My current attic situation consists of a 20M dipole, a 30M and two 40M
MicroVerts, and an 80M Hamstick Dipole. Using a homebrew antenna switch, I
can switch between all these and use a tuner in the shack to make everything
look good.

I was thinking of doing the following and am looking for
opinions/sugestions/comments both good and bad.

I would remove all the stuff above and run ~100 ft of 14G insulated solid
copper house wire around the perimeter of the attic. Use the control cable
for the switch to run a Icom AH-4 auto-tuner connected to the wire. The
wire will be run in "T" figure (I'll forgo the ascii art). Basically; West
~15', North 15', East 10', North 15', East 10', South 15', East 10', South
15', and back West near the start of the run. I only have access to the
metal conduit runs on the attic for ground.

This is the setup I had, along with a homebrew balun to feed the coax) for
my SWL days and it worked pretty well. I pulled the wire down when I put
all the other stuff up there but can re-install in any configuration
available. The longest straight run I can make is ~ 35' diagonally. Woulkd
I be better off just running a straight piece rather then all the ziggin'
and zaggin'?? How about putting it up as a big "Z" (25' West, 35'
diagonally NE, then 20' East)??

Any inputs on this plan are appreciated befor I spend the $$ on the tuner.

Thanks,

Tom - AC9TS

"Tom S" wrote in message
...
...I was thinking of doing the following and am looking for
opinions/sugestions/comments both good and bad.

...run ~100 ft of 14G insulated solid
copper house wire around the perimeter of the attic. Use the control
cable
for the switch to run a Icom AH-4 auto-tuner connected to the wire. The
wire will be run in "T" figure (I'll forgo the ascii art). Basically;
West
~15', North 15', East 10', North 15', East 10', South 15', East 10',
South
15', and back West near the start of the run. I only have access to the
metal conduit runs on the attic for ground.

[snip SWL talk] The longest straight run I can make is ~ 35' diagonally.
Woulkd
I be better off just running a straight piece rather then all the ziggin'
and zaggin'?? How about putting it up as a big "Z" (25' West, 35'
diagonally NE, then 20' East)??
Any inputs on this plan are appreciated befor I spend the $$ on the tuner.
Thanks, Tom - AC9TS


I'd go for the long run or perhaps a 90 degree "L" using the two longest
possible lengths.

35' is close to a 1/2 wave on 20 and 2 halves on 10 making it harder to
match (high Z) on those bands. It's nice to keep your antenna away from an
even number of half waves so the impedance isn't too high.

HOWEVER, using the conduit for "ground" means that IT WILL BE part of the
antenna. It will probably be near the antenna. Not good.
It is anther random variable. Not good.

Not being "good" doesn't stop many of us. SO...RF is fickle...try it.
--
Steve N, K,9;d, c. i My email has no u's.

"Tom S" wrote:
My current attic situation consists of a 20M dipole, a 30M and two 40M
MicroVerts, and an 80M Hamstick Dipole. Using a homebrew antenna switch, I
can switch between all these and use a tuner in the shack to make everything
look good.

I was thinking of doing the following and am looking for
opinions/sugestions/comments both good and bad.

I would remove all the stuff above

Leave the old antennas up there. That makes it easy and fun to make comparisons
to see how well your new antenna does as compared to the old.

and run ~100 ft of 14G insulated solid
copper house wire around the perimeter of the attic...

This sounds like you almost have a loop. You might consider trying a random
length loop around the perimeter edge of the roof. one big advantage is that it
requires no ground with which to work against. I have about 200' of wire in mine
which peaks at about 20' up. I feed mine with ladder line, but for short runs
coax is ok as the loss would be small. I lucked out because by using a 4:1 balun
it turned out that my TS870's internal tuner is happy with it on all HF bands
except 80 and 160. For those bands an external tuner works fine. It's no DX
antenna, but I never have any trouble making or finishing QSOs. And compared to
my 40M Hamstick attic dipole, the loop gets on average about a 2 s-unit better
report.

Tom and others,

I'm very interested in what you work out. I just moved into the city and
have an old house with a big attic. There is really no place on the lot
(very small 2500 sg ft lot) to put any antennas. The attic is the third
floor the peak being 30-35 feet above ground. There is no metal in the
attic accept one condiut for a light and the cast iron soil pipes for
venting the drains.

I have an AH-2 tuner that I am hoping I can make work with my kenwood TS-
690S. I do have a little ICOM 760 mobile that I will use if I absolutely
have to but that's really for my car (not currently installed).

So any thoughts on strait or loop. For strait I can go 50' Also should I
run COAX from the main floor to the tuner in the attic and use the castiron
soil pipe as ground OR should I have my 50' straight and then bring the
antenna on the outside of the building down to ground level (inverted L)
and keep the AH-2 in or very near the shack?

Thanks,

Kevin N9JKP



posted and mailed]

Any inputs on this plan are appreciated befor I spend the $$ on the
tuner.

Thanks,

Tom - AC9TS






This is the setup I had, along with a homebrew balun to feed the coax)
for my SWL days and it worked pretty well. I pulled the wire down
when I put all the other stuff up there but can re-install in any
configuration available. The longest straight run I can make is ~ 35'
diagonally. Woulkd I be better off just running a straight piece
rather then all the ziggin' and zaggin'?? How about putting it up as
a big "Z" (25' West, 35' diagonally NE, then 20' East)??