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Station Building

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Subject: Station Building
From: (Bruce (AA8U))
Date: Fri, 7 Jun 1996 21:52:21 -0400 (EDT)
I seek the wisdom of the multitude.

I have been building an inverted-L antenna. It has an 80M CW trap and is
resonant on 1825 and 3575 approx. Seems to work fine. The vertical section
is 58' as that is what my trees will allow. The 80m trap ends up being about
six feet from the top end of the vertical section. The horizontal section
tips up a bit. I have the feed point mounted at the top of a ground rod, not
deep, and it sticks above the ground about 1.5'. There are six 133' radials
and about eight 68' radials, all insulated #16 copper, laying on the ground. 

My question is, given the height limitation, would it be a better antenna
with the feed point raised to about 10' with the radials elevated, loosing
an additional ten feet of radiator in the process? Or would it be better to
leave it ground mounted and elevate the radials. Maybe just elevate the long

I haven't modeled this one because I don't know how to model the Undilla
KW-80CW trap with AO 6.5  Maybe some of you have already done it.

This inverted L will be the 80/160 tx antenna for our ZK DXpedition on
Rarotonga in July. It may have to be ground mounted, radials included. If we
can get it elevated the ground losses might be less. 

The feed point, when operated on 160M, is fed via a 28:50 un-un. I take this
out when on 80M. Bandwidth is a bit on the narrow side, but I take that to
indicate the ground losses aren't prohibitive. The MFJ says the feed point
is about 30-35 ohms without the un-un on 160M.

I intend to make up a bunch more shorter radials, about 16-20', just in case
it has to be ground mounted.

Anyone care to pass along your thoughts?

Since this is directly related to contesting, station building,
DXpeditioning, antenna technical, etc. I am not shy about posting this one. :')

Please respond to, tnx in advance.


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