On Jan 21, 2:28*pm, carlos2007
wrote:
Yes, I turn the tone control fully clockwise and move the passband
tuning too, but I cannot get improvement in weak signals.
I have tried with a multi mode audio filter, a *Datong FL-3, no
results.
With respect to the antenna it is a Wellbrook 1530+.

Now, I hesitate in buying *a R7A or a Collins 390A and to selling the
R8b.

--
carlos2007

First of all, I'm glad that you are reconsidering buying a new
expensive radio. It won't solve your problem, since I had the same
issue with not understanding speech from weak tropical band signals
with my R7. I had a Sherwood SE-3 synch detector (your R8B has a
synch built-in) and ran the audio out to a good speaker, but still it
was too bassy. I thought about using a graphic equalizer to adjust
the tone. Here was some great advice I received on this forum years
ago:


"If bass rolloff is only what you're after. There is a
simpler way. Put a non-polarized capacitor between the R--7
and the speaker. There are numerous nomographs for picking
the right cap for your situation in most any radio
handbook. Audio handbook, too, for that matter. But you'll
likely want to cut and try anyway.

Its simple, cost efficient, and it doesn't require a ground,
so you can do it with most any radio."

I went to a Radio Shack and looked through the catalog for the low cut-
off frequency of different capacitors, and just attached one wire to
the capacitor on one end, and put the other end into the speaker.
Huge improvement. Experiment with different cut-off frequencies for
your personal taste, shouldn't cost very much and certainly cheaper
than a new rig.