[R-390] Measuring Sensitivity - Ramblings...

[Barry]

Having some 150-ohm and 1-ohm 1% resistors, I made a 100:1 voltage divider
as discussed.  This definitely makes measuring the sensitivity an easier
task.  With this, I am seeing from 0.5uV to 1.5uV on the bands I tested.  I
need, though, to make a sniffer and see if some of what I'm seeing may be
attributable to leakage.  Hopefully, there isn't too much leakage and these
figures are pretty close to accurate.  By the way, I divided the observed
output level by 200 to get these figures.  If it is really only a factor of
100, then these figures are 1/2 what they should be.  I need to find out
which way to do this.  Maybe I can measure it at a higher voltage level with
my VTVM to know which is correct?

I'm observing something I didn't expect, though.  The radio seems to hear
better when fed by the unbalanced connection.  I hooked up the balanced
connection by feeding it into the left-hand pin (as observed from the rear),
but I did not ground the other pin.  I just happened to think of that.
Perhaps that will make a difference.

At any rate, when I use the unbalanced input, the antenna trimmer maxes the
signal at 3-o'clock with only one max point.  Is this normal or should there
be two peaking points on the trimmer like when using the balanced input?

Thanks,

Barry - N4BUQ