-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
-
A Winner has been selected for the 2025 Radioddity Cyber Monday giveaway! Click Here to see who won!
ATV
- Thread starter C2
- Start date
C
CDX126
Guest
I've done slow scan TV, but not fast scan TV.
I was wondering what you are really allowed to do?
I guess you cannot really supply any programming because you end up just being a broadcast station, which is not allowed.
I was confused because I see an ATV repeater just broadcasting the color bars for a long time, like over a day. I thought I could make up some video shorts for fun and hit the repeater.
I guess I don't see how you really have a 2-way with video.
I was wondering what you are really allowed to do?
I guess you cannot really supply any programming because you end up just being a broadcast station, which is not allowed.
I was confused because I see an ATV repeater just broadcasting the color bars for a long time, like over a day. I thought I could make up some video shorts for fun and hit the repeater.
I guess I don't see how you really have a 2-way with video.
C
CDX126
Guest
CDX126 said:
Code is not a requirement. Anyone with a Tech or higher class may use any legal mode on VHF and up.
Well, the reason I ask is because there is an ATV repeater locally and all I see are hams sitting in front of a camera during their net, which is cross-linked to various other bands.
The ATV uplink is on 23cm and cross-links to channel 57, to another 70cm repeater, to another 1.25M repeater, to another 2M repeater. Holey moley, thats 5 repeaters, plus then go on another 2M simplex freq.
Yep, I've heard them on all 6 frequencies including the television. :shock:
And they did not return my email asking about ATV
The ATV uplink is on 23cm and cross-links to channel 57, to another 70cm repeater, to another 1.25M repeater, to another 2M repeater. Holey moley, thats 5 repeaters, plus then go on another 2M simplex freq.
Yep, I've heard them on all 6 frequencies including the television. :shock:
And they did not return my email asking about ATV
I'm pretty active on ATV.
ATV here in Australia is a little different to the USA. There you can buy an ATV transmitter off the shelf. We have not had that luxury, so we have been building our own for many years.
We used to have two 70cm channels, 426MHz AM and 444MHz VSB. Our 70cm band falls maining inbetween 432-440.
We used to have a 50cm amateur band with an AT channel on 579MHz. This was withdrawn many years ago and ATV repeater outputs shutdown later. It was an excellent window to ATV at the time since it was ch35 UHF and could be seen on a normal TV without anything special.
We have 2 ATV repeaters here in Sydney on 444MHz VSB and 1250MHz FM. The inputs and outputs are reverse the reverse of the other.
I have my built my own ATV transmitters for 426,444,579MHz and 23cm (1.2-1.3GHz 100W), 13cm (2.4-2.45GHz 100W), 9cm (3.3-3.8GHz 60W), 6cm (5.4-5.8GHz 30W), 10GHz (5W), 24Ghz and 75Ghz.
They might sound complex, but ATV transmitters are simple to build. This one can transmit 25 watts (no sound) I use it for remote pictures on my hang glider and motorcycle.
http://www.funbusters.net/radio/ham/426.jpg
It is nothing more than a oscillator with an modulator and a PA underneath.
FM transmitters can use a simple common base oscillator, again with a pre-emphisis varactor modulated and some sort of PA like the Motorola chips.
Old analog satellite receivers make excellent demodulators for FM TV and all you need is a good low noise pre-amp like an MGF1302 for 23cm and satellite LNC's modified can do some of the other bands, or you can simply make your own downconverters using double ballanced mixers.
ATV here in Australia is a little different to the USA. There you can buy an ATV transmitter off the shelf. We have not had that luxury, so we have been building our own for many years.
We used to have two 70cm channels, 426MHz AM and 444MHz VSB. Our 70cm band falls maining inbetween 432-440.
We used to have a 50cm amateur band with an AT channel on 579MHz. This was withdrawn many years ago and ATV repeater outputs shutdown later. It was an excellent window to ATV at the time since it was ch35 UHF and could be seen on a normal TV without anything special.
We have 2 ATV repeaters here in Sydney on 444MHz VSB and 1250MHz FM. The inputs and outputs are reverse the reverse of the other.
I have my built my own ATV transmitters for 426,444,579MHz and 23cm (1.2-1.3GHz 100W), 13cm (2.4-2.45GHz 100W), 9cm (3.3-3.8GHz 60W), 6cm (5.4-5.8GHz 30W), 10GHz (5W), 24Ghz and 75Ghz.
They might sound complex, but ATV transmitters are simple to build. This one can transmit 25 watts (no sound) I use it for remote pictures on my hang glider and motorcycle.
http://www.funbusters.net/radio/ham/426.jpg
It is nothing more than a oscillator with an modulator and a PA underneath.
FM transmitters can use a simple common base oscillator, again with a pre-emphisis varactor modulated and some sort of PA like the Motorola chips.
Old analog satellite receivers make excellent demodulators for FM TV and all you need is a good low noise pre-amp like an MGF1302 for 23cm and satellite LNC's modified can do some of the other bands, or you can simply make your own downconverters using double ballanced mixers.