Ian,
Either the LPA or the KPA is compressing above 5/50W.
Set the K3 to 5.5 watts and check power output on each band. Then set
the K3 to 10 watts and check power output on each band. Then repeat
the process at 55 and 100 watts.
That should tell you if the LPA or KPA is compressing and will allow
Elecraft Support (when you e-mail or call them) to focus on the source
of your problem. If you have 5.5 and 10 watts (or close) at the low
power test the LPA is OK and the KPA is going into compression for
some reason (check power supply and the +13V pins on the headers).
If you do not have 5.5/10W on the LPA test, your LPA is going into
compression and it may need to be swapped or connections checked.
73,
... Joe, W4TV
On 2/24/2016 7:40 AM, Ian - Ham wrote:
Jerry,
Thanks for the response. I'm curious, however, why removing the 100W PA and
running calibration tests at 10W would matter, if I'm already seeing
expected results at the 10W power level. That is, I set the output power on
my K3 to 10W, and transmit using a full duty cycle mode. On the external
power meter, I see 10W, on all bands. This would seem to me to indicate that
there isn't an issue with the low power amplifier.
Thank you.
--Ian
Ian Kahn, KM4IK
Roswell, GA EM74ua
[email protected]
10-10 #74624, North Georgia Chapter #2038
PODXS 070 #1962
K3# 281, P3 #688, KAT500 #860, KPA500 #1468
-----Original Message-----
From: Jerry [mailto:[email protected]]
Sent: Tuesday, February 23, 2016 10:53 PM
To: Ian Kahn <[email protected]>
Cc: [email protected]; [email protected]
Subject: Re: [Elecraft] K3 #281 Perceived Output Issue
Remove hundred watt PA. Install a 10 W jumper. Run through the 10 W
calibration. Measure record and share the results.
It is logical to expect that this is where the issue is starting.
Sent from my iPad
On Feb 23, 2016, at 10:25 PM, Ian Kahn <[email protected]> wrote:
Several people offered some very good suggestions and asked several
valid questions about my testing. Here are answers to many of those
questions:
1. The meter I'm using in the test is a known-good MFJ-815B HF
power/SWR meter.
2. I'm using a known-good 300W dummy load for my "antenna", so any
reflected power is minimal, as is SWR.
3. I do have the internal ATU installed, but it is in BYPASS, as I
have a resonant antenna on 20m-10m and use the KAT500 for 40m/80m, or
when I run power.
4. Test results at lower power levels:
10m 10w out - 10w on meter; 25w out - 19-20w on meter; 50w out - ~30w
on meter 12m 10w out - 10w on meter; 25w out - 20w on meter; 50w out -
30w on meter 15m 10w out - 10w on meter; 25w out - 20w on meter; 50w
out - 35w on meter 17m 10w out - 10w on meter; 25w out - 20w on meter;
50w out - 35w on meter 20m 10w out - 10w on meter; 25w out - 20w on
meter; 50w out - 40w on meter 40m 10w out - 10w on meter; 25w out -
20w on meter; 50w out - 40w on meter 80m 10w out - 10w on meter; 25w
out - 20w on meter; 50w out - 40w on meter
I also ran the TX Gain Calibration from the K3 utility one more time,
with a different cable. Here are the results of that calibration (note
- I didn't run the milliwatt calibration because I don't use a
transverter with the IF Out. It just goes to my P3):
K3 Tx Gain Calibration data written on 2016-02-23 at 22:18:30
K3 Serial Number 00281
K3 MCU revision 05.38. RS-232 speed 38400 bit/s.
Elecraft K3 Utility Revision 1.15.8.18
1900 kHz TxGain LP 52
3750 kHz TxGain LP 30
5336 kHz TxGain LP 56
7150 kHz TxGain LP 46
10125 kHz TxGain LP 52
14200 kHz TxGain LP 23
18110 kHz TxGain LP 24
21200 kHz TxGain LP 19
24930 kHz TxGain LP 25
29000 kHz TxGain LP 30
52000 kHz TxGain LP 24
1900 kHz TxGain HP 46
3750 kHz TxGain HP 48
5336 kHz TxGain HP 87
7150 kHz TxGain HP 62
10125 kHz TxGain HP 58
14200 kHz TxGain HP 28
18110 kHz TxGain HP 21
21200 kHz TxGain HP 18
24930 kHz TxGain HP 18
29000 kHz TxGain HP 27
52000 kHz TxGain HP 13
After running the TX Gain Calibration again, I checked the above
output numbers, and they stay the same. It seems as if I am losing
about 20% of my output power for any setting above 10w, except on 10m,
where at 100w I seem to be losing about 50w. It also seems as if maybe
there is an issue with the internal 100w PA, based strictly on my
observations and a wild guess.
If there are any other suggestions/recommendations, I'm all ears. If
not, the next step is an email to the good folks in Aptos.
Thanks and 73,
--Ian
Ian Kahn, KM4IK
Roswell, GA EM74ua
[email protected]
10-10 #74624 North Georgia Chapter #2038 PODXS 070 #1962
K3 #281, P3 #688 KAT500 #860, KPA500 #1468
On Mon, Feb 22, 2016 at 5:40 PM, Don Wilhelm <[email protected]>
wrote:
Ian,
Try TX Gain Calibration again - use a different coax jumper between
the K3 and dummy load - that could possibly be faulty. If that does
not correct it, contact Elecraft support.
73,
Don W3FPR
On 2/22/2016 5:29 PM, Ian Kahn wrote:
Don,
I upgraded the MCU and ran the TX Gain Calibration at that time,
successfully. I also ran it again Friday night, while testing, to
make sure that wasn't the issue. It ran successfully both times.
Thanks.
Ian, KM4IK
On Feb 22, 2016 5:24 PM, "Don Wilhelm" <[email protected]> wrote:
Ian,
Did you upgrade after MCU version from 5.13 or below to 5.14 or greater?
That requires you to do the TX Gain Calibration (see 5.14 Release
Notes). K3 Utility makes the task easy - just connect a dummy load
that is good for 1.8 to 54 MHz and capable of 50 watts or greater
and the process is automatic - follow the prompts in K3 Utility, it
will take only about 2 minutes to complete after the dummy load is in
place.
If K3 Utility fails the TX Gain, there is one more chance - do each
band manually (see the Calibration part of the manual).
If that does not correct it, contact support.
73,
Don W3FPR
On 2/22/2016 11:21 AM, Ian Kahn wrote:
Reposting, since this didn't seem to get out when I originally sent
it last Friday evening. If you get this a second time, please
forgive the noise.
Thanks and 73,
--Ian
Ian Kahn, KM4IK
Roswell, GA EM74ua
[email protected]
10-10 #74624 North Georgia Chapter #2038 PODXS 070 #1962
K3 #281, P3 #688 KAT500 #860, KPA500 #1468
---------- Forwarded message ----------
From: Ian Kahn <[email protected]>
Date: Fri, Feb 19, 2016 at 10:37 PM
Subject: [Elecraft][K3] K3 #281 Perceived Output Issue
To: "[email protected]" <[email protected]>
All,
I have what I think is an output issue with my K3 s/n 281. When set
at 100W output, I am getting the following approximate output
values:
10m ~55w
12m ~40w
15m ~50w
17m ~60w
20m ~60w
40m ~70w
80m ~70w
160m ~70w
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