Dear Topbanders, I would like to share with you an
experience using AIM4170 to measure our beverages.
Prior to the last CQWW and to install our 6th beverage, instead of using the
Autek or the MFJ to test the installed ones, I decided to play with the AIM4170
in TDR mo
David,
Thanks for sharing the study.
I am trying to digest it. Need to go through it again.
He says: " There is an optimal height for an elevated groundplane,
that height is not at ground zero, and is typically around 0.05
wavelength. (The statement the higher-the-better is not always true f
Got a lot of mail about this, teaching me to shut up because I don't
have much free time.
Look folks, as you all know, just about everything with antennas works
in some fashion and there's a sliding scale. It's not all black and
white. With elevated radials, it isn't as if putting radials at 20
Hello Peter
I haven't done any work on this, but Ralph has. Have a look at this site
and others of his:
http://www.arising.com.au/people/holland/ralph/shortvert.htm
David
G3UNA
- Original Message -
From: "Peter Voelpel"
To:
Sent: Wednesday, November 09, 2016 4:57 PM
Subject: R
Think of a dipole close to the ground, it will not be efficient with all
that coupling to earth and resulting losses.
73
Peter
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of David
Cutter
Sent: Mittwoch, 9. November 2016 17:37
To: Mike Waters; Rob Atk
Hi Topbanders !!!;
Finally I got an FCP isolation transformer for 160m...I am planning install a
160m Inv L + FCP...I am wondering if I can add 80m to this system.
I know the 160m FCP isolation transformer only work on 160m but maybe adding a
relay is possible to work on 80m.
Any idea?
Thanks
I recall reading from Ralph Holland that 0.015 wavelength was a good height.
David
G3UNA
- Original Message -
From: "Mike Waters"
To: "Rob Atkinson" ; "topband"
Sent: Wednesday, November 09, 2016 4:11 PM
Subject: Re: Topband: 160 m inverted L
Fifty feet?! That means the feedpoin
Here are some photos of the omega match (L-network) tuner I was referring
to earlier. No inductor needed. Visit
www.w0btu.com/files/antenna/160m_inv-L
and click on 100_3761.JPG there.
As I said, that tuner
(1) easily handled the full legal limit and
(2) the bigger capacitor there was overkill. The
My elevated radials are now 24m up but sloping.
Big difference to before where I tried 4m high radials.
I went from a T-vertical to a driven tower with top load as an elevated
groundplane some years ago and that is the best transmit antenna I ever
used.
It is also outstanding on receive. I can hear
Fifty feet?! That means the feedpoint --the bottom of the antenna-- would
be 50 feet up! Do you know how high the top would have to be? I don't agree
with that at all. And I've never heard of anyone who ever did that.
The four elevated radials in these tests were just 16 feet high! And what
is mor
thanks Rob,
The best I can do in my situation is 10 feet high for the 160M elevated
radials.
A far cry from 50 feet :-(
I will work on maximizing the size of my ground screen under the inverted L.
Hopefully this will increase some of the efficiency lost from the low
elevated radials.
Its toug
The rule of thumb for effective elevated radial height is 1/10
wavelength, so on 160, around 50 feet up.
73
Rob
K5UJ
_
Topband Reflector Archives - http://www.contesting.com/_topband
Folks,
You don’t need expensive vacuum capacitors or bread slicers/toast racks to
match your 160 metre ‘L’. I use a low pass L-network consisting of 0.95
microhenrys in series and 1600 pF in parallel with the coax.
The inductor is not real and is made by slightly extending the length of the
a
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