DID TEURS

so lde r one end terminal and
the arm toge ther. Then
sol d e r ab out 3/ 4- i nc h
lengths of wire to eac h end
terminal. Bend the leads
strai ght back from the front
of the pot and set it aside
for a few m oments.
Pu II the bottom cover off
the rig to expose the transmitter
circuit board . R1 34 is
located behi nd the deviation
pot. (See Fig. 2.) Snip
the resistor in half, crush
the ca rbon and composition
from the leads, and
bend the leads straight up.
Now solder the leads from
the pot to the leads protruding
from the circuit
board. Be carefu l - not too
much heat-you don't
want the so lder to flow on
the foil side of the board.
To adjust the pot, set it
for about SOOk and get into
a QSO on a Pl -controlled
repeater. Sl ightly increase
the res is tance o n each
transmissi o n. When t he
other stations report that
they ca n no longer hear the
tone, note the position, but
continue increasin g the resista
nce until you ca n no
longer hold the machi ne.
Then set the pot midway
between those two points.
If you fi nd that you ca n no
longer hold the m achine
w hile the tone is sti ll audib
le, chec k the frequen cy of
the tone.
As long as you have the
rig on the benc h, you m ay
as well consider o ne other
simple m od . M y ri g is in and
out of the car severa l times
a day. A t that rate, it d id n't
take long for the p hone
plug coax connector to bec
o m e l o o se a nd interm
ittent. After taking the rig
apart several times to
tighten up the con nector, it
finally dawned o n me that
there must be a better way.
O ne way would be to replace
the phono jack with a
chassis-mount BN C connector.
That would requ ire
some (slight) mechanical rew
ork of the box, however.
Since m y mechanical ability
is zero-I can't even put
the ca p o n a peanut butter
jar witho ut getting it crossthreaded-I
began considering
alternative so lutions.
I decided that a short piece
of coax and a few connectors
could do the trick.
For m ost practical purposes,
the input and output
characteristics of a halfwave
sec tion of coax are
the same. If you were to
solder a half-wave section
of coax to the o ut put of the
rig, you w ould effectively
move the outpu t point to
the end of t he coax. That is
the theory.
To pu t theory into practice,
sol der a UG-89/U BNC
connector to one end of a
piece of so l id-d ie lect ric
RG-S8. O n the other end,
solder a phono
plug. The
distance from the open end
of the UC-89 to t he tip of
the phono plug sho uld be
24-1/2 inches.
Now, tack so lder the
phone plug to the antenna
connector on the rig. I emphasiz
e tack solder, beca
use you may eventually
have to take the rig apart
f or m a intenance, and a
completely so ldered co n­
nection would be a bea r to
get apart.
Replace the phone plugs
in your ca r or shack, o r
wherever else you operate,
with UC-88fU connectors;
you' ll be back in business
"LOOK"
THIS BIG G IS THE
SYMBOL OF
METROLINA'S FASTEST
GROWING HAM DEALER
(803)366-7157
800-845-6~83
D
G.I.S.M.O.
2305 CHERRY ROAD
ROCK HILL, S.C. 29730
w ithout in termittent coax
connectors.
There are seve ral other
mods w hi ch I would l ike to
describe in futu re artic les.
D
Service Department
Call 803-366-1158
In the meantime, you ca n
en joy operation w it hout
interm ittent coax connector
s a n d w ithout t he
hum.•
DO
DO
D
([J: 9 P
ro.
....R T Of ~'--"L-~ _
"'" ~
1:
r
n • •
::::"
,,~
rH~~nT
Fig. 1. The tone generator, 1(102, and the electrical I~
cation of R134 in the output circuit.
..
-1 ~ 1_~
Fig. 2. The physical/ocation o f R134 behind the transmitter
de viation pot. Most minor components have been omitted
for clarit y.
73 Magazine · April, 1981 97