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Re: Re: AO-40 V-Rx




>Wayne replies:
>
>As the AO40 schedule shows, the VHF uplink is only on when the transponder
>is off.  I think it is used primarily to control the RUDAK.

This has been covered here before (we do need a FAQ!).  The V-Rx is on 
during these times for RUDAK and for command station use.  It is prudent 
command practice to cycle receivers.....

>I don't know
>why the VHF uplink isn't enabled when the transponder is on.

Also covered here before.  The V-Rx and the U-Rx cannot be active at the 
same time!  They are both controlled by a single bit, telemetry byte #1CA, 
bit2 (1 = VRx on, 0=URx on).  You can see this info. in P3T if you rest the 
cursor over the U-Rx or V-Rx entry in the Status window.  This is a safety 
feature to prevent being able to turn them both off and losing the command 
link.  Because the great majority of downconverters in use have an IF near 
145 MHz, using the 145 MHz uplink would create SEVERE desense.  For this 
reason, we have favored 435 MHz uplink.

>The VHF uplink is deaf, so a LOT of power would be required to use it.

This is ABSOLUTELY INCORRECT.  There is no problem whatsoever with V-band 
receiver sensitivity.  Where does this stuff come from???



-- 
  ________________________________________________________________________
  Stacey E. Mills, W4SM    WWW:    http://www.cstone.net/~w4sm/ham1.html
    Charlottesville, VA     PGP key: http://www.cstone.net/~w4sm/key
  ________________________________________________________________________

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