Sunday, December 22, 2019

AL-80B Keying Interface

KV5R wrote a nice article (Amp Interface) on building a solid state keying / relay interface for use with Icom rigs, using an SPST-NO MOSFET switch. I also have an Icom rig and an Ameritron AL-80B.

The nice thing about this is it's super simple, much faster than a mechanical relay and is opto-isolated.

I had ordered some parts for another project a while back, part of which was to rebuild the keying interface so I could key two devices. That project got shelved, but today I decided to rebuild the interface as originally planned since I had the stuff to do it.

Version 1 (with the heat shrink removed):

I had this hanging out the back of the rig, that was ok.

Version 2:

Only the orange and grey wires are used from the Icoms pigtail, the rest are just tucked out of the way.

The solid state switch's control voltage is 3 to 10V, but work ok from 12V. With two of them I wired them series for use with the rigs accessory jack which supplies 12V when keyed. With this I can independently key two separate devices with a closing current of 3A at up-to 60V each.

Parts I used:
  • Project box is a "Zulkit Waterproof Plastic Project Box ABS IP65 Electronic Junction box Enclosure Black 3.94 x 2.68 x 1.97 inch (100X68X50mm) (Pack of 2)", from Amazon. I have found it quite difficult to find good project boxes.
  • DIN plug and pigtail came with my IC-7300, I simply cable tied once for strain relief and a second time looping it through two small holes I drilled to stop the cable from rotating. This secured it nicely since I didn't have anything better on hand.
  • Solid state relay is a Crydom DMO063, Mouser part # 558-DMO063. Can also be found on Amazon, and other places.
  • Barrier Terminal Blocks TERMINAL STRIP 6 LUG, Mouser part # 158-1006.
  • RCA Phono Jack, Mouser part # 490-RCJ-032.