[GLOWBUG] kinda long: need guidance for HB rig

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From: Paul Mills (quahog@localnet.com)
Date: Thu Apr 03 2003 - 20:31:41 CST


Hello all,

 JA9MAT's 'Compact Transmitter in an Altoids Tin' put a bee in
my bonnet. I have been wanting to get on 30M qrp for a while,
preferably with a small transmitter that I could use with my
TS-520. I know, The TS-520 doesn't have 30M, but the WWV switch
will put you there, and I tweaked the input coil to about 10.109
center, and have been hearing some pretty good stuff!

 Well, a coupla weeks ago, my younger bro. was cleaning out his
old CB shack in the ancestral manor (at the Lord and Lady's firm
request), and pulled out some old tube-type CB rigs and a hybrid
marine AM'er (2182 MHz etc.). What a treasure-trove of parts
for glowbug HB! I tore into them like a madman, un-soldering
parts and checking tubes, some of which may be difficult or
impossible to find these days. I even got an old Gonset G-14 CB
that looks like it would be no sweat to convert to 10M AM. I
plan to do as close to a real restore as I can, but that's for
another time, as are the pair of 12DQ6a's, mod transformer and
large coils I got from the marine rig.

 What is relevant here is that I got a couple of 6GH8A's which
are a sub for the [6|5]EA8 in JA9MAT's rig. Only hesitation I
have is having to build a power supply for them with these old
power transformers. I would prefer to leave that for another
time. Well, it occured to me to look at the TS-520 schematic
for a solution, and there it was (maybe). The transverter
connector has a +210V output that may solve my problem.

 Q. Has anyone ever done anything like this?

Couple more Q's

 The JA9MAT rig is cathode keyed. Will I be able to key it with
my MFJ-422D keyer? It does solid state and grid-block with
jumper settings. Will I need to add something like a high
voltage FET, an IRF-5something to accomplish this?

 I have some power tubes -- 6BQ5 and 12AB5 -- that I would like
to experiment with. I seem to remember the 6BQ5/EL84? as a
guitar amp tube. Am I on the right path here for a full qrp
gallon here?

 Is the simple tank circuit output in the JA9MAT rig OK for
harmonics at that power level? would I need to add an external
LPF?

TIA,

Paul KB1GEJ


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