K2 Transmitter Alignment - A layman's perspective

[Don Herring-3]

OK, after reading a good number of post on aligning the K2 transmitter, and
adding my own observations, I think I finally have my head around the
process.

I don't know that this has been summarized in a single post, and the intent
of this post is to verify what I think I now know, plus provide some
information for future builders.

Firstly, I am not a heavyweight (or even a lightweight for that matter) in
RF electronics or circuitry, but I obviously know enough to be able to
assemble a kit such as the K2.

Having said (typed?) that, if I am off base with my assumptions and
observations about the alignment process, would those in the know please
point out the errors in my logic.

There are two key points about the alignment process.

First, from what I have read here on the reflector, it appears that the ALC
circuit is bypassed whenever the K2 is placed into 'tune' mode.  Because of
this, there is a good chance you will see different power level readings on
the internal watt meter each time the K2 is place into 'tune'.  These
different power levels are also reflected on an external watt meter (I'm
using an OHR WM-2 ).  In my own case I was seeing three different ranges of
power output (roughly 1.4-1.7, 2.2-2.7, 3.8-4.1).

Second, and this is the important one, these power level fluctuations really
don't matter because the process is really not about setting the output
power level.  The goal is to peak the inductors.  And this can be done no
matter what power level is showing on the watt meter.

Having the OM-2 did help make sense of the process.  No matter what the
power level was, the peak spot for the inductor was consistent across the
various levels.

In other words, you adjust the inductor/caps to achieve the peak level of
power for whatever range of power is showing on the watt meter.

In normal use, I'm achieving an output level consistent with what I have
dialed power control to.  It seems my reception has also improved.

Hopefully this will help make some sense of the transmitter alignment
process.

And again, if I am off base in any way, please point this out.

73

Don Herring
W4DHH
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[Don Wilhelm-4]

  Don,

Your analysis is "right on".

The only thing I can add is that *if* during the tuning process, the
output power rises significantly (let's say to greater than 5 watts),
there is a possibility that you will not be able to discern the peak
because the RF Gain of the transmit stages may hit a limit and mask the
peak.  That is why the instructions tell you to reduce the power if it
soars too high.  You can reset the power level by either moving the
Power control or exit TUNE and re-enter it.  I use the later method,
just a tap followed by a press of the TUNE button - my fingers are well
practiced at it!.

73,
Don W3FPR

On 9/9/2010 9:16 AM, Don Herring wrote:

> OK, after reading a good number of post on aligning the K2 transmitter, and
> adding my own observations, I think I finally have my head around the
> process.
>
> I don't know that this has been summarized in a single post, and the intent
> of this post is to verify what I think I now know, plus provide some
> information for future builders.
>
> Firstly, I am not a heavyweight (or even a lightweight for that matter) in
> RF electronics or circuitry, but I obviously know enough to be able to
> assemble a kit such as the K2.
>
> Having said (typed?) that, if I am off base with my assumptions and
> observations about the alignment process, would those in the know please
> point out the errors in my logic.
>
> There are two key points about the alignment process.
>
> First, from what I have read here on the reflector, it appears that the ALC
> circuit is bypassed whenever the K2 is placed into 'tune' mode.  Because of
> this, there is a good chance you will see different power level readings on
> the internal watt meter each time the K2 is place into 'tune'.  These
> different power levels are also reflected on an external watt meter (I'm
> using an OHR WM-2 ).  In my own case I was seeing three different ranges of
> power output (roughly 1.4-1.7, 2.2-2.7, 3.8-4.1).
>
> Second, and this is the important one, these power level fluctuations really
> don't matter because the process is really not about setting the output
> power level.  The goal is to peak the inductors.  And this can be done no
> matter what power level is showing on the watt meter.
>
> Having the OM-2 did help make sense of the process.  No matter what the
> power level was, the peak spot for the inductor was consistent across the
> various levels.
>
> In other words, you adjust the inductor/caps to achieve the peak level of
> power for whatever range of power is showing on the watt meter.
>
> In normal use, I'm achieving an output level consistent with what I have
> dialed power control to.  It seems my reception has also improved.
>
> Hopefully this will help make some sense of the transmitter alignment
> process.
>
> And again, if I am off base in any way, please point this out.
>
> 73
>
> Don Herring
> W4DHH
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html