[amsat-bb] Thoughts on ISS packet switch back to 145.825 MHz (long)

Greg D ko6th.greg at gmail.com
Mon Apr 17 23:14:19 UTC 2017

Hi Mike,

I think APRS-IS itself is fine.  Essential, actually.  Not suggesting it
should change, or is directly involved in the problem.

So, doing some more digging, the vanity site I thought of was
http://www.ariss.net/, and a few others that are similar.  BUT, the map,
and the table below it, clearly show stations that have live operators
behind them, as demonstrated by the 2-way messages listed. And the more
I look into the stations list, I'm thinking that Steve is doing some
pretty clever filtering to weed out the ones that are just beacons
(though I do see a few in there).  I thought I saw a bunch that appeared
to be unattended, but now I'm not so sure.

So, perhaps, I'm off a bit about the vanity aspect of the unattended
beaconing?  Are there sites that list row upon row of call signs that
aren't live?  If there isn't a billboard for unattended beacons, why
would someone engage in doing that?  A vanity beacon that only the
originator knows about isn't very vain.  Perhaps something else, but not

Greg  KO6TH

Mike Diehl wrote:
> Greg,
> You make a good point about the complications of dropped packets. I have some good recordings of voice stations getting a call back when as little as a single letter of their call was heard. It's amazing how well we can learn the voices of other ops when you're on regularly. This simply doesn't happen on packet.
> Another complication is that it is on simplex. That means on a 10 minute pass the maximum amount of time possible to digipeat is 5 minutes if the channel is fully saturated. Subtract out the ISS beacons we end up with less than 50% of the pass available for ISS to hear you.
> I'm not sure what the best solution is. You do bring up an interesting point about APRS-IS. Maybe it's possible to have them black list fixed beacon stations and remove the vanity aspect like you mentioned. 
> 73,
> Mike Diehl
> AI6GS 
>> On Apr 17, 2017, at 1:26 PM, Greg D <ko6th.greg at gmail.com> wrote:
>> Gabriel Zeifman wrote:
>>> It's not complicated. However much it may be insisted ISS packet is not
>>> SO-50, it is practically the same thing (single channel operating on FM).
>> Actually, the ISS digi is worse.
>> With voice communication, one can sometimes pick up the start or tail of
>> a call sign, as the astronaut demonstrated, and use that to filter a
>> second try.  With digital, any bits that get corrupted result in no
>> reception at all.
>> I hate to suggest this, and admit I am assuming a cause without
>> supporting evidence, but it might be necessary to remove the "vanity"
>> aspect of ISS digipeating, and take down or hide from general view the
>> reporting sites that support it.  While a useful tool for
>> troubleshooting, I suspect the vanity aspect of seeing your call in a
>> public list day after day from an unattended station may be too strong a
>> draw for some, resulting in the clogged channel.  The SatGates that
>> monitor for ISS and other APRS satellite traffic are still important
>> part of the infrastructure, so that the information can be datamined
>> from APRS-IS if you need it for troubleshooting.  But the consolidated
>> lists of who has been seen digipeating through the ISS, I think, may be
>> contributing more trouble than they are worth.
>> Greg  KO6TH
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