[Antennas] My W3EDP

2002年5月22日 06:29:29 -0400

At 09:00 PM 5/21/2002 -0400, Joe Falcone wrote:
Joe,
You don't say whether the 4:1 is with an antenna tuner of not. Without a 
tuner, 4:1 sounds about right, on some bands. I have one, and I can load 
it from 160 to 10 using a 4:1 balun at the intersection of the 85' wire and 
counter poises (8', 17' and 67'), and about 25' of RG8X to a tuner. The 
tuner is either a LDG Z11 or a KAT2 (on a K2). The antenna was designed to 
be used with a tuner. Before I used the coax, I brought the wires right 
into the shack and used a MFJ 900 tuner which couldn't get a 1:1 SWR on all 
bands, I forget which, but that's more an indictment of the tuner than the 
antenna. The 8' and 67' counterpoises helped a little on 10 and 80. The 
antenna is very inefficient on 160 because lack of a good ground and low 
radiation resistance. If you start adding wire, you can get a SWR better 
on one band at the expense of one or more other bands, as the wire gets 
closer to odd multiples of 1/4 on one band and farther away on some others.
>I have the same question as the fellow who was trying to load the 90 foot 
>wire on 160 meters.
>>I got a 85 foot length of commo wire, (this stuff is all steel stranded) 
>and ran it from the tuner out through the wall (maybe about ten feet is 
>inside), up through the one tree to another tree. Secured the end with a 
>piece of black nylon rope. Then I had the 17 foot counterpoise laying on 
>the floor around the edge of the floor.
>>The best I can get this SWR down to, using the autek antenna analyzer, is 
>about 4.0 to one. Now, I am not saying that this super bad or unusable, 
>but I thought that I should be able to do a little better than that. When 
>I get it to the lowest SWR I can which is about 3.0 to one, the frequency 
>is about 7.190.
>>First of all, I imagine I should add a little wire. But what then?
>>By the way, the antenna does get out in that I can communicate with it.
>>Joe.

>
73, Chas, W1CG