Satellite Internet

Satellite Internet Forum.

Welcome, Guest.
Welcome to this satellite broadband discussion forum. Wherever you are and whatever your problem we are here to help each other. Connecting to the internet via satellite is not always easy but is critically important to those in remote places or with poor terrestrial infrastructure. Both service providers and customers are encouraged to contribute. Register at the bottom of the forum home page if you wish to contribute or ask question. May 2018: GDPR: Updates to Privacy and Cookies policies: As you may know, a new EU data protection law called GDPR will apply from Friday 25th May 2018. As part of satsig's commitment to protecting the privacy of site visitors and forum members, I have therefore updated the Privacy and Cookie policies. There are now links leading to these policies: Disclaimer, Terms of Use and Privacy, Forum User Agreement, Forum Rules and Cookies at the bottom of the home page and all forum pages. Read the Forum rules.
      Satellite internet forum          
Pages: 1

Dish misaligned=burned up Trias??

(Read 15230 times)
Ex Member
Ex Member


Feb 15th, 2009 at 8:48pm  
I have heard from various sites that even if you are able to get on line with a KA band system (xplornet Canada) with decent speeds, your dish may not be properly aligned, and the result is that the Tria will ramp up it's output wattage to "talk" to the satellite. 

It has also been suggested to me (by my installer) that this is BS and that if you tweek the dish for maximum speed, the aim will therefore be correct. We are in a very remote location in Northern Canada, and getting a installer out to "peak" the dish is out of the questions,,, involving a float plane and many hundreds of dollars.

My question is what is the true answer, and if there is a better way to peak the dish beyond speed test and a simple sat finder meter, I would like to know it?

Thanks,

Icarus
Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #1 - Feb 15th, 2009 at 9:53pm  
I am not clear with your answer.  Are you agreeing with me that The Tria "ramping up" it's output is nonsence, or my thinking that it is BS is nonsense?

I don't have a spectrum analyzer.... any suggestions.  I do have a simple Sat finder analog meter with attenuation.

Thanks for the input,

Icarus
Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #2 - Feb 15th, 2009 at 11:29pm  
Quote:
My question is what is the true answer, and if there is a better way to peak the dish beyond speed test and a simple sat finder meter, I would like to know it?
You were given the "true answer" when you asked the questions on the DLSR/Wildblue forum. Yes, incorrect reflector alignment of the Wildblue reflector can contribute to premature failure of the transmitter component of the TRIA

Of all the methods of optimizing antenna pointing, the so-called "speed test" method is by far the least accurate. In doing so, receive margins and transmitter isolation are totally ignored. The best way to set up, is with the APA and the proper attenuator filters and a simple L-band signal strength meter. After initial access, the L-band meter will suffice. But everytime the antenna angles are altered to the point where the satellite signal is lost, you must once again revert to the APA and attenuator steps of the alignment process.

Presumably you're working without a manual. I have a copy of the manual that was in effect when Wildblue first started using Anik-F2. But it's almost 12MB in size, so not feasible to post here. Contact me via this site's personal message system, and provide an email address. I'll send you the manual. It has the step-by-step process, to include APA settings and attenuator placement.

//greg//

Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #3 - Feb 16th, 2009 at 12:35am  
Greg,,

Thank you for the info... Seems you lurk on different sites!

I do have a copy of the wildblue install instructions.

I have downloaded all the pages and printed them.  (I assume that this is the manual you are suggesting.  So if I am reading you correctly,, if I have access, I can now use the L band meter to peak.  Is this correct?

I am not "trolling" for the right answer, but as this thread demonstrates, there are varying opinion on the subject, leaving one who is not that educated on the technology wondering what the "real" answer is.  As I stated in the first post, my installer has suggested my method, and even using his high tech equipment we can't get it any better than with my method, so it leave me a bit confused.

