Hi Joe, KK0SD Or you can place the patches side by side and crossed by 90 degrees with one of them advanced 1/4 wavelengt (1.23") free space in the axial direction and feed them with equal feed line lenght.
It is easer because these panels are patch style antennas already supplyed with the same lenght of coax cable and a connector but in any case you need a power splitter with characteristic impedance of 35 ohm to transform the 25 ohm of the paralleled antennas to the 50 ohm of the main feed line or a load as a preamplifier. The problem here is that since they are pach style antennas you cannot establish immediately if crossing one patch vertically polarized and the other one orizontally polarized the generated CP is RHCP or LHCP and you need to make a measurement of circularity sense of radiation with respect to a reference CP antenna as for example an helix antenna. Just in case you want RHCP and instead you get LHCP it is sufficient to rotate one patch by 180 degrees and the sense of the current flowing in the side of the patch where the coax is connected will flow in the opposite direction reversing LHCP to RHCP and vice versa. The best solution instead to use two HG2414P linear paches is to buy only one circularly polarized patch model HG2409PCR if you need to radiate RHCP or a model HG09PCL if you need to radiate LHCP To illuminate a dish and radiate or receive RHCP from reflection on it's surface for use on satellites hopefully P3E in the future ? it is necessary the patch model HG09PCL wich radiates LHCP toward the dish. By the way a patch antenna has a lobe of radiation of about 150 degrees wide at the -10 dB points and as a feed it is suitable for dishes having a very low F/D ratio under 0.45 to prevent spillover. Tanks to John ,W9EN to provide me with the internet address in order to find the technical data of the above WiFi panels. The HG2414P is a linearly polarized patch. http://www.34t.com/PDF/hg2414p.pdf The HG2409PC is a circular polarized patch (LH or RH available). http://www.34t.com/PDF/hg2409pc.pdf 73" de i8CVS Domenico ----- Original Message ----- From: "Gary "Joe" Mayfield" <gary_mayfi...@hotmail.com> Cc: <amsat-bb@amsat.org> Sent: Tuesday, June 08, 2010 4:53 AM Subject: [amsat-bb] Re: CP antenna from 2 WiFi panels > You can place them side by side and introduce the delay in the feed line of > one as well. > > 73, > Joe kk0sd > > -----Original Message----- > From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On > Behalf Of John Belstner > Sent: Monday, June 07, 2010 9:37 AM > To: Greg D. > Cc: amsat-bb@amsat.org > Subject: [amsat-bb] Re: CP antenna from 2 WiFi panels > > Hi Greg, > > These panels are patch style antennas and as such you will not be able to > place one behind the other to obtain circular polarization. Placing one > next to the other will at best produce an elliptically polarized pattern, > and you should use a 50 ohm splitter to keep your impedance 50 ohms. The > shape of the patch and position of the feed point is typically how you > obtain circular polarization with a patch antenna. > > Or, you can obtain RHCP with the same or more gain and less trouble by > making a Helix. A sheet of aluminum, #8 copper wire and and a piece of PVC > of the right diameter is all you need. > http://brneurosci.org/helix-antenna.html > > Or, you can try just a single panel and see how it performs for a while. > > Good luck! > > 73, John W9EN > DM13le > w...@amsat.org > > > > > > > > > On Jun 6, 2010, at 1:15 PM, Greg D. wrote: > > > > > Hi folks, > > > > Before I start nailing stuff together, I just want to verify what I'm > doing... > > > > I want to make a 2.4ghz Right-Hand Circular antenna from two flat panel > Wi-Fi antennas. The idea is to mount them at 90 degrees from each other, > with one 1/4 wavelength in front of the other. Combine the two feeds with a > simple Tee (the feeds are of equal length), and into the pre-amp. Since I'm > not transmitting, I'm not too worried about the resulting 25 ohm impedance > (or should I be?). > > > > If it matters, the panels are from HyperLink Technologies, their model > HG2414P, with a claimed 14dBi gain. > > > > So, the questions: > > > > 1. 1/4 wavelength at 2401 mhz is ((3 x 10**8 / 2401 x 10**6) / 4) meters, > or about 1.23 inches. Right? > > > > 2. Most of our 2.4 ghz satellite downlinks seem to be either linear or > RHCP, so I'm guessing that RHCP is probably the preferred construction. > (Yes?) > > > > 3. Looking at the Satellite Experimenter's Handbook (figure 7-10), I > believe the panel rotated 90 degrees counter-clockwise as seen from behind > the panels should be the one farther out in front, for RHCP. (Their picture > shows clockwise for LHCP.) Is this correct? > > > > Thanks, > > > > Greg KO6TH > > > > _________________________________________________________________ > > The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with > Hotmail. > > > http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=PID28 > 326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_5 > > _______________________________________________ > > Sent via amsat...@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...@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...@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...@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
