Author Topic: Field exchange SB-22/PT  (Read 699 times)

Offline dsk

  • **
  • Posts: 4192
Field exchange SB-22/PT
« on: November 15, 2019, 03:21:17 AM »
SB 22/PT is made in several versions during the years.
The first ones had a heavy metal case, the later plastic.  The older operators packs had that retractable cords, but no jack for resting the plug. That rest jack on the newer ones had an extra switch cutting transmitter power to prevent discharging of the battery.
Later models could have trunck-packs for connecting to CB lines, in addition could it be a keypad.

Mine is one of the older ones, I have modified a line -pack to a trunk-pack and use a rotary dial for dialing.
I have not been willing to pay for those expensive parts,  shipping and customs to Norway of several 100 dollars.
When I served, we used a handset, but a headset was the standard. In my setup I took another handset more suitable for my use.
dsk

PS I modified to use some rechargable batteries I have.  (18650 lithium battery)   DS
« Last Edit: November 15, 2019, 03:31:40 AM by dsk »

Offline RB

  • **
  • Posts: 1424
  • Love old phones
Re: Field exchange SB-22/PT
« Reply #1 on: November 15, 2019, 12:25:24 PM »
sweeet! I like the handset, and the dial mount ! :)

Offline dsk

  • **
  • Posts: 4192
Re: Field exchange SB-22/PT
« Reply #2 on: November 16, 2019, 12:44:53 PM »
sweeet! I like the handset, and the dial mount ! :)

I like to improvise, and the Dial was an old Antwerp dial, on witch I did put belt clip on the back side and a logo in the dial-center.
The handset was on I had without anything else but it has press to talk it is comfortable to hold and has a good receiver (equal to most German receivers) and a good electronic transmitter-capsule suitable here, but polarity sensitive.  The handset has a logo with the brand  Gfeller, (Albiswerk AG, Gfeller AG ?)  (logo pictured)

dsk
« Last Edit: November 16, 2019, 01:01:10 PM by dsk »

Offline countryman

  • **
  • Posts: 556
Re: Field exchange SB-22/PT
« Reply #3 on: November 16, 2019, 02:59:42 PM »
"in 1896 Christian Gfeller founded a mechanical workshop for telephones and railway signals in Bümpliz.(...) 1984 Gfeller AG* and Autophon AG merged.(...) 1987 Autophon, Hasler and Zellweger merged to Ascom."
(http://www.query.sta.be.ch/detail.aspx?ID=546950)
It seems Gfeller was a major supplier for fhe swiss army.

*AG = Swiss public company.

Offline dsk

  • **
  • Posts: 4192
Re: Field exchange SB-22/PT
« Reply #4 on: January 06, 2020, 12:22:49 AM »
Due to the limitation in how lagre uploads we may put here a good pdf manual is located here: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwiLkJv7nO7mAhXU5KYKHbjACl4QFjAAegQIAxAC&url=https%3A%2F%2Fradionerds.com%2Fimages%2Fb%2Fbe%2FTM_11-5805-262-12.pdf&usg=AOvVaw0sZaZ0gRvkW12Nq5p5Cdwc

More info about the SB22 is here and ther e on the net:
http://www.prc68.com/I/SB22.shtml

dsk

PS attatched the PDF where the late pages are removed, this waas only blank pages, and forms ti fill out ...    DS
« Last Edit: January 06, 2020, 12:45:09 AM by dsk »

Offline dsk

  • **
  • Posts: 4192
Re: Field exchange SB-22/PT
« Reply #5 on: April 16, 2020, 03:25:15 PM »
Since it seems to be impossible to get the original DTMF unit for the cordboard, and my trunkpack also is a DIY version, I did get inspired of the German WWII solution: http://www.classicrotaryphones.com/forum/index.php?topic=22478.msg226592#msg226592


But of course I would like to have touch tone too, so I found a scrap phone with tone/pulse selector.   I did put in a jack, and some components.   I prefere the transformer to get the systems isolated from each other, the small transformer does not like the DC components, so I did put e capacitor in series on the CO side, and added a 470 ohms resistor to keep the DC path without loosing to much of the signal. On the SB-22 side I also added a capacitor to prevent it from stealing all the ring off power.

The diagram sketch shows how I wired it.  And ofcourse you have to see how small the transformer actually is.

The best of all, it woorks great on first try.
dsk

Offline countryman

  • **
  • Posts: 556
Re: Field exchange SB-22/PT
« Reply #6 on: April 16, 2020, 03:38:12 PM »
Bookmarked for later use...