After a period of inactivity, I set out to get my station going again. The
Beverages were not working with very low signal levels and I replaced 600 foot
RG6 feedline from shack to Beverage switch in the woods with new RG6 which
still had the plastic wrap around the spool.
I was surprised when things were no better. The "new" coax is not right. The
TDR sweeps show a straight line increase in impedance from 78 ohms to 95 ohms.
There are no impedance "bumps" seen. The 400 feet left on the spool do the same
thing as does 800 feet of the same stuff bought at the same time.
This stuff was bought on Ebay and is gel-flooded RG6 labelled "Commscope Inc.
GA390709 and GA3907022." I bought it in Sept 2014 and it has been stored ever
since in a dry heated basement.
Using an oscilloscope as a TDR I see that the impedance line is not level as
with good coax but slopes upward at an angle. I also checked by placing a 330
ohm resistor at the end of the cable and ran an SWR trace from 1-8 MHz with the
SWR only 2-2.5.
Why is this cable so lossy? Was it bad to begin with or did it deteriorate in 7
years?
What recommendations for good RG6 can anyone make. There has been lots of
critter chewing upon cables in the past so I guess gel-flooded cable would be
preferable. Should I spend $230 for DXEngineerings good stuff or can I get by
cheaper?
p.s. I went out and checked each Beverage at the switchbox today and 4 out of 6
were great. Only 3" of snow and temp was about 25 deg F. I was able to keep the
snow and dielectric grease off of my laptop.
73, Charlie W2GN
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