To much output power?


SE3X / Johan
 

Just recently bought a K3, old, ser.no 991 and I don't know much about it. My first Elecraft radio BTW and i enjoy it very much.

One thing though that puzzels me. Measuring output power and I read almost 140 watt with drive power set at 100 watt. Measuring chain: K3 - 1.5m of 50ohm coax - LP100 sensor - RF Choke - 4O3A antenna switch - 0.5m of 50ohm coax - Dummy Load.

Same set-up with a Flex 6700 reads 96 watt on my LP100. Input DC in idle is 14.0V, on PTT Flex reads 13.6V and 23A. Corresponding for the K3 is 13.4V and 25A. So relative betwen them K3 seems to output more as measured.

Could anyone provide some insights in possible reason to this high output? I appreciate power, but it seems a bit odd with this level from a 100 watt radio? Any ideas are very much appreciated.

73 / Regards
Johan
SE3X


Colin Smithers
 

I have measured thee K3s that were all set high, using a laboratory quality power meter. None were as high as 140 though, more like 120.

You can re-calibrate the power calibration through the menus. However the manual suggest calibrating at 50W, but the sensing is not quite linear and 100W will be wrong. This is the same for 5W/10W

I set mine for correct reading at 100W for IMD, and 5W for QRP sportsmanship.

73, Colin G4CWH


On 28 May 2021, at 12:57, SE3X / Johan via groups.io <se3x@...> wrote:

Just recently bought a K3, old, ser.no 991 and I don't know much about it. My first Elecraft radio BTW and i enjoy it very much.

One thing though that puzzels me. Measuring output power and I read almost 140 watt with drive power set at 100 watt. Measuring chain: K3 - 1.5m of 50ohm coax - LP100 sensor - RF Choke - 4O3A antenna switch - 0.5m of 50ohm coax - Dummy Load.

Same set-up with a Flex 6700 reads 96 watt on my LP100. Input DC in idle is 14.0V, on PTT Flex reads 13.6V and 23A. Corresponding for the K3 is 13.4V and 25A. So relative betwen them K3 seems to output more as measured.

Could anyone provide some insights in possible reason to this high output? I appreciate power, but it seems a bit odd with this level from a 100 watt radio? Any ideas are very much appreciated.

73 / Regards
Johan
SE3X


. .
 


Hi Johan, I do have a question.
I recently sold my K3 with SerialNo 991( I Still have config files for legal proof)l to some one in Sweden located just below Stockholm.
I'm still waiting for a significant amount of money to finalize this deal, not getting any response of the buyer anymore.
Now to read that the same K3 turns up about 650 Km more to the north.
Any thoughts about that ?

.........73......Klaas...PA3GGY................

On Friday, May 28, 2021, 2:47:00 PM GMT+2, k <pa3ggy@...> wrote:




----- Forwarded Message -----
From: Colin Smithers <colin@...>
To: Elecraft-K3@groups.io <elecraft-k3@groups.io>
Sent: Friday, May 28, 2021, 2:06:33 PM GMT+2
Subject: Re: [Elecraft-K3] To much output power?

I have measured thee K3s that were all set high, using a laboratory quality power meter. None were as high as 140 though, more like 120.

You can re-calibrate the power calibration through the menus. However the manual suggest calibrating at 50W, but the sensing is not quite linear and 100W will be wrong. This is the same for 5W/10W

I set mine for correct reading at 100W for IMD, and 5W for QRP sportsmanship.

73, Colin G4CWH


On 28 May 2021, at 12:57, SE3X / Johan via groups.io <se3x@...> wrote:

Just recently bought a K3, old, ser.no 991 and I don't know much about it. My first Elecraft radio BTW and i enjoy it very much.

One thing though that puzzels me. Measuring output power and I read almost 140 watt with drive power set at 100 watt. Measuring chain: K3 - 1.5m of 50ohm coax - LP100 sensor - RF Choke - 4O3A antenna switch - 0.5m of 50ohm coax - Dummy Load.

