Last one::
http://www.n4xy.com/PDFs/HMBW_Projects/Vintage_Keying_Adapter/Vintage_Keying_Adapter.pdf
Ed W3NR
One more for folks who like to build things. See the S-QSK Mini device near the top of my QRZ page. Smaller than a matchbook. It's a "no wires" design that accepts negative or positive input key lines (including a positive line from a PC computer port). S-QSK Mini is powered exclusively from USB (e.g., iPhone wall cube or PC COM port).
Uses a really tiny and inexpensive plug-in microcontroller for precise switching (and delay if required). Precompiled code is free to download and flash to the USB port. Input and outputs are optically isolated. Output device is a balanced plug-in MOSFET. Depending on the MOSFET chip chosen, it will switch any AC/DC voltage up to 400V at 250 mA or 60V at 2 A. RCA jacks for input and output.
I have nothing to sell. "One click" parts ordering through Mouser by following the linked instructions. Gerber PC board files are free to use as indicated on the QRZ page. 5 PC boards are about USD $2 from JLCPCB in China, slightly more from DKRed in USA. With shipping, PC boards are about USD $11 for 5 boards. Give the extras to friends or save for other switching projects.
Typical applications:
- Keyer-to-transmitter interface
- Computer-to-transmitter interface
- Generic transmitter-to-amplifier interface as an amp key line buffer and "relay saver"
- Anti-shock key-to-rig interface for older vacuum tube gear
- "Switch saver" by taking up to a 2.5 amp load off delicate switch contacts
- Switch and relay contact debouncer (software adjustable debounce time)
- Bug key contact debouncer (software adjustable debounce time)
- RF amplifier bias switch in electronic bias systems (software adjustable EBS hang time)
- Control of time-delayed step-start circuits
- Switching applications that require galvanic isolation
- Power relay for +12V station accessories
- Icom transceiver-to-amplifier buffer and pulse-stretcher to eliminate "RF tail" amplifier hot-switching (applies to: IC-7300, IC-9700, IC-705)
The files are linked to my business FTP server and some web browsers will give a litany of security errors. However, the links and files are clean.
www.w9ac.comPaul, W9AC