Fwd: Thoughts on ISS packet switch back to 145.825 MHz (long)

16 Apr 2017

      Stefan,
Did you listen to that last pass? There may have been only 10 stations, the
problem is then 8 of them are sending beacons every 30 seconds and have no
intention of making a QSO! This is a longstanding problem on the ISS 2m
digi. I don't agree about your claims on the reliability of the ISS digi; I
have routinely worked it and decoded my digipeated packets to the horizon
with an Arrow and HT, even on 70cm. With little doubt I would consider the
ISS digi one of out most reliable space based transponders, only not
functioning when shut off for more prudent matters aboard the station. The
ISS has a particularly sensitive receive, it will digipeat plenty, as with
most satellites.
As is a common disease among sat ops, people focus more on their transmit
than receive. Take a listen to an FO-29 pass on the weekend, odds are
you'll hear half a dozen stations calling CQ at the exact same spot in the
middle with excessive power, and none of them will make a QSO. Maybe you'll
hear a station crank the power up on AO-7 "because they can't hear
themselves" and knock it into mode A, ruining the pass for most. It IS QRM.
If you are preventing QSOs of people that can hear with blind
transmissions, that is QRM. Knock yourself transmitting beacons in Western
Australia, but over North America you will hear stations, and in any case
you will hear RS0ISS (on the condition that you CAN HEAR. You may assume
you are not creating QRM, but you often are. The ISS is not so different
than SO-50 actually, people blindly transmitting not being able to hear and
sharing a single channel, precluding other QSOs. I seem to recall hearing
you on a pass a few days ago and giving you a call (which I heard myself
clearly) and you didn't hear it. Maybe just a coincidence.
73,
Gabe
NJ7H
On Sun, Apr 16, 2017 at 5:18 PM, Stefan Wagener [email protected] wrote:
...
Thanks Mike,
Again, you don't seem to get the point. Based on your setup, TNC, software
etc you will NOT be able to decode every single packet and based on your
setup and the ISS position the ISS digipeater will not re-transmit. It's
the nature of the beast. No, you are not creating QRM if the ISS does not
repeat your packet. Listen to the path of the ISS and you will hear that
50% of the time the radio is silent. It does not TX since there are no
valid packets. Where is the QRM? There is none other than in you local
environment where nobody cares. Don't discourage those that are trying to
make it work. If you want a case, point out the stations and callsigns that
create QRM and are not listenting/responding!
Just check out the last pass over the US. You will find 10 stations,
that's a station a minute with room to spare. This is NOT SO-50!
73, Stefan, VE4NSA
On Sun, Apr 16, 2017 at 5:05 PM, Mike Diehl [email protected]
wrote:
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Stefan,
I think you're taking Gabe's comment too literal. The point he's trying
to make is that many stations just keep on transmitting when they can't
hear anything.
We can use that amateur radio on ISS as an experiment as an excuse but
that doesn't really fly. APRS is beyond an experiment as it is a well
established form of using APRS via satellite, nothing new here.
Furthermore, what is the point of trying repeatedly to transmit if you
can't decode? It is the golden rule for a reason and it applies everywhere,
satellite or terrestrial. If you can't hear it you can't work it, bottom
line. Until you can decode packets you're just creating QRM.
73,
Mike Diehl
AI6GS
...
On Apr 16, 2017, at 2:46 PM, Stefan Wagener [email protected] wrote:
Hi Gabe,
With all respect I very much disagree. The amateur radio equipment on
the
...
ISS is an experiment! Sometimes it works and sometimes it doesn't.
Based on
...
your location, equipment and ISS position you will* NOT* decode every
packet, and yes that includes your own packets. So folks will be trying
again and that's okay. *They don't become a source of QRM* on the ISS
since
...
the ISS will only re-transmit if its a good packet. They are exercising
their license privileges to work through the ISS and for many having
that
...
first digipeat after many tries is their success story and we welcome
that.
...
73, Stefan, VE4NSA
On Sun, Apr 16, 2017 at 1:43 PM, Gabriel Zeifman <
[email protected]>
...
wrote:
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I think the golden rule of working all sats applies to ISS as well: if
you
...
...
can't hear (or decode), don't transmit! It's easy to become a source
of QRM
...
...
if you keep transmitting in the blind when you can't hear.
73,
Gabe
NJ7H
...
On Apr 16, 2017, at 1:28 PM, Robert Bruninga [email protected]
wrote:
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...
...
I agree completely.  ISS digipeting should be for LIVE operators.  Or
for
...
...
...
LIVE things.... (a student experimental ocean going buoy for
example)...
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...
...
NOT for non-moving-fixed egos...
Bob, WB4APR
-----Original Message-----
From: AMSAT-BB [mailto:[email protected]] On Behalf Of
Patrick
...
...
...
STODDARD (WD9EWK/VA7EWK)
Sent: Saturday, April 15, 2017 7:51 PM
To: [email protected]
Subject: [amsat-bb] Thoughts on ISS packet switch back to 145.825 MHz
(long)
Hi!
Earlier today, I tweeted a quick comment about what I saw on the ISS
145.825 MHz digipeater just after 1900 UTC this afternoon. Since
tweets
...
...
...
are limited in length, I'm posting a longer message here...
In the past few weeks, once word got out that a replacement for the
failed
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Ericsson VHF HT on the ISS was being sent up to the station, many were
anxiously looking forward to seeing the ISS digipeater move from
437.550
...
...
...
MHz back to 145.825 MHz, where it had been until the old radio's
failure
...
...
...
in mid-October 2016. I understood that many would welcome this change,
but
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I was not jumping up and down with excitement. Unfortunately, after
seeing
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the activity on the ISS digipeater in the past day or so since the
replacement VHF radio was put on 145.825 MHz, my worries have been
confirmed.
For many, the move to 437.550 MHz meant many stations that could
easily
...
...
...
work 145.825 MHz would have to change. Whether it was a different
antenna
...
...
...
for the 70cm band or dealing with Doppler with the 437.550 MHz
frequency,
...
...
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almost all of the unattended stations that had been present on the
