DATV linear transponder on HB9TV-1 relay
For those interested, full details at
https://home.swissatv.ch/2024/12/une-premiere-mondiale/
73 de michel, hb9dug
A worldwide first?
Forum rules
This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.
Thank you
This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.
Thank you
Re: A worldwide first?
Very interesting Michel, i have wanted to do this for a long time but never got round to it!
Well done and i will keep an eye on the websdr!
73
Rob
Well done and i will keep an eye on the websdr!
73
Rob
Re: A worldwide first?
Hi Michel
Very interesting - any chance of a short CQ-TV article?
Noel
Very interesting - any chance of a short CQ-TV article?
Noel
Re: A worldwide first?
With pleasure Noel !
vy 73 de michel, hb9dug
vy 73 de michel, hb9dug
Re: A worldwide first?
Could someone please expand this a bit
Is this a repeater where the input is not decoded and then re-encoded
And the transport is passed from the Rx to the Tx, which may regenerate the signal
Or some form of translator/transmodulator where it exits at different parameters/mode
Bent pipe?
Cheers Roger VK5YYY
Is this a repeater where the input is not decoded and then re-encoded
And the transport is passed from the Rx to the Tx, which may regenerate the signal
Or some form of translator/transmodulator where it exits at different parameters/mode
Bent pipe?
Cheers Roger VK5YYY
Re: A worldwide first?
I am assuming it is a linear transponder, like on QO100, but mounted on a mast on a mountain, rather than in space. In a sense that is nothing new, we have had TV relays for many decades, but new in the amateur arena. Actually I do remember there was something similar tested for CW/SSB in the past.
I experimented with something similar using an Ettus B200 and Gnuradio around 12 years ago. As I recall, the main problem was the AGC and preventing strong signals on the input driving the output too hard, while retaining sensitivity.
The near-far effect, coupled with terrain losses, can represent signal strength differences of many orders of magnitude at VHF/UHF. While the same issue applies to the QO100 satellite transponder, it is not anywhere near as extreme as terrestrially because all ground stations are at similar ranges, and line of sight, so it is only the difference in transmit power and antenna gain. I am interested in how Michael has solved that challenge.
Mike
I experimented with something similar using an Ettus B200 and Gnuradio around 12 years ago. As I recall, the main problem was the AGC and preventing strong signals on the input driving the output too hard, while retaining sensitivity.
The near-far effect, coupled with terrain losses, can represent signal strength differences of many orders of magnitude at VHF/UHF. While the same issue applies to the QO100 satellite transponder, it is not anywhere near as extreme as terrestrially because all ground stations are at similar ranges, and line of sight, so it is only the difference in transmit power and antenna gain. I am interested in how Michael has solved that challenge.
Mike