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Old December 6th 11, 02:50 AM posted to rec.radio.amateur.antenna
Wayne Wayne is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 409
Default Feedline suggestions?



"J. C. Mc Laughlin" wrote in message
...

Dear Wayne (no call sign given): The use of "it" causes an ambiguity. If
the antenna tuner is "at" the antenna feed point, then 25 feet of RG-58
running to the shack will contribute very little to the overall loss of the
system.

A colleague has had success with an insulated wire on his roof fed in the
middle with an auto-tuner. The coax from the tuner has several type 31
chokes to kill common mode and the coax itself contributes very little to
the performance of the system.

On the other hand, such a short antenna as you are using (on the lower
bands) fed with RG-58 from a tuner in the shack is expected to have
significant losses. If this is the case, moving the tuner outside should
be tried.
73, Mac N8TT

-
Yes, the wording is confusing. The antenna is fed with about 25 feet of
RG-58 with the tuner next to the rig in the shack. The cable will be
changed to RG-8 tomorrow assuming that the winds finally die down here in So
Cal.

On 10 and 12 meters the performance is quite acceptable. I'm not the big
signal on the band, but it works well.

I'm hoping to slightly lengthen the antenna and get performance from 17 to
10 meters. Since the tuner to antenna VSWR will be very high, I'm pondering
ways of lowering the loss.

A separate loaded whip is used on 20 and 40 meters.

So far, the experiment has been good, and it is one of the few antenna
configurations that meet the established requirements. (established by the
xyl)

Thanks
Wayne
W5GIE /6








"Wayne" wrote in message ...

I am using a whip antenna mounted on a metal patio cover. Results are
good
on 10 and 12 meters, and contacts have been made down to 40 meters.
(Matches were not obtained on 15 or 30 meters) The whip is 8.5 ft long (a
longer whip is under consideration). It is fed through an antenna tuner
and
about 25 feet of RG-58. I'm about to replace that with RG-8.

Any comments on how to hold down feedline losses. One suggestion is to
use
two parallel lengths of RG-8 so that half the current runs through each.
Also, site geometry would allow open wire feed.

Possibilities?