145.825
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MHz frequency were gone. If you wanted to use the ISS digipeater to
work
...
...
...
other stations, this was a great opportunity. Many stations using
APRS-ready HTs and mobile transceivers were showing up, using a group
of
...
...
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memory channels to compensate for Doppler, and were making contacts.
Some
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...
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fixed stations, including those already capable of satellite
operating,
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...
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were also showing up. Even on the busier passes, the
437.550 MHz always seemed to be clear of the clutter from the
unattended
...
...
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stations that previously inhabited 145.825 MHz.
Fast forward to yesterday (Friday, 14 April). The ISS digipeater
switched
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...
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to 145.825 MHz in time for afternoon/evening passes over Europe
(around
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...
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1330-1400 UTC). Lots of stations showed up, based on looking at the
ariss.net web site. The same thing started to happen here in North
America, later in the day. The passes I worked last night were not
bad,
...
...
...
but there were more stations on one pass that went over much of the
continental USA than I'd typically see on 437.550 MHz.
By midday today (1900 UTC), it seemed like many more stations were on
the
...
...
...
frequency. I saw 11 other call signs on a pass just after that time
this
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afternoon. At best, there may have been 4 or 5 other operators at
their
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...
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keyboards or keypads, looking to make contacts.
The others were just squawking away, not answering APRS messages sent
to
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...
...
them. By the time the ISS footprint was reaching the east coast, the
frequency was congested. Lots of position beacons were coming through,
but
...
not much of anything else. This is not new; Clayton W5PFG wrote about
this
...
about a year ago, here on the AMSAT-BB list:
http://amsat.org/pipermail/amsat-bb/2016-April/058200.html
For the two passes I worked this afternoon, around 1900 and 2035 UTC,
I
...
...
...
made two QSOs on the earlier pass, and one on the later pass. A shame,
considering there were so many other call signs on the earlier pass,
and
...
...
...
even some rare spots - stations in DM44 in northern Arizona and CM86
in
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...
...
Santa Cruz CA were seen.
It is interesting that hams want to have their stations squawk on
145.825 MHz when nobody is at the keyboard. It could be doing it
24/7, no
...
...
...
matter if the ISS is in view or not. Would anyone think of setting up
their satellite station to automatically transmit their call sign and
location every 15/30/60 seconds to SO-50, unattended? I think not!
That
...
...
...
could be a violation of the regulations, and would definitely be poor
form
...
by that operator.
Bob Bruninga WB4APR has a couple of documents with recommendations for
beacon intervals when working the ISS digipeater. One mentioned a
5-minute
...
interval for unattended stations:
http://www.aprs.org/iss-aprs/iss-tx.txt
Another document recommends that unattended stations should be in
"receive
...
ONLY mode." (emphasis is Bob's):
http://www.aprs.org/iss-aprs/utiquet.txt
I agree with the latter. If your station is unattended, why have it
transmit at all?! It may be different for less-populated parts of the
world, where gateway stations may transmit and then receive their
beacons
...
...
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from the ISS, which will show up on ariss.net and other sites. For
Europe,
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and definitely North America, the gateways really don't need to
transmit
...
...
...
if they are unattended. There should be activity on most passes, maybe
even late into the night, to know 145.825 MHz on the ISS is up and
running.
Please don't misunderstand me... I think it is great for hams to set
up
...
...
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gateway stations listening on 145.825 MHz for the space-borne APRS
activity (ISS, NO-84, even NO-44 when it gets enough power to transmit
complete packets). But these stations, like other stations that aren't
operating as gateways yet transmit automatically, shouldn't
contribute to
...
...
...
the congestion on the frequency.
I know I am in the minority on the ISS digipeater moving back to
145.825 MHz. Between the unattended stations clogging up the frequency
and
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some local interference I hear on 145.825 MHz around my house, having
the
...
...
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ISS on 437.550 MHz was fun! I worked it from home, and on some of my
road
...
...
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trips in the past 5+ months. Even for some of my last NPOTA
activations
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...
at
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the end of 2016. I'll continue to work the ISS digipeater, almost
exclusively with my APRS-ready HTs (TH-D72A, or TH-D74A), looking to
make
...
...
...
QSOs by exchanging APRS messages with other stations. If you can work
packet from your station, and we are in the same footprints, I hope to
hear you (and see you on my screen) soon. Like W5PFG mentioned a year
ago,
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let's get more stations on 145.825 MHz making QSOs...
73!
Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
Twitter: @WD9EWK
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_______________________________________________
Sent via [email protected]. 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: http://www.amsat.org/mailman/listinfo/amsat-bb

Sent via [email protected]. 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: http://www.amsat.org/mailman/listinfo/amsat-bb

Sent via [email protected]. 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: http://www.amsat.org/mailman/listinfo/amsat-bb

Gabriel Zeifman

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