Hi Ken,W7KKE If STRaND1 has a circularly polarized crossed dipole antenna like that depicted in Fig 12 of the article "The Advantages of Circular Polarization for Amateur Satellite Ground Station " by K4KJ already in your hands than it is easy to understand why STRaND1 was stronger when you selected LHCP while approaching TCA and why after TCA, RHCP was stronger while the satellite was receding.
Fig-12 shows that if two crossed dipoles are mounted over the same plane and are supplied with 90 degrees out of phase than the polarizazion is RHCP in one axial direction and LHCP in the opposite axial direction and this can explain why the signal was stronger when you selected LHCP while approaching TCA and why after TCA, RHCP was stronger while the satellite was receding. BTW unfortunately actually there are not official informations from AMSAT-UK about the polarization of the STRaND1 70 cm antenna and without this information it's very difficult to answere your question. 73" de i8CVS Domenico ----- Original Message ----- From: "Ken Swaggart" <k.swagg...@charter.net> To: "i8cvs" <domenico.i8...@tin.it>; "Amsat - BBs" <amsat-bb@amsat.org> Sent: Monday, March 04, 2013 5:02 PM Subject: Re: [amsat-bb] STRaND1 polarity shift observation > Domenico, > > Thanks for sending the K4KJ article. > > However my question was why does STRaND1, which only has a whip antenna, > sometimes appear to exhibit circular polarity characteristics? I would > expect a whip antenna transmitting from space to have the same signal > strength on the ground using either RH or LH polarity on my receiving > antenna. > > 73, > Ken, W7KKE > > -----Original Message----- > From: i8cvs > Sent: Monday, March 04, 2013 00:42 > To: Ken Swaggart ; Amsat - BBs > Subject: Re: [amsat-bb] STRaND1 polarity shift observation > > Hi Ken, W7KKE > > The answere to your question is clearly described into the zipped article > "Circular Polarization" by K4KJ, 5 MB long that I have sent to you in > a separate email. > > 73" de > > i8CVS Domenico > > ----- Original Message ----- > From: "Ken Swaggart" <k.swagg...@charter.net> > To: <amsat-bb@amsat.org> > Sent: Monday, March 04, 2013 5:10 AM > Subject: [amsat-bb] STRaND1 polarity shift observation > > > > During my last pass at 0332Z, max elevation 45 degrees out over the > Pacific, > > I noticed that STRaND1 was stronger when I selected LHCP while approaching > > TCA. After TCA, RHCP was stronger while it was receding. I believe this > > cubesat uses a whip, so not sure what is causing this. > > > > Anyone have an idea why? > > > > Tnx, > > Ken, W7KKE > > CN75xa > > > > > > _______________________________________________ > > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > > Not an AMSAT-NA member? Join now to support the amateur satellite program! > > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
