Hoi Jean Marc
I'm active on sats for 20y i think, and did it the first years with simple yagis, which worked ok. Then made myself some crossed yagis with fixed RHCP, but with a ot of reading and understanding some things i made it all switchable. All crossed yagis have now exactly 1/4 spacings at the boom between the 2 planes, and all delay lines and phasing lines are well cut to the needed lengths with max difference of about 0.5°. The fun of switching now between R an L or R/L/V/H polarisations makes a big difference in both uplink and downlink, would never miss it again. I also have the MASPRO sat system with only R to L switch, but that relay is a simple print relay. The switch i made on some folded dipole is a coax relay to get more power on the yagi. I agree that switching is best on up- and dwnlink; i do this on all passes though.
Best 73's
Jerry,ON4CJQ
----- Oorspronkelijk bericht ----- Van: "Jean Marc Momple" [email protected] Aan: "on4cjq" [email protected] Cc: "mikflathead" [email protected], "amsat-bb" [email protected] Verzonden: Maandag 26 maart 2018 20:14:38 Onderwerp: Re: [amsat-bb] M2 432 polarity switch
Good Evening,
I again believe that I need to provide some feedback on the polarization issue.
In one using polarized antenna RHCP or LHCP it is quite obvious that one should be able to change the polarization when working the birds. The most evident example is AO-92, whereby you have to change same every minute or so to keep a constant Rx signal strength, this both on the uplink and downlink. It may be due to the spinning of the satellite which may have a higher rate than usual, AO-91 is much more stable on this aspect.
Whatever system you may be using to change the polarization is your own choice, what I wanted to stress is that for 100% reliability you need to be able to do so on both the uplink and downlink.
73
Jean Marc (3B8DU)
On Mar 26, 2018, at 8:39 PM, [email protected] wrote:
Hello Mike
there is a much cheaper way!! M² is good but VERY pricy. just put a tohtsu cx-120A or CX-140 coaxrelay in a box, a folded dipole and a 1/2 coax balun. The relay has 2 connections at 1 side and 1 connection at the other side. the one side with the 2 connections: connect each side of the folded dipole to either relay contact, the side with the 1 relay-conection is for the feeder to trx. i made this for 2m and 70cm crossyagis, and works FB for switching from RHCP to LHCP. the price for the relay cx-120: 37.50€ , a small plastic box: a few €'s....the price for the M²'s: multiply by 7 or 8
best 73's
Jerry,ON4CJQ
----- Oorspronkelijk bericht ----- Van: "amsat-bb" [email protected] Aan: "amsat-bb" [email protected] Verzonden: Zondag 25 maart 2018 15:58:45 Onderwerp: [amsat-bb] M2 432 polarity switch
M2 sells a driven element assembly that allows polarity switching for there 435 antennas. Has any one used this product and can comment? Is there a cheaper way to do this? Thanks Mike _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb