Yes, the tone control switch disables AVC when set to "C.W." I prefer
the independence of control that the S-40B provides.
But one advantage of the 8R-40 might be the open switch contact on the
tone control wafer when the switch is set to "C.W." It might be a good
place to mount a relatively narrow filter for CW operation.
Of course, what looks good on a schematic might be terribly difficult in
the actual physical receiver.
73,
Maynard
W6PAP
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On 8/4/24 16:34, Richard Knoppow wrote:
I have to look at the 8R-40, does the control turn off the AVC when
the BFO is operating? Does not on any of the S-20R/S-40 series. The
HQ-120-X and its successors are wired that way, manual RF when the BFO
is turned on. Not an arrangement I like very much. Evidently, the 8R-40
and S-40 were built for different markets. I wonder who the 8R40 was
intended for. Where were they advertised?
On 8/4/2024 6:09 AM, Maynard Wright, P. E., W6PAP via groups.io wrote:
One interesting difference between the S-40B and the 8R-40 is the use of
the tone control to control tone, BFO, and AVC. These are all
separately controlled in the S-40B. When the control is set to "C.W."
on the 8R-40, the tone control network is set the same as for "HIGH."
If one is using no external CW filter, "LOW" might be a better choice.
That works well for me when using the S-40B with an Elmac AF-67 for CW.
I haven't, though, compared the different runs of the 8R-40 to see
whether this arrangement persists throughout production.
73,
Maynard
W6PAP
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
