I keep cutting and cutting - and it is still too short
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com]On Behalf Of Dale Martin
Sent: Saturday, December 09, 2006 3:05 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 160m inverted l
If you've got an antenna analyzer like the MFJ-359, you can see where the
SWR is minimum. Cut off a few inches of antenna. See where the new minimum
SWR point is. Then you can figure how many kHz per inch the minimum SWR
point will move with each subsequent cut.
For instance, cut off 6 inches of antenna and find the minimum SWR moves
from 1818 to 1824. So, the kHz per inch is 1 kHz per inch. If you take off
six more inches, the minimum SWR moves to 1830, or 10 inches to move to
1834, etc.
Of course, it pays to be conservative when your are cutting wires, so always
cut for a lower frequency than the actual target until you get with a couple
of inches.
For my 1/4-wave half-sloper on 80, instead of cutting the wire to move it
into the phone band, I simply bring the antenna end back on itself to
shorten the overall antenna. I use the same method of calculating how much
will move how far, but without cutting the wire. :-)
73,
Dale, kg5u
>
> > John:
> >
> > Start out with about 130 feet of wire and trim about
> six inches at a
> > time until you get the min SWR where you want it in the
> band, usually
> > around
> > 1830 kHz or so. You should end up with something around
> 123 feet of
> > length
> > but that depends on the usual antenna things like
> everything else that's
> > around the antenna, etc. .
> >
> > 73 de
> > Gene Smar AD3F
> >
> >
> > ----- Original Message -----
> > From: <ny6dx@aim.com>
> > To: <towertalk@contesting.com>
> > Sent: Friday, December 08, 2006 9:27 AM
> > Subject: [TowerTalk] 160m inverted l
> >
> >
> >> I am trying to figure the length of inverted l using #12
> insulated wire.
> >> I
> >> come up with 120 ft is this right?
> >>
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