On 10/13/10 1:14 PM, Owen Duffy wrote:
Mike wrote in :

The big question I have always had regarding the balun was are we
reducing performance by eliminating feedline radiation? For a lot of
antennas, that may be a big part of the antenna system.

Claiming feed line contribution to radiation as a performance factor is
usually a specious claim, and more likely to be made by someone with a
commercial imperative than a genuine interest in radiation performance. You
know, if you can't solve a problem characteristic, call it out as a
feature.

I don't disagree, but certain antennas - the EH antenna comes to mind,
which resemble a tuned circuit on a stick. Get rid of the feed line
radiation, and you almost get rid of the whole antenna. But like you
say, its a "feature".

It's also not good practice.


In this case, feed line radiation would usually skew the pattern upwards,
not necessarily a desirable feature, probably not desirable in most
situations.

Not too desirable. Thanks for the clarification. Mine was a general sort
of response, not limited to this antenna.

- 73 de Mike N3LI -

On Oct 13, 1:42*pm, Mike Coslo wrote:
On 10/13/10 1:14 PM, Owen Duffy wrote:

Mike *wrote :

The big question I have always had regarding the balun was are we
reducing performance by eliminating feedline radiation? For a lot of
antennas, that may be a big part of the antenna system.

Claiming feed line contribution to radiation as a performance factor is
usually a specious claim, and more likely to be made by someone with a
commercial imperative than a genuine interest in radiation performance. You
know, if you can't solve a problem characteristic, call it out as a
feature.

I don't disagree, but certain antennas - the EH antenna comes to mind,
which resemble a tuned circuit on a stick. Get rid of the feed line
radiation, and you almost get rid of the whole antenna. But like you
say, its a "feature".

It's also not good practice.

In this case, feed line radiation would usually skew the pattern upwards,
not necessarily a desirable feature, probably not desirable in most
situations.

Not too desirable. Thanks for the clarification. Mine was a general sort
of response, not limited to this antenna.

- 73 de Mike N3LI -

Years ago I built a J antenna for 10m. I was actually pleasantly
surprised at how easily it tuned up compared to the 2m versions I had
buit. I checked for feedline radiation by checking for variarions in
VSWR while coupling a large mass(me) to the feedline near the feed
point. Little change was noted. Do the larger versions of this antenna
normally perform better(more predictably) or was this just a case of
dumb luck.

JImmie