If you feed it in one of the corners it will be kind of vertically
polarized. Feeding it in the bottom center or at the top it is horizontally
polarized. 1005/freq should give you the length of the delta loop, no bug
mystery.
Bob W6TR
----- Original Message -----
From: "K4SAV" <RadioIR@charter.net>
To: <towertalk@contesting.com>
Sent: Monday, October 30, 2006 10:30 AM
Subject: Re: [TowerTalk] 80 m delta loop
Glad you got your antenna working Gerry.
A quick look at your antenna with EZNEC shows a take-off angle of 27
degrees with a gain of about 0.15 dBi. It has a null overhead. Looking
in the azimuth directions, at 27 degrees elevation angle, the gain in
the plane of the antenna is about -7 dB compared to the gain
perpendicular to the plane of the antenna. It's not a bad DX antenna,
especially considering the low height. If you raise the antenna by 3
meters, you will get about 1 dB more gain and the take-off angle will go
to 25 degrees.
It should be a decent DX antenna for receiving as well, since there is a
null overhead and the take-off angle is fairly low (at least much better
than using a low dipole).
Jerry, K4SAV
Geert Hofman wrote:
>Hi,
>
>
>
>Some weeks ago I posted a question regarding my 80 m delta loop .
>
>I finally decided to go the "easy way" and cut off about 10 meters, to get
>it to resonance in the 80 m band
>
>It's now resonant around 3.650 Mhz and by replacing the "tuning bit of
>wire" I can get it up or down.
>
>
>
>Made this morning my first QSO with K1 land, so I am happy.... ( although I
>only got 449, whilst I read him with real 559, but am running only 100
>Watts)
>
>
>
>Out of curiosity though I modeled the antenna via MMANA but get very
>strange results...
>
>I assume there are more knowledgeable people on this group, who can tell me
>what really to expect.
>
>
>
>I made a small drawing below ...
>
>
>
>
>
> *
>
> 21 meter * * 21 meter
>
> * *
>
> * *
>
> * *° FEEDPOINT
>
> * * * * * * * * * * * * * * * *
>
>
>
> 42 meter
>
>
>
>Apex height is only 10 meter and baseline wire of 42 meter is only 2 meter
>from the ground.
>
>Feedpoint is very close to the corner , but was measured for around 3.600
>MHz, so pretty much in line with current resonance of 3.650 MHz
>
>
>
>Soil is average to good.
>
>
>
>Would like to hear what take off angle with max gain I can expect and some
>idea of the radiation pattern.
>
>
>
>
>
>Thanks for helping me out and hopefully we meet somewhere on 80 ( CW or
>BPSK )
>
>
>
>
>
>73's - ON4IG - OQ5A
>
>Gerry
>
>_______________________________________________
>
>
>
>_______________________________________________
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>
>
>
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