I've seen numerous posts about the PTT output line on the K3 and using older
amps. Yaesu's, Kenwood's, Icom's all share the same issue.
Unless you are running QSK and need instant keying, I would suggest adding a
small 12v relay inside the K3 that the solid state device keys and presents the
user with a set of dry, isolated contacts that can handle positive, negative
and up to 250v DC or AC. I have added this to several K3's to protect the
switching transistor from eventual destruction. Once again, if you are using
QSK, solid state due to it's fast switching time is your only option.
Yes, it means touching your K3 with a hot soldering iron, but it's a "pay me
now or pay me later" thing, sooner or later it will blow the switch if you are
hooking up older or HB amps that use other than low current positive keying
voltages.
Terry
----- Original Message -----
From: "Greg - AB7R" <a...@cablespeed.com>
To: elecraft@mailman.qth.net, 'ba...@mailman.qth.net, "Stephen'"
<pbsba...@buffalo.edu>
Sent: Thursday, February 12, 2009 10:18:50 AM GMT -05:00 US/Canada Eastern
Subject: Re: [Elecraft] K3 external qro keying line
Barry, The key out line on the K3 on not on a sub assembly, it is on the main
RF board. Im not sure of the relay on the SB220 but I suspect you may need to
use one of those AmpKeyer interfaces that the HeathGuy or Ameritron sells just
to be safe...or brew your own. It depends on the voltage requirement of the
amp's relay. ------------------------- 73, Greg - AB7R Whidbey Island WA NA-065
On Thu Feb 12 7:13 , "Barry, Stephen" sent: > > > > > > > > > > > > > > > > > >
>I���m a long time builder/operator of an early K2 (s/n >377) and have
considered going for the K3/10. > >�� > >I would use my SB220 occasionally for
more power since I can >get approx. 200 watts with 12 watts in. > >�� > >The
question I have is there a PA key line available from >the basic K3? ��Or, is
that circuitry on the KPA3 subassembly? > >If so, has anyone found a way to key
an amp with the basic K3? > >�� > >I enjoy reading the list serve and the good
advice from some >of the O/T submitters such as W2FPR, AC7AC and N0SS.�� Thanks
> >guys. > >�� > >I���d ask the Elecraft guys but I don���t want to >bother
them while they���re cranking out K3s. > >�� > >73. > >�� > >Steve/AE2G > >�� >
>�� > > > > > >
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