Scott:
I use several fan dipoles. Both use two elements. One operates on 40
and 30 meters (and I get 15 meters, 3rd harmonic of 40, free into
the bargain, but the SWR is a bit above 2 on 15 m, and I must use
tuner to match it to the K2. ). The other antenna operates on 80 and
20 meters (and I get 17/12 meters, 3rd and 5th harmonic of 80 meters
free into the bargain, but the SWR is a bit above 8 on 12/17 m. I
must use tuner to match it to the K2 on 17/12. However, the line
losses are acceptable, and the antenna is very effective on all four bands. )
Several gotchas. The elements do interact. The shorter element will
be non-trivially off from the "468" formula. The longer element is
pulled much less noticeably. However, if you're looking for low SWRs
of both bands, be prepared to do a lot of tweaking.
I agree with other posted comments. If you use more than 2 elements,
be prepared to do a very great deal of very frustrating of tweaking.
Very important: Construct your antenna in such a way that the short
element cannot wrap around the long one. If it does wrap, it will
pull your painstakingly tuned antenna way off the desired resonant frequency.
Other caution: Do not suppose that you can simulate a fan dipole on
EZNEC. The condition of two parallel elements of unequal length very
close together is one place where the computer model departs from reality.
I do not use baluns, and it does not seem to have caused me any trouble.
Good luck,
Steve
AA4AK
At 04:44 PM 2/19/2007, [EMAIL PROTECTED] wrote:
Hi
This is a little off topic, but I don't know of a better place to
find someone that would know the answer to my question.
Many years ago I used one coax to feed three different inverted V
antennas all for different bands. At the time I thought they worked
just fine. Worked all kinds of dx with the setup. I have been told
lately that the unused antennas on the setup would pick up additional
noise.
Has anyone ever done any testing with multiple antennas on one
feedline to see if they really do pick up extra noise?
I'm thinking about putting up new inverted V antennas on 160, 80, and
40 meters and feeding them with one coax. Sure beats antenna
switching and it always seem to me that the signal would go to the
resonate antenna. I always used a coaxial balun in the feedline.
Any ideas would be appreciated.
Thanks
Scott N5SM
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