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Re: Comparison of the K4 to the T41 on frequency stability

 

The TCXO-equipped T41 may have its faults, but stability or accuracy is
not one of them.

- Jerry


On 2025-02-11 17:25, K9HZ wrote:
HAVE A LOOK AT THESE TWO NOTES. AN EASY COMPARISON OF THE K4 AT $7K
VS THE T41¡­ NOT COMPLETELY 1:1 BUT CLOSE ENOUGH¡­.

FROM
´¡³¢¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­.

I just tried my rig with the Ver53.12 I sent you for frequency
accuracy. I am using the TXCO and waited about 30 minutes to let
everything warm up.

* First checked the T41frequency calibration with my Rubidium 10MHz
source, WWV@10MHz, and my Siglent SDG2122X Sig Gen at 10MHz. All three
indicated a T41 frequency error of about -0.4Hz, using the T41 SAM AM
detection method.
* Then transmitted into a 50 ohm DL at 7.200000MHz and measured the
frequency on my HP 53131A counter and SA. The counter result was
7.200000.8 MHz, a 0.8Hz difference and less than 1Hz with the SA. The
Siglent 3021X SA was set to 7.200000MHz center freq with a span of
1KHz and BW of 1 Hz.
* The Rubidium source showed 10.000000.85 on the counter. Looks like
my counter needs to be recalibrated slightly. On the Siglent 3021X SA,
set to 10.00MHz with a span of 1KHz and BW of 1 Hz, the reading was
10.000000. Hz, so I am pretty certain of my sources and the frequency
readouts.
* The T41 CW transmit frequency was within 1 HZ out of 7.200000MHz.

I would suggest you check the calibration of your T41 with WWV, if you
can, using the SAM AM detection mode.

AND THIS FOR THE K4 FROM JIM
±·8°¿²Ï¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­.

FROM: [email protected] <[email protected]> ON BEHALF OF James
DeYoung - N8OQ via groups.io
SENT: Tuesday, February 11, 2025 6:45 PM
TO: [email protected]
SUBJECT: Re: [Elecraft-K4] K4 On FMT

This afternoon while it snowed I did 2 minute sampling of each of the
Bodnar GPSDO carrier located at 7.05000 MHz, CHU 7.850000 and CHU
3.330000 MHz.

The K4 frequency on the display was positioned to put the each carrier
at +2 KHz near the middle of the receive passband. WSJT-X FreqCal was
used to make the measurements for two minutes sampling (Measured - K4
Tuned display) to the nearest 0.001 Hz. The summary stats follow.

The spec for the K4 is 0.1 PPM using just the internal TCXO. So all
three of these checks show better than the spec. There are still
small state changes in the data but within the K4 spec. My K4 was
actively using the 10-MHz input, Menu: Ext Ref. Lock. Somewhere I
read, but couldn't find the note today, was that a 10-MHz external
input was not expected to bring huge improvements in frequency
accuracy/stabiliity over the internal TCXO.

Jim (N8OQ)



Links:
------
[1] /g/AmateurRadioBuilders/message/6051
[2] /mt/111135419/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Re: Display Board evaluation help

 

Bill,
?
If you don't get any body else, I do have a spare display I can run at 3.3v and just change my main board J8 jumper to run the display at 3.3v.? Not a problem for me,
?
I thought that 90 degree IDC connectors on the front, back, and top edges would make the cable paths easier but I don't know what it does to board real-estate.
?
73,
?
Hank - wz3hmt
Comparison of the K4 to the T41 on frequency stability

 

¿ªÔÆÌåÓý

Have a look at these two notes.? An easy comparison of the K4 at $7K vs the T41¡­ not completely 1:1 but close enough¡­.

?

From Al¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­.

I just tried my rig with the Ver53.12 I sent you for frequency accuracy. I am using the TXCO and waited about 30 minutes to let everything warm up.

  • First checked the T41frequency calibration with my Rubidium 10MHz source, WWV@10MHz, and my Siglent SDG2122X Sig Gen at 10MHz. All three indicated a T41 frequency error of about -0.4Hz, using the T41 SAM AM detection method.
  • Then transmitted into a 50 ohm DL at 7.200000MHz and measured the frequency on my HP 53131A counter and SA. The counter result was 7.200000.8 MHz, a 0.8Hz difference and less than 1Hz with the SA. The Siglent 3021X SA was set to 7.200000MHz center freq with a span of 1KHz and BW of 1 Hz.
  • The Rubidium source showed 10.000000.85 on the counter. Looks like my counter needs to be recalibrated slightly. On the Siglent 3021X SA, set to 10.00MHz with a span of 1KHz and BW of 1 Hz, the reading was 10.000000. Hz, so I am pretty certain of my sources and the frequency readouts.
  • The T41 CW transmit frequency was within 1 HZ out of 7.200000MHz.

