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Re: Satellite Downlink Power Combiners?



Concerning feeding multiple XMTR's into one antenna...

On Mon, 23 Sep 2002, Howie DeFelice (and others) wrote:

> I have done this both ways, using a high power combiner (6 dB loss per
> port) and using linear amplifiers (equally poor efficiency)

Poo.  As I feared.  But then if we took the same four 5W XMTRS and ran
them to their own antennas, then we wouldnt have these losses.  But I
guess if we have to colocate them all very close together, the mutual
coupling sucks up all that power as losses in the others.  Or the worst
case of intermod you've ever heard?... So there is no easy out. :-(

I guess one way is to combine two to a vertical whip and two to a
horizontal whip and then hopefully they would be orthogonal and avoid
about half of the power loss.  But again, there  may be so much near field
coupling as to still cause problems?  These four transmitters would be
operating full duplex with multiple receivers in the 435 MHz band...

de WB4APR, Bob


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