Topband: Inverted L Questions

Scott Northcutt
Tue, 28 Nov 2000 10:17:47 -0600

Greetings Topband Gurus.

I need to tap some of the collective wisdom of The List as I am soon
about to embark upon my "160 m from a city lot" adventure.  

Initially, I think that the weapon of choice will be an Inverted L for
both transmit and receive.  I don't have room for much else (Beverages,
etc.) at the moment.  I do have a couple of trees that will give me the
50-60 vertical feet and 100 or so horizontal feet that I need to string
it.  Is there a formula for figuring the length or is "in the ballpark"

I have acquired a ~600-1800 pF variable cap of the air-dielectric
variety (refugee from an old tuner I think) which doesn't have much
plate-plate spacing but I think that it'll work.  I have no amp so I'm
hoping that 100 W won't make it arc.  Am I off in the right direction?

I hope to feed it with some RG-58-type coax as that is the only run I
have that is long enough to get from the shack to the antenna feedpoint
tree.  Will this type of coax be OK?  I have assumed "yes" since I don't
think that it will attenuate too much 1.8 MHz energy in the 100 feet or
less that the run covers.  Is this a safe assumption?

Finally, the ingredient I am missing now is wire.  As my wife and 2.5
small kids are still fond of eating and keeping the house heated, my
radio budget isn't exactly huge.  I have officially put in my request
with Mr. Claus for one or two 500' spools of 12 gauge solid copper wire
(with black insulation for low neigbor-observability) which I am hoping
will serve equally well as both the radiator and the (buried?) radials. 
This is where I really need the info.  Is 12 AWG solid sufficient? 
Would bare copper be better?  What about the radials?  Does insulated
wire work OK in this role?  I can realistically only get two or three
1/4 wave radials in the ground.  I might be able to get a few more 1/10
wave wires in the ground.  Advice?

Please forgive all the verbiage for such an un-impressive setup.  I just
want to get this done right the first time in my limited available
antenna construction time (the XYL does NOT understand) so that I have
something that will play on 160.  With no special RX antennas and only
100 watts, I know that I will not be a Force To Be Reckoned With but I
at least want to be able to get in the game.  I am going to miss ARRL
160, unfortunately, but perhaps there is hope for Stew Perry.  I suppose
that I'll have to start going to bed early, too, if I want to cash in on
the darkness just prior to sun-up...bad news for a life-long night-owl

Thanks for any wisdom that you can pass along.  I enjoy reading all the
stuff that you wizards kick around on this reflector.  I've learned a
lot just by lurking.

73 from Nashville, Tennessee.
Scott Northcutt

FAQ on WWW:     
Administrative requests: