dish alignment

[Brct203]

I use the longitude readout from GPS to determine true south. I walk about 20 feet in front of the dish a set a stake where the longitude is the same as the dish location - that should be my true south reference. I tried the compass in a phone but found that wasn't very accurate so I don't use any of those apps. I did a string test just a few days ago and that turned out OK. I'm not sure about feed centering though. There doesn't seem to be an easy and accurate and inexpensive way to set it. I'm trying to fabricate a laser pointing solution - see the images of my first attempt. I don't think a tape measure is a very accurate way to center the feed but I'll probably give that a try.

I wonder if that method for determining the South is accurate enough. 20 ft is not very far, so a few inches off and your South is wrong enough to cause serious alignment problems. Is there any way to can see things about 200-300 ft away and determine a point that is exactly south of where the dish is? Either by looking on google map, or maybe with your GPS method?

However, I also think that the alignment might not be the main problem here, and that the core of the problem is with the dish/feed/LNBF. That's the one to tackle first.

Did you check the focal length? Does it match what the brochure says? If I remember well, there was a Tek2000 dish that had some problems in that department, so I guess it's worth double-checking it

 

[zack]

No. I adjusted the skew for maximum level and that's where it landed.

Looking at that picture, I see that you have turned the feedhorn all the way clockwise that the length of the slots in the arms let you!

I hope that was not your skew adjustment!

Why is your feedhorn mounted this this way?

Your LNBF skew is adjusted by those small screws around its base, leaving the feedhorn alone!

If I am whistling dixie , please ignore!

 

[FTA4PA]

Looking at that picture, I see that you have turned the feedhorn all the way clockwise that the length of the slots in the arms let you!

I hope that was not your skew adjustment!

Why is your feedhorn mounted this this way?

Your LNBF skew is adjusted by those small screws around its base, leaving the feedhorn alone!

If I am whistling dixie , please ignore!

Hi zack, I think I understand what you are saying but if you look at his pic from behind the dish

you can see that the arms do not appear to be twisted on the scalar to compensate for skew. I think the angle of the pics taken from the front of the dish could possibly give that impression though. Biggest problem, as stated in previous posts, appears to be that the scalar/lnbf are not parallel to the face/center of the dish and will need to be adjusted. This has yet to be determined but there may also be an issue with the arms not placing the scalar/lnbf at the proper focal distance, which if that is the case, is not johnnynobody's fault as there was some confusion with these dishes a few years ago with where the arms needed to be mounted to obtain correct focal length. I would hope this has been corrected by now though. Perhaps iBoston can add something here as I believe he had a problem with his lnbf arms.

Yes, he did. Here is the thread: Anyone buy the tek2000 dish?

And another here from a different member: Tek2000 and their 12ft dish.

 

[ZetaMale]

Hi zack, I think I understand what you are saying but if you look at his pic from behind the dish

you can see that the arms do not appear to be twisted on the scalar to compensate for skew. I think the angle of the pics taken from the front of the dish could possibly give that impression though. Biggest problem, as stated in previous posts, appears to be that the scalar/lnbf are not parallel to the face/center of the dish and will need to be adjusted. This has yet to be determined but there may also be an issue with the arms not placing the scalar/lnbf at the proper focal distance, which if that is the case, is not johnnynobody's fault as there was some confusion with these dishes a few years ago with where the arms needed to be mounted to obtain correct focal length. I would hope this has been corrected by now though. Perhaps iBoston can add something here as I believe he had a problem with his lnbf arms.

Yes, he did. Here is the thread: Anyone buy the tek2000 dish?

And another here from a different member: Tek2000 and their 12ft dish.

This is NOT a TEK2000 dish.

 

[FTA4PA]

This is NOT a TEK2000 dish.

OK, thought you were working with the Tek2000 now since it was ordered in early June and you said your other dish was going to the scrapyard once you got the new one. Since you don't have the Tek2000 up yet then that still leaves the issue of scalar/lnbf alignment that should be addressed on the current dish. Hope you can get it sorted out.

 

[ZetaMale]

I wonder if that method for determining the South is accurate enough. 20 ft is not very far, so a few inches off and your South is wrong enough to cause serious alignment problems. Is there any way to can see things about 200-300 ft away and determine a point that is exactly south of where the dish is? Either by looking on google map, or maybe with your GPS method?

I'm more likely to be a couple inches off 300 feet away. Besides, the city told me that houses and streets in my neighborhood are oriented in true south fashion. I'm in the ballpark for true south. I've fine tuned the north/south alignment using the method in the manual.

However, I also think that the alignment might not be the main problem here, and that the core of the problem is with the dish/feed/LNBF. That's the one to tackle first.

Maybe so but my tests are showing that everything is fine. No warped dish, using a string from the center of the scaler to different points on the dish show that I'm within a 1/4 inch, my makeshift laser pointer shows that I'm hitting the center of the dish. I've checked elevation and declination several times. Even so, I'm not positive that the feed is centered accurately enough.

