Topband: Inverted L in contact with leaves

[AB2E Darrell]

Hi Pete,
No effect noticed here for leaves with L wire running over tree.
I just reinstalled my 160m Inverted - L on a taller tree (fed 10ft off ground, 80ft vertical , about 52ft horizontal). It's been up all summer with leaves, it goes over the top of 95ft oak. My vertical wire is #12 THHN, insulated solid copper. I have 5 tuned radials of the same wire, but thinner gauge is also OK. I feed it with a 1:1 Balun Designs balun. I trimmed it slightly but it resonates about 1845 and gives me all the CW band. Tested with Acom 2000A at 1500W out....seems very stable as before mounted on a  shorter tree at about 65ft.

Pete, even 1 tuned radial for your L, you should see it working and loading up OK if you want to test.

I used to easily find the tech supplement online from Butternut for tuned radials, but it looks like it's now gone.
Check this document out https://rudys.typepad.com/files/elevated-ground-systems-article-final-version.pdf . N6LF did some modelling and looks very similar to ON4UN's conclusions in his lowband book that 4 tuned radials achieve 60% of the efficiency of 100+ radials on the ground. Some may dispute this, but I've never had enough real estate to put down a full ground radial field of 100+, but I do have room to put up 4 elevated radials. They can slope, go up and down but if you can, mount them about 10ft above ground.
The tuned radials are about 3.5% shorter than the 1/4wave element (see the formula). I cut them all the same as the element, and then gradually shorten them to adjust for resonance, depending on how the SWR looks.

In the past, the L has worked great for me. I now have about 115 countries confirmed on 160, all with an L.

73 and best of luck with the project,
Darrell AB2E


________________________________
From: Topband <topband-bounces at contesting.com> on behalf of N4ZR <n4zr at comcast.net>
Sent: Thursday, August 29, 2019 11:23 AM
To: topband reflector <Topband at contesting.com>
Subject: Topband: Inverted L in contact with leaves

My inverted L is taking shape - about 60 vertical, the rest horizontal.
For a couple of months anyway, it is touching a number of leaves in the
vertical section.  I assume that's not a concern, but thought I'd ask
before I get a lot of radials down. First short radial is down and
MFJ-259 results look promising.  It's just a problem of waiting for lawn
mowing to stop hi.

--

73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector