Charlie wrote:
>There was a firm who advertised in the classified section of QST who made
>various kits for both the SB-220 and SB-200. Their name was Harbach and they
>were located in Florida. ...
If one prefers to brew their own keying device, beware that the keying
voltage is NEGATIVE... be careful if you're using a solid-state device.
Harbach upgrade kits are based on QST articles published over the last 25
years... and they all work nicely. Once you've installed the Soft-Key kit
in the amplifier, you can key it safely with ANY rig, without worrying
about damage from voltages or currents. The transistor used imposes a
milliamp or two, and less than a volt on the rig. The kits can actually be
used on many other types of amplifiers, just check your schematic and
proceed carefully. I've installed 8 soft-key kits, and only 3 of 'em were
in Heathkits.
Mr Harbach passed on about two years ago. Jeff W8CQ took over the
business, moved it to his QTH in Brownsburg Indiana. Harbach's original
documents were in WORD format, I converted 'em to PDF format for Jeff's new
web-page. Looks like he's got a kit for the Drake L4's and an
opto-isolated one for the 30L-1. You can download a copy of the
installation guides to take a look:
http://www.harbachelectronics.com/
Cheers/73!
DK :-)
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73's from KW0D Dave in LeClaire, Iowa
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