Yes, the previous owner added caps on the IF to tune it down to 455. The job
is well executed-- not hacked. I am just looking for the real specs on the
part. Perhaps this was modified by a CW or SSB guy.

Lionel Sharp writes:

My information says that the IF frequency is 470 Khz. Perhaps the IF
frequency has been changed to 455 Khz on the receiver in question to
suit the added filter.
Lionel L Sharp, VK4NS

nhoj wrote:
Steve---- What is the IF frequency of the BC 312. You are using a 455
khz filter. John

Steven Swift wrote:

I am restoring a 1937 BC-312.

A previous owner had installed a Collins mechanical filter in the 1st
detector stage (normally a coil with crystal phasing).

The Collins filter is part number 526-9395-00 and labelled "F 455 Z 7"

From google searches, it appears that this might be an SSB filter, but I
haven't found an exact reference.

Anyone know what this really is? I have to decide whether to "un-modify"
this stage or leave it as-is.

TIA,

Steve.




--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA

"Steven Swift" wrote in message
...

Yes, the previous owner added caps on the IF to tune it down to 455. The
job
is well executed-- not hacked. I am just looking for the real specs on the
part. Perhaps this was modified by a CW or SSB guy.


Might have been modified by an AM guy, since the 7-kHz filter
passband would yield a 3.5 kHz AM bandwidth.
Odd that he padded the IF stages--I'd have
thought they would have easily tuned down another 15kHz without issue.

Pete