[Elecraft] Collins 30L-1 amp with the K3

[Paul Christensen]

> I want to use a Collins 30L-1 amp with my K3, when I plug the 30L-1 amp
> control cable into the K3 KEY OUT jack, the 30L-1 keys.  The 30L-1 is 
> keyed
> by grounding it's key line (pulling -160 DC to ground).

Butch:

Consider this alternative:

http://home.att.net/~jacksonharbor/keyall.htm

It's optically-isolated and keys substantial voltage of either polarity, 
including AC loads up to 2.5 amps.  Perfect for the Collins 30L-1.

Another option is to externally convert the 30L-1 to full QSK operation and 
use an interface like that offered by Ameritron (QSK-5), or Array Solutions' 
"QSK Master."  These two devices should take care of the rig to amp 
interfacing.  If you're into construction projects, see AD5X's related 
construction article on his website.

Paul, W9AC


----- Original Message ----- 
From: "Eric Swartz WA6HHQ - Elecraft" <eric at elecraft.com>
To: "Butch Schartau" <k0bsbutch at gmail.com>
Cc: <elecraft at mailman.qth.net>
Sent: Saturday, August 29, 2009 3:32 PM
Subject: Re: [Elecraft] Collins 30L-1 amp with the K3


> HiButch,
>
> Do not hook the K3 directly to the 30L-1. The K3 only switches positive
> voltages to ground on TX. Hooking up a negative voltage will not work
> and may damage the Keyout keying transistor.
>
> An external relay or a negative voltage keying transistor buffer are the
> best ways to do this.
>
> Butch Schartau wrote:
The K3 specs says
>> +200 VDC, at 5 amps, I guess the K3 does not like the minus voltage on 
>> the
>> 30L-1 key line, any suggestion other than an external relay?
>>
>> Butch K0BS
>>
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