[Milsurplus] GF-11, #4381

[Mike]

JOHNGRU@aol.com wrote:

> Questions: info on the antenna used on the aircraft? i assume this
> was an "electrically short" antenna, because of the way the output
> circuit is designed. is this correct, and what is the approx. length
> of the antenna & feed line??

According to the GF-11/RU-16 manual:

Operation from 6 to 9 mcs:  Antenna should be "T structure having a
flat-top section which is between 15 and 18 feet long, with a down lead
about 9 feet long to the lead-in insulator.  If an L antenna is used,
its total length ... should be 20 to 25 feet."

Operation below 4 mcs:  "...total length of wire should be 35 - 50
feet..."

> and the purpose of measuring the modulator plate current ???

Useful for troubleshooting.  The manual contains a table of expected
values of modulator current.

> what voltage did the GF-11 use; the dynamotor output voltage/voltages?

14 vdc for the LV supply.  The dynamotor is rated 425 vdc/163 mA
output.  The manual lists 415 vdc as typical output with a 14 vdc
supply.

> does anyone have any idea of the voltage ratings of the by-pass caps.
> 500 volts too high on the 837s ??

The HV bypass caps are all paper caps rated at 300 or 400 wvdc (even
though the dynamotor put out a slightly higher value), depending where
they are in the circuit.  As the capacitors will be 60 years old, I
wouldn't bet a whole lot on them surviving for long when exposed to
those voltages, or even when exposed to substantially lower voltages.

> i will pay anyone for a copy (or for copying) of the GF-11 manual.
> 
> i need a schematic diagram of the control box (CW-23097) and the
> interconnect between it and the transmitter.

Send me your address.  When I get back from vacation in a few days, I'll
make you a copy of the pertainent parts of the GF-11/RU-16 manual.

73,
Mike / KK5F