Dear All
I also use a 'low' tower to support an inverted L. This is 60 ft with a
15 ft stub mast on which there is a tribander and VHF beams.
Recently mentioned on this list were slopers, inverted Ls and shunt
feeding the tower. I have experimented with a half sloper on 160 m and
came to the conclusion that 75ft with the sloper attached at 60 ft is
too low at 160 m. It is possible to add a loading wire to the tower but
I didn't have too much joy with that since the loading wire had to
follow a similar direction to the horizontal part of the L.
Then to inverted Ls and shunt feeding. I've used the extended Inv L for
many years, which I now use with 4 elevated radials. But a straight 1/4
wavelength seemed to work OK as well and seemed to be less affected by
other nearby antennas. My (probably mistaken) feeling was that an
extended L would place the current portion further up the vertical
section which would be preferential.
I've also thought about trying to shunt feed the tower but I am using a
tilt over tower with antenna cables hanging down on two sides. Concerns
are decoupling these rotator and feeder cables RF wise and ensuring a
good connection between tower sections, without major engineering
activities.
So in case it's back to inverted Ls (either extended or regular) it
would also be nice to have views on the original question. What
theoretically and practically appears to give the best results, the
extended L or the quarter wavelength L.
73s Dave
--
This Email comes from Dave Court - EI3IO, G3SDL, OZ3SDL
QTH (Grid) Locator - IO63WF
Web Site: http://EI3IO.com
EI7SDX:SHANDX DX packet cluster web site: http://shandx.ath.cx
Cluster Access telnet://shandx.ath.cx:5000
Node Access telnet://shandx.ath.cx:7400
QSL address: 'Connogue', River Lane, Shankill, Co. Dublin, Ireland
Tel: (EI) +353 1 272 2066 or (GI) +44 28 9099 6474
Skype Username: Connogue or Connport
VoIP: sip: 1996474@sipgate.co.uk
Professional Web Site: http://connogue.com
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|