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RE: PCSAT - dumb questions



Hello Louis

> Recalling a recent discussion, this is why having strong authentication
> on the command links is useful, and why that discussion was useful
> to pursue.

PCSat _does_ have challenge-reponse authentication on the command channel -
and you will not be successful connecting unless you can reply correctly to
the random challenge-response.

During the recent PCSat recovery I must have logged on the the bird a
hundred or so times, and unsurprisingly I never saw the same
challenge-response sequences.

What these unauthorised connections amount to is an unintentional 'denial of
service'. Once the unauthorised connect attempt times out (ie, a correct
response is not forthcoming), the authorised station will connect. But the
timeout takes a valuable slice of the pass and is very frustrating.

The effect of this for a command station is no different to a QRO station
keeping their PTT pressed for a couple of minutes - ie, jamming the uplink.

My point here is that in this case it wouldn't matter how good your
authentication is.

73 Howard G6LVB


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