FW: [Elecraft] K3 and StepIR/Icom PW-1

[Greg - N4CC]

Adam -- I guess it depends on the user.  Certainly having the ALC 
connected (if it were compatible) would be preferred...but my point 
is that saying " the K3 should not be used as an exciter for the 
PW-1" [without ALC] is not entirely accurate.  it is possible to use 
the PW-1 without ALC.  It can be done and done quite safely.  Granted 
you lose a measure of protection but if you use the K3 as I do -- 
where it recalls the drive setting by band, a unique feature of the 
K3 -- it is less likely that not having the ALC connected will ever 
be an issue.   If you change the power settings frequently and are 
not careful to return them to the desired drive level when operating 
the amplifier then your chance of damaging the amp increases without 
the ALC.  Cheers.  73 de Greg

At 10:53 PM 9/7/2008, you wrote:
>Hi Greg,
>
>The PW1 uses the ALC loop as an essential part of its protective subsystem,
>as described in the service manual excerpt  which I sent you. Any one of
>several anomalous operating conditions (including over-drive and load
>mismatch) will pull down the ALC line to reduce the drive. This is the
>amplifier's first line of defence.
>
>I would never put an expensive piece of equipment such as the PW1 at risk by
>connecting it to an exciter without a fully-functional ALC loop.
>
>Cheers for now, 73,
>Adam VA7OJ/AB4OJ
>
>-----Original Message-----
>From: Greg - N4CC [mailto:n4cc at alltel.net]
>Sent: 7-Sep-08 19:05
>To: Adam Farson
>Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1
>
>I'm using the K3 with a PW-1 and the beauty of it is you don't need the ALC
>if you use the K3's capacity to store the power level (drive
>level) for each band.  Obviously if you use the K3 barefoot at 100 watts you
>would have to be careful to turn it back down with the amp but I just leave
>it at the saved settings that I have established for output for each band.
>The proper drive level does vary somewhat by band.  You are right about the
>ALC ..the K3 ALC is not compatible with the PW-1 and you should not connect
>the ALC line between the two.  73 de Greg
>
>At 09:08 PM 9/7/2008, you wrote:
> >  Hi Tom,
> >
> >The K3 should not be used as an exciter for the PW1 unless the polarity
> >of its external ALC input has been changed from positive-going
> >(original) to negative-going (range 0 to -4V). Failure to heed this
> >warning will result in extensive damage to the PW1, necessitating
> >costly repairs (as much as
> >$1800!)
> >
> >http://www.ab4oj.com/icom/main.html#alc
> >
> >Cheers for now, 73,
> >Adam VA7OJ/AB4OJ
> >
>
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