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

Stefan Wagener wageners at gmail.com
Sun Apr 16 01:43:53 UTC 2017

Hi Patrick,

Thanks for your post and feedback. It is much appreciated.

 I am too looking once in a while for an ISS contact. On the other hand, I
have realized that many stations are actually on the keyboard and they
answer, but I don't decode it on my system and they might not either. I see
it later on the web. In addition, folks are not that quick in response also
and trying to type an answer and get a packet out especially on a less
elaborate station is not always easy. Yes, I am using UISS with
pre-recorded answers and a quick mouse click but I still need a few tries
to sometimes see or hear my own packet repeated. So, bottom line for me, be
happy for the few contacts and help others along :-)

73, Stefan, VE4NSA

On Sat, Apr 15, 2017 at 6:50 PM, Patrick STODDARD (WD9EWK/VA7EWK) <
amsat-bb at wd9ewk.net> wrote:

> 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
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