I would be cautious about using a transformer above 40 meters, as the
stray capacitance may be too large. I haven't tried it, though, so it
might work with some transformers.
73,
Scott K9MA
On 1/8/2018 20:22, VE3GAM wrote:
the End Fed Half Wave Antennas group on Facebook,
started by N4LQ, Steve Ellington,
promotes the use of a 49:1 transformer
Steve does have a couple of videos on Youtube where
he shows you him making one of these transformers
check out how to build one,
image is on Elgin Amateur Radio Society's website
<https://elginradio.files.wordpress.com/2017/10/49-1-unun.jpg";>
List of vendors of these if you do not want to build your own
49:1 Transformer Vendors
-------------------------------------
myantennas
http://myantennas.com/wp/
hyendcompany
https://www.hyendcompany.nl/
balundesigns
http://www.balundesigns.com/
MFJ
MFJ-1982LP/MP/HP, MFJ-1984LP/MP/HP
http://www.mfjenterprises.com/
packtenna (QRP only)
http://packtenna.com/
communicationworld
https://www.communicationworld.nl/antennes_end_fed_zelfbouw
2017.10.12 Al VE3GAM
al ve3gam
--------------------------------------------------
From: "K9MA" <[email protected]>
Sent: Monday, January 08, 2018 8:39 PM
To: <[email protected]>
Subject: Re: [Elecraft] PAR/LNR EFHW antenna
On 1/8/2018 16:59, Rich Arland wrote:
Failing that path, has anyone hooked an EFHW to the internal ATU
with good results? I would also include a cut to frequency ground
radial that I would lay out below the antenna. That would be the
easiest thing and simple to employ.
That definitely will not work: The impedance of the EFHW is much to
high for any internal ATU to match. The 64:1 balun may work, though
I haven't tried one. QRPKITS has a QRP tuner, but it works only on a
single band. Most any of the external antenna tuners will work,
though they may be lossy.
The best solution, I think, is to build your own L-network tuner.
One coil, a 3-position switch, and one variable capacitor. You don't
have to get a perfect match, just within the range of the internal
ATU, like 3:1. Once you find the right coil tap positions, the
internal ATU should be able to handle the small mismatch with
different antenna installations, etc.
It may seem like a lot of trouble, but if you can match the EFHW,
it's just about the most effective simple wire antenna you can use.
73,
Scott K9MA
--
Scott K9MA
[email protected]
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![https://elginradio.files.wordpress.com/2017/10/49-1-unun.jpg"](https://elginradio.files.wordpress.com/2017/10/49-1-unun.jpg"){kind=link}