Any thoughts on HW-18 sensitivity?

[WB4LNM]

I have an HW-18 that I have changed over to crystal controlled operation on
3920 kHz LSB for state SSB net use.

I'm guessing that mine was the HW18-1 for 4450-4650 kHz or -2 for 4400-4600
kHz instead of the -3 for 1800-2000 kHz since it had an upper sideband BFO
crystal instead of the LSB which would have been in the -3.

My unit does work, but the sensitivity on receive seemed poor, despite the
fact that the driver plate coil, L3, peaks well on 3920.  The DISTANT / LOCAL
switch does work and is on DISTANT.

I wound a separate front end coil and ran the antenna directly to that.  Seems
to help some, but is still lacking sensitivity that I would expect.  Tubes
check out OK.  Spec list says it should have at least 10 dB S+N/N output on
0.5 uV.  I'm not getting that.  The TR diode is a 57-27.  I think that was
just a power supply diode, something like a 1N4004.

Unfortunately, I don't have an HP-23, so I'm having to run it off of a Collins
KWM-2  +12VDC converter supply.  Same voltages which check out ok.  However,
it does not leave much time for long-term checkouts between battery swaps!

Looking for some ideas.  It has been a while since I had it open, but am
considering delving into it again before the end of winter.  Thanks in
advance.   73     John....   WB4LNM

"One of the Hams from Heath"

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