[amsat-bb] APRS Messaging QSOs

[Patrick STODDARD (WD9EWK/VA7EWK)]

Robert,

There are a few issues at play currently...

1. Availability of orbiting digipeaters. The current ISS packet system
appears to be hard of hearing. It can hear strong signals, and those
with lower-power stations - like the APRS-ready HTs - are only able to
get through on the higher passes. If the new ISS radio and power supply
are installed and set to operate an APRS digipeater, this issue with
the ISS digipeater may go away.

Besides the ISS, NO-84's digipeater is rarely on. FalconSat-3 is
available, but that requires more sophisticated radio gear due to its
use of 9600bps packet and operating cross-band. FalconSat can be worked
with just a Kenwood TH-D72 or TM-D710G, as those radios support cross-
band packet at 9600bps, and (try to) do that full-duplex.

2. Unattended stations. This has been an issue for a long time on
145.825 MHz. It is not legal for US stations to operate in the
145.800-146.000 MHz and 435-438 MHz subbands unattended, yet it
happens. I referenced this in articles I wrote for the AMSAT Journal
and QST in the past couple of years, and those are available from the
"Articles" folder in my Dropbox space at http://dropbox.wd9ewk.net/

3. Button-pushing. It can take many presses to generate a very short
message using a DTMF keypad on APRS-ready radios. Some of the radios,
the Kenwood HTs and mobile radios in particular, provide a way to store
prepared messages (they are called "phrases" in the Kenwood manuals)
that can be called up with fewer button presses. Others use programs
like UISS on a Windows system to handle APRS, including messaging.
UISS can work with software like AGWPE or SoundModem, avoiding the need
for a TNC.

The APRS messaging protocol takes care of showing the sender and
recipient. This can leave the message text to convey information like a
grid locator(s) and state, or a "TNX/73" at the end of a QSO. The AMSAT
Journal article I co-wrote about packet on the TH-D72 and TH-D74, which
is available from:

https://www.amsat.org/station-and-operating-hints/

described my message setup. I store 3 prepared messages in my radios,
and normally use two of the 3 in making QSOs, following the process
outlined in AMSAT Field Day rules for a complete QSO.

A small computer could be useful here, allowing more radios to be used
with the orbiting packet digipeaters. A TNC probably isn't needed, if
the audio hardware on the computer is connected to the radio's speaker
and mic jacks. If the small computer could compile a list of stations
heard, and the user could select one of those stations for a message,
that could reduce the button pressing needed to send messages.

Hoping for the new ISS radio and power supply to be installed and
activated soon...






Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
Twitter: @WD9EWK or http://twitter.com/WD9EWK






On Wed, Aug 26, 2020 at 7:02 PM Robert Bankston via AMSAT-BB <
amsat-bb at amsat.org> wrote:

> It's a shame that their are not more APRS messaging satellite QSOs being
> done via ARISS and other satellites.  Is this because...
>   * Lack of equipment?  * Erratic operational schedules?  * Proliferation
> of non-attended stations (beacons)?  * Too much button pushing?
> Most ops you an HT and very few of those have APRS messaging capability.
> Those HT's that do (including mobiles) are a bit clunky and require fast
> thumbs to complete all of the necessary steps to complete a QSO.  Of course
> the more you do it, the more second nature it becomes, but that circles
> back to the erratic scheduling.
> One solution could be to develop an app or software with prescribed
> message formatting and QSO automation, similar to similar FT8.
>   (click on target call in station list)  * [Target Call] [My Call] [My
> Grid]  * [My Call] [Target Call] (Target Grid]  * R [Target Grid]  * RR [My
> Grid]  (click on log QSO)
> Single board computers could easily handle the task (even the Pi Zero),
> for those worried about keeping their station small. Only thing left would
> be a microarduino TNC or soundcard and a couple cables to the HT mic and
> earphone jacks.
> Just a thought.
> 73, Robert KE4AL
>
>