[AMPS] exciter to amp coax length

Tom Rauch W8JI@contesting.com
Fri, 10 Mar 2000 10:20:15 -0500


> Sure, and in this case the original indicated input SWR was more like
> 1.5:1 than 1:1, hence the length of feedline mattered.  I'd still like to
> know why a higher indicated SWR (on the TS-930) translated to higher
> output, plate current and grid current on that one band, but for now it's
> enough just to have things back behaving normally...

Most solid state rigs are conjugately matched at an impedance 
higher than 50 ohms. That's so the rig will remain linear if the load 
impedance is slightly above 50 ohms.

The only penalty is excessive current in the exciter's PA stage 
when driving lower impedance loads, and a slight loss of efficiency 
driving low Z loads.

Ignoring SWR shutdown systems, most broadband exciters like to 
see an impedance somewhat higher than 50 ohms.


73, Tom W8JI
w8ji@contesting.com

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