[Premium-Rx] RF-590 VLF sensitivity improvement

[ToddRoberts2001 at aol.com]

After some careful listening today I noticed the RF-590 does have some 
fluorescent display noise at about 15.6KHz with a rough audible broad 3rd harmonic 
around 46-47KHz and this can drift in frequency a bit. The fundamental at 
15.6KHz is audible even with the antenna disconnected, I would say about an S-1 
signal level. Interesting that this fluorescent display noise frequency is very 
close to the standard horiz. osc frequencies used in standard TV sets. Using an 
outboard upconverter with a 4MHz LO the noise can be just about eliminated 
with the receiver tuned to 4015.6KHz and using shielded antenna connections to 
an outside antenna. Display noise on VLF would still be a problem if using a 
loop antenna or any antenna in close proximity to the receiver though. 73 Todd 
WD4NGG