[Premium-Rx] 6790 filters

[Bob Betts]

Charles:
I agree with that. We have been through that several times with various R&D designs.
Depending on the frequencies, filter loop imedances and other variables, solid state switching can come with unwanted results. I suppose there are some newer diodes that have lower capacitance and other more desirable characteristics, but for the most part we have avoided them.
A recent project with headend amps and bandpass filter switching would never have passed spec without the use of relays. Admittedly, the requirements were kind of tight, but then, that's a good thing...especially when working around the front end of a receiver where compromises are not good..
 
If anyone has any modern data on newer s/s devices or techniques to accomplish this kind of switching - I'm am all ears, and would love to learn about it.
 
Bob
 
<snip>
I'll take relays any day over PIN switching.  I think of PIN 
switching as something used by manufacturers who are more interested 
in cost than quality, and the use of regular signal diodes for RF 
switching as something used by manufacturers who just don't care how 
their gear works.  Sometimes, other considerations dictate the need 
for solid state switching (vibration, magnetic shielding, power 
limits, contract spec, etc., etc.), but IMO it is a last resort.  I 
have almost always managed to find a way to avoid it.

Best regards,

Charles




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