Thank you for your input,, and I appreciate the insight of those who have forgotten more than I will ever know,

Icarus
Back to top
« Last Edit: Nov 17th, 2014 at 9:31pm by Admin1 »  
 
IP Logged
 
Ex Member
Ex Member


Reply #4 - Feb 16th, 2009 at 5:07am  
Yes you can - on a functioning system - further peak the dish with your SSLM. This step is related to the push-pull method you mentioned before. But be very careful not to lose the signal, or you face the potential of having to start all over with an APA and attenuators in hand. But this advice assumes that you're actually on the correct sub-carrier, and not locked onto a sidelobe.

Moderators don't lurk, this is my job. And there's nothing high tech about WildBlue installers equipment. It's a simple combination of filters, attenuators, cabling, and a signal level meter. The filter component  (APA) is in fact proprietary, but I surely wouldn't call it high tech. And the cable/connectors/attenuators/SLM are all generic parts bin stuff that you can pick up nearly anywhere. Pretty sure I could get everything (less the APA) from RadioShack, and get change back from a $20 bill.

Cable/connector selection and length also play an important roll in optimizing the signal too. You can have performed the best pointing job in the world, but it's all for nought if the cable path is substandard.

Optimizing the pointing angles on Wildblue systems is more technique than it is equipment. You can hook up fanzy gizmos that cost more than the satellite gear, but they won't get you any more accurately pointed than will just the basic components I described. But those components are the mandatory minimum. I wouldn't consider a pointing job optimized - with anything less.

And there's something wrong with your link. The HTML menu opens, but none of the imbedded PDF hyperlinks will open Acrobat Reader. And no, the file I have is an actual WildBlue installation manual put out by the NRTC.

//greg//
Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #5 - Feb 16th, 2009 at 5:30am  
Greg,

No offense meant by lurking,,, I was just commenting on the fact that you show up on different forums.  Try this search: "3387_Point%20and%20Peak%20Test%20Job%20Aid-20070115.pdf"

These are the PDFs of the Wildblue install instructions.

One question still confuses me re: the apa pointing device. I don't understand about sub bands and side lobes.

Every time I have had to move the dish, I have aligned it as per my technique, and it locks right on, the modem locks, and I get on line as normal.  I assume that the modem would lock and I couldn't get on if we were on the wrong sub band or side lobe.

So in this case, how would the apa help me, since I can get on what seems to be the proper band and lobe?

I am really not trying to argue with you (or anyone) I am trying to better understand how this stuff works so that I can keep it optimized.

I have been offered to have someone read my SVT numbers,,, which I am told can tell me if I am properly peaked as well.

Thanks for the help,, I certainly don't have a lock on any of this stuff by any stretch.

Icarus
Back to top
« Last Edit: Nov 17th, 2014 at 9:32pm by Admin1 »  
 
IP Logged
 
Ex Member
Ex Member


Reply #6 - Feb 16th, 2009 at 6:29am  
The Ka-band spot beam is not just one flashlight beaming down over a circular area of the earth. Within the beam are sub-carriers, at least eight per beam that I'm aware of. Your installation work order specifies to which you're assigned, and you set the APA to filter out all the rest. The SSLM is used during the optimization phase, and the attenuators are required during the provisioning (or re-provisioning) phase.

As to the sidelobe, each sub-carrier is an individual radio frequency carrier. It's composed of a main lobe (the strongest concentration of RF energy) and pairs of harmonics (weaker mirror images of the main lobe). The harmonics are referred to as sidelobes. Because of the mirror imaging, it's possible for a WildBlue TRIA to lock onto a sidelobe by mistake - since a copy of your unique bitstream will be there as well as on the main lobe. But because of the lower magnitude of power of the sidelobe, the modem is going to interpret it as an attenuated signal. The software inside the modem automatically ramps up the transmitter power to counter this attenuation. Except it's perceivedl attenuation  due to the fact that you're not "tuned" to the main lobe. So the modem is telling the transmitter to run at increased power - for no good reason other than a bad pointing job. And when REAL attenuation sets in (rain, sleet, etc) there's little to nothing left in reserve.

Now does it make a little more sense why relying on an online speed test is a completely unreliable (not to mention unprofessional) method of setting antenna pointing angles?

