[Elecraft] Tuning K3 with linear amp

[Bruce McLaughlin]

Thanks Don.  I will do that very soon.

Bruce - W8FU

-----Original Message-----
From: Don Wilhelm [mailto:w3fpr at embarqmail.com] 
Sent: Monday, May 12, 2008 7:19 PM
To: Bruce McLaughlin
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Tuning K3 with linear amp

Bruce,

Yes, do load the latest firmware.  It does contain some ALC changes.

73,
Don W3FPR

Bruce McLaughlin wrote:
> I am still exploring my new K3 (it's less than one week old.  I discovered
> an odd issue while tuning it with my Commander HF 2500 amp.  With the ATU
> off and the power lowered to about 3 watts I activated the tune function.
> While watching the output on my Coaxial Dynamics wattmeter I gradually
> raised the K3 output power while tuning the amp.  When I got to around 13
> watts drive from the K3, the wattmeter was showing a carrier power of 1 KW
> from the amp.  The drive power of 13 watts indicated on the K3 was
unusually
> low for an indicated output of 1 KW carrier.  When I then spoke into the
> mike and flipped on the peak reading circuit on the watt meter, it showed
> only 500 to 600 watts pep which was low in my experience.  Usually with an
> indicated carrier power of 1 KW I should at least get around 1400 or more
> indicated peak power on modulation.  I gradually increased the drive from
> the K3 until the peaks showed 1 KW or a bit more.  When I again checked
the
> output of the K3 it showed a bit more than 23-25 watts which is what I
> usually get with my other radios.
>
> This behavior is different than my other radios.  It appears to require a
> low drive level to show 1 KW carrier output from the amp but with a low
peak
> reading.  I suspect something is happening with the ALC but I'm not sure.
I
> should mention that I have yet to load any firmware updates.  It has
> whatever version it had when it left Aptos on May 2.  Could that be a
> factor?
>
> Bruce - W8FU 
>   
>


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