*deleted* wrote:
>
> Gerald,
> I think I would be more inclined to forget about the remains of
> the Henry and rework the SB220 if there is something wrong with it.
> Ive used a 220 for contesting and never had any troubles with it.
> Im not sure what you mean by "parasitic syndrome"
Hi,
...and thanks for the reply. I do intend to re-work the SB-220;
I think they're fine amps and it has served me well to this point.
The "parasitic syndrome" comment was somewhat tongue-in-cheek, as I
know a great degree of debate has gone back and forth on this issue
on this reflector (I have skimmed thru <most> of the reflector archives)
as well as in the ham mags. Depending on whose point-of-view you
subscribe to, it sounds like the classic "case": square mica on GND
leg of grid-to-ground RF choke cuts loose with a dramatic KAPOW! during
hurried tune-up on 10M while I was chasing a VR6 when the band opened up
to the Pac a few weeks back, collapsing the pi-windings on the rfc and
distorting the form and frying the parasitic suppressors (stock) at the
same time. Oh, the 5.1 V bulkhead Zener for bias looks like its gone
too.
I intend to re-fit the AG6K parasitics to it and replace C18 w/
a 500V silver mica, but I'm concerned about the current capability of
most of the 1uH RF chokes I'm seeing in replacing RFC-4 (i.e. the little
434-1100 on p.244 in my Mouser cat), but on the other hand, I guess
the thing <IS> sorta supposed to act as a fuse anyhow, hi!
The Henry just looks like a challange to fool with. I'm bad
about that (ask my XYL!); I'm the kinda guy that will buy <three>
basket-case Super Pro 400's and try and make <two> good ones out of it!
The advantage that I can envision here is that the stock SB-220 ps
was designed when pwr limits were different and I don't think I'm
getting
quite as much out of a pair of 3-500Z's as they are capable of
delivering
(while still allowing adequate safety reserves). That's why I'm trying
to get to 3kV on the plate, they're rated to 4000V and the -220 in SSB
pos only puts a bit over 2000 on 'em key-down.
OTOH, we may well be splitting straws over fractional dB gains
here; but I've heard guys debate well into the night over lesser gain
differences in antennas, hi! I'm just not trying to fool myself into
thinking I'm a RF injuneer or compentent enough circuit designer to be
able to consider <ALL> the parameters that might go into a consideration
of what is the <best> way (cost/benefits in consideration) to get the
most juice out of a pair of -500Z's (or poss. the -600's if/when they
become available.). Tnx agn for taking the time to reply.
73, Gerald W5BA
cdent@tenet.edu
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