<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">You could use a PIN diode switch to switch between two antennas at a rapid rate. If you synchronize that switching with gathering a block of samples from the A/D, say, with an output pin driven by Mercury, so the signal processing knows which antenna generated which samples, you could create an approximation of diversity. Basically alternating doing the FFT/processing on each set of samples under the assumption that the signal you're homing in on is fairly constant across 2x the sample period so you don't mind missing every other block. I think you'd be able to approximate the in-between block ok for near-constant signals by interpolating the FFT bin values, or reconstruct a single signal by grabbing blocks at above the Nyquist rate and filtering -- but I'm no expert. <div><br></div><div>You have to compromise between sample block length and switching frequency, obviously. You probably wouldn't be able to use it to listen to fast CW, but you could do DF'ing with it. <div><div><br></div><div>Steve, K9SRB</div><div><br><div><div>On Sep 22, 2011, at 2:38 PM, Joe Martin K5SO wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">***** High Performance Software Defined Radio Discussion List *****<br><br><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Curt, <div><br></div><div>I don't know anything about "doppler scanning" so I couldn't say. Maybe someone else knows. </div><div><br></div><div>The problem with frequency diversity and related "frequency agile" approaches is that the source needs to be transmitting on more than one frequency, right? </div><div><br></div><div>Joe K5SO</div><div><br><div><div>On Sep 22, 2011, at 1:31 PM, Curt, WE7U wrote:</div><blockquote type="cite"><div><font class="Apple-style-span"><br></font>Are there advantages to going this route as compared to say a doppler scanning setup?<br></div></blockquote></div><br></div></div>_______________________________________________<br>HPSDR Discussion List<br>To post msg: <a href="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</a><br>Subscription help: <a href="http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org">http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org</a><br>HPSDR web page: <a href="http://openhpsdr.org">http://openhpsdr.org</a><br>Archives: <a href="http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/">http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/</a></blockquote></div><br></div></div></div></body></html>