[amsat-bb] ARISS test [REPORT]
bruninga at usna.edu
Fri Oct 27 20:36:45 UTC 2017
Pretty Good Test Report on USA pass of ISS at 1834 to 1839 UTC on 27 Oct
Conclusion, HT's outdoors with whip antennas do not hear as well as we
thought and the Uplink is more challenging than we thought. But certainly
gave the thrill expected of monitoring the ISS pass with an HT. This was
during mid-afternoon class time on a Friday over Maryland with noob
We had 6 radios, One was an Oscar class ground station plus 5 HT's outside.
* The Oscar station heard 11 stations (out of 32 packets total)
* HT with long dual band whip heard 4 stations
* HT with full size 1/4 whip heard 3 stations
* HT with long dual band whip heard 2 stations
* HT with rubber duck heard 2 stations
* HT with arrow heard one (but had bumped radio on 145.830!)
Of the 11 different stations heard by the OSCAR station:
* Two were heard 6 or 7 times
* One was heard three times
* four were heard twice, one using 5W & ELK, one 10W to quad, one 10W to
* four were heard once, one was a mobile,
HTs Receive performance: all of the stations heard by the HT's were from the
same 5 in the middle of the pass, with none being more than 250 miles away.
The other six stations heard by the Oscar class ground station were up to a
bit farther up to 600 miles away.
All 5 of our HTs were on the Planned-Test-1-minute schedule and NONE were
heard by the ISS(digipeated).
Of all the 11 stations, three of the four heard twice were following the
suggested protocol and so were assumed to be on a 1 minute schedule. So,
during an 8 minute pass, only got two packets through even though they had
modest beams on uplink. Again, probably during the middle of their overhead
geometry. But for our 4 minute window, then they had a 50% success rate.
The APRS-IS captured a total of 30 packets during the same time frame that
we got 32 and only 2 or 3 were missed by either of us. There were 8
different Igates with four of them contributing 4 to 6 packets and four
contributing one or two. All of this data was from the 4 minute pass window
from first station heard by the Oscar class station to the last one heard by
that station. The APRS-IS of course heard other stations before and after,
but the window was only taken during our OSCAR class pass.
The downlink was sparse and it is doubtful that there was too much overload
on the uplink, (though we all know that the downlink says NOTHING about what
the uplink receiver on ISS is having to deal with). But that could be
eliminated if we could get someone in Hawaii to do the same test. Horizon
to horizon with a few radios at the same time. On the same 1 minute test
The students with the handhelds were not skilled operators and so the
attitude of the HT's and antennas relative to the ISS track should be
considered completely random.
For what it's worth.
From: Robert Bruninga [mailto:bruninga at usna.edu]
Sent: Friday, October 27, 2017 1:17 PM
Subject: QIKCOM-1 and ARISS test
We have not heard from QIKCOM-1 but since we asked users to include their
Power and Antenna gain and beacon once a minute for these few passes, we are
going to finish the day by seeing what we hear from ISS.
We already see a few people giving that data, so we are going to switch our
uplink from the path of APRSAT back to the path of ARISS for the remainder
of the day. This will give us all an idea of what hits ISS and what does
not. I've seen these so far:
WN9Q>CQ,RS0ISS*,qAR,WA8LMF-SG::APRSAT :5w 14el klm cross yagi
KB6LTY-3>CQ,RS0ISS*,qAR,W0ARP-15:=3429.70N/11712.30W- power 20W - 9.2 dbi
Attended packets only to end of today's test.
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