----- Original Message ----- From: "Gus" <g...@8p6sm.net> To: <amsat-bb@amsat.org> Sent: Thursday, March 13, 2014 2:20 AM Subject: [amsat-bb] Re: Question for the antenna gurus
> Thanks for all info, Dom. > > to construct a large (2M) helix with light weight, a non-traditional > design of some sort might be tried. Perhaps paint the helix on the > surface of an inflatable cylinder, with conductive paint? Hi Gus, 8P6SM In my opinion it is best to use for the helix a thick annealed aluminum pipe because an inflatable cylinder for 2 m and 70 cm with conductive paint has been experimented for high frequencies but the tube is extremely large in diameter for 2m and 70 cm. > > Also, what if the coils/turns are something other than circular? perhaps > rectangular or triangular? If you use a coils/turns rectangular shape elements with a proper reflector and feed system you make a "Qubical Quad " > > The brain has been tossing out crazy ideas recently, but in my > experience, crazy ideas are not always crazy... > If the ideas are supported by a right theory they are not crazy ideas as it was demonstrated by Dr. John Kraus W8JK the inventor of the axial-mode helix antennas. I suggest you to read the book "BIG EAR" by John Kraus edited by Cignus Quasar Books Chapter 13 CORKSCREWS containing the Kraus idea on how borned in his brain the idea to invent the axial-mode helix antenna. In a separated email I have sent to you the article "The advantages of circular polarization" by K4KJ that explain the above matter with many drawings and pictures. Have fun. 73" de i8CVS Domenico > > On 03/12/2014 04:49 PM, i8cvs wrote: > > Hi Gus, 8P6SM > > > > Mounting 3 turn helix antenna for 2400 MHz concentrically > > inside a 3 turns helix antenna for 1268 MHz was used as a > > feed both wounded LHCP to illuminate a ground station prime > > focus dish for RHCP uplink and downlink on Mode-L/S for > > AO40 and it worked very well. > > > > If you plan to build a 10 turns RHCP helix antenna for 70 cm > > conentrically into a 5 or 6 turns RHCP helix antenna for 2 meters > > in my opinion it should work as well but the weight of this > > antenna will be very very hight and not practical to be used in > > comparison with yagi antennas. > > > > 73" de > > > > i8CVS Domenico > > > > ----- Original Message ----- > > From: "Gus" <g...@8p6sm.net> > > To: <AMSAT-BB@amsat.org> > > Sent: Wednesday, March 12, 2014 9:33 AM > > Subject: [amsat-bb] Question for the antenna gurus > > > > > >> Regarding axial-mode helix antennas, what happens if you build a helix > >> for each of two different bands (like 2M/70cm), and mount them > >> concentrically, on the same backplane? > >> -- > >> Gus 8P6SM > >> The Easternmost Isle > >> _______________________________________________ > >> 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 > > > > > > -- > Gus 8P6SM > The Easternmost Isle > _______________________________________________ > 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
