Re: Nasa talks on EMC, Grounding, Bonding g& Shielding

#33739

Very interesting.? I'll have to go through the whole presentation again to have a better understanding, but here's what I recently did.

I've built a v12 on an aluminum chassis.? I have a single point ground for power.? I twisted the power lines for each board and then covered them with braid.? I grounded only one end of the braid to the chassis based on something I read a long time ago (Faraday shield).? I covered these with nylon braid to prevent random contact with the chassis.? This seems to have reduced my noise floor a bunch (10-15 pixels if you will) and it seems to reduced "birdies" at various points on each band but I'm not sure this is the right way based on the presentation.? The power lines are not signal lines so there is no need to have a current return path for a "signal" (opinion).

I don't know if the mounting screw holes on the boards are connected to the board ground plane, but I grounded each board to the chassis with a short braid (not a pig tail). The power lines braids are grounded at one end to the chassis at various convenient points, the braids not pig tails.? RF connectors are grounded to the chassis, but everything else (headphone, key, ptt, encoders, displays) are not grounded to the chassis.? The 20W PA is not grounded to the chassis.

This all gets back to my excessive noise thread.

Thoughts? Ground both ends of the shields?

Thanks

Mark

KU3O

Re: Latest DSP and SDR book color images

#33738

On 2025-05-03 09:17, Duane B via groups.io wrote:
What is FDIM?  I'm familiar Hamcom and Hamcation.
Thanks,
Duane


           - Jerry, KF6VB

Re: Initial Test of Main V12.6 board

#33737

开云体育

Yes, you can temporarily remove the hat.? Program the Teensy, turn the power off… and replace the hat if you want.

?

Dr. William J. Schmidt - K9HZ J62K(J68HZ) 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

?

Owner – Operator

Villa Grand Piton – 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@...

?

Show quoted text

From: [email protected] <[email protected]> On Behalf Of John Owens K1JO via groups.io
Sent: Saturday, May 3, 2025 11:19 AM
To: [email protected]
Subject: [SoftwareControlledHamRadio] Initial Test of Main V12.6 board

?

I'm following the Main Board build instructions. The first tests went well, i.e. 3.3 and 5v tests.

On the next test, i.e. loading the i2cscan.ino, the serial monitor reported No I2C devices found. However, in another popup window, it said Press Button on Teensy to manually enter Program Mode, with i2scan.ino.hex 1% used on the status line.
With the audio hat on top of the Teensy 4.1, I cannot access the "button". Should I remove the Teensy from the Main board, remove the Audio Hat, and then program the Teensy by itself first?

Best regards,

John K1JO

Re: Latest DSP and SDR book color images

#33736

https://qrparci.org/fdim

Re: t41 main board j22 connections

#33735

Thank you too, rick. just having a senior day overlooking the info several times!

Re: t41 main board j22 connections

#33734

thank you tim, just having a senior (80 this year) moment, kept looking past what I was looking for.

Initial Test of Main V12.6 board

#33733

I'm following the Main Board build instructions. The first tests went well, i.e. 3.3 and 5v tests.

On the next test, i.e. loading the i2cscan.ino, the serial monitor reported No I2C devices found. However, in another popup window, it said Press Button on Teensy to manually enter Program Mode, with i2scan.ino.hex 1% used on the status line.
With the audio hat on top of the Teensy 4.1, I cannot access the "button". Should I remove the Teensy from the Main board, remove the Audio Hat, and then program the Teensy by itself first?

Best regards,

John K1JO

Re: Latest DSP and SDR book color images

#33732

What is FDIM?? I'm familiar Hamcom and Hamcation.?
Thanks,
Duane

Show quoted text

On Wed, Apr 30, 2025, 8:27?AM John Owens K1JO via <johnowenschina=[email protected]> wrote:

Thanks Jack. I hope you have a good time at FDIM, wish I could attend and get to meet you.
John K1JO

Re: FW 66.9 bug

#33731

I return from a family outing on Friday. Remind me then when I have access to the code and I can show the non-programmers how to do that. Meanwhile, if you haven't done so, download and install the Arduino IDE and Teensyduino. There are instructions online how to do that.

After Friday, I'll show how to print out your EEPROM values and then place them as your defaults, and write them to the SD card.

Jack, W8TEE

On Wednesday, April 30, 2025 at 09:50:50 AM EDT, Tim via groups.io <w4yn@...> wrote:

Is there a way for us no IT guys to easily do this, maybe save to SD card?

TX IQ cal is tiresome !

Tim?

