[TenTec] What makes the 238 good or any other tuner good?

[Roger Borowski]

I certainly won't disagree with you and I am also fortunate enough to not
require an antenna tuner on any band but 160 (didn't get the built in
antenna tuner in the Orion as I don't need it).   Not all hams though are
lucky enough to have antennas or the space for antennas that will present a
descent match across all of the amateur bands, and an antenna tuner is the
only option.

My question to Rog is:

What type of antenna do you use on 160 mtrs that will allow descent coverage
of the band without a tuner?   I would think that most 160 mtr antennas that
can be erected by the average ham would require a tuner.

Personally, I have two phased verticals that are 66 ft tall and linear
loaded.  Each have 120 (+ or - a few) radials that are 135 ft in length.
My 2 to 1 bandwidth is 40kc with a  resonant freq of 1840.    A good ant
tuner is the only answer I know of short of putting remote tuned matching
networks at the base of each tower.  Granted, there is some loss in the coax
as the antenna is used above or below 1840,  but it is not something I can
not live with.

Dick K8ZTT

Hi Dick, I have two transmitting antennas for 160 meters at present. One is
a 5/16 wavelength inverted L  that is 68 ft. tall and about 98 ft.
horizontal fed with a remotely tuned vacuum variable at the base of the
insulated vertical section. This antenna also has a vacuum relay at the top
of the vertical section to isolate the horizontal wire and while also
simultaneously shorting out the series vacuum variable at the base by means
of another vacuum relay. This allows operation on 80 meters as a quarter
wavelength vertical. The relay at the top has the coil wires fed through the
center of the 2" mast tubing. I also have a rotary inductor inline at the
base to adjust the resonant point on 80 meters while it is self resonant at
3,870KHz., about as far up the band as I care to operate. To QSY down to
3,505KHz. requires only about 3 1/2 turns of the 3" diameter motorized ribon
inductor. On 160 meters I can cover the entire band with the vacuum variable
remotely tuned with a 3 RPM DC motor and gear drive. For reasons really
unbeknownst to me, with the vacuum variable relay energized to short it out
the series capacitor and just about 1/2 turn of the ribbon coil in series
with the inverted L, I get a flat match and excellent performance on 30
Meters also. This was a suprise discoverery and unexplained bonus! This
system was not perfected in a weekend, but took lots of trial and error with
both relay and mechanical problems to overcome, but it has been operational
to my satisfaction for it's fourth season now. I have approximately 3500 ft.
of  #6 Ga. solid copper wire stretching to my meager suburban lot property
limits from the base of this structure, some as short as 15 ft. and some
bent around the back of the property twice and nearly 200 ft. in overall
length. The actual number of radials is about 60-65 as I started with 16 and
added more as time allowed and saw diminishing results on 160 meters after
48, although 48 seemed better than 32 but had no effect on bandwidth
decrease any more, with 160 meter usuable bandwidth at any given point being
approximately +/- 20KHz.  My total lot size is just a bit shy of one half
acre.
The other 160 Meter antenna, if you will, is simply a gamma match to my 70
ft. tower supporting a TH11DX topside, which provides the top loading for
the gamma matches, I have one on the other side for 75/80 meters also. They
are both fed with remote tuned vacuum variable capacitors mounted in grey
plastic electrical enclosure boxes near the tower base. Both attach to tap
points on the tower at about 55ft. and 42 ft. respectively and are spaced 36
inches from the tower legs on opposite sides. I used IIX Equipment
(www.w9iix.com) model SO-1 standoff brackets on the tower legs and stranded
#4 Ga. insulated electrical down wire. Both cover the entire 160 and 80
meter bands quite nicely. Because of the location of this tower, the
counterpoise system was limited and I find that the other vertical/inverted
L system generally outperforms that of the gamma feeds although on some rare
occasions, I can hear and work stations with the gamma fed top loaded tower
that I cannot even hear on the other antenna, likely due to angle of
radiation being significantly different I suspect. The tower, by the way, is
guyed with 6700# Phillystran but is grounded at the base.
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