Tri-Mode Keyer by WA7RSO

05/21/2020

Keyer Development

This "Tri-Mode-Keyer" was originally designed and constructed about or before 1972-1973 by myself WA7RSO.

• I originally first "Breadboarded" my design to test the design concepts, then the circuit boards were made manually, by laying out each individual trace with drafting tape on a transparency above a grid lined paper base.
• Negatives were created with Orthomatic Film for high contrast to expose the photo-resist-coated PC boards later.
• Both sides of each circuit board was accomplished this way, and blank copper-coated fiberglass boards were cleaned, and treated with "Negative Photo Resist", then exposed to UV light for an appropriate amount of time to activate the Resist.
• Then immersed in Tri-Chlor to to remove the unwanted Resist, and then on to the acid bath to remove the copper between the traces, leaving the copper traces for components.
• Holes were manually drilled for through-hole components, which were then added and soldered in place (or socketed).
• Standard TTL chips that became available at that time were incorporated (they were quite new at that time).
• After all parts soldered and the circuit tested, both sides of the boards were spray coated (except for the socket tabs).
• Now in the process to reduplicate the original, and also with SMA devices, and also to incorporate various programable CPU's and LCD's.
• These new ones will be known as "Multi-Mode-Keyers", with more personalities than the "Tri-Mode" had.

Keyer Personalities

Special Note: This Keyer is unique in that it has 3 or 4 "Personalities"

It will first do Self-Completing Dits and Dahs, as well as the "Iambic Mode" of alternating automatically between Dits and Dahs when both paddles are closed simultaniously, and will emulate a Vibroplex Bug.

A quite unique mode, not seen on any other Keyer, is the ability to instantly switch to "Holding the Dah" when both paddles are "Squeezed", as a "Squeeze-Mode", allowing the sending of extended Dahs (like a Bug) for the "Pause" character, thereby allowing a definate personality that the old timer's like with the "Bug", and also establishing a minimal proper length Dah, but allowing a personal touch of longer or streched out Dahs.

< < I personally used this mode the most..>>

Another aspect I desired was to incorporate "Calibrated Speeds" that could be instantly switched, or "Variable".

The original design allowed for either 110VAC or 12VDV (for mobile or camping).