A few things.............either a broad band or tuned RF amp ahead of the
1st mixer. A tuned RF amp affords better image rejection, especially with
single conversion receivers that have only a 455kHz I.F. amplifier. I.F
coils and antenna coils wound with Litz wire are also helpful. A selective
I.F. strip, using either Litz wire wound coils or ceramic filters are good.
FETs in the input stage are good for cross-modulation rejection. Good audio
amplifier etc, etc, etc.
I hope this helps.

Pete

"Stranger_On_The_Bus" wrote in message
lkaboutradio.com...
It's true - it is an amazing little perfomer. Outperforms the Grundig
Mini
300 and G1000A on mediumwave. Very thrifty on batteries too - I've been
listening for about 100 hours on the original set, still going strong.

I've always found it interesting the variation in MW performance amongst
pocket portables. What is it about this particular model that makes it
such a high AM performer, while models costing much more aren't - it isn't
as if Sony is aiming this at the hobby market or anything.

At any rate, it is certainly a worthy radio for anyone to have.