Did you check the focal length? Does it match what the brochure says? If I remember well, there was a Tek2000 dish that had some problems in that department, so I guess it's worth double-checking it

The manual says that the focal distance should be 56-1/8". I measured 56". The string test I mentioned above for determining centering showed that I'm within 1/4 inch. The manual says that I need to be within 1/32" - I've never been able to get that kind of accuracy on any dish.

 

[ZetaMale]

OK, thought you were working with the Tek2000 now since it was ordered in early June and you said your other dish was going to the scrapyard once you got the new one. Since you don't have the Tek2000 up yet then that still leaves the issue of scalar/lnbf alignment that should be addressed on the current dish. Hope you can get it sorted out.

I have the TEK 12 footer but I haven't begun assembly yet. Kind of hard to do with 90-100 degree weather - not to mention 20 mph winds lately. It'll be replacing the Parclipse dish with it. Anyway, the dish I'm working on is a KTI CKD-12. I uploaded the manual to this website some time ago if you're interested in looking at it. Yeah I hope I can get this sorted out since I want better performance. It seems that assembly and alignment is much more critical these days. It seems like it should be a slam dunk but obviously not.

 

[FTA4PA]

I have the TEK 12 footer but I haven't begun assembly yet. Kind of hard to do with 90-100 degree weather - not to mention 20 mph winds lately. It'll be replacing the Parclipse dish with it. Anyway, the dish I'm working on is a KTI CKD-12. I uploaded the manual to this website some time ago if you're interested in looking at it. Yeah I hope I can get this sorted out since I want better performance. It seems that assembly and alignment is much more critical these days. It seems like it should be a slam dunk but obviously not.

I know what you mean - gonna be near or in the 90s here for the foreseeable future and with health issues no way I can work outside in those temps. Lining up digital does seem to be more critical than analog. I will take a look at the manual you posted. Again, best of luck getting things working.

 

[ZetaMale]

I know what you mean - gonna be near or in the 90s here for the foreseeable future and with health issues no way I can work outside in those temps. Lining up digital does seem to be more critical than analog. I will take a look at the manual you posted. Again, best of luck getting things working.

Not to mention how hot the metal gets. I'm considering getting a 12'x12' canopy to provide shade but then there's that wind that gets gusty - sometimes suddenly.

 

[ZetaMale]

Use the sun to determine exact true South. ESRL Global Monitoring Laboratory - Global Radiation and Aerosols

Use the pole shadow to determine reflector aiming. Align the dish with the true South shadow and observe if the feedhorn is centered on the AZ axis of the reflector.

I must be using this wrong because it shows solar noon at 12:58 local time while another website shows it an hour earlier. The 11:58 time is the one that I believe to be correct. I'll try again tomorrow.

 

[mikekohl]

I must be using this wrong because it shows solar noon at 12:58 local time while another website shows it an hour earlier. The 11:58 time is the one that I believe to be correct. I'll try again tomorrow.

If you are on daylight time, it's going to be closer to 1pm.
Solar noon during standard time is close to 12 noon (give or take a few minutes for seasonal deviations).
This is assuming you are close to the beginning of each time zone (90 W for Central, 105 W for Mountain).
Then you would factor roughly 4 minutes for each degree east or west of those points.

 

[ZetaMale]

If you are on daylight time, it's going to be closer to 1pm.
Solar noon during standard time is close to 12 noon (give or take a few minutes for seasonal deviations).
This is assuming you are close to the beginning of each time zone (90 W for Central, 105 W for Mountain).
Then you would factor roughly 4 minutes for each degree east or west of those points.

I'm at 103.6W. I am on MDT. The website Titanium provided showed the sun azimuth at 233 degrees at the calculated solar noon which is nowhere near true south. But, I did try determining true south using a method of determining true east/west by using the shadow from a stick at two different times about 15 minutes apart. The result was that true south was more west than what my GPS receiver showed. I guess the shadow method would be more accurate since the GPS shows the readings with an accuracy of +/- 20 meters which, of course, is significant. I guess I need a military grade GPS which I probably couldn't afford even if it was possible to get one. Google Earth seems to show that my shadow method is correct when I enabled grid lines. I always assumed that the streets around here were built on true north/south - close but no cigar. Who knew? I might mess with the dish before the sun goes down tonight.

 

[arlo]

Johnny I'm following this closely only because a short time ago I was in a dilemma like you.
Could you condense this into what you have, don't have, trying to achieve please?

I have a button hook feed 12 footer.
I did all of the string calcs.
Set my LNBF (Titanium) and scalar right where the numbers came out to be. Focus just a touch inside of the feed throat just like they told me to.
Used my fabricated throat jig to make sure the LNBF was dead nuts pointing at the dish center.
Because my button hook feed lets me easily move the scalar in and out I found that the calculations put it in towards center a little too close.
I was under illuminating the dish. I could take a piece of sheet metal and move it in from the dish edge about a foot before my signal started to go down.
So I moved the scalar out away from the dish center a little at a time until the piece of metal decreased signal a couple of inches inside of the rim. Of course my LNBF was always checked to point at dish center and adjusted for max signal.
One thing that didn't change until the final LNBF/Scalar adjustments was skew being at 0 at dish zentih. That came later. Use a Sharpie to mark the scalar/0 skew reference.
I used 99W to grab a signal. It's very strong. Then I searched for 103W because it's about the weakest sat I get in the arc.
It was there where I peaked my dish mechanically to get the strongest signal. Never touching the LNBF at all while setting it for the strongest signal.
Now I had a good strong signal that's where I moved the LNBF carefully to get the absolute strongest signal.
I alternated between H-V tp's to tweak skew. Locked everything down. Now that part was finalized.

