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:
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 <
wrote:
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:
I agree completely. ISS digipeting should be for LIVE operators. Or
for
LIVE things.... (a student experimental ocean going buoy for
example)...
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
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
I was not jumping up and down with excitement. Unfortunately, after
seeing
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,
almost all of the unattended stations that had been present on the
145.825
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
memory channels to compensate for Doppler, and were making contacts.
Some
fixed stations, including those already capable of satellite
operating,
were also showing up. Even on the busier passes, the 437.550 MHz always seemed to be clear of the clutter from the
unattended
stations that previously inhabited 145.825 MHz.
Fast forward to yesterday (Friday, 14 April). The ISS digipeater
switched
to 145.825 MHz in time for afternoon/evening passes over Europe
(around
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
afternoon. At best, there may have been 4 or 5 other operators at
their
keyboards or keypads, looking to make contacts. The others were just squawking away, not answering APRS messages sent
to
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
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
from the ISS, which will show up on ariss.net and other sites. For
Europe,
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
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
some local interference I hear on 145.825 MHz around my house, having
the
ISS on 437.550 MHz was fun! I worked it from home, and on some of my
road
trips in the past 5+ months. Even for some of my last NPOTA
activations
at
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,
let's get more stations on 145.825 MHz making QSOs...
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum
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AMSAT-NA.
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Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership.
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expressed are solely those of the author, and do not reflect the official views
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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.
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of AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite
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Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb