illrrrrrrW

Being qui te activ e on two me ter F M ,
I' ve recently felt a need to add some
versatil ity to my setup by installing a
remo te control system fro m my mo bil e to
ba se st ati o n. T he circuits I came up wi th
are ex tre me ly stable and reli able thro ugh
wide tem pe rat ure and volta ge variat ions.
The encoder an d decoder ar e eq ually usable
for sub contro l of co nvent ional tonecontro
lled in-band repeaters.
Encode r
T he encoder is a standard LC fee dba ck
ty pe, and is as stable and acc urate as th e
quali ty of the compo nen ts used in th e
collector circ uit. I used a standard 88 mH
toro id for the ind uctance , and then figured
ou t C I and C 2 fr om f~ 1/(2rr.,fLC) where f
is frequency in he rtz , L is ind uctance in
henrys, an d C is ca pacitance in farads. T h e
cap acitors are in a ratio of 1: J to get a high
Q. so after arriving at IO(C I )2 /1I(C I)~ C
36
Bo b Kertesz VE2BZK
7794 Kildare R d.
Cote S t. Luc 268, Quebec
'"
II
" me
it CI VALU E IS 10 T IMES C2 ,
(C2 SHOUL D 8E O ,O ~-O,2 5 "F)
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o
21\129 2 5
cant. an page 38
73 MAGAZIN E