Isn't the K2 DSP done at the audio stage, not at an IF? Seems if this is
the case it will add little or nothing to dynamic range or IMD
discussions.
73, Duane
On Tue, 23 Dec 2003 11:14:28 -0500 "Tracy, Michael, KC1SX"
<mtracy@arrl.org> writes:
> While I don't have time this week to check the whole list that Bill
> posted, I looked at the 1 kHz data for the K2 and the Orion. The
> figures for the K2 should be 67 and 116 dB (both preamp on). The
> worst case data on the Orion is 84 dB for IMD (main rx, preamp off)
> and 118 dB for BDR (preamp on).
>
> Yes, the data for preamp on is usually *slightly* worse than with
> the preamp off, but generally they are pretty close. I don't have
> an explanation for the difference on the Orion as tested, but I
> would note that the 84 is a pretty significant drop from the 2 kHz
> point data (90 dB). The BDR at 2 kHz was 5 dB higher than at 1
> kHz.
>
> While I am on the general subject, the upcoming K2/KPA100 data will
> not include any influence of the optional DSP unit, as that was not
> in the radio tested.
>
> <Personal opinion> - I rarely offer my opinions on matters such as
> these because everyone's situation is different, but I think it is
> important to keep some perspective here. Let me share some thoughts
> on dynamic range versus real world band conditions. It has been
> said that performance data at 1 and 2 kHz is critical to performance
> on 160 and the other lower bands. In my opinion, I think operators
> need to ask themselves some questions on this.
>
> Dynamic range is a measure of the difference between the weakest
> signal that can be received and the strength of a strong signal that
> is interferring. The amount of dynamic range that is needed is
> therefore dependent on how weak a signal you want/need to hear.
> When the band gets *really* crowded with S9+40 signals, are you
> honestly trying to pick out signals that don't even move the S
> meter? I doubt this is true for most operators.
>
> If the radio is acting like it is overloading, then attenuation is
> called for - that is why radios have this feature. If you are trying
> to copy an S5 with some S9+ interferers, then try turning off the
> preamp and adding 6 or 10 dB of attenuation. Yes, the S5 will no
> longer move the meter, but the radio will have less problems with
> overload and IMing.
>
> 73, Michael, KC1SX
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>
--------------------------------------
Duane Calvin, AC5AA
Austin, Texas
http://home.austin.rr.com/ac5aa
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