[SPAM] [Elecraft] A Front-end with an IIP3 > +50dBm ?

[Geoffrey Mackenzie-Kennedy]

Thanks Gian. At this QTH, which is in the first hop zone of 40m BC signals 
on their way to N.America, the receiver's IMD3DR needs to be > 110 db approx 
at 2 kHz spacing if used for weak signal SSB DXing above 7130 kHz. Of course 
the LO must be very quiet.  The big problem I have here is BC transmitter 
phase noise and the enthusiastic levels of modulation some use especially 
when broadcasting music.

The old mixers might be fighting back but I don't think that they will win 
:-)

73,
Geoff
GM4ESD


Giancarlo Moda <i7swx at yahoo.com> wrote:
To: <elecraft at mailman.qth.net>


> Dear friends,
>
> A Front-End with an IP3 over +50dBm?
>
> Some of you may think …”it’s a joke ! Gian ‘s brain
> got heated-up by the South Italian sunshine” ….
> Maybe….
>
> Our friend Martein, PA3AKE, as you know, has done
> quite an important work on looking and measuring
> performances associated to the H-Mode Mixer with
> different kind of switches starting from the FST3125
> and ending with the FSA3157, resulting with IP3 around
> +50dBm. But what can we do with a mixer like that when
> front-end Band pass filters may have problems to reach
> an IP3 of +40dBm (see the CDG2000 input coils and
> transformers IMD limitation) without talking about the
> post mixer roofing filter that may not even reach an
> IP3 of +30dBm.

<snip>