[Elecraft] Re: K2 Power Callibration

[jferg977 at aol.com]

From: "Don Wilhelm" <w3fpr at earthlink.net>
Subject: RE: [Elecraft] K2 Power Calibration
To: "Cathy James" <prjames at mindspring.com>, <elecraft at mailman.qth.net>
Message-ID: <NGEDLJLDCGJIHEGPMIJPEEBJEEAA.w3fpr at earthlink.net>
Content-Type: text/plain;   charset="iso-8859-1"

""Adding either the KAT2, KPA100 or KAT100 options will include a proper
wattmeter in the K2 system and the display will indicate the proper 
power
(if the wattmeter is calibrated properly), but the basic K2 uses only 
an RF
Probe type detector and reports the 'power' based on the assumption 
that the
load is 50 ohms non-reactive.  Try a dummy load and if you see a major
discrepancy, you can blame the interconnecting coax or the wattmeter - 
the
basic K2 power indication is quite correct when the laod is a 50 ohm 
proper
dummy load.

73,
Don W3FPR""

Don, I attribute a fair amount of the convulsions involved in getting 
my K2 callibrated to an inaccurate wattmeter.  It came on the manual 
tuner I bought.  I fed a 50 ohm dummy load through the tuner with it 
set to "bypass"   I got readings on the wattmeter much higher than 
those that I was actually putting out as we ascertained when we later 
used a good wattmeter.

I think this speaks somewhat to assumptions about what the k2 builder 
will already have or purchase for the project.  I already had a good 
DMM  which agrees in the areas we checked with a really good Fluke - no 
fluke apparently.  The manual for the KPA100 suggest you may have 
problems if you callibrate with a bad wattmeter.  Soooooo, if you can 
use the rf probe which you build with the k2 kit and a DMM, why not 
suggest this as an alternative method to anyone who suspects his 
wattmeter is not good or (gasp) doesn't have one?  Or am I all confused.

Incidently 5087 works so well, I can't believe the range I get both in 
and out on ssb 20, 40 & 80- meters with just the 23 foot whip.  73,  
John KI4NGH