Chris,
Yes, those currents are too small for normal operation.
That sort of thing could happen if you are not driving a 50 ohm pure
resistive load. Do you have a good dummy load on the K2?
Is the coax (and any adapters) between the K2 and the dummy load good?
The reason for the above question is the way the basic K2 detects power
output and also the way it controls the power output level.
The detector is not a wattmeter, it is a diode detector and reports the
RF voltage to the microprocessor. If the impedance at the antenna jack
is higher than 50 ohms, the RF voltage will be higher than normal and
the microprocessor will calculate the power wrong.
If your dummy load and coax are good, you will have to will have to do
some analysis. The easiest would be to check the internal current
metering - use you DMM to measure the input current and compare that
with the reading on the K2 - they should agree within 5 or 10 percent.
If not, check the Current Sense components on the Control Board
(schematic will tell you which ones they are).
If the internal current meter is correct, then use an RF probe to
measure the RF voltage developed at the K2 output jack and compute the
power based on that RF voltage - V squared divided by 50 - compare that
value to the power reported by the K2.
If those values are significantly different, check the components in the
RF Detector section of the RF Board - schematic sheet 4 in the lower
right corner.
73,
Don W3FPR
On 6/29/2013 9:03 PM, ChrisM wrote:
I just finished my K2, #7054, and am doing the 40m transmitter allignment.
Power Supply 12v 29amp switching.
Voltage and Current at 11.7v and approx 220mA, Freq at 7100.
I peaked L1 and L2 no problems. Have 2W on setting and reading approx 2W
with internal power meter. When I set the power to 5W Internal meter
measured approx 5W but current only increased to just over 500mA. At 10W
internal meter read a bit over 10W but current only at approx 660mA. No
change in voltage. The manual states the current should be 1.3 to 1.6 Amps
at 5W and 1.8 to 2 Amps at 10W.
I have read about little or no power out with high current, but not good
power out with almost no current increase.
Could the power meter/or current meter be incorrect, did I mess something
up, or is this Ok (Some Kind of Magic)?
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