If I had an up 125 out 125 wire out in the clear on 160m, I'd keep it.
Questions would be how you were feeding it, did you have brick wall
common mode block to keep the antenna from using the feedline as a
radial, and whether it was suspended next to a tower.
Putting up a 160 wire using a tower as support is the kiss of death.
It becomes a glorified miscellaneous tower matching scheme, usually to
a tower that has not been prepared for that (60 buried radials, etc).
Unless you are FEEDING the tower as a radiator, keep 160 antennas AWAY
FROM TOWERS.
Two 130' radials will turn nearly any antenna into a dummy load. Do
NOT do this. That will put anywhere between 30 and 70 ohms resistive
in series with your radiator. Your counterpoise should display no
more than one or two ohms series resistance. It is possible to do
this even in confined spaces. Wimp radials like this can be used
against a very High Z feed, e.g. 450 ohms where 70 in series with 450
is only a 15% loss, but there just is no need to do that.
Unless you have a dense radial field below, you want the 1/16 wave
with the current max in it at the top of the vertical run.
On 80 meters there is a great deal of anecdotal evidence that
describes an end-fed halfwave L performing better than the models. It
probably has something to do with getting the current max above ground
clutter, though my personal official line is "not currently explained,
while too persistent to ignore".
Up 125' and out 110 puts the current max in the top 1/16 of the
vertical run, and produces a feed R in the 300, 350 +J500 magnitude,
which can be matched by a coil from ant to ground and cap from ant to
feedpoint. In NEC4 this produces a low angle radiation that is less
than 1 db below a reference commercial 1/4 wave with 120 buried 0.4
wavelength radials run with the same environment description.
Effectively shortening your antenna to move it's current max to the
bottom and then counterpoising your antenna with two 130' radials will
be a disaster.
73, Guy.
On Tue, Nov 30, 2010 at 2:30 PM, <w7dra@juno.com> wrote:
> here is what i plan to do, i hope i have the correct procedure
>
> at present i have a 1/2 wave inverted L up 125 or so and over 125 or so,
> can't remember what exact dimensions are
>
> i plan to drop the far end and pull it back to the bottom of the tree, so
> i have a kind of fat 1/4 wave wire.
>
> should be off the ground by about 20 feet (ladder high!), and should be
> about 15 feet wide at 3/4 the way up the tree
>
> attach two 130 foot radials and connect with RG8 coax down to the shack
> about 30 feet away
>
> make a two or three turn loop at the end of the coax and check resonance
> with my heathkit grid dip oscillator
> ( i could fire up the 833a and find the freq where the SWR is lowest?)
>
> change length of the antenna until resonant at 1.8 mcs
>
> and i will be good to go
>
> any suggestions from you good people?
>
> i live on the side of a cliff and only two radials can be run
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