K2 preamp & attenuator combos

[Mike Markowski]

I'm writing some rig control code for the K2 and came across this in the
KIO2 manual at the PA command:

"Note: the preamp and attenuator can be turned on simultaneously under
computer control to provide four different RF gain levels."

Two variables each with two settings gives you four combinations.  Easy
enough, but does it really buy you anything to turn on both the
attenuator and the preamp simultaneously?

73,
Mike ab3ap
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[John Huffman-2]

Mike -

I have seen rig control programs use the four combinations to simulate four
steps of volume control since the volume knob can't be changed by computer control.

73 de K1ESE
John

Mike Markowski wrote:

> I'm writing some rig control code for the K2 and came across this in the
> KIO2 manual at the PA command:
>
> "Note: the preamp and attenuator can be turned on simultaneously under
> computer control to provide four different RF gain levels."
>
> Two variables each with two settings gives you four combinations.  Easy
> enough, but does it really buy you anything to turn on both the
> attenuator and the preamp simultaneously?
>
> 73,
> Mike ab3ap
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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> Elecraft web page: http://www.elecraft.com
>

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[Ron D'Eau Claire-2]

In the real world, there's not much advantage to using both the attenuator
and preamp together. The preamp offers about 14 dB gain. The attenuator
offers about 10 dB attenuation, so using both of them produces an effective
preamp gain of about 3 dB.

Since the purpose of the preamp is to provide enough gain to override
internal mixer noise on the higher frequencies where band QRN is very low,
and the purpose of the attenuator is to reduce the gain when band QRN is
very high to improve the dynamic range of the receiver, using both of them
gives you the ability to "tweak" the gain slightly by 3 dB instead of steps
of about 10 to 15 dB. That might be useful when trying to keep the gain down
to the absolute minimum needed to avoid overload where several rigs are
working next to each other, such as a field day setup, but that's about the
only situation where I could envision that such fine adjustment might be of
value.  

Ron AC7AC



-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Mike Markowski
Sent: Sunday, February 18, 2007 10:22 AM
To: Elecraft
Subject: [Elecraft] K2 preamp & attenuator combos


I'm writing some rig control code for the K2 and came across this in the
KIO2 manual at the PA command:

"Note: the preamp and attenuator can be turned on simultaneously under
computer control to provide four different RF gain levels."

Two variables each with two settings gives you four combinations.  Easy
enough, but does it really buy you anything to turn on both the
attenuator and the preamp simultaneously?

73,
Mike ab3ap
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