[JMS] Info needed on 90800 transmitter

[JAMES T HANLON]

Cal,

1)  The original coils for the 90800 are in the 430XX series.  The =
proper coils for 80 meter operation are the 43082 in both the 807 and =
6L6 plate sockets.  The cathode coil for 160 meter crystals doubling in =
the plate of the 6L6 is the 43680.  If you use 80 meter crystals and go =
straight through in the 6L6, you set the cathode coil switch to "out."

2)  The Key terminal, "K," on the ceramic terminal strip is wired to key =
both the 6L6 and 807 cathodes together. =20

3)  I just use a bnc connector mounted in a bracket that I hang off of =
one of the screw holes in the chassis.  You may need to supplement the =
number of turns on the link to achieve the desired loading. =20

4)  The manual calls for a high voltage supply between 500 and 750 =
volts.  It doesn't specify the total current draw - there is a voltage =
divider network that derives voltage for the screens and 6L6 plate.  200 =
ma should be plenty.  Limit the voltage to 600 if you intend to modulate =
the 807.  You will also need -45 volts for grid bias on the 807 - I use =
five, nine-volt transistor radio batteries in series.  And of course you =
will need 6.3 volts at 1.8 amps for the filaments.

Jim, w8KGI


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