[Elecraft] KX-3

[Joe Subich, W4TV]

 > We looked at this in independent reviews and our in-house plots. The
 > keying BW looks pretty much the same on all three rigs. The 100 W K3
 > may be a tiny bit better, but there's nowhere near "twice" the
 > difference.

While the graphs in QST are not the best in the world, I'm comparing
the K3 and KX3 at -60 dB.  At that level the "outside" of the K3 is,
at most +/- 300 Hz while the KX3 is at least +/- 500 Hz.

In any case, the published composite noise level of the K3 - even with
the original synthesizer - is equal to the KX3 at 2 KHz while it is in
some cases as much as 25 dB better in the 10 - 100 KHz range.  While it
might not be an issue at 10 - 15 Watts, that's a whole lot of phase
noise when run into the KX3 into a KXPA100 to drive a "full gallon".

73,

    ... Joe, W4TV


On 5/31/2016 4:12 PM, Wayne Burdick wrote:
> Joe,
>
> The KX3, KX2, and K3/K3S should have virtually the same keying
> bandwidth. They all use the same raised-cosine keying envelope shape,
> and this is by far the dominant factor unless the transmit final
> amplifier is being overdriven.
>
> We looked at this in independent reviews and our in-house plots. The
> keying BW looks pretty much the same on all three rigs. The 100 W K3
> may be a tiny bit better, but there's nowhere near "twice" the
> difference.
>
> The K3S (or K3 with KSYN3A upgrade) does have the edge in composite,
> wide-band transmit phase noise. RMDR for the K3S (or K3+KSYNA) is
> roughly the same.
>
> Wayne
>
>