On Tue, 10 Feb 2009, Tim Wescott wrote:

I believe there was a regular brand rig (Kenwood?) of about that era that
also used the same mixing scheme, and had the same frequency fixed IF, if
not all the same matching impedances. I can't really recall, though,
other than I was thumbing through a replacement filter catalog and
noticed it because I had the SB-201.

That sounds familiar, though I can't remember which brand it was either.

I just did some searching, and I was thrown off by the mention of "early"
in the first post.

I was thinking of the Heathkit Commanche as a small receiver suitable
for mobile operation, and it was used in tandem with the am Cheyenne
transmitter. A check shows that receiver used a 3MHz IF. The Mohawk,
which was a full blown receiver, used 1682KHz and then down to 50KHz,
obviously not a standard combination in Heathkit receivers. The HR-20
Mobile SSB receiver used a 3MHz IF too. A quick search doesn't turn
up what IF's the matching SSB transmitters were using, but I assume
they too were 3MHz.

So then Heathkit moved to 3395KHz, and that was pretty standard for
a really long time. I think even the HW series of monoband SSB
transceivers used the same frequency, though they used multiple
crystals rather than prebuilt crystal filter.

It's all relative, but I think of "early" as the pre-SB line, not
the SB line itself. Heath kept the SB line going into the seventies,
with cosmetic changes but the same basic design.

Michael VE2BVW