[Elecraft] K60XV with KAT2 ALC problem

[Gregory P. Daly]

oops.... you're right... now that I look through the scattered pile of
paper under the bench.... never mind... at least I was looking at the
right signal ;-)

Thanks


Greg.

On Sun, 2005-03-06 at 18:23 -0500, W3FPR - Don Wilhelm wrote:
> Greg,
> 
> Take a look at the K60XV errata sheet, and look for the 470 ohm resistor
> that is supplied with the K60XV - that resistor is to replace R6 on the KAT2
> board.
> 
> The problem is that all options that drive the VFRDET line except the KAT2
> use tri-state drivers, but it would be difficult to change the KAT2 to a
> tri-state driver - so the KAT2 output interferes with the K60XV output
> signal when the K60XV is active.  The increased value resistor almost
> eliminates the interaction and does not hurt the KAT2 when it is used.
> 
> 73,
> Don W3FPR
> 
> > -----Original Message-----
> >
> > With the tuner plugged in, the ALC voltage, on pin 6 of J13 on the
> > K60XV, varies from 0.820V at minimum power to 2.971V (Fluke 8060A with
> > current calibration sticker, all the digits are correct) when it stops
> > going up, at .70 mW indicated, it looses ALC control.
> >
> > With the tuner unplugged, it seems happy, ALC runs from 0.811 to 3.505V
> > when it's claiming to be making 1 mW (it really only makes 0.820 mW but
> > I can live with 0.8 dB low. I'll work on calibration later).
> >
> > I looked at the tuner, R6 (47 ohms) is present and correct. R6
> > "isolates" the ALC buss from the low output impedance of the LM358 that
> > makes the forward power indication on the buss.
> >
>