Andy, DF9OX wrote:
"Problem is: Now I have a fine AM medium-wave gamma-matched tower.
Resonance frequency is below 1700 kHz, Variabel-cap says abt 130 pF.
Bandwith +/- 15kHz (border SWR 2).... Could be rented by AM-Pirates....
:-)...
Question: How can I bring the QRG up to 1830kHz?"
==========
On a shunt-fed tower with a gamma (single capacitor) match, there are
only three ways (to my knowledge) of raising the frequency of the best
SWR:
1) Move the shunt wire tap point down the tower, closer to ground.
2) Decrease the spacing of the shunt wire to the tower.
3) Use a larger diameter shunt wire or use a multiple shunt wire "cage".
Andy says that options 1 and 2 are not possible, so option 3 is his only
possibility unless he decides to change his single-capacitor "gamma"
match to some other method of tuning.
73, de Earl, K6SE
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