I tried TWO good watt meters on the K2 and I found that the K2 is NOT accurate.
The ONLY place I found it to be accurate is at exactly two watts. I also found
that my K2/100 will go down to 100 Mw then jump to just over one watt, then to
over to three and etc, it's not a smooth transition. I
100 MW now that's what I call QRPP !
When is the next Elecraft QRO amp due ?
:)
73
Stewart G3RXQ
On Wed, 24 May 2006 07:45:19 -0700 (PDT), Curt wrote:
I tried TWO good watt meters on the K2 and I found that the K2 is NOT
accurate. The ONLY place I found it to be accurate is at exactly two
The basic K2 power ouput indication is very accurate when operating into a
50 ohm non-reactive load. If it is driving anything other than that load,
the indication will be inaccurate - he basic K2 does not have a wattmeter, t
does have an RF Probe type detector which reports the RF Voltage to the
Curt,
The base K2 power reading is quite accurate if (and only if) the load is 50
ohms pure resistance. See my other post on the subject.
Since you have a K2/100, the included wattmeter should be as accurate as
your calibration of it. Prhaps you should re-do the calibration - or
possibly both
Thanks Don,
So with my basic K2, I should get agreement between the K2's setting and
its output when driving my 50 ohm dummy load. I'll check it that way
and report back.
I never completed the RF probe with the K2 (didn't need it). I assume
it simply converts RF AC voltage into DC voltage
It's a standard diode peak detector I believe, so it would indicate 31.7
VDC (minus the drop) at 10 W for a 50 ohm load. I expect the drop is
about 0.3 V.
Larry N8LP
Darwin, Keith wrote:
Thanks Don,
So with my basic K2, I should get agreement between the K2's setting and
its output
Ya lost me there Larry. P = E^^2 / R. R is 50 ohms, P is 10 watts, E
works out to sqrt(500) or 22.36 volts. But are we talking RMS, peak, or
peak-to-peak?
Let's see, if my number is an RMS and you're number is peak, then 22.36
is about 22.4. Multiply by 1.41 and I get 31.6 Pretty close to
- Original Message -
From: Don Wilhelm [EMAIL PROTECTED]
To: Darwin, Keith [EMAIL PROTECTED]; elecraft@mailman.qth.net
Sent: Wednesday, May 24, 2006 9:29 AM
Subject: RE: [Elecraft] K2 power output measurement accuracy?
K2 - all it takes is a known non-reactive 50 ohm load. I use 1
Rick, K7MW asked:
With my K2 into a DL1, my WM-2 meter shows up to 20 % higher power than my
DMM and slide rule indicates. Is the DL1 likely more accurate than my WM-2
meter. If so, I will recalibrate my K2 with the DL1 and DDM. Than I will
have a stronger QRP signal and be able to work 300
At 15W the DL-1 is by far more accurate. It is probably within a few
percent, based on a normal random distribution of resistor values, and
5% worst case if they're all off in the same direction. Keep in mind
though that the resistance changes as temperature rises... so it's best
to take a
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