Same set-up with a Flex 6700 reads 96 watt on my LP100. Input DC in idle is 14.0V, on PTT Flex reads 13.6V and 23A. Corresponding for the K3 is 13.4V and 25A. So relative betwen them K3 seems to output more as measured.

Could anyone provide some insights in possible reason to this high output? I appreciate power, but it seems a bit odd with this level from a 100 watt radio? Any ideas are very much appreciated.

73 / Regards
Johan
SE3X


Colin Smithers
 

Oops...


On 28 May 2021, at 14:32, . . via groups.io <pa3ggy@...> wrote:



Hi Johan, I do have a question.
I recently sold my K3 with SerialNo 991( I Still have config files for legal proof)l to some one in Sweden located just below Stockholm.
I'm still waiting for a significant amount of money to finalize this deal, not getting any response of the buyer anymore.
Now to read that the same K3 turns up about 650 Km more to the north.
Any thoughts about that ?

.........73......Klaas...PA3GGY................

On Friday, May 28, 2021, 2:47:00 PM GMT+2, k <pa3ggy@...> wrote:




----- Forwarded Message -----
From: Colin Smithers <colin@...>
To: Elecraft-K3@groups.io <elecraft-k3@groups.io>
Sent: Friday, May 28, 2021, 2:06:33 PM GMT+2
Subject: Re: [Elecraft-K3] To much output power?

I have measured thee K3s that were all set high, using a laboratory quality power meter. None were as high as 140 though, more like 120.

You can re-calibrate the power calibration through the menus. However the manual suggest calibrating at 50W, but the sensing is not quite linear and 100W will be wrong. This is the same for 5W/10W

I set mine for correct reading at 100W for IMD, and 5W for QRP sportsmanship.

73, Colin G4CWH


On 28 May 2021, at 12:57, SE3X / Johan via groups.io <se3x@...> wrote:

Just recently bought a K3, old, ser.no 991 and I don't know much about it. My first Elecraft radio BTW and i enjoy it very much.

One thing though that puzzels me. Measuring output power and I read almost 140 watt with drive power set at 100 watt. Measuring chain: K3 - 1.5m of 50ohm coax - LP100 sensor - RF Choke - 4O3A antenna switch - 0.5m of 50ohm coax - Dummy Load.

Same set-up with a Flex 6700 reads 96 watt on my LP100. Input DC in idle is 14.0V, on PTT Flex reads 13.6V and 23A. Corresponding for the K3 is 13.4V and 25A. So relative betwen them K3 seems to output more as measured.

Could anyone provide some insights in possible reason to this high output? I appreciate power, but it seems a bit odd with this level from a 100 watt radio? Any ideas are very much appreciated.

73 / Regards
Johan
SE3X


Keith_WE6R
 

I would replace D36 & 37 on the RF board. Early radios had weak ones that failed causing power run-away.
Our # E560048   Digikey BAS70INTR-ND

Set the WMTR LP to 70 and WMTR HP to 30 (defaults) to start with...
Then run the 5 & 50w TX gain calibrations with the K3 Utility.
Then calibrate the LP and HP wattmeters again, typical #s are; 60-100 LP and 35-55 HP.
Keith WE6R Elecraft K3/K4 Tech.


. .
 

Dear Group members.

A few days ago Johan SE3X put out this request for help.
Since the serial he referred to has been mine until a few weeks ago and I sold the K3  to someone else that still did not pay all the money we agreed upon I was surprised.
In this group I openly asked Johan for an explanation, which by some of you could be considered I'm blaming him for the current situation.
THIS IS NOT THE CASE.....in several personal E-mails the situation has been discussed, contents not to be disclosed to the group, and I've come to the conclusion
Johan SE3X is NOT related to any scam or fraud related actions.
This make certain his name is cleared in case anybody might think otherwise.

......73...........Klaas....................PA3GGY..........................


