In a previous post I noted that the sensitivity of the IC-7000 starts getting worse in the middle of the MF band, growing increasingly more deaf with lower frequency, as bad as 25uV on 310 for instance. Measurements done with preamp on.
Dallas Lankford informed me yesterday that this effect is due to the preamp. If the preamp is disengaged, and a Norton push-pull preamp is placed between the antenna and receiver instead, the IC-7000 will remain its excellent sensitivity at least down to 200 kHz.
Indeed it is so. The receiver was very quiet when I tuned the LF band with the preamp on. When I switched it off, the signal level increased dramatically! I noticed this down to about 200 kHz, when the difference tended to decrease. Ingøy-153 was about equal level with and without preamp.
I didn't bother to put up the signal generator for exact measurements. Maybe I will one day. Today's Word of Wisdom then: If you want to tune LF with the IC-7000, do NOT engage the preamp.