I would suggest you check the calibration of your T41 with WWV, if you can, using the SAM AM detection mode.

?

And this for the K4 from Jim ±·8°¿²Ï¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­.

?

From: [email protected] <[email protected]> On Behalf Of James DeYoung - N8OQ via groups.io
Sent: Tuesday, February 11, 2025 6:45 PM
To: [email protected]
Subject: Re: [Elecraft-K4] K4 On FMT

?

This afternoon while it snowed I did 2 minute sampling of each of the Bodnar GPSDO carrier located at 7.05000 MHz, CHU 7.850000 and CHU 3.330000 MHz.

?

The K4 frequency on the display was positioned to put the each carrier at +2 KHz near the middle of the receive passband.? WSJT-X FreqCal was used to make the measurements for two minutes sampling (Measured - K4 Tuned display) to the nearest 0.001 Hz.? The summary stats follow.

?

?

The spec for the K4 is 0.1 PPM using just the internal TCXO.? So all three of these checks show better than the spec.? There are still small state changes in the data but within the K4 spec. My K4 was actively using the 10-MHz input, Menu: Ext Ref. Lock.? ?Somewhere I read, but couldn't find the note today, was that a 10-MHz external input was not expected to bring huge improvements in frequency accuracy/stabiliity over the internal TCXO.

?

Jim (N8OQ)
Re: Display Board evaluation help

 

Didn't see you on had 3.3 version, sorry.
Re: Display Board evaluation help

 

Bill,
?
Set to 5v.? Sorry just saw your message.
?
Hank -WZ3HMT
Re: No Audio V12 troubleshooting

 

When I first built my Main Board, there was no audio. Bad solder
joint(s).
I put the board under a microscope and teased the pins of the DAC chip
with
an Xacto knife. If they moved, they weren't soldered. I also had a few
Teensy pins that weren't soldered.

- Jerry, KF6VB




On 2025-02-11 14:40, Tim via groups.io wrote:
I looked at pin 24 on Tweensy, Daudio-Out that goes to U5 audio
processor.
There is a signal there but it does not look any thing like a digital
signal, I do see an occasional spike that coinsides with pulse I hear
in headphones.
Anyone ever looked at the D-Audio output from Tweensy with a scope to
see what it looks like?
Tim W4YN



Links:
------
[1] /g/AmateurRadioBuilders/message/6047
[2] /mt/111133148/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
No Audio V12 troubleshooting

 

I looked at pin 24 on Tweensy, Daudio-Out that goes to U5 audio processor.
There is a signal there but it does not look any thing like a digital signal, I do see an occasional spike that coinsides with pulse I hear in headphones.
Anyone ever looked at the D-Audio output from Tweensy with a scope to see what it looks like?
Tim W4YN
?
Re: K9HZ PA

 

¿ªÔÆÌåÓý

Hi Wade¡­ the Assembly manual covers all of these topics¡­?? IF you need help with the input attenuator, just ask for the specific example (formulas are in the manual)¡­

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?

From: [email protected] <[email protected]> On Behalf Of Wayde VA3NCA/AD2GX via groups.io
Sent: Tuesday, February 11, 2025 11:47 AM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] K9HZ PA

?

Hi Dr Schmidt, and everyone here!

?

I'm finally getting to start the build of your 20W PA semi-kit. I will eventually use it with my T41 build as I get there, but would like to experiment a little with it as a standalone amp in the meantime.

?

Does anyone have a generic block diagram on how this would integrate into an arbitrary other radio? I assume the following needs consideration:? rf-in power matching ( via the input power pad on board)? , rf-out lpf , ptt voltage interface conversion (if necessary), and TR switching? Anything else that would need to be handled?

?

If a specific other qrp radio integration has been documented someplace, I'd be interested in reviewing that too!

?

Thanks! and 73, Wayde VA3NCA/AD2GX?
Re: K9HZ PA

 

Hi Dr Schmidt, and everyone here!
?
I'm finally getting to start the build of your 20W PA semi-kit. I will eventually use it with my T41 build as I get there, but would like to experiment a little with it as a standalone amp in the meantime.
?
Does anyone have a generic block diagram on how this would integrate into an arbitrary other radio? I assume the following needs consideration:? rf-in power matching ( via the input power pad on board)? , rf-out lpf , ptt voltage interface conversion (if necessary), and TR switching? Anything else that would need to be handled?
?
If a specific other qrp radio integration has been documented someplace, I'd be interested in reviewing that too!
?
Thanks! and 73, Wayde VA3NCA/AD2GX?
Re: Easy metal production facilities

 

¿ªÔÆÌåÓý

Huh¡­ I¡¯m gonna have to check this out¡­

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?

