If it a receive only antenna you'll probably be alright ... If you
need a little more capacitance you could parallel a fixed cap with a
trimmer ... the main drawback is you'll probably only have 20Khz of
bandwidth without making adjustments to the cap ... For a receive only
antenna you can always scrounge a polycon cap out of a cheap radio,
they usually run around 200pf and I've gotten several from radios for
a buck in a dollar-only store ... the ones I snagged were TRF AM
receivers with a TA7642 (ZN414 clone) TRF IC in a TO-92 package as
well as a small ferrite loopstick
If it's for transmitting you'll probably want to use a larger diameter
tubing and an air variable with fairly wide spacing or a vacuum
variable for high power
JR
--- In loopantennas@..., "l_atape" <l_atape@...> wrote:
Dear community,
I am searching for a simple solution for building a material-saving
magnetic loop for the 15 m HAM band.
If possible, I would like to use 0,8 cm flexible copper tube.
Unfortunately, I have just little 1 - 50 pf trimmer capacitors, not
more.
Is there any possibility to build a. m. antenna with the material
available?
