Bipolar PI design

[ivconic]

In the meantime you changed some components... some 100k resistors are now 47k, ok, I can't figure out which is the correct schematic now. Among other things; I need clarification on:
1) C13
2) C23
3) Q7 (3906 on schematic in the book, 3904 in recent schematics)

[Carl-NC]

The latest schematics, Gerbers, and code will always be posted in relevant ITMD3 forums. I will probably keep all revisions posted (assuming there are future changes) so that you can get any version you want.

C13 can be just about anything, 10n-100n is fine. It's just a noise filter for the pot.
C23 can be 10p-33p, or left out (as it is in the book schematic). It's also a noise filter (R13-C23), but you want it faster than R9-C14.
Q7 is NPN, 3904. Another book schematic error.

[ivconic]

[ivconic]

...

[Carl-NC]

I've moved the PI-GB discussion to a separate thread.

I have only just ordered a "final" PCB to build & test the bipolar design. You can wait for me to verify, or you can take the risk and start one yourself. I don't expect any major problems as I tested the design on a patched PCB and it was working fine. The only risk is if I missed any of the patch mods in the latest design.

[ivconic]

[ivconic]

Last update based on Carl's corrections (click to enlarge):

[algan]

Hi, Carl what would the circuit look like if a TX was built with SPDT gate drivers

[ivconic]

I have not neglected and forgotten this topic.
I am waiting for the conditions to be created so that I can order the production of the pcb at JLPcb.
I have a series of various holidays and huge commitments behind me, so this is going slower than I planned.
In the meantime, I "customized" Carl's pcb design to my own preferences.
It is possible that I overdid the ground plane on the top&bottom layers!

Carl, please in case you have completed Bipolar PI; to write here the first experiences.
In case something needs to be changed or repaired; that I would not order a pcb build until I add any corrections.
Here is my "rendering" of the pcb in Sprint Layout.

[Qiaozhi]

Please be aware that Chinese New Year (Spring Festival) begins on the 29th January.
It's the year of the snake.

[ivconic]

Oh yes, my colleague is on vacation now. Today he emailed me from another place which is quite far from where he works.
I forgot to ask him how long the vacation last.
Anyway, I remember from before that this is the month of holidays and vacations in China.
I don't know if they have the same customs at JLPcb.
Things will go a little slower.
But it doesn't matter, because I'm waiting for confirmation from Carl about this detector.
I have learned patience over the years.
So no problem, this diy will be done as soon as the conditions for it are created.

[Carl-NC]

Just today I received V2.1 PCBs. I am off this weekend to play in the snow but next week I will start building it.

[ivconic]

Cool!
Take your time.
Looking forward.

[algan]

I am also waiting for confirmation, but can you tell me what kind of wire is suitable for making TX and RX and how many microhenries should they be? Thank you.

[Carl-NC]

The bipolar PI design can use a mono coil, same as the other PI designs. 300uH was the common value and any jacketed (PVC, etc) stranded wire will do, I used 24 AWG.