[Elecraft] KX3 To SB1000 Amplifier

Matt Zilmer iPhone mzilmer at roadrunner.com
Wed Nov 30 16:50:18 EST 2016


Welcome to the fold, Paul. 

-Matt
Always store beer in a dark place. - R. Heinlein
[iPhone]




> On Nov 30, 2016, at 13:05, Paul Hvidston <phvidston at gmail.com> wrote:
> 
> (had to change email subscription to post to reflector. lets see if this one works...)
> 
> The AL80A uses a 12V 100mA relay coil that is pulled to ground to
> activate. There is no back-EMF diode in the circuit. The KX3 keying
> output is simply the open drain of a 2N7002 low-power MOSFET, also with
> no back-EMF protection other than its internal channel diode and an
> additional 0.01 uF cap. You could probably "get away" with it, but I
> would not recommend it. There is limited protection on the I/O of the
> KX3. The lines typically have RC networks to limit RFI and current, but
> driving an inductive relay is asking a bit much. A safer solution would
> be a simple driver to protect your KX3 from a repair trip to the factory.
> 
> On a similar note, the Black Friday sale pushed me off the fence and I
> ordered a KX3 (my first Elecraft), woo hoo! I've got an SB-200 that I can hook up
> to the KX3 to provide about 80 watts out if I want QRO while saving up
> money for a linear for the little guy. My SB-200 has the Harbach keying
> circuit so it's good to go. The Harbach circuit was not quite designed
> correctly, but that's a story for another list, HI.
> 
> vy 72 de Paul/N6MGN, Montana
> 
> 
>> On 11/29/2016 1:13 PM, David N. via Elecraft wrote:
>> Hello AllI just ordered a New KX3 (Kit)I am wanting to know if Keying My Heathkit SB1000 (Ameritron AL80A)  amplifier with key line off of the ACC2 will be a problemIt says that it is good for 30v @ 100ma. My Amplifier is 12v relay. Not sure current. I would think itwould be fine. But just wanted to check. I won't be able to order my KXPA100 till next year. Have to save the penny's for that one.Thanks
>> David KR4OWK2/100 4320
>> 
> 
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