I started the first round of antenna work getting the 80 meter half square
back up and replacing the final piece of coax to my 160 loaded half wave
dipole L. SWR on the half square is OK and I am also back on 60 meters
making a few contacts late Saturday night.
I checked the SWR on my 160 L (made from a Spi-Ro dipole that is only 100
feet long). I last used the L to work PY3CEJ in late May. The first thing
I noticed is the antenna low SWR changed from 1840 to below 1800 (1.2 min at
1792). SWR went above 2 to 1 at 1822 and was out of sight by 1860. Using
my Ten Tec 229 tuner I don't have enough capacitance to tune out the
inductive reactance. The manual says add a 1000pf transmitting mica or
ceramic cap (there is a place on the rear of the tuner for this). I have
two 300 pf which I put in parallel and the SWR can be tuned flat on 1850 and
stays below 2 to 1 to 1875. At 1900 its 4 to 1.
If anyone has a 1000pf cap that is transmitting quality (the micas I use are
3750 wvdc) please let me know. I have a 500pf 10KV doorknob but three caps
in parallel looks sloppy and I don't trust doorknobs at RF which is AC
(although Ten Tec uses 6KV DC caps and I have blow them using my old 160 L).
The L is mounted in a tall tree and the horizontal portion has leaves all
around. It may go back up in frequency when the leaves fall off.
73 Dave K4JRB
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