-----Original Message----- From: Robin Midgett K4IDC@comcast.net To: AMSAT-BB amsat-bb@amsat.org Sent: Mon, 15 Sep 2014 6:23 Subject: [amsat-bb] Lindenblads
Hello to the group, I'd like to hear from any users of the Lindenblad antennas regarding switching polarity & circularity. Based on the article on the AMSAT web page by W6SHP at http://www.amsat.org/amsat/articles/w6shp/lindy.html, I'm led to believe that the maximum effect comes from having one Lindy for each of RHCP & LHCP per band in addition to being able to invert the polarity of each. I'd like to hear from users concerning how often switching between RH & LH circularity yields benefits as compared to switching polarity on a single Lindy.
I have used for some time a small satellite station composed of two lindenblads, one for 145 MHz and the other for 435 MHz. The UHF one was a parasitic lindenblad from a well known project of some years ago that I think is still available on the web (I don't remember the details now). I have commented on my experience with lindenblads on this mailing list a few times in the past, so there might be my messages in the archives (if they exist at all). What I can say is: signals are nowhere near the ones you can have with even small yagis with azimuth and elevation controls, also adding two preamplfiers under the antennas greatly improved the chances to make QSOs. I was able to work many contacts with that setup (FT-847 as rtx), mostly CW on the linear sats, but also some FM contacts on all satellites available some years ago (2008-2010), and of course some SSB contacts on the linear sats. I assume that having switchable polarity can only make things better.
HTH Frank IZ8DWF