From: [email protected] <[email protected]> On Behalf Of Doug W via groups.io
Sent: Tuesday, February 11, 2025 10:48 AM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Easy metal production facilities

?

On Tue, Feb 11, 2025 at 10:24 AM, jerry-KF6VB wrote:

*** My guess is ...if you have to ask...

?

Actually it doesn't look that bad.? A while ago I cobbled together a slimmed down face plate to fit on a smaller printer bed and just uploaded it to oshcut to see what I'd get.? The powder coat set up fee adds quite a bit if you go that route but if someone really wants it and is willing to put together a group buy, by the time you get to about 10 pieces the powder coat price with setup drops to about the same as the raw or deburred single options.

?

?

?
Re: Easy metal production facilities

 

On Tue, Feb 11, 2025 at 10:24 AM, jerry-KF6VB wrote:
*** My guess is ...if you have to ask...
?
Actually it doesn't look that bad.? A while ago I cobbled together a slimmed down face plate to fit on a smaller printer bed and just uploaded it to oshcut to see what I'd get.? The powder coat set up fee adds quite a bit if you go that route but if someone really wants it and is willing to put together a group buy, by the time you get to about 10 pieces the powder coat price with setup drops to about the same as the raw or deburred single options.
?
?
?
Re: Easy metal production facilities

 

¿ªÔÆÌåÓý

Figgered that because OSH Park for PCBs is insanely expensive¡­

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?

From: [email protected] <[email protected]> On Behalf Of jerry-KF6VB
Sent: Tuesday, February 11, 2025 10:24 AM
To: [email protected]
Cc: K9HZ <bill@...>
Subject: Re: [AmateurRadioBuilders] Easy metal production facilities

?

On 2025-02-11 08:13, K9HZ wrote:

Well¡­ this is interesting: Laser Cutting and Sheet Metal Services |
OSH Cut [1]

Wonder what is would cost to make a case for the T41 ?

*** My guess is ...if you have to ask...

I was looking at OSHpark board service. For the same deal as $2 from
JLCPCB, their price was $80. Except only 3 boards instead of 5.

- Jerry, KF6VB

Re: Easy metal production facilities

 

On 2025-02-11 08:13, K9HZ wrote:
Well¡­ this is interesting: Laser Cutting and Sheet Metal Services |
OSH Cut [1]

Wonder what is would cost to make a case for the T41 ?
*** My guess is ...if you have to ask...

I was looking at OSHpark board service. For the same deal as $2 from
JLCPCB, their price was $80. Except only 3 boards instead of 5.

- Jerry, KF6VB
Easy metal production facilities

 

¿ªÔÆÌåÓý

Well¡­ this is interesting:?

?

Wonder what is would cost to make a case for the T41 ?

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?
Re: Display Board evaluation help

 

¿ªÔÆÌåÓý

Perfect Hank, Thanks.? What voltage is your display jumper set to on the Main board?

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?

From: [email protected] <[email protected]> On Behalf Of Hank Terwilliger via groups.io
Sent: Tuesday, February 11, 2025 9:01 AM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Display Board evaluation help

?

Bill,

?

I have a working V12 single transceiver.? My initial cable of 12" worked when it was on my bench but when I mounted in the encloser it quit working.? Not sure if that is long enough for a test for you, but when I build a new cable less than 5 inches the display started working.

?

I would be happy to test the longer cable out with your board and give feedback.? Could also make a longer cable than required if needed to test.? Let me know.

?

73,

?

Hank - WZ3HMT
Re: Conductive Paint

 

¿ªÔÆÌåÓý

Thanks for summarizing.

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?

From: [email protected] <[email protected]> On Behalf Of chris corcoran via groups.io
Sent: Tuesday, February 11, 2025 8:10 AM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Conductive Paint

?

Well, that¡¯s 4 hours of my life I won¡¯t get back. ? Rohde & Schwarz hade doing an online seminar ref EMC DEMC 2025 , obviously to sell their equipment, but normally some gems hidden.

?

3 things that come to mind from presentation:

?

  1. Lovely small presentation on using a VNA within an EMC environment, ¡°Multi functional tool for EMC labs¡±

I think links top the presentations will be available from the 13th from above url, don¡¯t quote me¡­

  1. But the star was the last presentation where there was a case study on a metal enclosure. Slot Antenna¡¯s duh!.

?

