[Elecraft] Setting KPA100 Bias?

Fri Oct 18 08:53:01 2002

Hi

I use the analog bar graph on my Fluke 87 DMM to set the bias to the corr=
ect value immediately after hitting tune. The reading will climb over the=
 next second or 2 but I ignore anything after the initial reading. That i=
s why I like the bar graph on the Fluke DMM as it has a 40 times a second=
 reading rate while the digital display has a 4 times a second reading ra=
te.  Analog is better for making this type of peak reading that is why Fl=
uke includes the bar graph on most of their meters. If your DMM does not =
have this feature then try to use the first or second reading after you h=
it tune. Go out of tune and try again several times until you get a good =
reading as soon after hitting tune as you can.

Don Brown
KD5NDB

----- Original Message -----
From: JAKidz
Sent: Friday, October 18, 2002 12:41 AM
To: [email protected]
Cc: [email protected]
Subject: [Elecraft] Setting KPA100 Bias?

Greetings, Tom and the Group:
How fast is "when you first enter TUNE mode"? Given 532 mA, my target is
932 mA. When I hit TUNE in CW TEST, it looks like the current is followin=
g
an exponential curve, the rate of increase slowing to a slow change after
about 25 seconds. If I set R6 for the target current in a few seconds, th=
e
plateau is about 1.2A or higher and I wouldn't say it is slowly drifting
higher from the 932 mA. Is the resistance in my jury-rigged meter cabling
between the power supply and the K2 cable causing an unusually long
time-constant?

Is N5WU's method, posted by Tom, of measuring the voltage change across R=
7
likely a better method in my case?

Or am I about to enter the Trouble Shooting mode in the upcoming Transmit
Tests?

Thanks much.
John, K7JG.

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