Just to follow up. When I talked to support, they recommended sending
in for service.
After getting the rig back, I've only used it for IF at 100 mW on 50
MHz with transverter. And had a weird loud audio buzz problem. See
separate email describing that. Have reported to Elecraft; still
To follow up on Victor's point, did some more measurements this morning.
Setup:
KX-3 minimal adapters to 40 dB directional coupler to load
terminated unused port of coupler
measured port through 3 ft patch to Kanga US AD8307 RF power meter
I have good calibration data for the power meter, but
Additional comments:
Same test at 7MHz results with about 1A current. Suggesting KX3 power
amplifier efficiency difference between 7 and 50 MHz.
Using same DL1, added Elecraft W1 and MS utility to measure SWR. At 50
MHz KX3 displays SWR = 1.5 whereas W1 indicates SWR = 1.1:1.
May I suggest W1
Hi Drew,
50 MHz TX constant 4 W carrier:
KX3 #1658
KX3 PS 13.2 during XMIT
ATU bypass
Elecraft DL1
KX3 SWR 1.5
Current = 2.3A
John KN5L
On 5/8/20 6:52 PM, Mooneer Salem wrote:
> I got 2.36A current consumption @ 5W using a dummy load and the TX button
> on 50.100MHz USB with my KX3 (S/N 3262).
Good point, Victor. And why I included that SWR reading. Other bands
read fine. I have high confidence in the load and adapter (tried
swapping both just in case). I could measure the load and adapter the
next time I'm in the lab at work if I want to be absolutely thorough,
but it is a
I think 1.6:1 is high for that kind of dummy load, if it's in good shape.
Should be close to 1:1.
Anyway, you can't really say there is a problem unless you have a better match.
Current draw is sensitive to mismatch.
--
Vic
On May 9, 2020 2:32:15 AM GMT+03:00, Drew Arnett wrote:
>Walter,
>
Hi Drew,
I got 2.36A current consumption @ 5W using a dummy load and the TX button
on 50.100MHz USB with my KX3 (S/N 3262). The voltage dropped from 13.74V to
13.67V during transmit. (Measured using an in-line Powerpole meter attached
between a 54Ah LiFePO4 battery and the KX3.) Hopefully this
Walter,
50 MHz TX constant 4 W carrier measures 13.53 V on DMM (outside the DC
power plug), 13.3 V on KX3 meter, 2.9 A on KX3 meter and 1.6 to 1 VSWR
on KX3 meter. Microwave dummy load with BNC to N adapter.
I didn't measure all of this when the rig was new, so have no baseline
to know what is
What voltage? What frequency?
It will pull more current at lower voltages. The power stages are less
efficient at higher frequencies, especially 12m and up.
wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)
> On May 8, 2020, at 4:19 PM, Drew Arnett wrote:
>
>
What do you see for current draw on the KX-3? Manual says 1 to 2 A typical.
I'm seeing 3 A at less than full power on one band. Yikes! Makes me
wonder if the repair shop is open? Elecraft website says hunkered
down and mostly work from home.
Thanks and best regards,
Drew
n7da
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