[WARC] Fwd: Re: yet another try.

[Clare Jarvis]

----------  Forwarded Message  ----------

Subject: Re: yet another try.
Date: Tuesday 22 May 2007 19:13
From: WO0W <WO0W at acegroup.cc>
To: Clare Jarvis <clarej at hbci.com>

Hi, Clare

Your antenna looks good.  However, EZNEC will put a split source at the
junction of the two wires instead of on the first segment of wire 1 like
it does with the single source you used and will model a balanced feed
point correctly.  Also, the high accuracy ground is much more accurate
than the MININEC ground, unless a wire touches ground.  MININEC ground
is inaccurate at low height above ground like this antenna.

Modeled thusly, EZNEC calculates maximum gain in the direction of the
VEE at a takeoff angle of 18°.  Very nice.  Performance on 80 and 40
meters is good, except very narrow bandwidth on 80.  It certainly
outperforms an inverted vee at that height above ground.

Be sure to convert the dimension of wires to a constant value, like feet
or meters, not a wavelength value, if you wish to explore how it
responds to frequency changes.

Thanks for letting me see it.  I'll save the description.  Did you meet
Roy Llewallen?  What a pleasure that must have been.  I've been using
his software for about 20 years now.

73 de Red

Clare Jarvis wrote:
>Hi Red,
>
>In studying the antenna book I found the table between angle and antenna
>length in terms of wave lengths.  I have determined that it offers very good
>gain in a bi-directional manner and feeding at 20 meters is easy.
>
>The gain is actually quite good at both 40 and 80 meters.  Much better than
>dipole but the antenna is so reactive at that frequency that much though
>would have to be used to determine a way to feed it.   I wnet to Dayton over
>the weekend and got a chance to talk to the authors of eznec.   Learned a
> few things that made my efficiency at trying variations much higher.
>
>attached is the latest incarnation.   Let me know what you think.
>I have been unsucessful in terminating it to yield a uni-idrectional
> antenna.
>
>73 Clare

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