Cave / field phone

[DiCaver]

Hi,

I've read a lot of posts, but didn't found what I'm looking for. Maybe I'm not looking under the right name. I've also read "Please READ ME FIRST before posting!", so I hope that this post is not "duplicated"

I'm looking for "plan, electric circuits, map" for field phone. I think that you called like that ... you know: outside the cave is receiver with battery, than you take a "double wire" in to the cave and where ever you want to contact with an base in front of the cave you just connect (I think that I saw a name) bubblegum phone and call them.

Or whatever "cave phone circuit" that is "easy" to build


Thanks and have a great time, Marko

[NZcaver]

Hi Marko, welcome to the forum.

"Field phone" is a military term. In the US, old military surplus field telephones using two-conductor wire are the basic standard for cave rescue communication. The most recent generation of phones are reasonably light, reasonably cheap, and very rugged. For most people who may use them for rescue and cave projects here in the US, it's cheaper and easier to buy military surplus equipment than to build new phones from scratch. If you want some of these phones, contact me directly (private message) and I can give you further advice.

However if you don't want military phones, or need something even smaller and lighter, there are options for building your own. The most basic options include the old cave rescue telephone project and the cheap field telephone. A more advanced design is the single-wire Michie phone, and the circuit diagram can be found here. The British have a similar single wire telephone design, and their page contains detailed information including the circuit diagram and construction details.

These last two single wire telephone designs have quite good range and clarity, as do the more modern military surplus field telephones (1970's and newer). The older field phones and basic home-made designs (including the bubblegum phone) - not so much. I've come up with a couple of my own devices and modifications, which connect with regular field phones on a 2-conductor wire system. But I haven't really got around to publishing them yet.

Good luck, and let me know if you need more information.

[Leclused]

Hi Marko,

Cave radio's/phones that works without a line through the cave exists too

- The nicola by graham Naylor (the link I had appears to be broken so google for it)

- In our club one of our members build ones based on the schema's of John Hey "Heyphone"
see here http://www.scavalon.be/avalonuk/technical/radio1.htm
and here http://www.scavalon.be/avalonnl/technical/radio2001.htm (only dutch)

If you want you can always contact the builder H Jorens or send me an e-mail and I'll forward it

BR

Dagobert (Sc Avalon - Belgium)

[NZcaver]

Hi Dagobert,

Thanks for the information on your local version of the Heyphone. From Marko's post title and description, I assume he's looking for information on telephones (connected by wires) - not radios (wireless). But even here in the US, some people get confused and think field phones are "radios" and vice-versa.

We have a couple of previous topics on the forum specifically about cave radio communication and cave radio location. I also play with cave radios myself from time to time.