Topband: Receivers

[Tom Rauch]

> When you trick out your R4C's with high level
mini-circuits mixers,
> how do you deal with this very low-side injection problem
on the
> 2nd mixer? Did you switch to a high side LO, or do you get
enough
> LO to IF isolation from the mixers you are using that the
high order
> LO harmonics bleeding through to the IF are not a problem?

My initial mods in the 70's and 80's used a crystal to
up-convert the 50 kHz to just above or just below the first
IF, I forgot which. You have to watch how you do that or the
tone shifts with passband.

Now I use double balanced mixers that suppress the
harmonics, even when driven with almost square waves.