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[aprssig] Satellite positions: FREQUENCY

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Mon Oct 17 02:16:36 UTC 2011


On 10/15/2011 4:29 PM, Bob Bruninga wrote:
> So, the format for these courtesy position reports for Satellites should be:
>
> SATNAME>APRSAT:=DDMM.mmN/DDDMM.mmWSCCC/999/FFF.FFFMHz EL %LOW  de KJ4ERJ
>
> This will cause the radio to display the DIRECTION and DISTANCE to the satellie, and its frequency which can be instantly tuned with one button.  And the Kenwoods with voice synthesizer can speak the elevatio angle of HIGH , LOW or MEDIUM if spelled out (I think).

Ok, I just had an aha moment and still need a better explanation....

Isn't the Direction to the current satellite location the Azimuth that's 
already in the query response?  And it's really only needed if you're 
using a directional antenna like a Yagi, in which case you need the 
Elevation from the query message response as well.  And if you're mobile 
with an omni, you really don't care much about the Azimuth but still 
might be interested in the Elevation (hard to work if too nearly overhead).

And the course/speed component, I still question the usefulness of as 
the radios that you're asking for this posit for don't really do justice 
to that either, at least I haven't seen a radio yet that can do 
dead-reckoning?

Elevation low, medium, high is kind of redundant and non-specific with 
the actual elevation that was received in the message.

de KJ4ERJ is just visual fluff that will be in the path of the 
(original, possibly not 3rd party) packet for those that are trying to 
track down the origin.

So, can you tell me again (yes, I'm slow sometimes) just what 
information you actually expect to find helpful in this courtesy 
position packet?  I'm still trying to understand the justification for 
two independant packets on the precious RF channel when it seems like 
the required information is all in (or can be added to) the original 
query response.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

PS.  Yes, I skipped the QSY frequncy because I'm not familiar with how 
many of the birds are single frequency VHF/UHF frequencies.  I suspect 
that the QSY information can't handle satellite UHF/VHF splits, and the 
ISS just isn't on voice FM all that often to be worth sending an entire 
position packet with every query if it's only there for one bit of 
information sometimes.  Oh, and the HF birds aren't really QSY'able 
either, are they?




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