RW> RW>> If I tune an antenna with the swr bridge at the antenna and then
RW> RW>> place the swr bridge at the other end of the coax, there's a
RW> RW>> difference. 1.2:1 at the antenna, 1.9:1 at the tx. No amplifier,
RW> RW>> No antenna tuner, no etc.. Now what do I tune to get 1.5:1 or
RW> RW>> less at the tx?
RW>I don't have a bridge, per sey.  It's a Bird 43 wattmeter, which I have 5,
RW>25, 50 and 100 watt, VHF/UHF slugs for.  A little too large to connect to 

RW>VHF/UHF antenna.  I use a piece of (RG8A) coax cable with teflon
RW>connectors, cut to an uneven number of multiple half-wave lengths.  In 
his
RW>case, it's a UHF antenna and the test coax is 7 half-wave lengths long.
RW>(.66 x 246/F(460MHz)=4.235" x 7 = 29.65" long, connector end to connector
RW>end.
RW>I haven't cut the test coax for this frequency, as I figure the one I have
RW>cut for 445MHz (30.65") should be close enough.  Also, my antennas don't
RW> FM>      If you replace the antenna with a good dummy load, is the SWR at
RW> FM> the transmitter end of the cable still 1.9:1?  That would suggest a
RW> FM> conflict between the design of the SWR bridge and the characteristic
RW> FM> impedance of the cable.
RW>The wattmeter and test coax are 1.0:1 into either one of two oil filled,
RW>50ohm dummy loads.  With the site coax between the transmitter and
RW>wattmeter into the dummy load, the swr goes up.  With the antenna
RW>connected, it goes higher.
RW>Except for a few long hard-line cable runs to the top of a 200ft tower,
RW>most of the antennas I sell are used near the 50 foot or lower level and
RW>are fed with 9913 or RG8A.
RW>I suspect the site cable used has been contaminated by weather as the
RW>antenna checks out perfectly under all my tests.  I've suggested the owner
RW>switch to a new piece of RG8A or 9913 cable and try again.
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I think that you are correct, there is something wrong with the cable or
connectors.  Try putting the watt meter and dummy load at the antenna
end and measuring the power lost in the cable.  If the system is 50
ohms, then the swr readings can only go down as you move away from the
antenna unless you just hapen to hit some unusual spot in the coax.
If the antenna is only 50 or so feet from the antenna it should not be
too hard to replace it and it should only cost around $ 50 or less for
the coax and connectors.  Shouldn't take too much time to scoot up the
tower and do a temporary install.
Not to tell you anything you don't know, but that 9913 type can fill up
with water very easy.  That will throw the readings way off, especially
if there is a low place in the coax and the water is collecting
somewhere up the line.
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