COLLINS 30K, MODEL 1 AM TRANSMITTER (Serial #11)
& COLLINS 310A EXCITER UNIT (Serial #11)

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Pi-network to replace the original swinging link assembly. It utilizes a
B&W 850A, R-175A RFC, and a couple of large variables. Unfortunately
the 850 did not do the trick due to the high plate load R of the 4-125A.

The 850A was replaced by a ceramic bandswitch and a combination of B&W miniductor
and hand wound 3/16" copper coil. This is the test setup to determine tap positions.
The resistor at bottom center represents the plate load resistance.

This view shows temp alligator clips that are easily moved during testing.

Here is the final configuration; small 10-meter coil; large coil for remaining bands

This view shows the silver plated 10-meter coil, RFC on teflon form, tuning cap and bandswitch.

Loading capacitor at bottom center and coaxial antenna relay

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