Hi all,

Allison has given important information on mixers data.

His comments are very usefull.

I would like to underscore the last note:

All of that is good but unless the post mixer amp, IF and filters
following it are up to the task and well matched the results can be
very disappointing. When going to that level of performance one
needs to look at the recieving system and examine carefully.

It is right to relook at a receiver design when selecting a high
performance mixer. The limiting problems will show up in other stages
as the improuvements may not be very detectable.... amplifiers,
filters, l.o. phase noise...

Well one need to start from somewhere to improuve a receiver. If the
non mixer stages have a maximum IP3 of around +15dBm, certainly a
+35/40dBm mixer may not make much of a difference, unless it is
replacing a NE602. In this case you may use the I7SWX 1 transformer
double balanced mixer using the FST3125 (half of an H-Mode mixer) with
an IP3 of +25dBm.

As an example, I defined with afriend of mine a mod on the Elekraft K2.
The 1st mixer (TUF) was replaced by an I7SWX 2T H-Mode Mixer followed
by a 10kHz BW 2 xtal roofing filter . Two tones at 7.050 and 7.070 MHz

IP3 Results of the K2 we

Original mixer: +15dBm
with H-Mode Mixer: +27dBm

as you may see these are important differences. The actual limiting
stage is the original post mixer amplifier.

73

Gian
I7SWx