[Antennas] Need antenna info

[Charles Greene]

At 04:28 PM 1/26/2002 -0500, IamSF5@aol.com wrote:

Bob,

A few antennas come to mind:

1. Off-Center-Fed antenna 135' long with the feed point at 90' and 45'  Put 
a 4:1 balun at the feed point and use coax the rest of the way down.  It 
helps to have the balun at the support as it is heavy.   I used to have one 
here and it worked super.

2.  A dipole fed with two coax wires.  Connect the center conductor of each 
coax to dipole and leave the shield unconnected at the top and connected 
together at the bottom.  Tune in the shack with an antenna tuner.   Use a 
4:1 balun or 1:1 at the antenna tuner if your antenna doesn't have a built 
in one, or if you have RF in the shack, put the balun near the base of the 
antenna.  I had one 40-10 and it worked very well.  It could have been on 
80-10.

3.  A third is to just feed a dipole at the antenna with coax, but I've had 
trouble loading this type of antenna where it was a high impedance at the 
antenna (2nd, 4th harmonics).  Or try a 1:1 balun at the top.  Same caveat.

4.  Use a trap dipole.  You can buy a commercial built one.

5.  Use a W9INN antenna.  He has at least one if not more models to cover 
80-10/15, of different lengths.  I used one on field day and it works FB.

6.  Make your own multiple dipole antenna, using separate wires for each 
band, except for 40/15.  Try to find one from QST or another magazine, as 
with several wires which is necessary to get the WARC bands, it's difficult 
to avoid interaction between them.

For performance the best bet is the OCF antenna as it has a 200-300 
impedance on most bands and a low SWR on the coax of less than 2:1 which 
means low losses in the coax.  Some of the antennas are more obtursive.  If 
you are into building your own balun, there are enough of them to be found 
on the internet.

GL


>Hi Guys/Gals,
>Can someone tell me what would be a good antenna for 80 through 15 meters and
>can be used with coax?
>I have to use coax and that is a must because the management wants no wires
>near the edge of the roof where someone can trip and fall over the edge.
>I can bury the coax under the stone thats on the roof and bring it over the
>edge and drop it down.
>So far all I see on some sites say to use ladder line.
>Any help is greatly appreciated.
>Thanks
>Bob

73, Chas, W1CG