antenna work on this one!
John - GI7UGV