Date   

Re: [Elecraft] KPA1500 SWR Tolerance

Paul Baldock <paul@...>
 

I keep the SWR below 1.2, using Autotune and manual tweaking. This is necessary to keep the gain reasonably constant across a band. I store values for Wet and Dry if necessary , and then use the ^OS ^PB function assigned to PF1 to select between them. I set/store my max drive power level to achieve 1.3KW PEP (on an external meter) and never turn it up even if the output power drops a little. So far the amplifier's finals have survived.

- Paul KW7Y

At 07:43 PM 3/16/2020, you wrote:
I've long been aware that my KPA1500 would not run at full power (1.5 kW) unless the SWR was very low. (This is SWR at the input to the ATU, if used.) The current ATU firmware does a pretty good job of keeping the SWR below about 1.3:1, which usually is low enough. In any case, I just ran a simple test on 160, where I have an antenna I can easily tune to 1:1, or deliberately higher. The ATU was engaged, but it's settings were not changed during the test. The SWR indicated was that at the ATU input (amplifier output). I found that the output power remained nearly constant up to 1.4:1, but the current increased from 58 to 62 A. (This with no adjustment of the K3 power, though the indicated input power varied slightly.) At 1.5:1, the current exceeded 65 A and the amplifier faulted. By reducing drive, I was able to run it at 1.4 kW output and 60 A. The above is typical of my experience on other bands, etc. The effect of SWR on the amplifier, of course, depends on the actual impedance at the amplifier, so in some cases it may be more or less sensitive to SWR. Do others see similar effects? 73, Scott K9MA -- Scott K9MA k9ma@sdellington.us ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to paul@paulbaldock.com


Re: [Elecraft] [Elecraft-K3] Interesting P3 Anomaly

Al N1AL
 

Yes, what you're seeing is IF leakage, not the RF signal.  The level level is uncontrolled and depends on the isolation of the PIN diode switches, etc.

Yes, you can see it by transmitting, with the RS-232 cable that normally goes between the K3 and the P3 temporarily disconnected.

Because it is the IF signal, it doesn't show distortion caused by the transmitter PA.  Still, it does display the frequency response of the transmitted signal, which can be useful when setting up the TX equalizer.

Alan N1AL

On 3/15/20 8:09 PM, David Box wrote:
Don't know what you mean "doesn't represent your transmitted signal" It is leakage of your signal at the IF, I see it with my SDR that is tied to the P3 IF out and it looks exactly like the signal I see on a spectrum analyzer using a coupler.
de Dave K5MWR


On March 15, 2020 8:11:07 PM CDT, Brian K0DTJ <huntinhmb@coastside.net> wrote:
As I recall, if you disconnect the RS232 thru the P3 to the K3 it the
P3 will display your spectrum since it doesn't know to mute during TX.
Someone from Elecraft said it was due to "leakage" and is at IF so
doesn't represent your transmitted signal. Seems like you found a
software way to do this. :-)


Re: [Elecraft] Interesting P3 Anomaly

David Box
 

Don't know what you mean "doesn't represent your transmitted signal" It is leakage of your signal at the IF, I see it with my SDR that is tied to the P3 IF out and it looks exactly like the signal I see on a spectrum analyzer using a coupler.
de Dave K5MWR


On March 15, 2020 8:11:07 PM CDT, Brian K0DTJ <huntinhmb@...> wrote:
As I recall, if you disconnect the RS232 thru the P3 to the K3 it the P3 will display your spectrum since it doesn't know to mute during TX. Someone from Elecraft said it was due to "leakage" and is at IF so doesn't represent your transmitted signal. Seems like you found a software way to do this. :-)

73,
Brian, K0DTJ
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Re: [Elecraft] Interesting P3 Anomaly

Brian K0DTJ
 

As I recall, if you disconnect the RS232 thru the P3 to the K3 it the P3 will display your spectrum since it doesn't know to mute during TX. Someone from Elecraft said it was due to "leakage" and is at IF so doesn't represent your transmitted signal. Seems like you found a software way to do this. :-)

73,
Brian, K0DTJ


Re: Interesting P3 Anomaly

Mel Farrer, K6KBE <farrermesa@...>
 

As was explained to me when I reported it to tech support, way back, it is a timing horse race.  Normally you don't see the TX signal.

