ATN Talk
Welcome to ATN Talk, our community forum. Please feel free to post comments and discussions pertaining to amateur television and the Amateur Television Network.
Digital ATV
The basic question is:
"How is the future ATN Network going to work using digital transmission?"
If we have a HiDes HV-100EH Modulator and, of course, a linear power amplifier at our QTH we would need a HiDes HV-110 receiver at each repeater site. I assume we will be using 434 MHz as the Input to the Repeater site. Also I assume we would need another HiDes Modulator and Linear amplifier operating at say 1.2 GHz to send the digital signal back out to the Repeaters coverage area and of course a HiDes receiver at each QTH to receive the digital signal. In order to operate in the HD mode, 1080i or 1080p, we would need to use the HDMI input and output connections of the HiDes equipment. Aspect ratio would be 16x9. No point in going digital unless we could transmit and receive an HD picture (interference not withstanding).
Now to me another problem is linking all the repeater sites together in HD. Are the Repeater Controllers compatible with the HDMI output from the HiDes units and what about the 5.9 GHz link transmitters and receivers? My guess is probably not. And is the current plan to keep the current analog system in place and just add the digital stuff on top?
Does anybody have a cost estimate for this digital upgrade?
Hi Mike!
All of our ATN hilltops in Southern California (except Mt. Ord) and Arizona have the HiDes HV-110 receivers for DVB-t digital use. Currently, they are set up to utillize the 434.000 MHz input, receiving QPSK modulation with 2 MHz of bandwidth under NTSC standard definition technology (4:3 / 480i resolution).
To experiment with HD-ATV, we will need an input frequency that will accommodate a full 6 MHz of bandwidth. With the satellite band and remote base that occupies our 434.000 MHz ATV input at most repeaters, we are unable to utilize HD in this frequency due to the large bandwidth. We are looking at transmitting on 2.4 GHz from the QTH side, using the HiDes HV-202E exciter with a 7 watt amp. The receiver on the hill will be the HiDes HV-122 - 2.4G receiver. The repeater exciter / transmitter will either be the HiDes HV-202E, or the HV-320E, which is capable of transmitting in the 1200 MHz band, mated to a 20 watt linear amplifier. The ATV'er will be using the HV-122A to receive 1200 MHz HDTV from the repeater.
We are also looking into pro broadcast DVB-T equipment from DVEO, but most pro broadcast equipment using DVB-T is from 100 - 960 MHz.
I will be donating the initial equipment for our HD-ATV project. The equipment will arrive in February and plans to install and test out the equipment will be in March of 2019. If all goes well, we will install the HDTV transmit and receive units at Mt. Wilson for HD-ATV trials to see if our members like the experience. We will initially set up our equipment using HDTV 720p resolution utilizing H-264 format from the exciter, with a NTSC SD converter to be coupled to our analog controller for the link to Santiago Peak for all ATV'ers can watch both analog transmission and the HD digital transmission (even though it will be still an analog signal coming into Santiago Peak).
Cost for the HD gear for the ATV'er: HV-122A receiver is $300.00 US, the HV-202E is about $600.00. 2.4 GHz linear Amps can vary from $250.00 - 450.00 depending on the source.
Hope this helps Mike!
73,
~Roland
Roland Hoffman - KC6JPG
Digital Systems Director
Amateur Television Network
Hi Roland. So your confirming what I was thinking that initially we would send and receive an HD picture to Wilson, but the received HD picture at Wilson would be converted to analog SD for transmission over the links? Nobody that was receiving a signal from any other repeater would see an HD picture! Is this correct?
Mike
Hi Mike! That would be correct. For our initial install, only the local repeater (Mt. Wilson) will be able to transmit HDTV, but the links will still be 720x480i to be compatible with NTSC standard definition at Santiago and the other repeaters at this point in time.
Thanks!
~Roland
Hi Roland, Mike,
Has this already been set up? Is that what is allowing the youtube Live stream to happen?
https://www.youtube.com/watch?v=jC3MldrXYnw
This is the link to the W6ATN Santiago Peak repeater- which(if the above is established) would should be broadcasting the downconverted SD content from MT Wilson.
Is there a page on this site that lists the capability of each repeater and if one has priority over other? I might not even be asking the right questions, I'm not sure what it is that I don't know yet 😀