On Thu, 1 Apr 2004 11:58:42 -0500, "Macman"
wrote:

My SWR's are basically flat on the lower end of the 2m scale, but there is a
significant jump starting at 146.000 thru 147.999. Starting at 147.000,
it's pushing the 3:1 threshold and going over the 3:1 threshold the higher
in the freq band I go.

I have a discone antenna and would like some suggestions as to tuning
methods. From what I know, if the SWR's are high on the 'top' end of the
range, the main vertical whip needs to be trimmed.

Does that sound right or is there something else I need to check on first?

Thanks.


Hi OM,

There is no "tuning" of Discones. They are what they are,
broadbanded. Their lower frequency of use is basically defined by the
length of the lower skirt elements (verging on quarterwave). The
higher frequency is more a function of the feedpoint gap between the
disc and the cone. If this is adjustable, you are in luck. If it is
not adjustable, something else is broke.

As you describe a vertical whip, that is NOT the usual part of a
Discone, but is a means to offer an even lower single band's coverage,
usually 6M. It's addition is not a bonus at higher frequencies (and
may actually make the antenna deaf). However, this has nothing to do
with SWR. If this is a 6M addition, and you have the option of
removing it entirely, try that.

73's
Richard Clark, KB7QHC