Would be a nice feature. 

Mel, K6KBE

On Sun, Mar 15, 2020 at 2:20 PM Bob McGraw - K4TAX <rmcgraw@...> wrote:
While working 6M this afternoon, I used my P3 Utility to capture the
stations signal that I was working.  While the capture was taking place,
about 3/4 through the capture screen, of course the P3 display had
frozen as normal during this time.   The station turned it to me, I
pressed the TX switch and started talking.  As soon as the P3 capture
completed, and I while was talking, I noticed an active waveform on my
P3.  After some further tests, I realized this is my transmitted
waveform being displayed on the P3.  {How do you like them apples?}

Normally one does not see their signal on their P3.  But in this case,
as the P3 Utility completed the capture and reverted the P3 to normal
operation, it was then capturing my transmitted signal from the IF stage.

Maybe I've missed this feature in the past.  Has anyone else come across
the phenomenon?   Certainly a nice feature to have as it does capture
the IF signal.  Changing power levels makes no difference.

And NO , I don't have the TX monitor option.

73

Bob, K4TAX






Interesting P3 Anomaly

Bob McGraw - K4TAX
 

While working 6M this afternoon, I used my P3 Utility to capture the stations signal that I was working.  While the capture was taking place, about 3/4 through the capture screen, of course the P3 display had frozen as normal during this time.   The station turned it to me, I pressed the TX switch and started talking.  As soon as the P3 capture completed, and I while was talking, I noticed an active waveform on my P3.  After some further tests, I realized this is my transmitted waveform being displayed on the P3.  {How do you like them apples?}

Normally one does not see their signal on their P3.  But in this case, as the P3 Utility completed the capture and reverted the P3 to normal operation, it was then capturing my transmitted signal from the IF stage.

Maybe I've missed this feature in the past.  Has anyone else come across the phenomenon?   Certainly a nice feature to have as it does capture the IF signal.  Changing power levels makes no difference.

And NO , I don't have the TX monitor option.

73

Bob, K4TAX


Re: Possibly wide signal on 80m

wb6bee
 


Re: Possibly wide signal on 80m

David G3YYD
 

Two things I can think of.

 

There was an additional capacitor accidentally installed on some 100 watt PAs that caused an oscillation look at Elecraft website for serial numbers that needed the capacitor removed and mod leaflet.

 

The other is the PSU is faulty easy enough to check or substitute different PSU/battery.

 

73 David G3YYD

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Ignacy Misztal
Sent: 11 March 2020 15:16
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Possibly wide signal on 80m

 

"Noise pedestal" applies to K3 or K3S with the new synthesizer. My K3 is old in the 2k series with the original synthesizer. 
It turned out that my signal was 40 KHz wide, with spurs every 700 Hz.  Embarrassing

Ignacy, NO9E 
 


Re: Possibly wide signal on 80m

Ray Maxfield
 

I would Adjust the Power Out Level to see if it changes.

Ray WA6VAB

 

From: Ignacy Misztal
Sent: Wednesday, March 11, 2020 8:15 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Possibly wide signal on 80m

 

"Noise pedestal" applies to K3 or K3S with the new synthesizer. My K3 is old in the 2k series with the original synthesizer. 
It turned out that my signal was 40 KHz wide, with spurs every 700 Hz.  Embarrassing.

Ignacy, NO9E 
 

 


Re: Possibly wide signal on 80m

Ignacy Misztal
 

"Noise pedestal" applies to K3 or K3S with the new synthesizer. My K3 is old in the 2k series with the original synthesizer. 
It turned out that my signal was 40 KHz wide, with spurs every 700 Hz.  Embarrassing.

