ATV on 6cms - It's Cheap and Easy on 5665MHz

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g8gtz
Posts: 1195
Joined: Wed Apr 07, 2010 6:26 pm

Re: 5665 user map

Post by g8gtz » Fri Oct 20, 2017 5:44 pm

That's interesting - I'm coming up your way next Saturday and may put the gear in the car...

Also, in effort to help you try and work people, I've started a Google map showing stations on 5.6GHz - https://www.google.com/maps/d/u/0/edit? ... 996143&z=7

This is just like the Portsdown users map - it is user editable and to protect people's data, I've only put call signs and very approximate locations in so far.
However, you can edit, add to, move or delete your own pin and can also add new stations that are on the band.

There's also been a few updates to the 5.6GHz wiki page - https://wiki.batc.tv/5.6_GHz

73

Noel

K3RW
Posts: 7
Joined: Mon Mar 20, 2017 11:41 pm

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by K3RW » Sat Oct 21, 2017 7:17 am

Newbie to 6cms here. Great info on the FPV method to get on 6cms! I've been looking at trying FPV on the audio side to get on 6cms, and feed it to a dish to send it from a mountaintop in the United States. ARRL VUCC award requires 5 grids for 5ghz and above. Given the proximity of our chosen site, it should be very easy to get 3 of them and 2 of them are no more than 40-50km. Seems very doable. Plan is to have one fixed unit work the 5 grids, while a second rover goes to spots in the clear on them.

I'm a little lost on how to do the audio-only feed. Would I just connect the audio, ground, and voltage points, and ignore the video input? I read that for FM voice 'this is achieved by simply putting high level (1v p to p) audio on the yellow video tx phono and listening with a powered amp on the yellow Rx phono amp.' Um, I am not sure what that means.

And second, at least a few of the receivers claim to be A/V receivers, but do not apparently all receive the audio portion--which is a problem if I'm trying to send audio-only. Any recommendations here?

Please reply to this thread or message me direct--I may not get forum posting notifications sometimes for unknown reasons.

Thanks so much! --73

g8gtz
Posts: 1195
Joined: Wed Apr 07, 2010 6:26 pm

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by g8gtz » Sat Oct 21, 2017 7:43 am

Hi,

Re Audio only - you literally put 1v (or as much as you can manage) audio on to the yellow transmit phono and this modulates the main high level carrier with audio rather than video (ignore the 2 red and white audio phono connectors). On rx, just connect the yellow phono to the line in audio amp. You do it this way because audio sub carriers are 20 dB down on the main carrier.

Re audio compatibility - that's probably because there is some choice of audio sub carrier frequency (5.5, 6.0 and 6.5 etc) and not all the units will transmit / receive any, some or all the same as the others. In the UK we tend to use the 6MHz sub carrier as the main audio channel when in video mode.

73
Noel - G8GTZ

g0mjw
Posts: 981
Joined: Sat Sep 20, 2014 9:15 am

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by g0mjw » Sat Oct 21, 2017 9:27 am

Wouldn't it be better to put much less than 1V of audio into the video input? Then it could be made more comparable with a standard WBFM receiver.

Mike

g8gtz
Posts: 1195
Joined: Wed Apr 07, 2010 6:26 pm

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by g8gtz » Sat Oct 21, 2017 10:06 am

Yes you could and the s/n performance would improve if using a NB receiver.

However, as we are currently also using the FPV receivers, which have a very wide IF filter (27 MHz??) for the video, so we need to use wide deviation on Tx to get a good s/n out of the receiver.

The receivers use a 480MHz IF so in theory you could tap off and drive an SDR etc... But this is all about the KISS principle and if you want to improve the system performance it is probably best just to start again with a down converter etc which would be capable of driving an SSB rxr and DATV system...

Noel

G8JAN
Posts: 47
Joined: Mon Feb 25, 2008 7:12 pm

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by G8JAN » Sun Oct 22, 2017 7:26 pm

Hi all be gentle with me this is my first post! Noel got myself and Pete G4NJJ fired up about 5Ghz ATV earlier this year. One of the main reasons being like our early days on 10ghz, the equipment to get started is cheap and I like cheap!

