[AMRadio] Non-ordinary Antennae


John Lawson jpl15 at panix.com
Mon Jan 29 21:26:20 EST 2007



   Brett (et al) I will add that, while I still think that two adjacent 
parallel coaxial cables do *not* make a balanced *anything* (I am 
researching the facts to back up my big mouth) my antenna system here at 
KB6SCO is a horizontally-disposed rectangular / nearly square loop of 
about 480 feet circumference, realized with #14 copperclad wire, attached 
to the tops of my backyard fence at the 5' level, and the eaves of the 
back of the house - using 4" long cuts of 1/2" PVC pipe, drilled through 
on one end to accept a 3" drywall screw, and slotted near the other end 
for the wire. It is thus a quasi-NVIS - I call it my "RF Fountain" - watts 
go straight up and then spray everywhere.

   At the feedpoint of this loop, which is also the (little-used) gate into 
the back yard - I use a dual #8 barrier strip, to which is attached 
450-ohm plastic-jacketed commercial ladderline ("window" line) - and 
carried on the same PVC insulators into the shack (in the garage) via a 4" 
hole I popped in the stucco with a hole saw.

   I currently run a Viking Valiant into an Ameritron ATR-15 tuner, thence 
into the balanced feedline.   SWRs anywhere on 80/75 that I'm licened for 
can be brought down to 1.1:1, and there has never been any kind of 
heating/arcing that I'm aware of. 160 is fairly touchy, but 1.3:1 can be 
achieved. 40 tunes up nicely, and on 20 I can also get down to about 
1.3:1.  15 and 10 just plain don't work - so I don't use those bands.

   I've had two sympathetic neighbors agree to alert me to any 
interference, there is none - however this is also a completely new 
housing development and all utils are underground - everyone has cable or 
dish-TV - that also helps.


  This antenna is stable, quiet, has garnered QSOs all over the western 
hemisphere on 80M, and is only barely susceptible to the monster static 
charging that we are prey to here in the high desert of northern Nevada.


    And a lot of folks took great pains to tell me that I'd never get a 
watt out, angle of incidence this, radiation resistance that...  so I just 
made myself familiar with the rudimentary math involved, a bit of antenna 
design theory... hey, it's Only A Hobby!!!



Cheers

John
KB6SCO
DM09fg

PS: Wait til I get the 1KW RCA B'cast rig up and making Power... ;}



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