Polar mount questions

[Jason S]

I have some questions about setting up a polar mount; hopefully it's mostly to check my work. Sorry for the long post and no photos. If there is something I missed, maybe someone can say something.

Back story:
I have the 7.5' Echostar (KTI) dish that I've refurbished. I then setup the dish, plumbed the pole scanned in 97W and then set it to 99W back at the end of October. I didn't adjust elevation or declination from what was set when I got the dish.

In the meantime, I've been wanting to get this dish motorized and have purchased an actuator controller. Also, the acquisition of a larger dish is in the works. All the dishes have been fixed, so I don't have experience with setup of a motorized dish or polar mount.

My polar mount setup and questions:
Researching polar mount setup, I read and re-read here: http://www.geo-orbit.org/sizepgs/tuningp4.html. I found reading this thread prior to beginning my adjustments to be helpful: http://www.satelliteguys.us/xen/threads/new-dish.340774/#post-3513356. I also used the information that DK_Sat posted on my rebuild thread, post #12 here:http://www.satelliteguys.us/xen/threads/echostar-dish-rescued.342569/ to make sure that the LNBF was at the correct distance from the dish.

Additionally, I double checked my azimuth using http://www.dishpointer.com/
For whatever reason, I was under the impression that 97W was due South, but realized that 95W was closer to due South. As due south would be a 'theoretical' C-band satellite at 95.8ºW, I tried to align the polar mount in that direction and then slightly moved the dish east to 95W.

To move the dish, I hooked a 18V Milwaukee battery pack to wire leads with alligator clips and used this to power the actuator.

At 95W, most transponders would scan in but several were very weak (specifically the several horse channels). So entering the lat/long and satellite on http://www.satsig.net/ssazelm.htm gave me the numbers for proper elevation and declination.

Using the data from Satsig.net, I checked the polar mount and found that the angles on my mount didn't quite match. I chose the horse channel with the weakest reception which was fluctuating at 5- 25% quality. I then started by moving the elevation to the number Satsig specified for 95W. That dropped the Quality and the receiver unlocked.

With declination adjustment on the dish, the receiver got a lock and about 70% quality on what I thought to be the weak transponder. The other transponders still had good Q, so I decided to check things to the west.

I began moving the dish to the West. I moved to the western satellites one by one. I locked and tried to peak for the transponders that were preloaded in the Manhattan receiver by moving the dish east or west. I was able to scan in every C-band satellite up to and including 139W.

At that point, the actuator had some adjustment problems from my cleanup job as well as the polar mount clamp being in the wrong spot. So at 139W, I used post # 10 from FaT Air here: http://www.satelliteguys.us/xen/threads/4-more-actuator-gets-me.344855/ to position the actuator in the proper position.

I then returned the dish to 95W and began going to the East. I repeated what I did going west and got to 83W, which I believe will be my east limit due to tree interference.

The questions below may be a bit vague, but any insight would be appreciated. I can provide some additional information on what got scanned once the game is over...

As all the Western satellites would scan in something (channels or transponders), does it sound like the dish is tracking the arc pretty well? Or, did I just get the 'low hanging fruit' and finer tuning would bring in more?

With going through transponders and slowly moving the dish east/west to scan in channels I noticed some Q fluctuations on transponders that wouldn't lock. Moving the dish up/down didn't improve any of the locked extreme west transponder signals. I presume this to be a case where there may not be enough dish to lock some of the transponders?

 

[FaT Air]

I locked and tried to peak for the transponders that were preloaded in the Manhattan receiver by moving the dish east or west.

Did you "move the dish" with the actuator, or twist the mount on the pole?? When not on your (closest to) southern satellite, the actuator does elevation, twist of mount on pole does E/W,
Maybe this page(s) that I wrote will explain in more detail, or generate more questions?
http://theho.web.fc2.com/BUD/9525/

 

[KE4EST]

I presume this to be a case where there may not be enough dish to lock some of the transponders?

True some transponders will not lock in with a 7.5 foot dish. Also remember that when receivers are shipped with pre-programmed transponders, some of those transponders may not be active currently as things change all the time. Also the transponders may have been entered incorrectly, so you can't go by what was already in there.

 

[mmewrench]

I normally set up my true south satellite first, then set up adjacent satellites on both sides of true south. In your case you would use 95 w as your true south, peak the azimuth and elevation, then move to 99w and do the same. Now go east to 91w(approximately the same distance from true south) and do the same thing. Before moving further west on the arc go back to true south and see if your signal and quality have changed.The problem with doing the west side first and then coming back and doing east, is that your zenith (highest point of the arc) may be set east of true south, and you wouldn't know it until you moved east of true south. Declination should only be set once you are centered on the arc.

I have a pretty good view of the southern sky so using the above method I am able to track 37w to 139w C and Ku band.

 

[Jason S]

Did you "move the dish" with the actuator, or twist the mount on the pole?? When not on your (closest to) southern satellite, the actuator does elevation, twist of mount on pole does E/W,
Maybe this page(s) that I wrote will explain in more detail, or generate more questions?
http://theho.web.fc2.com/BUD/9525/

Thanks for the link. Your page does add more detail.

For the azimuth satellite, 95W, I centered the polar mount and then moved the dish to the top (highest point) with the actuator and bumped it a bit east. I then twisted the polar mount on the pole (with the mount on the original installed elevation settings) to get the best Q on the receiver. The actuator has a bit of slop to it, I could observe the Q increase or decrease by playing with the slop in the actuator on the azimuth satellite as well as bumping the actuator and playing with the slop on the other satellites.

