K2 CW Tone

[a.yoshida]

K2 #4504
A few days ago I received RST 597 report on 20m CW.
Then checked transmitted CW monitoring with other radio.
Following is subjective report.

80m >>> 599
40m >>> 599
30m >>> 599
20m >>> 597 Carrier seems to be modurated by hum.
17m >>> 598 Same as above
15m >>> 599
12m >>> 599
10m >>> 599

K2 is far enough from magnetic source.
Changing power (2W, 5W, 10W) does not make any difference.
I do not know why tone is poor only on those 2 bands.
Any suggestion please.
 
73 de aki, ja1nlx
[hidden email]
http://www.asahi-net.or.jp/~yy7a-ysd/

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[Geoffrey Mackenzie-Kennedy-2]

Good Evening Aki,

Is the frequency of the *hum* modulation  the same as the frequency of your
sidetone, or one of its harmonics or sub-harmonics?

73, Geoff
GM4ESD

----- Original Message -----
From: "a.yoshida" <[hidden email]>
To: <[hidden email]>
Sent: Friday, May 06, 2005 11:21 PM
Subject: [Elecraft] K2 CW Tone

> K2 #4504
> A few days ago I received RST 597 report on 20m CW.
> Then checked transmitted CW monitoring with other radio.
> Following is subjective report.
>
> 80m >>> 599
> 40m >>> 599
> 30m >>> 599
> 20m >>> 597 Carrier seems to be modurated by hum.
> 17m >>> 598 Same as above
> 15m >>> 599
> 12m >>> 599
> 10m >>> 599
>
> K2 is far enough from magnetic source.
> Changing power (2W, 5W, 10W) does not make any difference.
> I do not know why tone is poor only on those 2 bands.
> Any suggestion please.
>
> 73 de aki, ja1nlx

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[Geoffrey Mackenzie-Kennedy-2]

Aki,

You wrote on Staurday May 07, 2005:

> I think it is not related to sidetone.
> I hear just like tone which is heard when K2 is very near power supply.

          I understand.

> But,,,,I am a little confused because I hear different tone with another
> radio. Now I do not know the best way for me to check transmitted
> CW.

          Perhaps the other radio is getting too much signal.  Another way
is to listen to K2's 20m second harmonic on 10m with the other radio, but no
more than S9.   To check 17m and if you can listen to above 6m with the
other radio, try K2's third harmonic 54.204 MHz up, again no more than S9.
This is a rough test to give you a quick check.

It would be a good idea to do two of these tests on each band,  One with K2
feeding a dummy load, and the second feeding the antenna, just in case on
20m and 17m there is a little RF feedback from the antenna or feeder.

> More check needed here, Thanks,

          Good luck.

73, Geoff
GM4ESD


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