He referenced an expensive (well to me, ?80ish) ?book Henry Otts Book ¡°Electromagnetic Compatibility Engineering¡± is a great resource for enclosure design

?

BUT, 2009 pdf version can be found

?

?

Pages 238 onwards, p270 mentions slot antennas.

Also mentions meters/displays on p287, a bit extreme for us amateurs?

?

?

  1. Also a dB calculator, I¡¯m sure there are others¡­..

?

?

hopefully helpful to someone¡­..

?

?

From: [email protected] <[email protected]> On Behalf Of K9HZ
Sent: 08 February 2025 15:46
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Conductive Paint

?

I¡¯m sure we should care about the EMI from the display too.??? Tell you what¡­ You work on the EMR and I¡¯ll finish getting the data line noise from propagating back into the radio¡­

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?
Re: Display Board evaluation help

 

Bill,
?
I have a working V12 single transceiver.? My initial cable of 12" worked when it was on my bench but when I mounted in the encloser it quit working.? Not sure if that is long enough for a test for you, but when I build a new cable less than 5 inches the display started working.
?
I would be happy to test the longer cable out with your board and give feedback.? Could also make a longer cable than required if needed to test.? Let me know.
?
73,
?
Hank - WZ3HMT
Re: Conductive Paint

 

Good stuff!? Thanks

On Tue, Feb 11, 2025 at 9:09?AM chris corcoran via <imnotanumber6=[email protected]> wrote:

Well, that¡¯s 4 hours of my life I won¡¯t get back. ? Rohde & Schwarz hade doing an online seminar ref EMC DEMC 2025 , obviously to sell their equipment, but normally some gems hidden.

?

3 things that come to mind from presentation:

?

  1. Lovely small presentation on using a VNA within an EMC environment, ¡°Multi functional tool for EMC labs¡±

I think links top the presentations will be available from the 13th from above url, don¡¯t quote me¡­

  1. But the star was the last presentation where there was a case study on a metal enclosure. Slot Antenna¡¯s duh!.

?

He referenced an expensive (well to me, ?80ish) ?book Henry Otts Book ¡°Electromagnetic Compatibility Engineering¡± is a great resource for enclosure design

?

BUT, 2009 pdf version can be found

?

?

Pages 238 onwards, p270 mentions slot antennas.

Also mentions meters/displays on p287, a bit extreme for us amateurs?

?

?

  1. Also a dB calculator, I¡¯m sure there are others¡­..

?

?

hopefully helpful to someone¡­..

?

?

From: [email protected] <[email protected]> On Behalf Of K9HZ
Sent: 08 February 2025 15:46
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Conductive Paint

?

I¡¯m sure we should care about the EMI from the display too.??? Tell you what¡­ You work on the EMR and I¡¯ll finish getting the data line noise from propagating back into the radio¡­

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?
Re: Conductive Paint

 

¿ªÔÆÌåÓý

Well, that¡¯s 4 hours of my life I won¡¯t get back. ? Rohde & Schwarz hade doing an online seminar ref EMC DEMC 2025 , obviously to sell their equipment, but normally some gems hidden.

?

3 things that come to mind from presentation:

?

  1. Lovely small presentation on using a VNA within an EMC environment, ¡°Multi functional tool for EMC labs¡±

I think links top the presentations will be available from the 13th from above url, don¡¯t quote me¡­

  1. But the star was the last presentation where there was a case study on a metal enclosure. Slot Antenna¡¯s duh!.

?

He referenced an expensive (well to me, ?80ish) ?book Henry Otts Book ¡°Electromagnetic Compatibility Engineering¡± is a great resource for enclosure design

?

BUT, 2009 pdf version can be found

?

?

Pages 238 onwards, p270 mentions slot antennas.

Also mentions meters/displays on p287, a bit extreme for us amateurs?

?

?

  1. Also a dB calculator, I¡¯m sure there are others¡­..

?

?

hopefully helpful to someone¡­..

?

?

From: [email protected] <[email protected]> On Behalf Of K9HZ
Sent: 08 February 2025 15:46
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Conductive Paint

?

I¡¯m sure we should care about the EMI from the display too.??? Tell you what¡­ You work on the EMR and I¡¯ll finish getting the data line noise from propagating back into the radio¡­

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?
Re: [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance

 

T41 V11 operates in full duplex during transmit calibration.? So perhaps predistortion can be applied.? That would be an interesting experiment.? But V12 will not work, unless the TX calibration issues are solved, or a 2nd receiver is added.
The next question would be whether or not the Teensy has the horsepower to do the job.
?
73 Greg KF5N
481 - 500 of 6518