On Friday, May 28, 2021, 7:25:10 PM GMT+2, Keith_WE6R <keithtrinity@...> wrote:


I would replace D36 & 37 on the RF board. Early radios had weak ones that failed causing power run-away.
Our # E560048   Digikey BAS70INTR-ND

Set the WMTR LP to 70 and WMTR HP to 30 (defaults) to start with...
Then run the 5 & 50w TX gain calibrations with the K3 Utility.
Then calibrate the LP and HP wattmeters again, typical #s are; 60-100 LP and 35-55 HP.
Keith WE6R Elecraft K3/K4 Tech.


SE3X / Johan
 

Tnx for information and suggestions. I have a long term plan to take the radio apart and re-fit it and make sure it's in 100% condition. It has some years behind I guess. If anyone have any idea on what year it would have been produced I would be happy for that info.

Just to make clear about Klaas, PA3GGY's, remarks earlier. I have an on-going conversation with Klaas to try to provide him with the information I have, and do what I can to help. From my point of view, I have bought it from a Swedish ham who is well known to buy and sell ham eq. I had no reason to believe anything but that he was the owner and in his rights to sell the K3. I have bought it and paid him the full amount and have done the buy in good faith.

I really hope that Klaas will get his money from his counterpart. I would be surprised if he doesn't. This person is well known advertising ham gear and participateing in ham fairs etc. He's a well established citizen and Klaas has confirmed to me that he found only good credentials when he did his "homework" before sending the radio.


SE3X / Johan
 
Edited

Thank you Klaas for your posting.

I'm very happy to understand from you that this sad situation is on it's way to it's proper solution. I like everyone reading this to know that there are no hard fellings betwen us and I think I have found a new ham friend in Klaas.  

Klaas has given me a lot of back-ground info about the K3, and I have promised I will make sure it has found a good new home :)

If anyone have the feeling that our postings, mine and Klaas, not are in perfect sync. That has a very simple explanation. I'm, as the newbee I am in this group, will have my postings approved by the moderators before published. Hopefully the moderators will find that I'm only posting according to the rules and that they could trust my judgement in what I post. 

Johan


Russ Tobolic
 

After reading this thread I decided to finally look into the power output issues I have had over the last year or so in which the readings on my LP100 were always 10 -15 W higher than the display on the K3. I had been setting the output on the K3 to 85W to to get 100 on the LP100. Reading WE6R's comment on early failures of D36 and D37, I replaced them both on my vintage 2008 ser. #732 with new BAS70's. However when I run the TX gain calibration I now always get a ERR TXG at 14.2MHz as shown:

 

Elecraft K3 Utility Version 1.20.1.15

OS Version 10.0 Build 19042

K3 MCU version 05.57 on COM4 at 38400 bit/s

Starting 5 watt calibration

Calibrating at 1.900 MHz

Calibrating at 3.750 MHz

Calibrating at 5.336 MHz

Calibrating at 7.150 MHz

Calibrating at 10.125 MHz

Calibrating at 14.200 MHz

TX Gain calibration failed because transmit power did not reach the expected value

5 watt calibration failed

Elapsed time: 30 seconds

 

I also noted that during the test run at 5W, the LP100 would always indicate around 6.1W, but that may be because I haven't calibrated the internal wattmeter. I read elsewhere where someone having similar problems on 12M readjusted some trimmers in the BP filter and it fixed the problem at least temporarily. Before I start “tweaking” things are is there something else I should be looking at?

 

Russ, N3CO


Colin Smithers
 

Russ,

 

The K3 displaying 85W but outputting 100W is in line with my experience after measuring three K3s using a lab standard power meter.

 

I can’t comment beyond that.

 

73, Colin Smithers G4CWH

 

From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of Russ Tobolic via groups.io
Sent: Monday, June 14, 2021 6:10 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] To much output power?

