I am in Jeddah next to the Red Sea.
Sent from my iPhone
On Jan 5, 2013, at 18:19, Jim Lux <jimlux@earthlink.net> wrote:
> On 1/4/13 11:12 PM, Edward Sylvester wrote:
>>
>> Greetings All!
>>
>> I am in Saudi Arabia and had the opportunity to throw up some wire
>> antennas. I put up 30' of fiberglass mast on my 25' roof and
>> installed an 80m INV VEE fed with open wire line, straight to tuner.
>> Hears extremely well. Cannot transmit until I get a license, which
>> is in the works.
>>
>> I decided to take advantage of some tall coconut trees and installed
>> a triangular-shaped horizontal loop with >700' of wire fed with open
>> wire line, up 35-50', taking into account the sagging. This goes
>> straight into a 1:1 current balun at ground level. Coax run is about
>> 6'. No issues. Tunes perfectly.
>>
>> I ran some A/B comparisons with the Inv Vee and determined that they
>> are very similar in performance!
>
> Which is about what one would expect... both antennas are a decent fraction
> of a half wavelength in extent (so it's not like an amplified 6 foot whip or
> something).
>
> The receive performance is going to be dominated by the atmospheric noise, so
> whether the antenna has a different gain isn't going to make much difference.
> Lots of people use active receive antennas on 160 to good effect, especially
> as part of a phased array so you can steer the null towards some noise source.
>
> Where your two antennas may differ is on transmit: one may be better than the
> other in terms of resistive loss. They're about the same height above ground
> (a tiny fraction of a wavelength), they're both horizontally polarized,
> they've both got a low feedline loss, etc. I wouldn't expect a huge
> difference. If you were comparing the big loop against a loaded 20m dipole,
> yeah, more of a difference.
>
> What is your soil like? Are you in Eastern Province with either sand/rock or
> with sabkha (the latter is the topband dream substrate)? Or rocks and such.
> I doubt there's anywhere in Saudi Arabia with very deep topsoil (in the
> context of 160m wavelength and skin depth), except perhaps Hofuf in the
> middle of the Al Ahsa oasis.
>
> If you are in a coastal area with high salt content and high water table, you
> might think about a vertical.
>
>
>>
>> I was hoping the Loop would blow away the Inv Vee but was
>> disappointed when this did not occur. Has this been your experience?
>> I have tried to read as much as possible, but there are varying
>> opinions on loop expectations.
>>
>> Your opinion would be greatly appreciated. Frustrated....
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