While a bit dated now, mainly due to the100Hz display resolution (but 10Hz
steps from the knob or up/down buttons on the microphone), the Yaesu 757 GX
mark 2 is a good basis for LF work. The MDS(Minimum Discernable Signal) with
the preamp on (yep, it works on LF) is in the order of -137 dBm (at 182 kHz)
in the standard 600 Hz CW filter bandwidth (narrower CW filters are
available from third party suppliers) and the noise blanker really works on
LF as well as HF. With the rig 'broadbanded', the tx level out the
transverter port is about half the spec figure but still more than enough to
drive LF tx units etc. The antenna bandswitching logic connections on the
rear panel support a frequency slot from DC up to 1.5 MHz (not documented
but its there!) so one can distinguish between low band and LF antennas
automatically. Higher bands are no problem of course so cross band QSOs are
simple. Switch freq and the antennas follow.

BTW, thanks to Alan and Brian for reposting the original message from Walter
re the Puckeridge mast.