One certainly needs a tuner if one is going to connect the 50 ohm output of
a modern solid state rig to the high impedance at the end of a half wave
antenna. Of course this is done all the time. I recall that back in the
day, we could load a tube type rig with the plate circuits typical of that
day into just about anything, without an extra tuner. Not that it was very
efficient ! But it was kinda fun. Remember the old WWII era rigs that just
had a spring loaded terminal on the panel, and a single wire feeder was
attached to that. Of course, lots of tubes went up in smoke. Yellow hot
plates in the tubes would wreck them in seconds if you didn't adjust the
circuit FAST :)
73 de Gary, AA2IZ
----- Original Message -----
From: "Bwana Bob" <wb2vuf@qsl.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, July 12, 2005 7:07 PM
Subject: Re: [TenTec] vertical dipoles
You do need a tuner with a 1/2 wave end fed wire, but it is possible to
connect the wire directly to the tuner output. A counterpoise is still
required, but it can be much shorter than the counterpoise required for
a 1/4 wave antenna. See Moxon's book HF Antennas For All Locations.
73,
Bob WB2VUF
Bill Tippett wrote:
NJ0IP wrote:
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 the Par antenna, yes it can be used without
any feedline, just direct connect to the transmitter.
For an example, see a picture of me using mine directly
connected to my KD1JV ATS-2 QRP rig here:
http://users.vnet.net/btippett/cataloochee_divide_trail_qrp.htm
Guaranteed to cool you off in July just seeing that picture!
Classical end-fed networks do require at least a small
counterpoise. I'm not sure if the Par is using the connected
transmission line, or the case of the directly connected rig,
but I can absolutely say it works incredibly well. I have home-
brewed end-fed networks using info from AA5TB's site, but I
always use a quarter-wave counterpoise wire.
73, Bill W4ZV
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|