Portable activity tomorrow

Please post here if you are planning any significant ATV Activity such as DXpeditions or Contest participation
G8GKQ
Site Admin
Posts: 2074
Joined: Sun Mar 22, 2009 1:21 pm

Re: Portable activity tomorrow

Post by G8GKQ » Tue Apr 06, 2021 4:54 pm

Hi Martin, Colin and Gareth

I called a number of times in your directions during the afternoon, but nothing heard. You would have been in the beamwidth of my DVB-S2 transmissions to Noel on 146.5.

Pictures of our activities (in the snow) to follow.

Dave

g4eml
Posts: 384
Joined: Thu Apr 26, 2018 9:36 am

Re: Portable activity tomorrow

Post by g4eml » Tue Apr 06, 2021 5:37 pm

Hi Dave absolutely nothing heard from you or Noel. I managed to receive a testcard from Martin so not a wasted afternoon!

I suspected it might be wet in your direction! I could see it in the distance, luckily it didn’t reach me.

It also revealed some problems with my portable setup. The noise level from the Portsdown was about S3 on 2M. Definitely affecting the talkback and probably also the DATV reception. Some more screening and filtering needed.

73 Colin.

g8gtz
Posts: 1430
Joined: Wed Apr 07, 2010 6:26 pm

Re: Portable activity tomorrow

Post by g8gtz » Tue Apr 06, 2021 5:45 pm

It also revealed some problems with my portable setup. The noise level from the Portsdown was about S3 on 2M. Definitely affecting the talkback and probably also the DATV reception. Some more screening and filtering needed.
I think this is a common problem and one that deserves some attention - I certainly suffer from it. Not sure if it is the screen or the Pi itself.

As I said on Twitter "First outing of the year and probably one the coldest - certainly the first when I was in the middle of a snow storm! Worked Dave over 40km path on 146 MHz, 5665 FM and 5.7GHz DATV.
1.JPG
1.JPG (381.87 KiB) Viewed 225 times
2.JPG
2.JPG (149.01 KiB) Viewed 225 times
Still good to get out and remember how it all goes together!

73

Noel - G8GTZ

G8GKQ
Site Admin
Posts: 2074
Joined: Sun Mar 22, 2009 1:21 pm

Re: Portable activity tomorrow

Post by G8GKQ » Tue Apr 06, 2021 7:53 pm

Hi

I also suffered from RPi interference on 146 today. Once I had cured that (by moving equipment around) I received good pictures from Noel at just under 50 km. We managed 2-ways on 146, 5665 FM and 5762.5 DATV.

Dave, G8GKQ
Attachments
snap49.jpg
snap49.jpg (117.3 KiB) Viewed 208 times
snap63.jpg
snap63.jpg (89.14 KiB) Viewed 208 times
GKQ.jpg
GKQ.jpg (264.55 KiB) Viewed 208 times

g4eml
Posts: 384
Joined: Thu Apr 26, 2018 9:36 am

Re: Portable activity tomorrow

Post by g4eml » Tue Apr 06, 2021 8:34 pm

Yes, Moving cables around seems to help null out some of the interference. That would seem to hint that some more common mode chokes on the cables might be worth trying. They are obviously acting as antennas.

I have just had a look on the spectrum analyser and the noise is very broadband but seems to be centred in the VHF region. 70cms and above is not too bad.

Most of the noise seems to be coming from the screen. There is probably not much that can be done to reduce that.

I guess the only solution is to keep the antennas as far away from the gear as possible.

Colin.

g8vpg
Posts: 358
Joined: Fri Oct 11, 2013 9:35 am

Re: Portable activity tomorrow

Post by g8vpg » Wed Apr 07, 2021 9:07 am

With respect to the noise problems on 2m, my experience would suggest checking any Ebay voltage regulators that you may have. I've had terrible problems with some of these - 59+ on 144.750MHz. Also the earlier Satlink receivers put out a sprog on exactly 144.750. I'm waiting for the weather to warm up before venturing out!
73 Shaun.

Post Reply

Return to “ATV Activity and Contest Discussions”