[amsat-bb] AO-85: Tone or no Tone for SSTV

Paul Stoetzer n8hm at arrl.net
Wed Aug 30 13:16:30 UTC 2017


AMSAT recommends always sending the tone on AO-85. If it doesn't hear the
tone for two minutes, the repeater will turn off.

The 67 Hz tone is well below the SSTV signal's tones and will not interfere
with signal transmission. The lowest tone used in a Robot36 transmission is
1100 Hz and the highest tone is 2300 Hz (with the image transmission
occurring primarly between 1500 and 2300 Hz).


Paul, N8HM

On Wed, Aug 30, 2017 at 9:11 AM, Roy Dean <royldean at gmail.com> wrote:

> two questions:
> According to Amsat website, 67Hz tone is required for a couple of seconds
> to activate repeater.
> Once the repeater is activated, does it still require the tone every couple
> of minutes to stay on, or does it only start the timer after normal
> ("un-toned") activity stops?
> Will constantly sending the tone during SSTV Tx mess with the SSTV Rx?
> I'm planning on eventually trying my own image, and want to be sure I don't
> waste 36 seconds of valuable airtime.
> -Roy
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