[Elecraft] K2 RF Speech Processor?

[Karl Larsen]

Geoffrey Mackenzie-Kennedy wrote:
> Henry,  K4tmc at aol.com , 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.
>
> -------------------------------------------------------------------------- 
>
>
> 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