jimg wrote:

first disconnect the antenna from both receivers and short the antenna
terminals...turn up the rf gain and audio...both real quiet, i bet?
good.

then it's from the antenna-ground-rf front end combo... are you using
the 50ohm input on both, or the long wire input?

lets say, the long wire inputs....well, i doubt they have the same
input impedance...if your not using coax and don't have a reasonable
impedance match, then the antenna's are going to act very
diffferently...( how are they grounded? tied together? hmmmm)

if your using the 50 ohm inputs, have a well designed antenna with
good matching, then we have to discuss the reactive component at the
antenna input...and even the selectivity of the first if stage....
you really want to know, we'd have to take 'em into a lab with very
controlled conditions to trace out the diff...but it's not
magik...just complicated

wrote:

Before leaving the topic of noise and quiet receivers, I have a
question. Tonight I was listening to a couple of Spanish language
stations on 6185 and 6125 khz. On the Drake R8B, there was a background
noise behind these signals and in fact behind most of the signals on
this particular band. (It sounds like atmospheric noise--a vague, hissy
sound that fades in and out a bit, just as the signal fades in and
out). On the other hand, when I listened to these two stations on the
Lowe HF-150, there was almost no trace of the noise. Both receivers
were connected to the same antenna. I experimented with different power
sources. Powering the R8B from it's internal power supply vs. an
external power supply didn't have any effect on what I heard.

This noise isn't always there, although I've heard it before. What
puzzles me is the Lowe receiver's failure to be affected by it. Why was
it interfering with the Drake, but not the Lowe? The receivers were
sitting right next to each other (I tried separating them, just for the
heck of it, but it made no difference.)

Any thoughts?

Steve

Are you saying the noise could also be heard on the Lowe but it was just
lower?

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jimg
Oregon
USA