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 On 8/28/2011 7:41 PM, Don Wilhelm wrote: > Doug, > > The setup with CW Skimmer is about the same as for LP-Pan. CW Skimmer > is only the software, and it needs a baseband signal having I/Q outputs > to operate. Such a signal can be obtained from LP-Pan, or a Softrock > receiver, or a variety of other SDR devices that provide I/Q signals to > the soundcard inputs. > > I also note that there is a slight inconsistency between those "bulleted > features" and the P3 manual. > The manual states that its INPUT should come from a buffered IF output > on the transceiver, however the P3 OUT signal comes from a 3 dB splitter > - it apparently is not separately buffered in the P3. > > 73, > Don W3FPR > > On 8/28/2011 5:51 PM, DOUGLAS ZWIEBEL wrote: >> Buffered IF output to drive other equipment (CW Skimmer etc.) > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