?

--
Jack, W8TEE

Re: FW 66.9 bug

#33730

Is there a way for us no IT guys to easily do this, maybe save to SD card?

TX IQ cal is tiresome !

Tim?

?

Re: Latest DSP and SDR book color images

#33729

Thanks Jack. I hope you have a good time at FDIM, wish I could attend and get to meet you.
John K1JO

Re: Latest DSP and SDR book color images

#33728

We haven't had the time to upload them yet. It will likely be after FDIM before it gets done.

Jack, W8TEE

On Tuesday, April 29, 2025 at 08:04:16 PM EDT, John Owens K1JO via groups.io <johnowenschina@...> wrote:

Were the new color images uploaded anywhere? I found the old book's images, but they aren't the same.

John K1JO

--
Jack, W8TEE

Re: Restructuring the T41 code

#33727

Keep me posted on what you think about the books!

Jack, W8TEE

On Wednesday, April 30, 2025 at 03:36:09 AM EDT, John G0SDF via groups.io <jatkins295@...> wrote:

Phil & Jack. Thank you both for your book recommendations! I now have all 3 books, so no stopping me now!

?

Regards

John, G0SDF

--
Jack, W8TEE

Nasa talks on EMC, Grounding, Bonding g& Shielding

#33726

Some people may be interested

?

Site seems to take an age to load....

?

The grouding one is interesting ref differitial interconnections and ground bounce.

also

EMC Fundamentals Part 10: Grounding, Bonding & Shielding

?

I'm sure there are loads of others out there

--

73
Chris M0YGH

Re: Restructuring the T41 code

#33725

Phil & Jack. Thank you both for your book recommendations! I now have all 3 books, so no stopping me now!

?

Regards

John, G0SDF

Re: FW 66.9 bug

#33724

Smart...!


Dr. William J. Schmidt - K9HZ J62K(J68HZ) 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ

Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois

Owner – Operator
Villa Grand Piton – J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com

Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.

email:? bill@...

Show quoted text

-----Original Message-----
From: [email protected]
<[email protected]> On Behalf Of jerry-KF6VB
Sent: Tuesday, April 29, 2025 2:20 PM
To: [email protected]
Cc: Oliver KI3P via groups.io <oliver@...>
Subject: Re: [SoftwareControlledHamRadio] FW 66.9 bug

On 2025-04-23 13:44, Oliver KI3P via groups.io wrote:

reset the flash. This will delete all your calibration parameters, 
unfortunately, so only do it as a last resort.I got tired of doing calibrations over & over - especially the transmit IQ
cal.
So I have gotten into the habit of modifying EEPROM.c to put my calibration
numbers into the defaults.

               - Jerry, KF6VB

Latest DSP and SDR book color images

#33723

Were the new color images uploaded anywhere? I found the old book's images, but they aren't the same.

John K1JO

Re: Restructuring the T41 code

#33722

I must say as not yet retired EE, still have a few years before I earn that privilege.

?

I have dabbled in C several times over my career from university and onwards, back then the standard book was "The C Programming Language", by Brian Kernighan?and?Dennis Ritchie. Still a great reference book, but not really directly relevant to Arduino or Teensy. I think the best thing about programming now is the numerous libraries and functions available at your fingertips nowadays, that wasn't the case back when I was at university, the internet was still maturing - GitHub is a new millennium invention.

?

I've found it's the old "use it or lose it" paradigm, it's quite hard to maintain the C skills without using them regularly on top of all the other regularly used skills as an EE. I've also tried Python and JavaScript but lost most of that knowledge quickly. I hope to spend more time in the "developers world" myself, let's see how that goes.

?

All the best John on your journey.

?

Regards
Phil VK2KKZ

Re: t41 main board j22 connections

#33721

I am happy to send you a premade cable.?

I have a few from RC flying days.

My gift no charge?

PM me?

Tim

Re: t41 main board j22 connections

#33720

开云体育

John,

It is a three wire connector to the piggyback audio hat. I believe the hat is labeled L G R or R G L on the audio hat bottom.? That is the audio out of the top hat for transmit audio.? Discussed on page 1 of the assembly manual, item 3.? Hope that helps.

Rick, KN4AIE

?

Show quoted text

From: [email protected] <[email protected]> On Behalf Of john rader via groups.io
Sent: Tuesday, April 29, 2025 7:00 PM
To: [email protected]
Subject: [SoftwareControlledHamRadio] t41 main board j22 connections

?

I have looked at all schematics and construction files, where is the j22 connector on main board connect to?