[amsat-bb] Repeater interference on AO-92

[Jerry Buxton]

I don't know if it was mentioned, once the receiver is opened with a
67Hz tone AO-9n does not need to hear a tone with any transmission until
the one minute timer passes at which time the repeater TX stops. 
Hearing a tone with each transmission resets that timer, but it is quite
possible to make a QSO or cause interference during the one minute
without having the tone on your uplink signal.  A repeater output or
whatever other source of an unexpected signal such as a harmonic, could
be heard and repeated if it had better than ~ -120 dBm signal at the
satellite during that time.

Jerry Buxton, NØJY

On 4/28/2020 22:17, Eric Williams via AMSAT-BB wrote:
> I ran the experiments for 2 passes. 28Apr 1608 UTC and 29Apr 0245 UTC.  The
> first pass was just a few minutes before it switched to the video mode.  The
> second pass was high elevation and 11 minutes.
>
> It was mentioned that the interference might be from a 145.110 MHz repeater
> due to the 3rd harmonic.  Also mentioned were towns heard in the
> conversation and that there was a courtesy beep.  A repeater in our area
> that fits all those items in the N1CON repeater in Concord MA.
>
> For both passes I heard the bird fine and there were ongoing QSOs.  During
> the passes I transmitted periodically on the repeater announcing my call and
> 'testing' to cause some audio on the repeater.  Also had another station
> transmitting on the repeater.  Throughout the test I did not hear any
> interference on the downlink.  So also, I did not listen to the uplink
> frequency since there did not seem to be any interference at that time.  I
> am using different radios for TX and RX, and antennas that are far apart for
> the tests.
>
> I'll check from time to time listening to the downlink.  If I hear the
> interference, I can both check the uplink frequency and also listen to the
> local repeaters.  There are many in this area.
>
> 73,  Eric  KV1J  FN42 (West of Boston MA) 
>
> -----Original Message-----
> From: Eric Williams [mailto:kv1j at comcast.net] 
> Sent: Tuesday, April 28, 2020 11:14 AM
> To: 'amsat-bb at amsat.org' <amsat-bb at amsat.org>
> Subject: RE: Repeater interference on AO-92 
>
> Yes, I am also listening to the uplink freq.  Next pass is in about 1 hour.
> 73  Eric  KV1J 
>
> (I use digest mode for this list so pardon the not including the string of
> messages)
>
> -----Original Message-----
> From: Eric Williams [mailto:kv1j at comcast.net] 
> Sent: Tuesday, April 28, 2020 10:51 AM
> To: 'amsat-bb at amsat.org' <amsat-bb at amsat.org>
> Subject: RE: Repeater interference on AO-92 
>
> I am in the area of a suspected repeater. Also in the area of the towns
> mentioned to could be that machine.  I'll watch for the next AO-92 pass and
> announce my call of the repeater a few times and listen to AO-92.  So if you
> hear "KV1J" it is me testing for the interference.  I have not looked at the
> pass schedule yet but I can try a couple passes.
> 73,  Eric  KV1J  FN42
>
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
> are solely those of the author, and do not reflect the official views of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>