K-1 RIT Range mod, audio AGC.

Is there a modification to reduce the RIT range on the K-1 to
about +- 1KHz?

I'd also be grateful to know of a pot suitable for this mod that had a center detent. Or a multi-turn pot that would fit in the allowed space

Also, I'm looking for an outboard audio AGC circuit into about a 2 Watt amp.  I find that the sidetone is way too loud when I'm searching for weak signals and have the audio turned up.  Am now using a DSP-59+ for the AGC action but it is a bit noisy and physically large.

72,

Tim



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[Don Wilhelm-4]

Tim,

There are several ways to change the RIT range.  The circuit is a simple
voltage divider with the pot in the middle.  Currently each resistor is
10k - Front Panel R4 and R5 sit on each side of the pot and the series
combination is fed by the 6 volt regulated supply.  If you increase both
R4 and R5 (keeping both values the same) the voltage range controlled by
the pot will be smaller.  How much smaller is to be determined either by
calculation along with checking the datasheet for the MV209 Varactor or
experimentation.  Right now the offset voltage to the varactor in the
VFO is varied from 4 volts to 2 volts - and you may want to cut it by
about half that range (I have not checked the datasheet, that is only a
good guess, so you might try 24 k instead of 10k for R4 and R5 - if that
does not give you the range you want, try another value.

Ant 10k pot of the same size and mounting can be used in place of R3 -
if you can find one with a center detent, I am certain many would like
to know about it.  The problem with using a center detent is that zero
RIT offset may not occur right at the center of the pot rotation, and
you will have to fiddle with the relative values of R4 and R5 to place
the center where you want it.

No answer on the outboard "AGC" - but you might want to adjust the
sidetone volume down in relation to the signals using the ST L menu.
Having the sidetone volume follow the AF Gain control is an oft disputed
point for the K2 (which does not adjust sidetone volume with
AF Gain) - it seems it is not possible to please everyone.

73,
Don W3FPR

[hidden email] wrote:

> Is there a modification to reduce the RIT range on the K-1 to
> about +- 1KHz?
>
> I'd also be grateful to know of a pot suitable for this mod that had a center detent. Or a multi-turn pot that would fit in the allowed space
>
> Also, I'm looking for an outboard audio AGC circuit into about a 2 Watt amp.  I find that the sidetone is way too loud when I'm searching for weak signals and have the audio turned up.  Am now using a DSP-59+ for the AGC action but it is a bit noisy and physically large.
>
> 72,
>
> Tim
>
>
>
> ____________________________________________________________
> FIRE SALE: iPads for $23.74?
> SPECIAL REPORT: iPads are being auctioned for an incredible 85% off!
> http://thirdpartyoffers.juno.com/TGL3131/4c3cba2fc7cad27f3abst03duc
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>  

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