Ramsey Electronics AM25, Сборка и инструкция по эксплуатации

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AM25
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produce some heat and require a heatsink to carry the heat away from them.
When installing these parts, the transistor sits on the metal heatsink and a 4-
40 screw is passed through the transistor, heatsink and PC board, finally to
be tightly fastened with a 4-40 nut.
ˆ 98. Install Q9, TO-220 style NPN power transistor [marked TIP31] as
shown in the diagram. Use a 4-40 screw and nut to secure. Solder all
three leads.
ˆ 99. Install Q3, P16NF06 power FET in the same fashion as above.
ˆ 100. Locate D3, the red LED, notice that on of its leads is longer than the
other. Install D3 into the PC board leaving its leads at full length. The
longer lead goes into the PC board hole nearest the DIP switch. If
installed incorrectly, D3 will not light. D3 will later be fitted through the
front panel, so long leads are necessary.
What about those extra parts !!!???
This
completes the assembly of your transmitter
except for the low pass filter parts that are
dependent upon the frequency you choose to
operate on.
AM25 Final Assembly Instructions
You’ll need to determine what frequency you wish to set your transmitter to.
It really is not sufficient to just “check” the AM band for an empty frequency,
using the AM radio closest at hand. It is your responsibility to research what
AM stations can be listened to in your area and not to interfere with any of
your neighbors in their reception of
any commercially licensed broadcast
station. Usually a modern car radio (with external antenna) is extremely
sensitive and a good indicator of what stations will be received in your area.
Once your have determined what your operating frequency will be, refer to
the following chart for the correct values of C3,4,5,7 and L1,2,3. The
inductors will be wound using the remaining enameled magnet wire. If you
decide to change frequency at a later time, you can get more wire at any
electronics store or Radio Shack. The size is not vitally important, just as long
as you can fit all the windings on the core.
ˆ 101. Consult the frequency chart on the following page and install the
correct values for C3,4,5 and 7.
ˆ 102. Wind the toroid inductors. Consult the frequency chart again and
determine the proper number of turns for each inductor. Notice that L1
and L3 both have the same number of turns.
ˆ 103. Using the formula below, cut proper lengths of magnet wire.