[Elecraft] K3 Key Out

[Dave Zeph]

The Keying Transistor used in the Harbach Soft Key uses an IRF610 HEXFET
Power MOSFET, rated for 200V with an ON Resistance of 1.5 Ohm in a TO-220
Package.

The Elecraft K3 uses an IRF1630 HEXFET Power MOSFET, rated for 200V with an
ON Resistance of .4 Ohm in a TO-220 Package.

Don't see much of a gain by using the external device .....



73 ---> Dave, W9ZRX




> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net [mailto:elecraft-
> bounces at mailman.qth.net] On Behalf Of Don Rasmussen
> Sent: Monday, 01 September, 2008 18:20
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] K3 Key Out
> 
> I soldered up the soft key mod today, it's inexpensive
> and simple to install.
> 
> http://www.harbachelectronics.com/_mgxftp/pdffiles/SK220PICTORIAL.PDF
> 
> [Elecraft] K3 Key Out
> David Robertson darjar at comcast.net
> Mon Sep 1 17:40:33 EDT 2008
> 
> The K3 Key out may be rated for 200 volts but if you
> use it with an unmodified SB220 you are taking a real
> chance of damaging the K3 because there is no
> protection diode in the SB220 and the field collapse
> voltage can exceed 1000 volts.
> 
> 
> the SB220 was originally designed for relay keying.
> 
> 73
> Dave KD1NA
> 
> 
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