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My DATV station using a Portsdown and a Minitiouner is now taking shape, amplification and filters are the next step. As I can foresee most of my operation will be portable I'll also need to consider aerials. I am presuming that I'll mostly be using 2m or 70cm, possibly 23cm, with some kind of beam rotatable from the "comfort" of the van. Can someone give me a brief description of using talkback, polarisation etc etc.
Sounds like a great subject for a CQ-TV Article. Here are some ideas for you.
Most ATV talkback is on 144.75 MHz FM horizontally polarised. Although for local (under 50km) contacts 5 or 10W to a 5 element beam is adequate, you will need higher power if you are chasing any DX over 150km. If things get difficult, stations tend to switch to SSB, sometimes QSYing to the 144.170 - which is favourite frequency to find the French ATV stations on.
Talkback for 146 MHz TV is more difficult. Stations tend to use timed overs ("I'll transmit for 5 minutes while you look for me") and then switch back to voice.
If you have internet, you can also use https://www.dxspot.tv/. Once you have a login, you can use the chat channel. If you want to use the chat without the map (say on a tethered iPad or tablet) you can use the URL https://philcrump.co.uk/dxchat/?room=1 once you have logged in in another window.
I have also used text messages and mobile phone when things got difficult.
I like using a remotely controlled rotator, but have recently only been able to manually rotate my aerials. The key factor is that you should be able to monitor signal strength from where you are moving the aerials. I have tried the "move it a bit, go and see, move it a bit more, go and see again" approach and it's not ideal.
The last point that I would make is that you should pre-plan as much as possible. Look on this forum http://www.batc.org.uk/forum/viewforum.php?f=75 to see who might be active, and make sure that you have already calculated the bearings for all the stations that you know about. You can use the Contest Log Sheet http://www.batc.org.uk/contests/ATV_con ... YYMMDD.xls, fill in the stations and locators and then print it off before you go.