[TowerTalk] receiver protection

[Bob Lombardi]

I'm sorry, Tom, could you explain something....


 > I am looking at a design for receiver protection in an
SO2R environment
...
A bulb is a good choice Pete, generally better than any fuse
.....
 > If I stack 3 diodes in each direction, the forward
......
I just was measuring something like that today with a 50 ohm
source and load and  two tones near 5 MHz.

1N916's TOI -12dB and started to show IM at 0dBm each tone
(about 1/4 volt !)
1N4005 TOI -14.6dB and started to show IM at -3dBm
UF4004 TOI -15dB and started to show IM at -3.5dBm
1N5408 TOI -18.8dB and started to show IM at -5dBm

Stacking the diode pairs increased things about 6dB, as
expected.
..........................................

I don't see what you mean.  In the first line, is the TOI (IP3?) -12 
dBm?  If so, how can IM start to show up with the input -3?  That's above 
the intercept point?

Sorry if this is a bit dense.  It's not the way we talk about IP3 at work.



Bob
W4ATM