RRC 1258 Support in English > General discussion forum

Audio Hiss Solved

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VE6WZ:
Using both K3 twin and Yaesu FTdx-9000d radios with RCC1258 units for a long time I have had a bad audio hiss even with the volume turned to zero.

Solution: Do NOT use audio CODEC with 12 bit. I now use audio quality 2 which is 16 bit.
I found that even higher quality settings using 12 bit will cause audio hiss. 16 bit all ok.

I'm posting this in case others have the same problem.

de steve ve6wz.

cx6vm:
Hi Steve

thanks very much

just starting with remote and many things to improve. Is very noticeable the improvement changing from 12 to 16 bits!

73,
Jorge
CX6VM/CW5W

n6ldj:
Thanks.  16-bit worked here as well.  I was using Quality-0, "A-Law 8 kHz" and we had hiss.   It came from the radio end, and I thought it was the radio generating this (one channel was speaker audio that might have had audio PA hiss, but the second audio channel was low-level [300 mV] discriminator audio from a Motorola XPR4550 mobile radio).  Both channels had equal hiss before the fix.   Both are now fixed.

I modified the second audio channel input (ring, not tip) on the radio end to make it high-impedance (>100k ohm) so it would not load down the discriminator line.  This channel still has a bit more hiss, but its more than tolerable.

N6LDJ         

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