 

After reading this thread I decided to finally look into the power output issues I have had over the last year or so in which the readings on my LP100 were always 10 -15 W higher than the display on the K3. I had been setting the output on the K3 to 85W to to get 100 on the LP100. Reading WE6R's comment on early failures of D36 and D37, I replaced them both on my vintage 2008 ser. #732 with new BAS70's. However when I run the TX gain calibration I now always get a ERR TXG at 14.2MHz as shown:

 

Elecraft K3 Utility Version 1.20.1.15

OS Version 10.0 Build 19042

K3 MCU version 05.57 on COM4 at 38400 bit/s

Starting 5 watt calibration

Calibrating at 1.900 MHz

Calibrating at 3.750 MHz

Calibrating at 5.336 MHz

Calibrating at 7.150 MHz

Calibrating at 10.125 MHz

Calibrating at 14.200 MHz

TX Gain calibration failed because transmit power did not reach the expected value

5 watt calibration failed

Elapsed time: 30 seconds

 

I also noted that during the test run at 5W, the LP100 would always indicate around 6.1W, but that may be because I haven't calibrated the internal wattmeter. I read elsewhere where someone having similar problems on 12M readjusted some trimmers in the BP filter and it fixed the problem at least temporarily. Before I start “tweaking” things are is there something else I should be looking at?

 

Russ, N3CO


Larry
 

I have an LP-100A here as well that i bought just a couple months back.  I see the same differences you are seeing but to me it has to do with the SWR it's seeing.  I also run my K3 at 85W out.  My best band is 30M with an inverted V ant.  I typically see an SWR of 1:13:1 on that band and the LP100A shows close to 90W out with the K3 running 85W.  If i go up to 20M where i have a 4 El yagi  that's about 130 ft from the shack, i typically see around 100W out on the LP-100A  with 85 watts out of the K3.

Other bands like 15, 10, 40M i still run the K3 at 85W but the output showing on the LP-100A varies due to the SWR of the antenna.

Right or not that's the way it is.

Larry W0OGH


On 6/14/2021 10:09 AM, Russ Tobolic via groups.io wrote:

After reading this thread I decided to finally look into the power output issues I have had over the last year or so in which the readings on my LP100 were always 10 -15 W higher than the display on the K3. I had been setting the output on the K3 to 85W to to get 100 on the LP100. Reading WE6R's comment on early failures of D36 and D37, I replaced them both on my vintage 2008 ser. #732 with new BAS70's. However when I run the TX gain calibration I now always get a ERR TXG at 14.2MHz as shown:

 

Elecraft K3 Utility Version 1.20.1.15

OS Version 10.0 Build 19042

K3 MCU version 05.57 on COM4 at 38400 bit/s

Starting 5 watt calibration

Calibrating at 1.900 MHz

Calibrating at 3.750 MHz

Calibrating at 5.336 MHz

Calibrating at 7.150 MHz

Calibrating at 10.125 MHz

Calibrating at 14.200 MHz

TX Gain calibration failed because transmit power did not reach the expected value

5 watt calibration failed

Elapsed time: 30 seconds

 

I also noted that during the test run at 5W, the LP100 would always indicate around 6.1W, but that may be because I haven't calibrated the internal wattmeter. I read elsewhere where someone having similar problems on 12M readjusted some trimmers in the BP filter and it fixed the problem at least temporarily. Before I start “tweaking” things are is there something else I should be looking at?

 

Russ, N3CO


Wes Stewart
 


 It's funny (curious) that I referenced this three year old conversation just a couple of days ago. http://elecraft.365791.n2.nabble.com/K3-SWR-Numerical-Indication-td7643839.html

If you muddle through this you can see my comments, which address SWR uncertainties, but are somewhat applicable to this conversation because the same hardware is involved. The essence of this is that there are many sources of error in these measurements and we (you guys) are arguing about differences of 85 to 100 watts.  I don't know if anyone else bothered to compute this in dB, but I did and it's 0.7 dB.

That's a pretty small number to be generating all of this anguish,

Wes  N7WS


On Mon, Jun 14, 2021 at 01:24 PM, Larry wrote:

I have an LP-100A here as well that i bought just a couple months back.  I see the same differences you are seeing but to me it has to do with the SWR it's seeing.  I also run my K3 at 85W out.  My best band is 30M with an inverted V ant.  I typically see an SWR of 1:13:1 on that band and the LP100A shows close to 90W out with the K3 running 85W.  If i go up to 20M where i have a 4 El yagi  that's about 130 ft from the shack, i typically see around 100W out on the LP-100A  with 85 watts out of the K3.

