In a message dated 04-07-97 ROY WITT wrote to JEFF EDMONSON:
 RW> If I tune an antenna with the swr bridge at the antenna and then
 RW> place the swr bridge at the other end of the coax, there's a
 RW> difference. 1.2:1 at the antenna, 1.9:1 at the tx. No amplifier, No
 RW> antenna tuner, no etc.. Now what do I tune to get 1.5:1 or less at
 RW> the tx?
  Roy-
     Could it be that you tuned the antenna with the bridge at the antenna
end of a test cable?  With VHF/UHF antennas, I would expect the presence of
the meter and/or your hands, would affect tuning of the antenna.  When you
remove the bridge from the vicinity of the antenna, the antenna's SWR may
actually be higher.
     If you replace the antenna with a good dummy load, is the SWR at the
transmitter end of the cable still 1.9:1?  That would suggest a conflict
between the design of the SWR bridge and the characteristic impedance of the
cable.  Assuming a good bridge and the correct cable impedance, I would
expect a long run of cable to appear to lower SWR due to losses, not raise 
!
     What if you separated the antenna from the bridge by a convenient length
of cable, like one wavelength?  That should be close enough to avoid cable
losses, yet not be so close as to affect tuning.
     73, Fred, K4DII
 -> Alice4Mac 2.4.4 E QWK Eval:30Sep95 
Origin: Alice strikes back @
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