The location of my tallest tree is "just on" my property line. The property
slopes strongly front to back. Because of the location of the antenna, to
obtain a symmetrical field, I would have to go into my neighbors yard (but
he is cool about it all and thinks it is interesting). If non-symmetrical,
then I could completely keep it to my yard, but it would be limited because
of the limited space availability. Alternatively, I could put it further
down the hill, and have a more symmetrical pattern.
Probably an inverted L is my only reasonable solution. Would I have
interaction with an 80M vertical that would be nearby?
Thanks
Scott
-----Original Message-----
From: Rob Atkinson [mailto:ranchorobbo@gmail.com]
Sent: Sunday, December 07, 2008 9:44 AM
To: Scott MacKenzie
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] 160M Antenna - Ideas
If you have a support for the loop that is 560 feet tall then you don't need
an inverted L; you can at the least put up a 1/4 w.
vertical with no horizontal part at all. I am not sure what is limiting
your radial situation or why you need to involve a neighbor--I have my
inverted L feedpoint near one corner of my lot; some radials are only about
10 feet long, there are 100 of any length from 10 feet to 120 feet. don't
think you have to have 50 or 60 that are 120 feet long; just fit as many as
you can in your available space and it will work okay. Of course if you are
able to put down 60 that
are all 1/4 wave then that's fine. If you are planning to use this
antenna for a few years then no. 14 solid copper is a good investment.
The insulation on it doesn't matter; solid goes down easier than stranded
which tends to spring up; that gauge will withstand some physical wear
without breaking.
Invest in good coax for the same reason--you can leave it out on the ground
and not worry about it. 1/2 inch heliax is practically indestructible.
73
rob / k5uj
On Sat, Dec 6, 2008 at 10:21 PM, Scott MacKenzie <kb0fhp@comcast.net> wrote:
> I like that idea. I was concerned that I would have issues with
> changing the loop. I really like the loop, especially for working local
contacts.
> It works very well for 80M and 40M on Sweepstakes.
>
> The support I use for feeding the loop is approximately 560' tall -
> and I have a nice tree about 75' tall (also supporting a corner of the
> loop. That should make for a nice inverted L. The issue is radials.
> I need to figure out something, or talk nice to my neighbor to allow
> me to establish a radial field.
>
> There might be another suitable tree I could use....need to figure
> that one out - it is the radial issue that is causing me problems....
>
> Scott
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Rob Atkinson
> Sent: Saturday, December 06, 2008 9:55 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] 160M Antenna - Ideas
>
> I am also on a small lot in a city with a 1 wavelength 80 m.
> horizontal loop. Actually mine is 1 w/l at around 4 mhz so where I
> operate it's really more like .8 or .9 w/l. my lot is 50 x 100 feet.
> I found that the practice of feeding the end of the ladder line by
> tying each side together and working against ground is at best a
> compromise. Firstly, it only works if you have a pretty long
> vertical run of line. 30 feet vertical with 10 or 15 running over
> the ground to get under the feedpoint of the loop isn't enough.
> Secondly, you also have to have some kind of counterpoise. A tuner
> ground rod isn't enough. You say you have trees. If you have room
> for a 1 w loop on 80 then you have room to get on 160. I'd take the
> tallest loop support (I'll assume it is a tree) and use that to hold
> up a vertical wire. You run the wire up and through a marine pulley
> on a dacron rope shot over the tree to make an inverted L. The
> horizontal part of the L bisects the loop and ends at the opposite
> corner, so for example if the vertical is in the NW corner, then the L
> ends at the SE corner. Don't worry about it messing up the loop's
> performance, it won't. And the loop won't affect the L either. Run
> coax feedline out to the base of the L, do the necessary
> counterweighting with pulleys if you are using trees, spring-load the
> bottom insulator of the L if necessary so it can move with the trees
> and put down a radial ring (don't use aluminum) and as always, put
> down as many radials as you can with no. 14 solid, insulated that's sold
in 500 foot spools at most hardware stores.
> shop around for the best price, invest in a wire stripping tool,
> staple down the radials
> and they will eventually sink into the ground. don't worry if they
> are only 10, 20, 50 feet long, just fit them in the corner of your lot
> as best you can. If the horizontal part of the L is too long to fit
> in the loop, you can bend it around like this > or this ) and it will work
fine.
> Does it sound like this is what I did? Bingo! and the horizontal part
> goes right over my house and ends in a tree in my
> front yard. Try this before you resort to loading, voyagers,
> isotrons, etc.
>
> 73,
>
> rob / k5uj
> _______________________________________________
>
>
>
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>
>
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