Jack, Thanks for that information. I was not thinking about the P3 display. Harmful injection into the K3 would be no problem because it has a buffered output IF output, but you are correct, the Softrock LO will produce a spur on the P3 display even if it does not get into the K3 IF.
73, Don W3FPR On 8/28/2011 8:42 PM, Jack Smith wrote: > Don: > > I recently had a question from a prospective customer for a Z10000B > buffer amplifier about the need for additional isolation if a Softrock > is used with the P3's splitter IF output. > > I can't find a spec for the P3's isolation between the IF output port > and the IF Input, but 30 dB isn't a bad estimate for a 3 dB hybrid > splitter. > > Typical local oscillator leakage out of a Softrock is -40 dBm, so a -70 > dBm signal (approximately) will be injected into the P3's input if a > Softrock is connected to the P3's IF out port. This will appear as a > spurious pip on the P3's display at around -70 dBm. > > The LPPan has isolation and it's leakage is not a problem when used in > this fashion. But, I believe a Softrock will require additional > isolation, on the order of 60 dB or so, in order to be useful without > injecting a spurious pip into the P3. > > Jack K8ZOA > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
