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 bruninga@usna.edu 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:amsat-bb-bounces@amsat.org] On Behalf Of Patrick STODDARD (WD9EWK/VA7EWK) Sent: Saturday, April 15, 2017 7:51 PM To: amsat-bb@amsat.org 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 AMSAT-BB@amsat.org. 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 AMSAT-BB@amsat.org. 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