K3 Key Out

[Don Rasmussen]

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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[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: [hidden email] [mailto:elecraft-
> [hidden email]] On Behalf Of Don Rasmussen
> Sent: Monday, 01 September, 2008 18:20
> To: [hidden email]
> 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
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

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