You are talking about the two satellites I regularly access using a handheld radio at about 2.5W and either an Arrow dual-band antenna or simply a longer duck.
In my experiences, orienting the Arrow 90 degrees in either direction gives no discernable improvement on the RX signal: It's clear and wonderful no matter how I twist the Arrow.
Do the concepts os LHCP and RHCP come into play when you are trying to access lower elevation passes? AO-51 and SO-50 are so darned easy to hit with minimal equipment...and there is certainly NO "large difference between using RHCP and LHCP when listening to the downlink" as mentioned.
Clint Bradford, K6LCS 909-2421-7666
On Jan 2, 2008, at 11:14 AM, amsat-bb-request@amsat.org wrote:
...there can be a large difference between using RHCP and LHCP when listening to the downlink. That is one of the resons for at lot of us to have the possibility to switch between RHCP and LHCP...
Clint Bradford clintbrad4d@earthlink.net wrote:
> You are talking about the two satellites I regularly access using a
handheld radio at about 2.5W and either an Arrow dual-band antenna
> or simply a longer duck.
In my experiences, orienting the Arrow 90 degrees in either direction gives no discernable improvement on the RX signal: It's clear and wonderful no matter how I twist the Arrow.
My experience has been quite different Clint. There have been times when I've noticed a drop in signal strength, rotated my Arrow antenna 90 degrees, to find the signal strength back up. I had been told earlier by an experienced sat op of the FM birds that there would be shifts in polarization during passes that I would have to correct for. It appeared to me his advice was correct.
73, Gary -K8KFJ- AMSAT #32574 Sat VUCC #125
I have to agree with Gary. Being able to switch polarization of a linear-polarized Yagi will help, especially at lower elevation angles. At higher elevation angles the signal will be strong enough that it will be discernible on the Arrow regardless of the polarization. However, when the satellite is at lower elevation angles, the ability to switch the polarity so that it matches the signal coming from the satellite will provide a few extra dB of gain, which may be the difference between solid copy and noise. This has been my experience.
73, Zach KM7I
On Jan 2, 2008 4:39 PM, Garie Halstead K8KFJ khyberpass65@yahoo.com wrote:
Clint Bradford clintbrad4d@earthlink.net wrote:
> You are talking about the two satellites I regularly access using ahandheld radio at about 2.5W and either an Arrow dual-band antenna
> or simply a longer duck.In my experiences, orienting the Arrow 90 degrees in either direction gives no discernable improvement on the RX signal: It's clear and wonderful no matter how I twist the Arrow.
My experience has been quite different Clint. There have been times when I've noticed a drop in signal strength, rotated my Arrow antenna 90 degrees, to find the signal strength back up. I had been told earlier by an experienced sat op of the FM birds that there would be shifts in polarization during passes that I would have to correct for. It appeared to me his advice was correct.
73, Gary -K8KFJ- AMSAT #32574 Sat VUCC #125
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
Last night, I went back to just a vertical yagi , single 11 eleme, from crossed yagis.
The copy was really good, like it was when I first tested it before I adde the second Yagi.
Just goes to show what the wrong polarisation can do
---------------------------------------------------------------------------- Andrew Rich VK4TEC vk4tec@people.net.au mailto:vk4tec@people.net.au http://www.tech-software.net
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of Zachary Schrempp Sent: Thursday, 3 January 2008 11:33 AM To: Garie Halstead K8KFJ Cc: Clint Bradford; amsat-bb@amsat.org Subject: [SPAM] [amsat-bb] Re: AO=51 and Yagi Polarization Importance: Low
I have to agree with Gary. Being able to switch polarization of a linear-polarized Yagi will help, especially at lower elevation angles. At higher elevation angles the signal will be strong enough that it will be discernible on the Arrow regardless of the polarization. However, when the satellite is at lower elevation angles, the ability to switch the polarity so that it matches the signal coming from the satellite will provide a few extra dB of gain, which may be the difference between solid copy and noise. This has been my experience.
73, Zach KM7I
On Jan 2, 2008 4:39 PM, Garie Halstead K8KFJ khyberpass65@yahoo.com wrote:
Clint Bradford clintbrad4d@earthlink.net wrote:
> You are talking about the two satellites I regularly access using ahandheld radio at about 2.5W and either an Arrow dual-band antenna
> or simply a longer duck.In my experiences, orienting the Arrow 90 degrees in either direction gives no discernable improvement on the RX signal: It's clear and wonderful no matter how I twist the Arrow.
My experience has been quite different Clint. There have been times
when I've noticed a drop in signal strength, rotated my Arrow antenna 90 degrees, to find the signal strength back up. I had been told earlier by an experienced sat op of the FM birds that there would be shifts in polarization during passes that I would have to correct for. It appeared to me his advice was correct.
73, Gary -K8KFJ- AMSAT #32574 Sat VUCC #125
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
participants (4)
-
Andrew Rich -
Clint Bradford -
Garie Halstead K8KFJ -
Zachary Schrempp