Re: Microphone level adjustment question



I think the experts here, which I am not one, will tell you to do
Martien's stability mod no matter what. Its not hard to do and may save
you a lot of headaches.

Frank - W4NHJ

On 6/2/2010 9:09 PM, k9jri@... wrote:

When I listen to my Hendricks BitX20A on a local receiver I hear some
really rough audio at times. If I use my electret mic it is worse than
if I use an old 600 ohm dynamic mic with a DC blocking cap.

Back in the good old days, before ALC, I would use a scope to look at
the RF envelope for flat topping but I no longer have a scope. Is
there any simple way to detect flat topping other than to look at the
output with a scope?

My concern is that if I am NOT flat topping the finals badly then it
may be a sign of the instability problem pointed out by Martien
(PE1BWI) and I should apply his stability mods.

I would appreciate any input you might have on the proper way to
adjust the audio input levels without a scope AND and comments on the
likelihood that the is the instability that PE1BWI was talking about.

Oh yes.... the local receiver was not being overloaded. Both the local
receiver and the BitX20A were connected to 50 ohm dummy loads and I
was listening with headphones to prevent any feedback possibilities.

73 - Mike - K9JRI

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