Topband: SPAM:(L1) antenna question

[Guy Olinger, K2AV]

>From "mike l dormann":

"my antenna options seem to me to be a wire slanting from the window 
down to the parking lot below ... with an antenna tuner and the 
building neutral as a counterpoise."

The antenna you propose may actually have 2000 ohms end feed Z and 
more. Many tuners only add a 4:1 boost to a limited range of the tuner 
proper, and are anything but efficient in that mode.

Particularly with the low voltages at your power levels, you might 
want to consider a parallel LC network with one end of the coil to the 
wire and the other to "ground". Connect coax shield to "ground" and 
center conductor to a tap on the coil. Vary tap, coil size and 
capacitor for match.

My own experience with a "neutral" as ground in an apartment building 
was that it was very noisy, and it helped a lot to disconnect the 
connection to neutral during receive. The coax to the rig was enough 
of a counterpoise on receive. My sloping 80m halfwave worked well and 
Q's included Europe, Africa, South America and Antarctica with 25 
watts output from an 807.

I have had good luck with end-fed halfwaves using both tapped and link 
coupled parallel LC matches.

Good luck and 73, Guy. 



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