[Milsurplus] TRD-4 ant / Adcocks

[Marty R's GI-stuff haunt]

Adcock antenna:

  2 verticals* spaced a quarter-wave

      -and-

  connected with 3/4 ELECTRICAL transmission line length.

and fed at the third-length point.

Theory is incoming sig. on long-line end  reverses phase 180 deg.s
going to junction.  On short-line end, sig. goes thru space quarter 
wave & returns to junction a electrical quarter wave so again it's phase-
reversed 180 deg.s like from other ant. & they ADD

Now an incoming from the short line end.  Goes quarter wave to junction
& 3/4 wave to far antenna & back to junction.  They CANCEL at junction.

So steep null when "short-line antenna" pointed @ sig.

Antennas were used in 30s-50s radio range - the A / N thing.  That's
mostly what BC453s Q5-ers) were for & ranges were all over Pacific.  
No transmitters seem to survive oddly.  Sent cw ID & @, say 290kcs, they'd
get out for 100 mi.s daytime

Pacific range tale from a Coronado driver.  Radio range was one of
1st things done after a landing.  Get out the litter cases AND, the 
officers had to take leave - right?


  'rm

*can be vertical or horizontal dipoles.  A quarter-wave vertical is really
 a half-wave dipole where the ground systems mirrors the other half

 this get's clearer after a cup of Maxwell house.