[AMRadio] Filament choke

sbjohnston at aol.com sbjohnston at aol.com
Wed Apr 29 14:32:28 EDT 2009

I'm building a 160m grounded-grid amp around the GI-7B tube
(it worked so well in my SB-230 retrofit project:
http://www.wd8das.net/SB230.html    )

Anyone know of a source for a filament choke appropriate for this tube? 
  The filament draws only 2 amps, so the 30-amp ones I see available 
online are really overkill (and awfully large).  But for 160m I'm 
thinking that a somewhat higher inductance than might normally be used 
for 80-10m amps might be in order.  Say >50 uH?.  Bifilar-wound would 
be best, but two separate chokes would probably work too.

Should I not find a ready-made source, then I guess I could make one if 
I find some ferrite rod suitable for use at 1.9 MHz.


Steve WD8DAS

sbjohnston at aol.com
Radio is your best entertainment value.

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