[Elecraft] k3 - dual receiver & filters

Don Wilhelm w3fpr at embarqmail.com
Tue Feb 8 23:43:17 EST 2011


  Tom,

Yes and No.

If you plan to use diversity reception, then the matched filters are 
necessary.  If you do not plan diversity receive, then they are not 
important.

There is a subtle point here that is not often mentioned.  For wider 
filters, the offset is not as important as for narrow filters.  If you 
have the 5 pole 2.7 kHz filters (for instance), one with an offset of 
+40 and another with an offset of +20, if you set the offset for both 
filters at +30, it will be quite usable - only a difference of 10 Hz at 
a bandwidth of 2700 Hz - it will not be noticable.
But do not try the same thing with a filter width of 250 Hz - the 
results could be quite annoying.

I cannot say where the dividing line should be between wide and narrow 
-  a big part of it is in your ability to perceive slight differences.

That is the facts as I know them - the choices are yours to make.  The 
safe answer is YES, you need matched filters for diversity receive.

73,
Don W3FPR

On 2/8/2011 11:25 PM, tom kenville wrote:
> I have a single receiver K3, with various filters.
>
> For adding RCVR#2, do I need to get a set of matched filter pairs to
> complete that setup ?
>


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