"Modern VHF/UHF Front-End Design" (1985)

I don't worry about being it a TV carrier, but they identified the actual transmitter. There will be other transmitters on the same channel. Geometry of the moonbounce path will rule out a lot of them, but when e.g. listening to "Europe" there would have been a lot of candidates for a specific channel (not anymore, analog TV has ceased).

That is not what I mean. The "nominal" frequencies are known but those cannot be used to positively identify a transmitter.

This does not explain what I meant above. What I mean is that when the published transmission channel for some transmitter is 31 and thus the vision carrier would be on 573.25 MHz or 537250000 Hz, in reality it would be on 537250000 + n * 15625 Hz e.g. 537296875 Hz for some site and 537234375 for another (for PAL). This was probably done to reduce the interference when both transmissions were received due to propagation. When each transmitter is sufficiently stable, and a list of those offsets is known (you won't find it in your programme guide or other widely published channel tables), the exact frequency could be used to identify the particular transmitter.

However, while some operators went to great lengths to get all parameters as stable as possible so they even could be used as frequency reference stations, others merely used an OCXO and would have some frequency error all the time.

What is the absolute accuracy of an unmodulated FN audio carrier ?

For PAL/SECAM, The audio carrier was at 5.5 (CCIR), 5.996 (UK) or 6.5 (OIRT) MHz from visual carrier.

Detecting a signal 4.43 MHz from the visual carrier is really hard to detect.. That color subcarrier is transmitted only as 10 cycles at the back porch of the H-sync pulse.

I have heard of some real big EME station using SSB audio, but never FM.

If you have a 64.0 us (+/- Doppler) recycling analog shift register, you could cumulate multiple horizontal lines and hence improve the SNR.

For VHF Band I (E2-E4) multiples of fH/12 offsets were definitely used. I have never heard about UHF Band IV/V offsets, I do not know if it was used in Band III (E5 - E 12).

(1) The departure of the visual carrier frequency of a TV

carrier frequency.

(2) The departure of the aural carrier frequency of a TV

carrier frequency plus exactly 4.5 MHz.

Ok. I'm totally unfamiliar with PAL as we don't have it in the USA. I just scrapped the numbers for PAL from this web page.

Yes, where the EME station provides the necessary transmitter. However, I was suggesting that one can hear TV transmissions using a high power broadcast transmitter, where the broadcast stations provides the transmitter, and the user supplies the antenna and receiver.

It can also be done with one transmitter to many receivers. This was done using the 1000ft Arecibo dish in 2010: using SSB.

You can also do EME without any equipment, except a computah, when there is moonbounce activity:

Note that most amateur EME is now done with either CW (Morse code), JT65 digital modulation, or other modes using WSJT-X software:

It's assumed that in order to receive EME signals, one needs to compensate for two Doppler shifts. One for moon, and one for the earth. The bandwidths use are narrow enough that one could easily miss the Doppler shifted return. The controlling software does all the work.

By shift register, are you trying to overlap the various carriers of an ATSC (digital) comb filter? Sounds like it would improve the SNR by simply removing all the modulation sidebands and then summing all the delayed carriers. Nice idea, but I don't think that will do anything for the older NTSC (analog) video.

I don't know how it works in non-US systems. Actually, I don't know exactly how it works in the US.

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4.43 MHz is the frequency of the color subcarrier. The sound carrier is at 5.5 5.74 6.0 or 6.5 depending on the system, but remember the sound transmitter is 10dB less in power than the vision so it would not be the first candidate. (and of course the color subcarrier is even weaker as it is being suppressed in the line and only sent as a burst)

Maybe one can try FM radio transmitters, at least those are still on the air. But the identification (in small bandwidth) will be even more difficult. It is unlikely that you can demodulate RDS.

I remember I have read about it in articles about receiving TV via Sporadic E (Es) so it was about band 1. (E2-E4) No idea if those offsets were also applied to terrestrial UHF transmissions.

Cable networks do use them, or at least they commonly did. (in our current network it appears it is out of use, but then they are in the process of phasing out analog TV on cable too, all will be DVB-C)

It is also possible to receive the moon reflections of the transmitters used to locate satellites in orbit, like the "Air Force Space Surveillance System" (the Fence).

This signal is very strong indeed...

Hmm I see it has been switched off as well. I thought it would be in operation until its S-band replacement would be online, but apparently the USA have other ways to get orbital parameters which are good enough.