Yes, I've tried this and had horrible IM afterwards. A better solution
would be to use single diodes that each have about 1 volt of reverse bias.
The diodes, connected in reverse polarities relative to the antenna input,
will normally be completely cutoff until a voltage equal to the cutoff bias
+ the diode forward drop appears. Without the cut-off bias, there is a very
small non-linear current that begins to flow even at voltages considerably
less than 0.7 volt, and this is the mechanism that generates the
intermodulation. With the reverse bias, these small currents will not begin
until the voltage exceeds the reverse bias voltage. You need to be sure
that you use diodes that have a high enough frequency response too.
73,
riki :-)
K7NJ (4X4NJ)
-----Original Message-----
If I use back to back diodes across my receiver antenna input to protect it
from transmitted energy, will this cause additional intermodulation beyond
anything I would otherwise experience in normal operation?
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