Bob Schreibmaier wrote:
Hi Tom,
In article , you say...
I haven't asked anything impossible or even tough, since I only gave a
general bound on size, gave the rough band limits desired, and said we'd
like gain and directivity.
Well... :-)
On a band that has a bandwidth of roughly 4% of
its center frequency, you're going to be REALLY
hard-pressed to get coverage of both phone and
CW on an antenna that is a little over 40% of
full size. So far, no manufacturer has been
able to come up with the antenna you describe.
Many years ago, Swan Antennas had a 2-element
40 meter beam that used half size elements.
As I recall, it used loading coils midway
through each element. I'm not very sure, but
I think the boom length was about 16 feet.
I think they got somewhere around 100 kHz
between 2:1 points. That wouldn't even cover
the entire phone band, and the elements are
longer than your design requirements.
So, yes, you are asking for something very tough,
if not impossible.
But, I wish you good luck in your quest! :-)
73,
Bob
And also from my original post
"o Boomlength 30 feet
o Element length 30 feet "
which is a whole lot more than 16 feet.
But you are probably correct. It's impossible.
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