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(_ ) Install the left end bell using the same hardware as with the right end bell. Make sure that
each corner is interlocked with its adjacent panel or panels before tightening screws. This
can best be accomplished by placing the left end bell down flat on the table and lowering the
rest of the assembly onto it.
(} Compiete the cabinet by installing the bottom rails and rubber feet as shown in Figure 22F.
Use the large #10 sheet metal screws through the feet, the bottom pane) and into the rails.
(_) The transmitter can now be installed in the cabinet. Place the transmitter chassis in front
of the cabinet and pass the line cord plug through the left hole in the back panel. Now slide
the transmitter chassis ontothe rails and into the cabinet while guiding the line cord through
the back hole. Use ten #10-32 phillips head screws to fasten the front panel to the case and
eight #10 sheet metal acrews through the back panel of the case into the back chassis apron.
INSTALLATION AND OPERATION
NOTE: It should be noted that an Amateur Radio Operator and Station License is required to
place this transmitter on the air. Information regarding licensing and amateur frequency al-
locations may be had from publications of the Federal Communications Commission or the Am-
erican Radio Relay League.
'This transmitter can be used for novice operation only if the following three requirements are
met: (a) CW operation only. (b) Crystal control only, on assigned novice frequencies. (c) Re-
duced output power - plate power input must be kept below 75 watts by light loading on the final
amplifier stage. Plate current should be held below 90 to 95 milliamperes.
GROUNDING: The importance of 2 good ground that presents low inipedance at all frequencies
cannot be emphasized too strongly. What may be a perfectly satisfactory ground at 160 meters
could place the transmitter considerably above ground at the higher RF frequencies. As an ex-
ample, the length of the ground wire is sometimes critical. An8 foot wirefrom the transmitter
to ground would be a direct short at 160 meters but becomes one-quarter wave length at 10 met-
ers and therefore places the chassis at a highRF potential. Some hints that will be of assistance
in obtaining a good ground are:
1. Connection for the ground should be made to cold water or well pipes and/or multiple pipes
or rods driven approximately eight or more feet into moist earth. A salt solution poured
around the ground rods will further increase the conductivity to ground.
A more elaborate
installation might include a aystem of wires approximately one-quarter wave length long
laid a few inches under the surface of the earth in a grid or radial pattern, The use of one
or all of these grounding systems may be combined to form a good ground reference.
2. The electrical connection to the ground point should consist of a short heavy conductor (#12
wire or heavier, or copper braid). Ia short ground wire is difficult to obtain because of
transmitter location, several leads of random length may be used. The use of random leads
leasens the possibility that all leads should become one-quarter wave length at thefrequency
of operation, If the transmitter becomes hot at one particular frequency, the addition of a
ground wire cut to one-half wave length at this frequency may clear up the difficulty.
Some of the symptoms of inadequate grounding are manifested in the form of:
1, Inability to load the antenna properly.
2.
High RF potentials on the chassis or case of the transmitter.
8.
Undue voltage strain on output circuit components.
4, Final plate current reading affected by touching the panel or case.
LOCATION:
The transmitter should be located where free circulation of air is possible and
ebjects should not be placedon the case as this might restrict the circulation of air.
Good ven-
tilation is essential to insure maximum component life.
A table or desk of adequate strength
must be used to withstand the weight of the transmitter.
The considerations
mentioned
with
regard to grounding will also affect the selection of a good location, as will the point af entry of
the antenna feeder.
Page 58
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