The SVT is a fair troubleshooting tool. But it cannot be relied upon as a pointing aid. First, it's not real-time. Second, it's just a snapshot. The information contained in a SVT readout is only as good as the point in time that it was taken. Yes - when interpreted properly - it can indicate a good to mediocre to bad pointing job. So even when a SVT indicates antenna optimization is called for, you still have to break out the equipment and do it real time.

That "Point and Peak" PDF is the same as the push-pull test. It's performed AFTER the APA and attenuator steps are satisfactorily completed - or as a validation test if/when misalignment is suspected.

//greg//

Back to top
« Last Edit: Feb 16th, 2009 at 12:48pm by N/A »  
 
IP Logged
 
Ex Member
Ex Member


Reply #7 - Feb 16th, 2009 at 7:09am  
Greg,

Once again thanks for you help,   (I have all the pages,, I only posted the one for example).

I understand what you are telling me,,, sort of.

I am not quite sure "The attenuators prevent the transmitter from causing interference to other users on that beam, by suppressing the output during the optimization process.  " since the apa is on the RX side of the modem/Tria.  Search: "2085_Antenna%20Pointing%20JobAid-20070115.pdf"

As for performance under less than ideal conditions.  My system performs up to speed in almost every weather condition.  With heavy overcast and heavy snow it seems to be able to keep it's speed up.  I can't recall a time when the connection failed due to the weather.

When I return home I will, double check everything with the meter, speed test and SVC.  After that,, I guess I am on my own.

Icarus
Back to top
« Last Edit: Nov 17th, 2014 at 9:33pm by Admin1 »  
 
IP Logged
 
Ex Member
Ex Member


Reply #8 - Feb 16th, 2009 at 12:56pm  
I corrected my previous post relative to the attenuator misunderstanding. I was thinking of a different system alignment procedure, should have check the text for specifics. That was sloppy, and I apologize.

Chances are you're ok, a SVT report may confirm that. If true, then you only need the SSLM unless and until you have to reacquire a lost signal - OR - have to reprovision a replacement modem. But in the end, you will find very very few people in this field who consider online speed testing a valid antenna optimization tool

//greg//
Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #9 - Feb 16th, 2009 at 5:11pm  
Roger that,

After I get home,, I'll up date the SVT and the meter readings here just for you to evaluate,

Thanks for all your help,

Tony
Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #10 - Mar 28th, 2009 at 10:01pm  
FYI Update,

After returning home after several month absence, I remounted the dish. (I store it out of the weather when we leave for more than a month or so,, we are very remote and it seems like it might be an attractive steal.)

I had a bit of trouble locking the modem since the frost had heave the building a bit.  After getting my initial lock, I ran my speed tests a mentioned.  I was getting DL speeds of ~400, up load ~80.  Then I plugged in my $10 meter and tweeked the dish up and down, left and right until I got the max signal.  Testing the speeds again, now I was in the 490/110 range.  (This is a 528/128 service speed package) That is about the best I have ever done.  The speeds stayed consistent over the next couple of weeks, through snow storms, sleet , and an ice storm.  It supported Skype voip, including video most of the time.  At busy times of the day, the video would get a bit choppy, but the audio was always fine.

I really don't see how I could get it any better aligned.  Nobody was ever able to give me my SVT numbers however.  I go back to my original thesis,,, aiming ones own dish is not,, to coin a phrase,, rocket science.  A simple meter, speed test and you should be good,, at least with xplornet KA band.

Icarus
Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #11 - Jul 19th, 2009 at 5:58pm  
I have been reading this thread, similar to mine. I think it needs to be confirmed that after initial setup with the installer APA filter, you might NOT need an APA to reposition,even if you are off satellite,which WILL happen if you move the dish..
. Your little box that says left or right mounted on the tria, is looking for your beam and only that one..
if this is Not correct, let this be known. Other than the harmonics issue, if you
get a signal and it gets your modems 2 and 3 lights flashing you are on the right beam...then you tweek AZ and elevation.
Back to top
« Last Edit: Jul 20th, 2009 at 2:40am by N/A »  
 
IP Logged
 
Pages: 1