The Pease Ultraphone
A high performance Single-Wire voice telephone for expedition use
A high performance Single-Wire voice telephone for expedition use
The Ultraphone was designed to overcome many of the limitations of classic single-wire telephones. This includes weak audio when listening, power line hum and other interference, and poor performance on multi-kilometer lines with poor grounds and/or line defects. The Technical Article here gives a brief history of single wire telephones, then describes the Ultraphone in detail including schematics. This article also gives full construction details including a parts list. An appendix describes using the Ultraphone with only capacitive coupling to the phone line, and describes a specialized "mobile" version of the Ultraphone with schematic and parts list.
Universal circuit boards for the Ultraphone that can be used to build the expedition version or a phone with built-in 9V battery or external 12V battery or the mobile version are available for $2.50 USD each plus shipping. A few complete Ultraphone kits, with the aluminum cases pre-drilled for the version you want are available for $50.00 USD each, or $45.00 without drilling. If I am in a good mood, and have the time, I might consider building complete phones for a good cause for $75.00 each. Those building from a kit should print out these PCB Parts and Chassis Parts PDF layout sheets to sort and inventory the parts before starting construction. For those drilling their own cases, print out the Expedition phone layout here, the self-contained phone with built-in battery here, or the mobile phone here
Universal circuit boards for the Ultraphone that can be used to build the expedition version or a phone with built-in 9V battery or external 12V battery or the mobile version are available for $2.50 USD each plus shipping. A few complete Ultraphone kits, with the aluminum cases pre-drilled for the version you want are available for $50.00 USD each, or $45.00 without drilling. If I am in a good mood, and have the time, I might consider building complete phones for a good cause for $75.00 each. Those building from a kit should print out these PCB Parts and Chassis Parts PDF layout sheets to sort and inventory the parts before starting construction. For those drilling their own cases, print out the Expedition phone layout here, the self-contained phone with built-in battery here, or the mobile phone here