Your next task would be getting your dish to track the arc. Your skew will never change, the dish is focused.
Take your motor off of the actuator and run the shaft with a pair of Vice Grips. Mark down how many turns it takes to go to 101, 103, 105. Get your dish tracking those sats. Tons of links out there to get that ball parked.
The closer you get your dish mount on the pole for N-S and the polar angle dialed in, the better it will track those 3 sats.
Declination comes into play too. You'll be raising and pushing down on the dish rim to see how those changes affect your signal.
But remember. Once your dish is in proper focus that everything else is in the mount settings and you shouldn't have to touch the LNBF again until the very end.

....more coffee

 

[ZetaMale]

I got my true south problem resolved. Too bad it didn't make any difference in performance. Signal levels are still lower than expected. I'll mess with declination tomorrow and see if there are any other issues I can find.

 

[ZetaMale]

I'm still working on getting this thing aligned. I miss the good ol' days when alignment was simpler. I'm not sure that the instructions I've been using are entirely correct. The instructions at tvrosat claims that if I follow their instructions it'll be a "slam dunk" alignment. It ain't turning out that way. Right now I've got 89W to 107.3W but I lost everything west of 107W (I had sats to 125W but didn't have anything east of 91W when I started). Signal levels are much higher on the ones I can see though. I'm thinking that I don't have true south properly set but the alignment instructions indicates that it is set when you have an equal number of viewable sats (+/-) on each side of the arc. And it's strange that when I got the signal levels up higher that I end up losing services on that sat. It's been many years since I've done an alignment so it's tuff getting back up to speed, also. I'm going to have to go back to square one and start over.

 

[arlo]

I'm still working on getting this thing aligned. I miss the good ol' days when alignment was simpler. I'm not sure that the instructions I've been using are entirely correct. The instructions at tvrosat claims that if I follow their instructions it'll be a "slam dunk" alignment. It ain't turning out that way. Right now I've got 89W to 107.3W but I lost everything west of 107W (I had sats to 125W but didn't have anything east of 91W when I started). Signal levels are much higher on the ones I can see though. I'm thinking that I don't have true south properly set but the alignment instructions indicates that it is set when you have an equal number of viewable sats (+/-) on each side of the arc. And it's strange that when I got the signal levels up higher that I end up losing services on that sat. It's been many years since I've done an alignment so it's tuff getting back up to speed, also. I'm going to have to go back to square one and start over.

So where are you at on 91W? TP 4180 V 30000 5/6 is a strong one here.
Should be easy to find being next to 89W. Calculate how many counts or actuator shaft turns it should be for 2 degrees.
Do you have to lift up or press down on the dish rim to get signal? That should give you a clue as to how your dish is tracking.

 

[ZetaMale]

So where are you at on 91W? TP 4180 V 30000 5/6 is a strong one here.
Should be easy to find being next to 89W. Calculate how many counts or actuator shaft turns it should be for 2 degrees.
Do you have to lift up or press down on the dish rim to get signal? That should give you a clue as to how your dish is tracking.

91W is fine. I get no more improvement on lifting or lowering the lip. I can only see 91W to 107W. I had 113W until I moved to 91W (for a check) but had nothing when I got back to 113W. After 2 weeks of messing with this, I'm giving up and living with what I got. I am not happy.

 

[Bongu]

Have you done the string test to make sure the geometry is still good? Did you do anything that would affect the parabola? It sounds like you have done a lot of different things that should have delivered results if the dish were true. You have enough knowledge and ability that is for sure. You have great support folks here. If you go back to basics I am sure you can resolve this.

Sent from my SM-N975U using the SatelliteGuys app!

 

[arlo]

Yeah buddy don't give up. Too many sats up there to watch just a few.

https://www.arrowe.com/polarmount.htmlhttps://www.arrowe.com/polarmount.html

Polar Dish Mount

TrackingSat is a Satellite Tracking Program. TrackingSat is useful to assist users that need to install your antenna and align it with the satellites in orbit.

www.geosats.com

http://www.sbe24.org/techdocs/geosat/satgeom4.asp

And. The real deal:

https://www.cobham.com/media/68265/3.1_%20polar_%20mount.pdf

 

[clucas]

If I were you, I would go to each satellite you are able to get one by one and lift and press down on the bottom of your dish to see if there is an improvement. (You could also give a half turn or maybe a full turn on the elevation up and then down to check so you can return to your now working position if you lose the signal.) If that helps maybe your declination is off. I get to the ballpark using the measurements but find that trial and error is best for peaking.