Ignacy, NO9E 
 


Re: Possibly wide signal on 80m

wb6bee
 

Ignacy

Search this forum for "CW Noise Pedestal" and read that thread.  In the thread is a link to a modification for K3 that added a capacitor to the fans that "could" be your issue".    Cheap modification from Elecraft and easy to install.    The problem I had with my K3s required sending it back to Elecraft to repair.   It came back and is working great.

Don
WB6BEE


Re: K3S, MacOS, fldigi

Ray
 

Check K3s line output level
Ray
W8LYJ


Possibly wide signal on 80m

Ignacy Misztal
 

Today I was calling D2EB on 3521. Several hams wrote that my signal was S9 signal on 3524, a frequency of 9J2LA. 
I captured the signal by SDR-IQ. The spurs at about -40 db are about 4 KHz wide. What could be happening? 
My K3 is #2289. 
Ignacy, NO9E


Re: K3S, MacOS, fldigi

redarlington <rdarlington@...>
 

Make sure you're using the right sound device, but also turn the volume up on it in the audio control panel *for the usb audio codec device* as you watch the waterfall.  I've noticed with recent versions of fldigi it seems a lot less sensitive than it used to be.  I have to turn it up for fldigi, and back down for wsjt-x.

-Bob N3XKB

On Tue, Mar 10, 2020 at 2:18 PM <wh6ebs@...> wrote:
Oh, I also need to mention that my radio is a K3 with the KIO3B upgrade. Radio connects with a single USB cable. CAT and Audio CODEC work fine.

73

Tom
WH6EBS


Re: K3S, MacOS, fldigi

wh6ebs@...
 

Oh, I also need to mention that my radio is a K3 with the KIO3B upgrade. Radio connects with a single USB cable. CAT and Audio CODEC work fine.

73

Tom
WH6EBS


Re: K3S, MacOS, fldigi

wh6ebs@...
 

Hi Jim,

I suggest you check the Config - Audio Card settings in Fldigi. From your description it seems like Fldigi is not listening to the correct device.

I am running Fldigi successfully on a 2019 MacBook Pro/Catalina.

73,

Tom
WH6EBS


K3S, MacOS, fldigi

Jim
 

Hi folks,
Can anyone help with getting fldigi waterfall to appear? I'm using a 2019 iMac, Catalina fully upated, with a K3S and trying to get fldigi to work. However, I get no waterfall and the signal in the lower right corner (barely noticed it) only jumps a few pixels on strong signals. WSJT-X works fine, decodes great, and the waterfall on it is perfect. I've got plenty of signal on the P3 also. Just sitting on 14.074 shows absolutely nothing on the fldigi waterfall. I must be missing something simple, but can't figure out what. Thanks for any help!
73,
Jim, WD9HBC


Re: K3 Remote operating troubleshooting

WN3R, Dick
 

Figured it out. I was misled when LSB switched to CW on transmit. I forgot that was normal. 

Actual problem was that compression was too high. 


Re: New Elecraft SSB 40 meter net

Jim Shepherd
 

There is a major net on 7283.5 with over a hundred checkins at the same time. 7280 was clear.

Jim
W6US


K3 Remote operating troubleshooting

WN3R, Dick
 

Using K3 twins with RemoteRig. It’s been setup for 
years. Just got in the mood to turn it on. Works 
FB on CW. 

Transmit audio is a new problem. With or without mic
plugged in, as I advance mic gain, RF output
increases with no audio. I haven’t listened to it
yet on a separate receiver.  

Looking for anyone who experienced this problem 
and really good hints on the easiest way to
troubleshoot it. It would be wonderful  if i could fix it
without having all the remote gear moved to the shack.  It’s an hour trip between the station
and the operating position. de Dick, WN3R   

 

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