So, several weeks after originally starting this thread, I finally had
time this evening to sit down and take some voltage and current
measurements. I used my Astron SS-30 power supply connected to the 40A
DC-in port on my Rigrunner. I then ran the Elecraft power cord from a
25A port on the Rigrunner into the 12V DC-in on the back of the K3.
Everything measures 13.8V in standy/rx, all the way to the reading on
the K3 display, with the K3 showing .82A current draw in rxv. I would
measure the power at the 12V in port on the K3, but can't see a way to
get the probes into the powerpole connectors without damaging anything.
I ran my tests using FSK-D at 100W and into a known-good 300W dummy
load, so I could get 100% duty cycle for a few seconds with each
transmit. When I go to transmit, voltage on every band looks good, with
the voltage dropping from 13.8V to anywhere from 12.1 to 12.4 volts.
I'm concerned about some of the current readings, however. 80 meters
shows a current draw of 15.80A; 17 meters shows a draw of 16.35A; 15
meters shows a draw of 16.40A; 10 meters shows a draw of 12.93A. 12m,
20m, 30m, 40m, and 160m are all within the 17-22A current draw rating
for the K3. The RF output meter on the K3 shows 100w out on every band,
but I haven't put the rig on an external watt meter. Since these are
all below the nominal current draw given in the K3 owner's manual
(17-22A), is there something I should look at recalibrating? Or could
something more serious be going here that I need to be concerned about?
Or, am I worried about nothing? Further guidance is greatly appreciated.
Thank you and 73,
--Ian
Ian Kahn, KM4IK
Roswell, GA EM74ua
km4ik....@gmail.com
K3 #281, P3 #688
HRD v5.x/6.0 Test Team
On 12/25/2012 11:52 AM, AG0N-3055 wrote:
On Mon, 24 Dec 2012 13:58:35 -0500, Brian Alsop wrote:
The first rule in troubleshooting is to unplug everything that isn't
absolutely necessary to the equipment being diagnosed.
In this case all that would be needed is power, ant/dummy load and the K3.
Absolutely. Make sure you use good quality connectors, cables, etc. If
possible, plug the wattmeter directly into the RF output on the back of
the rig (NOT the tuner or amplifier), using a double male if possible,
and plug the PROPER, good quality dummy load directly into the
wattmeter.
Remember, every connector you go through, loses you fraction of a db.
How many connections, cables, etc., does it take to equal one db of
loss? Not too many. One db is 26%! If you lose 1db getting between
the output port and the load, the load will only see 74W with 100W
output from the transmitter. Something to think about. A typical old
style tuner will lose you around 5 watts or more.
Gary
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