[Elecraft] K3 and linear amp

[Toby Deinhardt]

Hallo Roger,

> delay times.  So far there's been no response from Elecraft concerning this
> subject after a few days of discussion on this list.  We don't even know if
> they could easily make the modification in the firmware.  

Elecraft has said in the past, several times, that they will be adding 
this to the menus sometime in the future. Also The FAQ on the Elecraft 
web site has the following information (for at least 6 or 7 Months now):

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Is there a relay output from the K3 to switch on an external amplifier? 
If so, is it done via the accessory connector on the rear panel?

Yes; it has its own connector (KEY OUT) on the rear panel.  The KEY OUT 
line is a MOSFET, open-drain (equivalent to open collector in a BJT 
device).  It can handle a lot of current AND a lot of voltage. Exact 
specs TBD.


Does the K3 have a variable delay (0-50ms) to control older amp TX 
relays (i.e., SB-220, L4B, etc.)?

Yes. It also has a separate PTT input jack, so you can pre-switch the 
amp using a footswitch, etc.  This delay is provided to prevent 
hot-switching of amplifiers and the adjustment range will cover any 
likely need.  The variable delay is a feature that will be available 
after initial shipment.


What is the voltage and current limit to control TX amp relays?

The keying device is rated at 200 volts, 6 amps.
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<http://www.elecraft.com/K3/K3FAQ.htm>


vy 73 de toby