Bill, you really have to be "a believer" to use these antennas if they
really work like the first two sentences of that link claim:
"The end-fed halfwave antenna is among my favorite for field operation. It
is easy to setup, can be used without a feedline, and performs well."
Can't remember ever seeing an antenna that could be used without a feedline
;-)
I guess they mean you can just insert it into the transmitter. (?)
Or was it a miss-print? Maybe he meant "without radials".
For single band operation, this is probably easy to achieve. Getting
multiple band performance out of these (when working more than QRP) might
prove challenging.
As a matter of fact I have been considering making my monoband 40m have-wave
vertical end-fed. All you need is 40pF C and a home-brew coil out of thick
wire with a single tap for 50 Ohms. Then some Tupperware "borrowed" from
the XYL to water-proof it. Should be easy enough.
For multi-band, the center-fed (with openwire) is a very forgiving
construction. You can't do much wrong. The length is not critical and
there is no matching to fuss with until you get to the matchbox.
Thanks for the Link Bill. Looks like there'll be lots of good reading
there.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Bill Tippett
Sent: Tuesday, July 12, 2005 7:32 AM
To: tentec@contesting.com
Subject: [TenTec] vertical dipoles
There is another alternative to
center-fed vertical dipoles It is not very
difficult to end feed dipoles which are
much simpler mechanically. There's
a good collection of information here:
http://webpages.charter.net/aa5tb/efha.html
Par Electronics makes monoband
commercial versions that will handle 100 Watts
without a counterpoise wire. More info here:
http://www.parelectronics.com/end_fedz.htm
They also make a multiband (10/20/40) version
which is limited to 25 Watts. It is not on their
website, but can be seen here:
http://www.universal-radio.com/catalog/hamwire/1952.html
I have the previous EF-20/40 version which has
now been replaced by the 10/20/40 antenna.
It is a fabulous antenna for portable / QRP,
costs <$60, and can be easily erected with
a slingshot into a single tree for support. It
is also quite invisible for those worried about
stealth.
In the IARU this weekend, I was
casually using one of these from a mountain
top cabin location ($60 antenna but a $1M
location!). Running maximum output from
my Elecraft K2 (~15 Watts), I made about
260 QSO's including many, many EU stations.
While it worked quite well on 20m (including
a UA9 in CQ Zone 18), I was absolutely
astounded at its performance on 40m. In
~40 minutes from about 0215-0255 Saturday,
I worked 27 DX stations, mostly EU but also
5B4 (first call), LU and CX. Before sunup
I added several VK's, ZL's and more South
Americans on 40m, although I had to work
harder than I did in working EU.
I have the components to make a
high-power matching system for one of
these and may try it from home to compare
it to a 180' EDZ up about 85'. I was very
impressed, but it could be that the portable
mountain top location was the key.
Par is owned by Dale Par W4OP
and he provides outstanding support.
73, Bill W4ZV
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