[Elecraft] KX3, ergonomy and performances

[Wayne Burdick]

On Mar 6, 2012, at 9:55 PM, Georges Ringotte F6DFZ wrote:

>  In a vast majority of cases, you need to have a near vertical front  
> panel to operate ergonomicaly a rig.
> Do you plan to sell a stand, like the one for the front panel of the  
> TS-480, to operate the KX3 at home ?

The KX3 was designed from the beginning to be operated at about a 30- 
degree angle with respect to the table. It has tilt feet in the rear  
that establish this angle. The LCD has a perfect viewing angle for  
this style of operation. The attached paddle and all controls were all  
optimized with this in mind, too. Try it :)

The KX3 can also be used hand-held, or in your lap, etc. But it works  
very well on a desk, picnic table, or other flat operating surface.


> IMD2 is a major issue in Europe, where strong BC signals on lower SW  
> bands recombine and appear as IMD in the upper ham bands. The KX3 is  
> the first Elecraft rig with electronic switching of the receiver RF  
> filters, others used relays. Can you tell if the IMD2 rejection of  
> KX3 will be in the league as K2 and K3?

Our KX3 field testers in Italy and Germany have had *no* IMD2 (or  
IMD3) problems that I know of, even on 40 meters.

This is probably because we used:

- very high-performance RF switches for the band-pass filters, preamp,  
and attenuator

- large PIN diodes at the input to the T/R switch

- a multi-pole high-pass characteristic within the T/R switch (to  
attenuate mega-size BC band stations below 1.5 MHz that might affect  
switches and diodes)

- our own custom high-level mixer

- latching relays for the low-pass filters and ATU

There are three related features:

- a built-in carrier-operated relay (I've transmitted at 10 watts into  
the KX3 without damaging it)

- an RF preselector for the 300-1500 kHz range that is supplied with  
the ATU option

- a high-performance RF isolation amp that eliminates LO leakage when  
needed (if another radio is being used close by on the same band)

That said, a superhet transceiver with very high intercept, like the  
K3, will have the edge in broadcast band IMD2. But so far, the KX3 is  
holding its own in Europe.

73,
Wayne
N6KR