That was the whole point. 7700 is out of band.

Tam/WB2TT

That was the whole point. 7700 is out of band.

Tam/WB2TT


Yeah, but its two wavelengths, it should probably perform at least as good or
better on 40 than it does on 80?? It would most certainly have a lower angle of
radiation. Again, I'm no electrical engineer, but I've always been led to
believe that the bigger the antenna the better...it should certainly resonate
efficiently on 10-80, in theory anyway..in the same way that a full wave is
better than a half wave or a quarter wave.

See: http://www.ku4ay.net/loop.html and
http://www.cebik.com/atl1.html which are just a few of the sites discussing
these fine antennas..

Steve
kb8viv

Steve,

You are right about the gain. I ran EZNEC on the 75 meter loop, and the gain
at 40 m is about 3db more than on 75. However, it is not resonant in band. I
got an impedance at 3850 of 40 + j5. Impedance at 7700 of 69 +j1, and
impedance at 7300 of 18 + j87 (That is an SWR of 10). Gets worse below
7300.

There is enough feedline and wire loss in the real world antenna that the
SWR measured from the shack is about 5:1 on 40 m.

Tam/WB2TT
"Desmoface" wrote in message
...
That was the whole point. 7700 is out of band.

Tam/WB2TT


Yeah, but its two wavelengths, it should probably perform at least as good
or
better on 40 than it does on 80?? It would most certainly have a lower
angle of
radiation. Again, I'm no electrical engineer, but I've always been led to
believe that the bigger the antenna the better...it should certainly
resonate
efficiently on 10-80, in theory anyway..in the same way that a full wave
is
better than a half wave or a quarter wave.

See: http://www.ku4ay.net/loop.html and
http://www.cebik.com/atl1.html which are just a few of the sites
discussing
these fine antennas..

Steve
kb8viv

You are right about the gain. I ran EZNEC on the 75 meter loop, and the gain
at 40 m is about 3db more than on 75. However, it is not resonant in band. I
got an impedance at 3850 of 40 + j5. Impedance at 7700 of 69 +j1, and
impedance at 7300 of 18 + j87 (That is an SWR of 10). Gets worse below
7300.

There is enough feedline and wire loss in the real world antenna that the
SWR measured from the shack is about 5:1 on 40 m.


Yeah, the rig's not gonna see a 50 ohm impedence, no question about that...It's
a compromise I guess...I'll let you know how it does though, I'll be hanging
wire this weekend for my 80 meter full wave horizontal loop...but if L. B.
Cebik, W4RNL
endorses em - thats good enuf for me hehe...he's sort of an antenna guru...

Steve
kb8viv

Tarmo Tammaru wrote:
You are right about the gain. I ran EZNEC on the 75 meter loop, and the gain
at 40 m is about 3db more than on 75. However, it is not resonant in band. I
got an impedance at 3850 of 40 + j5. Impedance at 7700 of 69 +j1, and
impedance at 7300 of 18 + j87 (That is an SWR of 10). Gets worse below
7300.

But notice the subject line compares 40m and 80m, not 75m.
--
73, Cecil http://www.qsl.net/w5dxp



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