Le 8 août 2009 11:54, i8cvs<[email protected]> a écrit : > Hi Jean, VA2SS > > Since the ELK antenna is a log-periodic antenna covering a wide > band from 2 meters and 70 cm it is difficult to connect 2 ELK in > phase and gain 3 dB in 2 meters and 70 cm as well. > > Also it is difficult to connect 2 ELK with a phase offset of 90° > to get circular polarization in 2 meters and 70 cm > > I would prefere to put one ELK horizontal and the other one > vertical feeding each antenna with an individual coax line. > > Using a coax relay in the shack you can immediately switch > from the Horizontal to the Vertical polarization. > > About the distance between the antennas over the plastic boom > the distance is a function of the antenna gain and higher is the gain > (in order do not overlap the aperture area of each antenna) larger > must be the distance between booms > > Since the gain of the ELK in the lover 2 meters band is 6.6 dBd > over the dipole or 6.6 +2.14 = 8.7 dBi over the isotropic then the > aperture area wich is a circle perpendicular to the antenna boom > can be computed using the following formula: > > / 2 > G x /\ > Aperture area= ---------- > 4 x Pi > > Since G= 8.7 dBi = 7.41 in power ratio > > 2 > 7.41 x 2 > Aperture area= -------------- = 2.36 square meters > 4 x 3.14 > > A circle with a geometrical area of 2.36 square meters > has a radius of > > \ /-------------------- > radius = \ / 2.36 / 3.14 = 0.86 meters > \/ > > Hence the distance between the booms is 0.86 x2 = 1.72 meters > > In this condition both aperture areas are tangents but it is better > to overlap the areas a 10 % to prevent the generation of side lobes > so that a distance of 1.55 meters between the antenna booms > is recommended. > > I hope this helps > > 73" de > > i8CVS Domenico > > ----- Original Message ----- > From: "Jean-François Ménard" <[email protected]> > To: "i8cvs" <[email protected]> > Sent: Saturday, August 08, 2009 4:00 PM > Subject: Re: [amsat-bb] Antenna project with 2 ELK antennas > > > Hi, > > I do not know much about antenna... But I tought that could be better > for satellite this way... I did not do any search at this time about > this project... it is only an idea that I had. > > If you have any suggestion for such project using 2 Elk antenna.... > please let me know. > > I don't want to spend much money at this moment... and I have only > these 2 antenna. > Wow !!
Thanks !! This is the kind of answer that I really like. I will try this with the recommendation you gave me. I'm not familiar with all those formulas regarding antenna, so a little help time to time is really helpful.... I like to learn, so you won't repeat the same thing twice. Thank again. Best 73 J-F VA2SS > 73 > > > 2009/8/8 i8cvs <[email protected]>: >> ----- Original Message ----- >> From: "Jean-François Ménard" <[email protected]> >> To: "AMSAT Mailing list" <[email protected]> >> Sent: Thursday, August 06, 2009 10:44 PM >> Subject: [amsat-bb] Antenna project with 2 ELK antennas >> >> Hi, >> >> I have 2 ELK antennas here, and I would like to do an experiment with >> these two antennas. I would like to stack side by side, one vertical, >> and one horizontal. >> >> 73 >> >> Jean-François Ménard >> VA2SS >> >> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= >> AMSAT www.amsat.org / Member #37102 >> ARRL www.arrl.org >> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= >> >> Hi Jean, VA2SS >> >> Staking 2 ELK antennas side by side,one vertical,and one horizontal >> what type of polarization you plan to get ? >> >> 73" de >> >> i8CVS Domenico >> >> >> >> > > > > -- > Jean-François Ménard > VA2SS > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > AMSAT www.amsat.org / Member #37102 > ARRL www.arrl.org > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > > > > > > > > -- Jean-François Ménard VA2SS =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= AMSAT www.amsat.org / Member #37102 ARRL www.arrl.org =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= _______________________________________________ Sent via [email protected]. 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
