EMRFD Message Archive 218

Message Date From Subject
218 2006-11-26 22:17:09 Mike Czuhajewski Why do we match mixer diodes?
In a post on another list, someone said they had checked some diodes
to get a matched set to build a mixer, then asked if anyone had
documented or seen first hand the benefits of matching them, how much
better it was and whether it was worth the trouble. I realized I don't
really know precisely why, except that it's Just One of Those Things
You Always Do. I would presume it probably gives better balance and
increased port to port isolation; is that the main or only reason?

I already have plans to do some experiments along these lines to see
what happens. To eliminate some variables, my test bed will be a Mini
Circuits SBL-1H mixer that I've milled the top off; it was painless
since I paid a hair over a dollar each for a batch of 25. Tomorrow at
work I'll remove the diode quad and eventually make some sort of
connector to allow me to plug in discrete diode quads made with
matched and mismatched diodes. Should be fun.

(Before anyone tells me that I can find the answer in EMRFD, I freely
admit, with great shame, that I have no idea where my copy is! I know
it's somewhere in the house. I think I made the mistake of leaving it
out somewhere and it got swept up during a spousal cleaning binge,
hidden to teach me a lesson!)