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Re: RE: Eagle




Because I don't want to deal with a 2m sat antenna. It is too big and bulky 
to move in my trailer for Field Day and Satellite demos. My 10ft M2 70cm 
cross yagi is much easier to deal with, along with my S Band dish. I would 
rather spend the money for a L Band amp than deal with the hassle of a 2m 
antenna. I am not even taking a 2m antenna to Field Day this year, nothing 
to use it on here in Atlanta. All our work will be on AO-40, look for us as 
W4BOC 4a GA.

W4SCO


At 07:08 PM 6/18/2003, you wrote:
>W4SCO wrote:
>
>If the uplinks are in the L and V bands and the downlinks are in the U and
>S bands, I would be interested (L/U and L/S and V/U and V/S).
>
>Wayne W9AE replies:
>
>I'm curious why you have such a strong preference for V/U instead of mode 
>U/V.  Most of us don't have a strong preference because we use the same 
>radios and antennas for V/U or U/V.  But there are three compelling 
>reasons why mode U/V may be preferable for Eagle.
>
>1. The path loss for the V-band downlink is less than for a U-band 
>downlink.  When the satellite uses omni antennas near perigee, the ground 
>station doesn't need as much antenna gain to hear a V-band downlink.
>
>2. V-band has high-power intruders in many parts of the world.  So a 
>V-band uplink gets QRM from high power cordless phones and unlicensed 2m 
>FM transceivers (these intruders can be thousands of miles from you and 
>still QRM the satellite).  Presently there are few high-power intruders on 
>U-band, with the exception of the PAVE PAWS radar that occasionally 
>plagues AO40.
>
>3. Mode V/S doesn't make sense for most hams because virtually all of the 
>available S-band downconverters use a V-band IF.  We would need two V-band 
>radios, or we would need to get new downconverters.
>
>The old argument for a V uplink (mode J) originated in Japan where the 
>populated areas had a high V-band noise level that made it difficult to 
>use for weak signal reception.  Japanese hams preferred to have downlinks 
>on the quieter U-band.  Things have changed since then.  Nowadays there 
>are very few high power paging transmitters on V-band (the paging industry 
>is virtually extinct).  And most V-band land mobile users have migrated 
>either to cellular phones or to digital or trunked services on higher 
>frequencies.  The result is that over the years V has become a more 
>desirable downlink band because the urban noise level has dropped.  And 
>over the years V has become a less desirable uplink band because of the 
>growing use of high power cordless phones and unlicensed 2m FM 
>transmitters in Southeast Asia and Latin America.
>
>Wayne Estes W9AE
>Mundelein, IL, USA
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