[Elecraft] K2 Problems

[kc4kgu@ENTERZONE.NET]

On Sat, 25 May 2002, Richard M. Cash, W4UGM wrote:

> I just finished my K2, #2639 and am having some problems. Most
> everything seems to work OK except that the output power decreases as
> the bands go higher. I get only about 6w on ten meters into a dummy
> load. Also, the ALC indicator does not work on 10. I've checked the
> components and re-soldered the connections several times. Any help
> would be appreciated. I have the basic K2 with the SSB adapter
> installed. 73 Richard W4UGM


Richard,

It is common to have less power out on 10m than at 75m or 160m.  I would
say that you should be able to achieve more than 6w though, once you have
the rig properly aligned.

I just put K2 #2490 into "QRP" configuration and I see the following power
levels with the RF power knob fully clockwise:

160m	14w
80m	16w
40m	16w
30m	14w
20m	13w
17m	16w
15m	13w
12m	13w
10m	10w

If you will notice, power out goes lower as we get higher in
frequency.  I get 10w on 10m even if I set the "Po28" setting to 15w.

As for your ALC not working on 10m, note that the function of the ALC is
to reduce power output to protect the final power transistors and/or keep
absolute peak power out reasonably close to what you have requested with
the RF power setting.  Since your K2 is not making "rated power" yet on
10m, you will see no ALC action because it is not having to reduce drive
to protect the transistors, etc.

One way to check this is to turn your RF power knob fully
counter-clockwise (request 0.1w power) and THEN talk into your
microphone.  With the MH2 (a HOT microphone by comparison to many),
SSBA=3 and SSBC=4-1, requesting 15w on 10m, I can whistle VERY loudly into
the microphone and not get any ALC action at all.  If I turn requested
power to something _LOWER_ than what K2 #2490 is capable of delivering,
say 5w for example, I will get ALC action, although it is VERY little, as
in one light.


In aligning your K2, keep in mind that there will often be more than one
position that will prodoce a "peak" in power output.  After two or three
tries, you'll most likely find the one that will produce closer to 10w
peak if not more than 10w.

Also remember that the band-pass and low-pass filters are shared between
the following bands:

Band-Pass
---------
80/160
40
20/30
15/17
10/12

Low-pass
--------
160
80
40
20/30
15/17
10/12


There will be come compromise when tuning.

I hope this helps.

73 de John - KC4KGU
Proud owner of the first production K2/100 on the air!
K2/100 #2490