K2 AGC pumping when I/O is polled

[W6IZT]

Elecraft team:

I am planning to use my K2 in CQWW with N1MM logger. When the radio is
polled by N1MM the radio behaves as if the RF gain was decreased. With no
antenna connected when the K2 is polled the S meter indicates an S6. I have
confirmed this effect when using DXBase as well, but since DXB does not poll
it is hardly noticeable..

I used my K2 earlier this year in GA QSO party with N1MM and didn't
experience this effect. I have since upgrade the FW in the K2 and added XV50
and X144.

Any thoughts?

73
Gregg

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[Don Wilhelm-3]

Gregg,

My thought is that your computer running the N1MM logger or with DXB is
generating noise that is being picked up by the K2.

The reason I state that is because there is no change in the receive signal
path that would affect the S-meter reading because of any polling or other
microprocessor activity.

You might try turning off the monitor to see if that is the source of the
noise, check to be certain the computer chassis is not connected to the K2
ground (there can be a lot of 'sneak' paths - like through a keying
interface or similar connections).

Good luck with your investigation.

73,
Don W3FPR

> -----Original Message-----
>
> I am planning to use my K2 in CQWW with N1MM logger. When the radio is
> polled by N1MM the radio behaves as if the RF gain was decreased. With no
> antenna connected when the K2 is polled the S meter indicates an
> S6. I have
> confirmed this effect when using DXBase as well, but since DXB
> does not poll
> it is hardly noticeable..
>
> I used my K2 earlier this year in GA QSO party with N1MM and didn't
> experience this effect. I have since upgrade the FW in the K2 and
> added XV50
> and X144.
>
> Any thoughts?
>
> 73
> Gregg
>
> _______________________________________________
> Elecraft mailing list
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[Vic K2VCO]

Gregg W6IZT wrote:

> I am planning to use my K2 in CQWW with N1MM logger. When the radio is
> polled by N1MM the radio behaves as if the RF gain was decreased. With no
> antenna connected when the K2 is polled the S meter indicates an S6. I have
> confirmed this effect when using DXBase as well, but since DXB does not poll
> it is hardly noticeable..

Very weird.  I use N1MM (and have used a number of other programs that
poll the K2) and noticed no effect at all on received signals.  I do
know that sometimes you can hear digital noise from the RS232 interface
with the antenna disconnected, but this is usually masked by band noise.
  Check the routing of the ribbon cable from the control board to the
KPA100 or KIO2.

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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