Hi Ed:
On Thu, 18 Mar 1999 09:13:37 -0500, Ed Bathgate, RMA Repair Dept x8785 wrote:
Ok, can I build a similar device?
Probably, as the inside is simple, but look around for
a used one. As more and more government/business's get
away from the low band, they will become easier to find.
How can they get a small can to do 6 meters?
Ah...the wonders of helical resonators! You have to
remember that these "cans" can only be set up for
NOTCHING a frequency, and not PASSING a frequency.
Look at any good commercial 2 meter or UHF radio. The
small square blocks near the antenna are helical
resonators.
What is inside the 'paint cans'?
A coil of wire (the helix) and a plunger on a threaded
rod which tunes the helix to the frequency of choice.
I already know of the heliax stub duplexer design...
I know a fellow who was selling his, it does not work
well according to him. I know where I can get paint
cans cheap...
Most of the heliax stubs are 1/4 wave length long, and
do basically the same as a helical resonator. The
shorted and opened stubs are there for usually the "C"
part of the "LC" circuit (creating the "50 ohm" in/out).
Tedd Doda CET
packet va3sed@va3sed
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