Ron -
Sounds good to me! The only thing I would add is that the reason the
bandwidth narrows is because each time the signal 'goes around', it
'sees' the L/C 'filter' again. Think of two crystal filters in series,
each 6 dB down at a given point. With two 'perfect' filters in series
that same point would be 12 dB down.
The Q-Multiplier was a tremendous improvement for the receivers
available when I was first licensed. I still remember my AMAZEMENT when
I saw my first Heathkit QF-1 in operation on a receiver 'just like mine'
(HQ-129X) in 1957! :-) I couldn't get my order in the mail fast enough!!!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Ron wrote:
A lot of discussion about "other lists" recently, but on an "other
list" recently I was apparently the only answer to this gentleman's
question about how the Q multiplier works. Question is was I even
close to being correct?
TNX es 73,
Ron WD8SBB
<snip>
Hi Ron,
THANKS for the reply to my question. You were the lone response and so
very
much appreciated. Your answer makes very good sense and I am glad
to know why and what I am tweeking on the 2-BQ !
Also have several B lines here and a Sherwood R4C which is absolutely
awesome.
cu on the bands
OM Jim N5KY
<snip>
Jim,
On a very high level, a q multiplier is an amplifier that has positive
feedback. That feedback causes the signal to get "re-amplified". The
positive feedback is why if you "push" it, it howls, squeals, or in
technical term goes into oscillation. When the amp comes close to
oscillation is also tends to become very narrow in its amplification
(aka looking for a single frequency to "almost" oscillate on) and so
also acts as a narrow band filter.
Hope that all makes a little sense.
Regards,
Ron WD8SBB
<snip>
Greetings to the group,
As I stare at the schematic for the Drake 2-B Q multiplier (the
2-BQ) I must admit to not really understanding how and why it works.
Work it sure does .......but I could use a bit of education from
anyone who is less clueless than I seem to be !
in need of education Jim N5KY
<snip>
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