So far the main interest is with reception of 5Ghz. The first purchase was the dipswitch set receiver but I soon discovered there is a better alternative
which scans the whole of the Drone band including of course 5.665 Ghz. (see links at the bottom of my post) The beauty of this little box is that it has USB output plus conventional Video and Audio outputs via a mini 4 pin plug. Using the NCH free Debut software on a pc laptop with the RX plugged into a USB port, it bypasses a few problems and is ideal for portable use. No extra PSU is necessary the RX is powered from the USB port. No video screen squelch defeat is necessary. Recording off air are made straight to the laptop. Frequency readout while scanning is seen on the laptop screen which disappears when the RX is locked onto a signal and finally a separate monitor is not required.

I think the whole point is to keep things simple especially for portable use. I've experimented with an external switch bypassing the function of the press button which starts the scan. This provided constant scanning and frequency changes in 2 Mhz steps. So far I have tried a 13 ft length of USB cable with no ill effects on the video. I've yet to check out the audio side of things. Pete G4NJJ tells me you don't see the frequency read out taking video from the miniature 4 pin connector instead of the USB connector. To run conventional Audio and video cables into the lap top I've used the Easycap dongle but like many other people so far I have never managed to get audio through the Easycap!

Still keeping things simple I think it's best to use an offset dish rather than a prime focus dish. That way you can experiment with differing ways to illuminate the dish. I see some people are using waveguide and even miniature log periodic aerials but my idea is to use a biquad (see my photo in this months magazine) also see the link below to a great website with diagrams and calculations to build your own quad or quads.


This is an Ebay link to the scanning receiverI purchased. Disregard what it say's about Android only it will work with a pc.. You can search for a better price than I paid.

[color=#4040FF]http://www.ebay.co.uk/i ... 1[/color]

This YouTube video shows how the receiver works with a PC.

https://www.youtube.com/watch?v=4ZBePhv ... e=youtu.be

This is the dish feed biquad antenna information.

[color=#4000FF]http://buildyourownanten ... ml[/color]


I hope this proves of interest, experiments are ongoing.

Pete

User avatar
G0NMY
Posts: 75
Joined: Wed Nov 11, 2009 6:10 pm

Re: 5665 user map

Post by G0NMY » Mon Oct 23, 2017 11:48 pm

g8gtz wrote:That's interesting - I'm coming up your way next Saturday and may put the gear in the car...

Also, in effort to help you try and work people, I've started a Google map showing stations on 5.6GHz - https://www.google.com/maps/d/u/0/edit? ... 996143&z=7

This is just like the Portsdown users map - it is user editable and to protect people's data, I've only put call signs and very approximate locations in so far.
However, you can edit, add to, move or delete your own pin and can also add new stations that are on the band.

There's also been a few updates to the 5.6GHz wiki page - https://wiki.batc.tv/5.6_GHz

73

Noel
Hi Noel
I tried the map link but access is denied so cant see it.
I have just ordered a a 2W transmitter so should be fun getting on another band on Analogue TV :D
Cheers Mark G0NMY
http://www.g0nmy.blogspot.co.uk/

¡ʎɐqƎ ɟɟo pɹɐoqʎǝʞ ɐ ʎnq I ǝɯᴉʇ ʇsɐl ǝɥʇ sᴉ sᴉɥʇ

M0SKM
Posts: 257
Joined: Sun Jul 13, 2014 3:15 pm

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by M0SKM » Tue Oct 24, 2017 11:05 am

OK I have access now but no edit like the Portsdown map.

Steve

G8XZD-TV
Posts: 94
Joined: Fri Feb 22, 2013 6:41 pm

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by G8XZD-TV » Tue Oct 24, 2017 4:20 pm

Can't easily find a way to add me, G8XZD, location Bristol.

g8gtz
Posts: 1195
Joined: Wed Apr 07, 2010 6:26 pm

Re: ATV on 6cms - It's Cheap and Easy on 5665MHz

Post by g8gtz » Tue Oct 24, 2017 5:22 pm


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