Other bands like 15, 10, 40M i still run the K3 at 85W but the output showing on the LP-100A varies due to the SWR of the antenna.

Right or not that's the way it is.

Larry W0OGH

 

On 6/14/2021 10:09 AM, Russ Tobolic via groups.io wrote:

After reading this thread I decided to finally look into the power output issues I have had over the last year or so in which the readings on my LP100 were always 10 -15 W higher than the display on the K3. I had been setting the output on the K3 to 85W to to get 100 on the LP100. Reading WE6R's comment on early failures of D36 and D37, I replaced them both on my vintage 2008 ser. #732 with new BAS70's. However when I run the TX gain calibration I now always get a ERR TXG at 14.2MHz as shown:

 

Elecraft K3 Utility Version 1.20.1.15

OS Version 10.0 Build 19042

K3 MCU version 05.57 on COM4 at 38400 bit/s

Starting 5 watt calibration

Calibrating at 1.900 MHz

Calibrating at 3.750 MHz

Calibrating at 5.336 MHz

Calibrating at 7.150 MHz

Calibrating at 10.125 MHz

Calibrating at 14.200 MHz

TX Gain calibration failed because transmit power did not reach the expected value

5 watt calibration failed

Elapsed time: 30 seconds

 

I also noted that during the test run at 5W, the LP100 would always indicate around 6.1W, but that may be because I haven't calibrated the internal wattmeter. I read elsewhere where someone having similar problems on 12M readjusted some trimmers in the BP filter and it fixed the problem at least temporarily. Before I start “tweaking” things are is there something else I should be looking at?

 

Russ, N3CO


Russ Tobolic
 

No anguish here over 0.7dB.  It's just that when I first set up my K3 13 years ago using the same LP100, the power readings between the two only differed by a few tenths of a watt (the LP100 was calibrated by Larry, N8LP).  I wished I had done a survey of K3 and LP100 users for differences in power readings but the deed is done and it looks like I may have fixed something that wasn't broke.  I was just keying off the suggestion by WE6R that early units (like mine from 2008) had weak diodes D36 & D37.  But I'm past that now.  The issue I have is that when running the TX Gain calibration it fails at 20M.  I get the ERR TXG message which my owners manual "indicates a problem with band-pass filter alignment or one of the low-pass filters.  In either case it could affect on or two bands.   See service manual."  I didn't know there was a "service" manual.  

Russ, N3CO


Ray Maxfield
 

Use a Real  Dummy Load, other wise ALL bets are Off !

WA6VAB  Ray  

 

 

 

From: Russ Tobolic via groups.io
Sent: Tuesday, June 15, 2021 6:59 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] To much output power?

 

No anguish here over 0.7dB.  It's just that when I first set up my K3 13 years ago using the same LP100, the power readings between the two only differed by a few tenths of a watt (the LP100 was calibrated by Larry, N8LP).  I wished I had done a survey of K3 and LP100 users for differences in power readings but the deed is done and it looks like I may have fixed something that wasn't broke.  I was just keying off the suggestion by WE6R that early units (like mine from 2008) had weak diodes D36 & D37.  But I'm past that now.  The issue I have is that when running the TX Gain calibration it fails at 20M.  I get the ERR TXG message which my owners manual "indicates a problem with band-pass filter alignment or one of the low-pass filters.  In either case it could affect on or two bands.   See service manual."  I didn't know there was a "service" manual.  

Russ, N3CO

 


Bob McGraw - K4TAX
 

If your LP-100 hasn’t been recently calibrated, it likely needs calibration.   It is customary to have test equipment calibration done by a standards company at least once a year.  

Just because it was correct once doesn’t mean it is correct twice.   Also a known 50 ohm resistive load is needed for accurate power measurement. 


73 
Bob, K4TAX


Wes Stewart
 

If you want to get into RF power measurement in more detail here is a good reference: https://www.hpmemoryproject.org/an/pdf/an_64-1a.pdf

There are later versions of this by the successor companies, but this one is easier to get and still valid.