Recently i read about an upgrade for the ts440 concerning
Originally, there are simple switching types built in.
For better high level performance i decided to replace
D2,3,4,5,6,7,...23,68 by the ECG553 PIN Diode.
The result was not so doubtless positive. i could not really
confirm an advantage. unfortunately, i have no measuring
equipment for determining the intercept point.
But on 40m , where i sometimes have problems using a 160/80/40/30/20m
5-band fullsize dipole, i still suffer intermodulation effects.
I can not really say, if it is much better after the replacement,
but i'm sure, it isn't worse (hi).
Some remarkable progress was the usage of the built-in tuner
in the receiving pass. that really helped espacially on the 10mc band
to overcome the problems of interference.
But best results and a final solution i found in using an external
preselector as described in the cq-dl several times.
That really did it!
Of course you need to add on to cinch connectors at the rear panel.
It is no real problem.
so, my advice:
dodn't modificate the diods or use of the tuner for reception.
The result is too poor compared with that of an external