If you haven't figured it out already the first few circuits ( simplest field phone) lend them selves well to quick assembly after the SHTF. All you need is a few handsets, battery's, switches and wire to throw them together.
They would be most useful say over a few 1000 ft from an O.P. to the C.P. better than radio as there is no possibility of intercept unless the enemy has access to the wire and a phone to connect to it to monitor with. You can of course build several sets in advance of needing them (which would be what I recommend). That could be as simple as screwing the bits to a small board or going to the trouble of getting small boxes made for electronic equipment and assembling a more finished device with a PTT and call switches, a battery holder, electronic buzzer and 5 way binding posts for the line. These could be small and much lighter than conventional sets, as they aren't built to military specs nor do they necessarily need to be. Remember they don't need to be perfect, they just need to be good enough.
In the near future I plan to cover 1) wire (a truly vast subject), 2) high voltage signaling circuits (schematics), 3) voice networks (more schematics), 4) specific Military field phones, (principally the EE-8, TA- 43 and TA -312 and the TP-1). and 5) a build an inexpensive knock off of the EE-8 with more modern components. I also will share an inexpensive and simple way to leverage your wiring to allow it to double as a circuit for data networking between computers.
I encourage people with specific questions to go ahead and ask them so I can address those issues in upcoming posts.
If there is sufficient interest I can assemble kits for people to buy so as to fabricate their own phones, baring that I can supply the URLs for companies where you may buy the parts yourself.
I just purchased two TA-43 field phones on eBay. It came with a wire pair and D cell batteries. Both phones can ring each other, but only one phone can hear the other speak. I noticed that on the phone that can hear the other, I can also hear myself speaking on that phone. On the other system, you can't hear yourself speak and can't hear the other phone. I swapped the ear speakers, and the problem didn't move, so I need to look at the yellow and blue wires connected to the ear piece speaker and follow them through the circuit. It would be nice to have a schematic or manual on that phone. Also, I can use the one good TA-43 field phone at my single LP/OP and maybe use a common analog phone in the house, as a workaround.
ReplyDeleteOpen up the phone ( six screws on top and the four around the clacker). take a 1.5 volt battery and apply it to the yellow and blue wires on the terminal block attached to the battery box, if the receiver and cord are goo you should hear a "click". The coiled cords often fail where they enter the body of the phone and the handset.
ReplyDeleteIf your phone passes this test let me know as the issue is deeper in the phone.