[Elecraft] KAT100 LEDs Gone Wild

[MC Carpenter]

that did it, thanks
----- Original Message ----- 
From: "Jack Brindle" <jackbrindle at earthlink.net>
To: <Unifiedtx at aol.com>
Cc: <elecraft at mailman.qth.net>
Sent: Saturday, November 20, 2004 2:05 PM
Subject: Re: [Elecraft] KAT100 LEDs Gone Wild


> Roy;
>
> Try adding several feet of coax between the tuner and the antenna and  try 
> again. It appears you may have a voltage maximum occurring at the  tuner - 
> adding the coax will move it out a ways. There are just some  impedances 
> and feedline lengths that tuners have a difficult time  handling. If, by 
> chance the antenna is open-wire fed, then add coax  between the KAT100 and 
> the balun...
>
> Note that the Bird will see different line characteristics than the KAT 
> because it has a different placement in the line, and thus different 
> voltage/current values at that point. It is the values at the tuner  that 
> are critical, because they are what the tuner's LC circuits have  to 
> match.
>
> One other thing - the K2 gets the SWR from the KAT, so if the KAT's SWR 
> display is changing, the K2's SWR display should also be changing.
>
> If all else fails, make a video of the display and advertise it on 
> late-night TV. Late-night viewers will buy anything these days, and you 
> just might get rich doing it!
>
> On Nov 20, 2004, at 8:22 AM, Unifiedtx at aol.com wrote:
>
>> I thought that installing MCU1.05 there would be ample RF sampling  rates
>> taken to avoid erratic LED displays.  The updated firmware seems not  to 
>> be  the
>> solution.
>> With a 50 ohm dummy load on the KAT100 output only the leftmost LED 
>> lights
>> up and K2 SWR is 1:1 regardless of power or band in use.  With the 
>> Carolina
>> Windom 80 attached to the KAT100 output and a Bird 43 wattmeter  between 
>> the K2
>> output and KAT100 input, I found the reflected power stayed at zero  and 
>> the
>> forward power stayed at max (regardless of band or power setting)  while 
>> the
>> KAT100 LEDs and K2 SWR reading were going wild.  The wildest LED and  SWR
>> activity occurs on 30 meters but does not occur on all bands.
>> I have already removed the white wire from pin 7 of the K2 end of the  IO
>> port and put a .01 pF cap from the white wire to the bare wire on pin  1.
>> My shack is on the second floor (over my garage) and I have tried to  be 
>> as
>> attentive to grounding as possible.  I use a common grounding point  that
>> attaches to a 1/2 " copper pipe (used only for grounding) that goes  down 
>> approx  10
>> feet to an eight foot buried grounding rod.  I believe the K2 erratic 
>> SWR
>> activity will stop when the KAT100 LED stray RF problem has been 
>> eliminated.
>> Has anyone made any changes or done any bypassing inside the  KAT100 to
>> eliminate stray RF and tame the LED display?  Roy Morris   W4WFB
>
> - Jack Brindle, W6FB, ex-WA4FIB
> ------------------------------------------------------------------------ 
> ---------------------
>
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