40-2CD proximity to 20-4CD

[TR19@chrysler.com]

*** Reply to note of 10/14/96 13:50
MANY YEARS AGO, I GAMMA MATCHED THE BOOM OF A 3 ELEMENT TELREX 20M BEAM
ON A 24 FT BOOM AS A ROTARY DIPOLE ON 40M.  WORKS GREAT. I BELIEVE THE
BOOM PLUS END ELEMENTS ARE SELF RESONANT VERY CLOSE TO 40 METERS.  TO TEST
THIS ASSUMPTION, I GRID DIPPED AN EXACT HALF-SCALE (3L10) BY HOSE CLAMPING
A 2 OR 3 FT PIECE OF WIRE WITH A SINGLE COIL IN THE MIDDLE OF THE BOOM.
IT RESONATED AT 15 MHZ, SO BY SCALE, THE 3L20 PROBABLY IS SELF RESONANT
AT 7.5 MHZ.  A 204BA ON THE SAME BOOM LENGTHBUT WITH AN ADDITIONAL ELEMENT
IS PROBABLY SELF RESONANT SLIGHTLY LOWER. THE END ELEMENTS PROVIDE THE
GREATEST LOADING. TO ISOLATE THIS INTERACTION, YOU WILL PROBABLY NEED TO
KEEP THE VBOOMS PARALLEL. OTHERWISE, SEPARATE TOWERS!
GL/73, TOM - N4KG


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