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[aprssig] CNSP-18 via ISS can work (FREQ MAP)

Robert Bruninga bruninga at usna.edu
Wed Dec 5 00:54:06 UTC 2012


I overlayed a sketch of three 145.825 LAT/LONG boxes on G6UIM's APRS Freq
Map that could shift FREQS over the Atlantic with 3 IF-THEN lines for the
three freqs 144.39, 145.825, and then 144.800.

See: http://aprs.org/transatlantic-freqs.GIF

Bob, Wb4APR

-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Steve Daniels
Sent: Tuesday, December 04, 2012 6:41 PM
To: 'TAPR APRS Mailing List'
Subject: Re: [aprssig] CNSP-18 via ISS can work

The idea proposed is to switch frequency based on Longitude, set two
longitudes, if you are West of both transmit on 144.390, west of one and
east of the other transmit on 145.825, east of both transmit on 144.800.
Easily implemented, cycling through the frequencies "wastes" two thirds of
the beacons, when you are using low mass kit and have limited battery life
you really need every beacon to hopefully be received. As you are
attempting
to gate through people who don't know you exist, and even asking people
who
do know to constantly sit at the radio changing frequency is a bit much.

When using the ISS you hopefully hit a satgate, and the ISS of course, but
with a reasonable beacon rate you stand a chance, which is better than
nothing at all. And of course with the footprint of the ISS can can more
easily organise a few stations to monitor.
Transalantic flights take a few hours so you would hopefully get some
packets through and received on a pass of the ISS that's also within range
of the USA or Europe.

At least one designer is hoping to implement a scheme


Steve Daniels
Amateur Radio Callsign G6UIM
Torbay Freecycle  Owner
http://uk.groups.yahoo.com/group/torbay_freecycle
APRSISCE/32 Beta tester and WIKI editor http://aprsisce.wikidot.com


-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Robert Bruninga
Sent: 04 December 2012 23:02
To: TAPR APRS Mailing List
Subject: Re: [aprssig] CNSP-18 via ISS can work

> I can't think of any way to have the [ISS]radio capture
> the Balloon's packets reliably since there would be so
> much traffic...

No, the only time the ISS is needed is away from land and there is no
other traffic out there.  Also, the ISS digi already supports WIDEn-N
digipeating as it is, so it would work as long as the radio was switched
to 144.39 or whatever freq the balloon was on.

But then the coordination to get the ISS crew to do such a simple thing at
exactly the right pass over the middle of the atlantc, would take a
month's planning.... IE, practically impossible.

The easy fix is to have trans-atlantic balloons ALTERNATE between
144.39/(144.80) and 145.825 on every other packet just for this case.
Then no one has to do anything, but monitor the ISS when it passes over
the Atlantic.

Bob, Wb4APR

--- John Ronan  wrote:

> Afternoon,
>
> Silly question,
>
> Would there be any possibility to get the ISS to listen for
> trans-atlantic balloons, even if just to verify if they are
> still transmitting?
>
> Cheers
> John
> EI7IG


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