Greetings from Singapore. I have been toying with the idea of trying 160m for a
few years now. My setup is a 270 foot doublet with 35 feet of open wire feeder
to an SG-235 500 watt autotuner mounted on the roof of my apartment. The tuner
is balanced with 30 feet RG213 coax wound on an 8 inch plastic pipe, then
another 70 foot coax run to the shack. The tuner has been modified so that it
can push out 600 watts true CW for a normal ragchew duty cycle without damage.
My rig is a K2/100 with a homebrew 600 watt transistor linear.
This has all worked fine from 80-10m and I have been quite successful on these
bands. However, the SG-235 will not load on 160m due to a lack of L in the
circuit (it needs at least 300 feet either side of the ladder line to affect a
match).
I am planning to construct a remote controlled balanced tuner using 2 x 28 uH
roller inductors and a 500pF vacuum capacitor in the near future to get me on
160m.
My receive antenna is a 20 foot diameter horizontal loop mounted below the
doublet, with a homebrew loop amplifier similar to the Wellbrook ALA 100.
I don't have space for a better loop - the area on the top of my apartment is
quite small, but I have permission to string the big doublet across the roofs
of the adjoining units.
Before I go down the homebrew remote tuner route, does anyone know a way I
could get the SG-235 to perform on 160?
Also, is the effort worth it when you consider that the doublet is only 35 feet
above the roof ( although both arms are 70 feet above ground in places where
the apartment units are separated).
I know from experience on 80m that noise is a huge problem here. It was the
main stumbling block for 9V1GO a few years ago when he was on topband.
Any thoughts and advice welcome.
73 de
John / 9V1VV
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