[amsat-bb] Fw: Re: New Satellite Downlink?
mspencer12345 at yahoo.ca
Sun Aug 29 08:36:31 PDT 2010
In my oppinion, I don't see much difference between the military broadcasting on
this satellite to hams and cross band HF contacts with military stations where
the military transmits on their own frequencies knowing that hams are listening.
Granted in some places it may not be legal to listen to 149.985 or for hams to
listen to non amateur broacasts but that is another issue.
If only the military can uplink to this satellite then I would expect that they
are accountable for what gets broadcast.
----- Original Message ----
From: George Henry <ka3hsw at att.net>
To: amsat bb <amsat-bb at amsat.org>
Sent: Fri, August 27, 2010 4:28:02 PM
Subject: [amsat-bb] Re: New Satellite Downlink?
Question: since there is no amateur radio allocation at 149.985, "we"
(hams) would be asking the Navy, to whom the downlink frequency is
allocated, to transmit one-way amateur communications thru this satellite,
Doesn't anyone else see potential legal problems involved here?
----- Original Message -----
From: "Robert Bruninga" <bruninga at usna.edu>
To: <amsat-bb at amsat.org>
Sent: Wednesday, August 25, 2010 11:27 AM
Subject: [amsat-bb] New Satellite Downlink?
> Possible new AMSAT Application?
> We may have access to two old TRANSIT navigation satellites with
> a 50 baud downlink at 149.985 (and 400 MHz). (presently coming
> over in the mid afternoon). My problem is, coming up with any
> meaningful application to use them for communications that would
> capture the interest of students, hams or volunteers in support
> of education, public service or emergency comms or just plain
> The downlink can be heard on an OMNI antenna (though I would
> suggest a 3/4 wave (55") vertical) and could be decoded by a
> simple software only application with a sound card. (someone has
> to write it)...
> The total useful message capability is about 500 bytes
> transmitted every 2 minutes (at 50 baud). The uplink is very
> specialized and can ONLY BE DONE from one (or two) very special
> commmand stations. These satellites of course were the original
> Navy Navigation satellite system (also called OSCARS) and so the
> message would be in-place of the normal navigation data. SO in
> a sense, this is a downlink BROADCAST application. Since ham
> radio is two way, I'm stumped for applications.
> The total message capability of 500 Bytes can contain one long
> ARRL bulletin, or 20 APRS position/status reports, or say 20 or
> so APRS text messages, or say 50 "callsign exchanges" or maybe
> even 1 thumbnail image... but what's the application?
> Even if we allow say, INTERNET link to the command station for
> "anyone" to contribute to the twice per-day upload, then
> everyone's receiver application can receive them... For what?
> So Im looking for ideas. All I can come up with so far is:
> 1) ARRL Bulletins? (I don't even know how often ARRL sends
> 2) Navy/Army/AF MARS broadcast bulletins...
> 3) Internet message in-to-command-upload-to message RF downlink.
> Two stations do this to each other and it counts as a two-way
> 4) ...
> Every scenario of interest usually begins with the much higher
> value of UPLINK from the individual field station, not
> downlink.. Hence I am stumped.
> HUMMH... Maybe purely educational? If the software can run on
> any PC with a sound card connected to any scanner... Then every
> school can use it as a satellite downlink signal of interest..
> What kind of thumbnail image can fit in 500 bytes? Send in your
> picture and get it downlinked on a given day?
> Will need a DSP volunteer to write the sound card decoder.
> Bob, WB4APR
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