Geoffrey Mackenzie-Kennedy wrote:
Henry, [EMAIL PROTECTED] , wrote:
Has anyone tried any of the DF4ZS RF speech processors
(http://jwm.de/afu/index0.htm) with a K2 yet?
For those who think the SSB "punch" is a little weak, maybe this
would help.
In fact, maybe this would be a good Mini-Module Kit.
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Great idea! Although I have not used DF4ZS's speech processor, I have
used various forms of this type of audio processor and RF clippers
over the years and have found that they are useful, perhaps more so
than low cost (not studio) audio compression devices. Personally if I
intended to buy one of his processors I would go for the larger
external unit, because reasonably good SSB filters should be used
before and after the RF clipping circuits, all followed by an audio
low pass filter at the output with a cutoff around 3kHz, all of which
I believe he has included in the larger unit. This could of course be
done with a smaller unit which included these items, but is there
enough space inside the K2 to fit it in? Also the processor should be
shielded to avoid the risk of RF feedback, and prevent the processor's
LO signal from getting out.
When used with a K2, I suspect that the K2's audio compressor should
be set for a small degree of compression, if any, and most / all of
the audio processing done by the RF clipper - just an unproven hunch.
73,
Geoff
GM4ESD
Hi Geoff, I would suggest if your making a mini-module let it be a
speech compression device, not a clipper. Compression increases average
power used and sounds louder. If set too high it sounds odd and can
create clipping that generates unwanted sidebands.
On my radio I run compression all the time. It works in conjunction
with the Automatic Linearity Control the radio has. If you don't have
ALC it is harder to set the Compression.
73 Karl K5DI
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