Before changing any elevation/declination settings, I had checked the original installation settings from when I got the dish. The original elevation was set near 45º, which was nowhere near the actual or modified latitude in the table on your website (or satsig calculations). The modified latitude elevation and declination in the table are very close to the numbers I used.

After east/west pole twist on the azimuth satellite, then adjusting elevation and declination from the original setting; I believe I had the dish peaked on my azimuth satellite. As I started going West from the top of the arc, I'd try to get the best Q on the receiver by using the actuator... I did not twist the dish on the pole, but would push/pull on the dish to look for any Q changes.

For what it's worth, going across the west side of the arc the satellites seemed to drop into place. A Q in the 70's is usually good quality on my receiver; the majority of the transponders that scanned in had a Q in the lower 70's, some were in the 80's and a few were in the 50's to 60's. Working to the east had similar results until I got to 78W, but was then looking into tree branches...

So at this point I'm uncertain if it may be off just a bit with due south or if there isn't enough dish or both?

From reading your post and website, as well as mmewrench's post, it sounds like there may be a little bit more fine tuning or at the very least least checking my work.

 

[Blindowl1234]

Jason S from what I'm reading you're getting a decent signal from 83W to 139W....If that's the case you're probably as good as it gets with the dish. I can tell you with my 8 foot dish I get most everything but some weak transponders are iffy. I learned from experience if I'm getting everything across the arc to leave it alone.

 

[Jason S]

True some transponders will not lock in with a 7.5 foot dish. Also remember that when receivers are shipped with pre-programmed transponders, some of those transponders may not be active currently as things change all the time. Also the transponders may have been entered incorrectly, so you can't go by what was already in there.

As I worked with the dish west and then east, the satellites essentially dropped into place. I figured some of the programmed transponders might be old data or possibly inactive at scan time.
However, there just were a number of transponders that appeared to show some faint signs of life but wouldn't lock.

 

[Jason S]

I normally set up my true south satellite first, then set up adjacent satellites on both sides of true south. In your case you would use 95 w as your true south, peak the azimuth and elevation, then move to 99w and do the same. Now go east to 91w(approximately the same distance from true south) and do the same thing. Before moving further west on the arc go back to true south and see if your signal and quality have changed.The problem with doing the west side first and then coming back and doing east, is that your zenith (highest point of the arc) may be set east of true south, and you wouldn't know it until you moved east of true south. Declination should only be set once you are centered on the arc.

I have a pretty good view of the southern sky so using the above method I am able to track 37w to 139w C and Ku band.

Thank you for the tips, mmewrench. I believe I'm pretty close with my setup. With yours and FaT Air's post, it sounds like there could be a little more tweaking to do.

 

[Jason S]

Jason S from what I'm reading you're getting a decent signal from 83W to 139W....If that's the case you're probably as good as it gets with the dish. I can tell you with my 8 foot dish I get most everything but some weak transponders are iffy. I learned from experience if I'm getting everything across the arc to leave it alone.

To borrow from the old Frosted Mini-Wheat commercials - The frosted side in me is saying "Stop where you are, hook up the actuator controller and enjoy what you got..."

With more rain this week, holidays and travel; it looks like any adjustments will have to be done later.

 

[FaT Air]

If lifting/lowering the dish, moving it L/R, only decrease the Q on your (closest to) southern and furthest E or W satellite. I'd call it 'good'.
Declination isn't adjusted after setting it. Only adjust elevation on your (closest to) south satellite. 'fudging' your dish slightly L or R with the actuator is OK to get the 'spin' of the mount closer to optimum. But for the real optimum -
Use the actuator and spin the mount on the pole on a satellite. that's not your (closest to) southern satellite. to peak Q. The further E or W the better.

You may find it a benefit to tweak the feed and find it's 'sweet spot'. Rarely are they 'there' as provided.
I do/did this at an eastern satellite. That way I don't/didn't have to reach over the dish to reach the feed.A simple step ladder and I can sit right beside it.

 

[Jason S]

If lifting/lowering the dish, moving it L/R, only decrease the Q on your (closest to) southern and furthest E or W satellite. I'd call it 'good'.
Declination isn't adjusted after setting it. Only adjust elevation on your (closest to) south satellite. 'fudging' your dish slightly L or R with the actuator is OK to get the 'spin' of the mount closer to optimum. But for the real optimum -
Use the actuator and spin the mount on the pole on a satellite. that's not your (closest to) southern satellite. to peak Q. The further E or W the better.

You may find it a benefit to tweak the feed and find it's 'sweet spot'. Rarely are they 'there' as provided.
I do/did this at an eastern satellite. That way I don't/didn't have to reach over the dish to reach the feed.A simple step ladder and I can sit right beside it.

Thank you again for the assistance. Being that I'm learning as I go, it sure helps to have some guidance on whether I'm on the right track or what I may need to get the setup right. I'm pretty sure that I'll have one more go at checking things over before I start programming the receiver and actuator controller...

 

[mmewrench]

Thank you again for the assistance. Being that I'm learning as I go, it sure helps to have some guidance on whether I'm on the right track or what I may need to get the setup right. I'm pretty sure that I'll have one more go at checking things over before I start programming the receiver and actuator controller...

There is a lot of useful information here:

http://www.geo-orbit.org/sizepgs/tuningp4.html#anchor801578

Should make for some good reading on a rainy day. Good luck in your quest for a larger dish. I'm up to 12 feet now but I know there is a fifteen footer with my name on it.