[CQ-Contest] [Fwd: SO2R Technical Question - Round II]

[Steve London]

 >After reading quite a bit on the WWW about SO2R....

 >I am assuming that you place band pass filters (what ever ilk) in line with 
 >BOTH radios.  That being the case (if it is) then using bandpass filters on 40 
 >you would be knocking down (but not eliminating) the harmonics on 20 meters. 
 >In addition if you have a 20 meter filter on your second radio, that do would 
 >have attenuation on the 7 Mhz energy.  So if the transmit filter on 40 
 >is...say....40 db down and the receive filter on the 20 meters station is 
 >another 40 db down....would not those figures combine?  That is a question!

No, that's not quite the way to analyze it.

The 40 meter bandpass filter on the 40 meter radio does two things: 1) Protects 
the 40 meter receiver from out-of-40 meter RF. 2) Reduces the level of out-of-40 
meter trash being generated by the 40 meter transmitter. Ditto for the 20 meter 
filter on the 20 meter radio. That's why it is important to have separate 
bandpass filters on both radios.

73,
Steve, N2IC