[Elecraft] K3 external qro keying line

[Tom Hammond]

The K3's T-R line output ("KEY OUT") can switch up to 200VDC @ 5A... so it will
easily switch the +120VDC @ 15-30mA from the SB-220.

However, it will NOT SWITCH a NEGATIVE T-R line voltage UNDER ANY 
CIRCUMSTANCES!
Users with amps which offer a negative T-R line control voltage will have to
provide alternate switching (relay, or solid state).

73,

Tom   N0SS

>phones, mic,
>line in, and line out


At 10:13 02/12/2009, Lee Buller wrote:


>HMMMM....  I thought the transistor on the K3 doing the switching is 
>pretty tough.  I guess we are talking about older amps and not the 
>ones that use 12 volts to switch.
>
>I have done the following to....  Radio Shack sells a 5v reed relay 
>that is pretty darn fast and has good specs.  I just used a dropping 
>resistor from a 12 volt line in series with the reed relay and 
>worked great for years.  I think I used a 180 ohm resistor.  Worked 
>great.  Not QSK, but I don't like QSK anyway.  Messes with my head.  HI
>
>Lee Buller - K0WA
>
>
>
>In our day and age it seems that Common Sense is in short supply. If 
>you don't have any Common Sense - get some Common Sense and use it. 
>If you can't find any Common Sense, ask for help from somebody who 
>has some Common Sense. Is Common Sense divine?
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