Again my Alfa Spid AZ rotor act again yesterday evening it loose his north setting as it is electronicly set with the control box. Very easy to reset but in the middle of a snow storm (25cm) i was unable to find something to point the beam physically to the north.
At the same time there was an AO-51 pass i adjust the rotor to an estimated north and i follow the whole pass manually writing down the real calculated azimuth and the one i got from a maximum signal swinging the rotor back an forth.
I make another pass doing the same operation to fined tuned my pointing and today on the 1549 EDT pass i was able to get the satelllite at 1 degrees AOS ans LOS!! signal was S7 most of the time and reaching S9 near TCA?
I don't know if AO-51 is still pointing towards the southern hemisphere but i notice only one deep fade and signal was much better than the first attitude change days and i think he never was so strong?
I'm guessing my "scientific" previous north pointing was bad or my UHF beam is shooting not towards he point? I'm always using automatic AZ tracking could be i was shooting aside of the target for a while...
Just try this on a pass could be you will be astonish too?
If AO-51 was returned back to his normal attitude i will have to reavaluate all of what i wrote above. "-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE
It depends what antenna system you have. If you use high gain antenna system, how can you see the differens? Best way is comparing with a no directional antenna before and after the clip over of the sat. But that's to late for that now. Perhaps we can start start to messure and after next clip over we can start al over again so we can compare the data. Messurements must be done with several passes and same equipment.
73 Dan ON5UE
-----Oorspronkelijk bericht----- Van: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] Namens Luc Leblanc Verzonden: donderdag 10 december 2009 22:33 Aan: amsat-bb@amsat.org CC: eu-amsat@yahoogroups.com Onderwerp: [amsat-bb] Loosing the north!!!
Again my Alfa Spid AZ rotor act again yesterday evening it loose his north setting as it is electronicly set with the control box. Very easy to reset but in the middle of a snow storm (25cm) i was unable to find something to point the beam physically to the north.
At the same time there was an AO-51 pass i adjust the rotor to an estimated north and i follow the whole pass manually writing down the real calculated azimuth and the one i got from a maximum signal swinging the rotor back an forth.
I make another pass doing the same operation to fined tuned my pointing and today on the 1549 EDT pass i was able to get the satelllite at 1 degrees AOS ans LOS!! signal was S7 most of the time and reaching S9 near TCA?
I don't know if AO-51 is still pointing towards the southern hemisphere but i notice only one deep fade and signal was much better than the first attitude change days and i think he never was so strong?
I'm guessing my "scientific" previous north pointing was bad or my UHF beam is shooting not towards he point? I'm always using automatic AZ tracking could be i was shooting aside of the target for a while...
Just try this on a pass could be you will be astonish too?
If AO-51 was returned back to his normal attitude i will have to reavaluate all of what i wrote above. "-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE
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On 11 Dec 2009 at 8:37, Danny Casier wrote:
Date sent: Fri, 11 Dec 2009 08:37:10 +0100 From: Danny Casier Danny.casier@skynet.be Subject: [amsat-bb] Re: Loosing the north!!! To: amsat-bb@amsat.org Copies to: eu-amsat@yahoogroups.com
It depends what antenna system you have. If you use high gain antenna system, how can you see the differens? Best way is comparing with a no directional antenna before and after the clip over of the sat. But that's to late for that now. Perhaps we can start start to messure and after next clip over we can start al over again so we can compare the data. Messurements must be done with several passes and same equipment.
73 Dan ON5UE
I have 24 elements UHF linear yagi and after the switch i got a lot of small fades with a huge one. When i realign correctly the antenna all those small fades disappear and i got only one small one per pass. I agree it's not the best way to test it but my main concern was my correct alignment to the north and i can confirm it was effective as i am able now to hear many satellites from 1 degrees up to half a degree at LOS.
"-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE
Hi Luc
"I have 24 elements UHF linear yagi and after the switch i got a lot of small fades with a huge one. "
You have also polarisation. So it's normal you have fading due the spin of the sat. 24 elements, that's about 30° of opening angle. That's small if your motorconrol is slow and the time need to reach the good position takes to long. It is possible, and typical when the sat goes over the 60 degrees elevation, the sat is moving so quick that your antenna system can't turn quick enough, so the sat moves out the opening cone of the antenna.
A good way to line up the antenna system is using the sun. (or the moon) (need blue sky hi hi) Run a program the gives you the az and el of the sun or (moon) and set the antenna system to that direction. Then follow the shadow of the antenna if it lines up with the boom. An outher way is following ISS when it is visible and see if the antennas moving in the same way as ISS. A couple months ago i was suppriced. I saw IIS moving more than 45° out (after) of my antenna system not because it was not good lined up but because i had not updated the keps within two weeks. My antenna system on 2m is about 45° of opening angle so i heard ISS loud. But when it was a small sat with tiny output signal, it was passed without hearing it only due using the wrong keps.
Now, I suggest not to climbing into your tower in a snowstorm to line up our antenna system. It is not good for bones and brain. Hi hi
73 Dan ON5UE
On 12 Dec 2009 at 11:10, Danny Casier wrote:
Date sent: Sat, 12 Dec 2009 11:10:18 +0100 From: Danny Casier Danny.casier@skynet.be Subject: [amsat-bb] Re: Loosing the north!!! final conclusion. To: amsat-bb@amsat.org
Hi Luc
"I have 24 elements UHF linear yagi and after the switch i got a lot of small fades with a huge one. "
You have also polarisation. So it's normal you have fading due the spin of the sat. 24 elements, that's about 30° of opening angle.
Hi Danny
I recheck the alignment on SO-50 and i can confirm my previous north alignment was wrong. I can gave half a degree of elevation and still able to hear the sat what it was not possible before. I will keep it as is for now and i will try some other tests on some faint signal from space eg: UO-11.
Could be the moon with JT65B will be a good practice target to have this pointing question solved once for all. I was planning some EME experiment when AO-40 goes silent but i never completed the project. Just check the link below it does not take a lot of power for some EME contact
http://www.vhfdx.net/jt65bintro.html "-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE
participants (2)
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Danny Casier -
Luc Leblanc