Hi Gregg,
That is exactly what I plan to use..............I have been
using that topology for several years now, so I've got the Diplexer design
nailed down pretty well. Take a look at my website, and you can see how
I've got this implemented. I've got a few downloadable zip files of some of
my designs (no, I won't hide the schematic from the final product).
I am not sure why more manufacturers don't use doubly-balanced mixers,
especially when you can purchase a Mini-Circuits ADE-3 mixer for around 3
dollars. We are talking about a mixer with an SSB conversion loss of around
4.7dB, which, since this is a passive topology, translates approximately to
a noise figure of around 5dB. Since this is a Level 7 mixer, the IP3 should
be around +14dBm. Compare this to an Analog Devices AD831 mixer, which has a
+20dBm IP3, but has a 12dB NF. To reduce the NF to that of the ADE-3, you
need to have an RF amplifier ahead of that mixer. Let's say that we need
10dB of takeover gain from the RF amplifier; we now have an IP3 of only
+10dBm from that AD831, and we still need all of those external support
components for that mixer.

Pete

Gregg wrote in message
t...
Behold, Pete KE9OA signaled from keyed 4-1000A filament:

You do have some good ideas, and I am listening. A DX switch won't be
necessary; we will have a great dynamic range.

Am I to assume then that you plan a double-balanced diode ring mixer?

--
Gregg
*Perhaps it's useful, even if it can't be SPICE'd*
Visit the GeeK Zone - http://geek.scorpiorising.ca