[Pro2006] Re: 2006 Audio Hiss

[pro2006@mailman.qth.net]

Unfortunately most modern tape recorders have a pretty decent Automatic Gain 
Control 
circuit which attempts to keep whatever audio is available at a decent 
recording level.

This is great for getting good recording at a lecture but a nightmare when 
using the VOX feature.
The relatively small hiss is amplified to the point that the recorder begins 
recording 
it and when a real signal appears (Squelch opens) the recording is hugely 
overmodulated for a moment as the recorders AGC attempts to lower it.

Some have used a small .001 capacitor and placed this across the recorder 
output jack on the rear of the 2005/2006. This will however effect the sound
quality by removing some of the low end portion of the audio.

I found that it was simpler to place a 1k ohm resistor in series with the 
center
lead of the wire from the scanner to the recorder.

Each recorder will need a different value resistor ( Different gain ) so try 
a temporary 
500, 1k and 1.5k ohm resistor from the junk box until you find the level that 
you like.

I found that a higher value resistor made the recording have less AGC pumping
because the signal level was ow enough that the AGC was already at near max.

Then shrink sleeve it and you have a nice attenuating patch cable.

Good luck
S
out


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