I finished the 150xt yesterday.
The enclosure is the nice part--it's just a plastic cassette case which
I spray painted black. It's very easy to modify, drill and cut. I used
hot glue to keep a thin piece of rubber under the circuit board, then
hot glued the circuit board onto the rubber. The two coils are 5mm
"Unicoils" from Coilcraft. The violet is 7½ turns and is 156nH with the
core removed. The green is 5½ turns and is 99nH with the core removed.
The crystal is a common 16MHz with a 20pF load capacitance. It was
ordered from overseas at a great discount on eBay. The final frequency
tunes at 160.050MHz.
A small hole was punched for the antenna wire. A power switch was added
and its hole carefully cut with an Exacto knife. 4x AAA rechargeable
NiMH provide 4.8 volts. The battery holder still fits inside the slim
The design may be simple, but the results are sturdy and professional.
Clear audio. A good range. And inexpensive and easy to build. The
design is flexible and allows using substitute and junk-box
parts. Some of small capacitors values were changed to my nearest
available value... i.e. 22pF to 27pF, etc. I'm making a few more
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Assembled 150xt Transmitter - By Pete Zenner