bcs621 feedhorn alignment

[gabshere]

Well i figured i would start a thread and just link it to Linuxman's .
we were adjusting the feedhorns I have a bsc621 ( actually i have two)

i first took readings with my Coolsat 5000 and then used my Traxis 3500
my polarity mark was pointing to 12:00 ( but was at 6:00)
i did adjust it to 8:00 and lost signal and moved it to 7:00 then to 4:00 then to 5:30 and reset it back to the original 6:00 . Now the main problem i actually think i'm having is the feedhorn has a lot of room to move in the scaler and it hard to get it level or straight in the scaler and the metal feedhorn is very easy to indent with the lockdown bolt.


......................................Coolsat 5K...Traxis ( before) Traxis (after)Coolsat 5K
G27 - 129W 11964 H Ku.....69% SQ........68% SQ........63% SQ........ no signal
G10 - 123W 11720 V Ku.....91% SQ........73% SQ........73%SQ.........88%SQ
G10 - 123W 3841...............94%SQ.........80%SQ..........80%SQ........94%SQ
G11 - 91W 3721 H C-Band 91% SQ.......78% SQ.........80%SQ.......94%SQ
G11 - 91W 12059 V Ku no signal.......no signal.......17%SQ no channel 63%SQ
AMC3 - 87W 12144 H Ku no signal........no signal........17%SQno channel 63%SQ
AMC2/16 - 85W 12195 H Ku 63%SQ........17%SQ no channel 23%SQno channel 66%SQ
G17 - 74W 11734 H Ku.........90% SQ........72% SQ........80%SQ.......94%SQ
AMC6 - 72W 12053 V Ku.......69% SQ........65-67% SQ.....67%SQ.......69%SQ
AMC6 - 72W 4040 V C-Band..87-90% SQ....71% SQ........72%SQ.......90-91%SQ

i still need a better method to check to see if its correctly seated into the scaler ( i suspect it wouldn't take a whole lot to be off and every little bit is throwing me off. i will try again to gain some center area of the arc I did lose ground in the center of my arc spirit TV on 87W was at 87 on the coolsat and now is at 70

included are pics of the old bsc621 with adjustment arrow and newer bsc621 with a number scale

 

[gpat]

George does the back side of your dish have a sight or alignment hole?
See How I did my feedhorn.
It was perfectly centered using a jig made from 1-1/4" EMT and a adapter to 2inch.
Or if you know your F/D distance the LNB is protruding from the scaler ring you can make a
ring thats the thickness out of PVC pipe(a square cut miter saw works great for this.)
Place the ring over the feedhorn throat and push it up against the scalar ring.
Then put a straight edge across and check.
If its skewed then you may want a third hand to loosen the LNB and put slight pressure on it for full contact then tighten it.
I dont understand why they dont make 3 or 4 set screws on the scalar ring so the LNB can be adjusted when tied down.

 

[linuxman]

Hey George,

Your numbers look pretty good, but I am a little confused by the headings. I take it that the last two columns are after your final adjustments?

Also here is a pic of the tool I made to line up the wave-guide. It ain't pretty, but it works great.



You can see the white tape over the hole in the front. That is there to give me a pin-point beam. The red marker line is to tell me where to line it up in the center of the wave-guide.

On the geosat, I put a little mark in the center of the cap to line up the red line with. With a co-rotor, I just use the probe with the cap off.

When the pin light passes through the center of the dish plate from N/S and E/W, you can rest assured that your are pretty darn close to the center.

Fred

 

[gabshere]

it kinda weird how you align the feedhorn and bring in stuff better one way and lose a bit on others. gained a bit on the east ku sats and lost a bit on the west sats no gain in the center (its where my ku is the weakest but c-band has good readings). So I figure its still slightly off. and have to either make a level with the laser i have ( and it looks like linuxmans) or find a cheap pointer laser that will fit something i already have . then i can align the feedhorn properly.

my arc still isn't perfect so i might have to look into that also.

in the time being i'm going to set my primestar back on a motor and hopefully get my 10 ft dish up and running.( later in the week)

 

[linuxman]

Hey George,

By the looks of the numbers in the center of your arc and the ends, I think the elevation on the dish is off just a tad. Could also be that it needs to be twisted slightly one way or another for best signal.

t kinda weird how you align the feedhorn and bring in stuff better one way and lose a bit on others. gained a bit on the east ku sats and lost a bit on the west sats no gain in the center

That and what you are describing in your last post suggest that. By the movement of the wave-guide increasing on the east then the west means that when you get the wave-guide centered, you might try the elevation adjustment. Or side to side twist.

Fred

 

[gabshere]

i will try the twist , and by this your saying to loosen the bolts and slightly move the whole dish on the pole a bit. i will try this befor trying the elevation. plus it will be easier. but will probably make me adjust the location of sats across the board ( on the receiver).

thanks

 

[gpat]

This is one thing I think I can help on.
For your "twist" tuning try to hit the furthest west sat you can and the furthest east.
With my tuning meter I was able to zero it right in on a west one(C4 for me) and its right on.

 

[linuxman]

i will try the twist , and by this your saying to loosen the bolts and slightly move the whole dish on the pole a bit.

Yes, the whole assembly.

I got the following from another site. It is a little easier to understand than the Geo-Orbit site.

if the dish is pointing at a satellite to the east of center and you have to push up on the dish to get a better signal, then the elevation angle must be adjusted higher. At this time, you adjust this by turning the entire mount to the east

To repeat, if the dish needs to be pulled down (lowered) for a better signal, then turn the mount the opposite direction (towards the higher point on the arc) and if the dish needs to be pushed up (lifted) to get a better signal, then rotate the entire mount away from the top of the arc.

Fine tune elevation. Once again, lift and pull the dish on the satellites on the low ends of the arc to see which direction produces a better picture (stronger signal). If lifting the dish on both sides produces a better signal, including the center satellite (or at least does not affect the center) then slightly increase the elevation angle.

If lowering the dish on both sides produces a better signal, including the center satellite (or least does not affect the center) then slightly reduce the elevation angle. Keep track how much you turn the bolt(s) that adjust the elevation angle so in case you overadjust you know how much to 'back up' the adjustment. A rule of thumb is to only move the elevation adjustment bolts no more than a quarter of a turn per adjustment. After each adjustment quickly check all satellites to see if they are better or worse. You might have to go from side to side and repeat the elevation adjustment steps before the dish tracks to your satisfaction.

Fine tune declination (end of the arc adjustments). If, and ONLY if, you can not get both sides to peak, and both sides would be too low or too high while the center remains the same; you can then do a small adjustment of the declination angle to get the two sides into peak with the top.

BUT, only do this if you can confirm that both sides are low or high while the center remains the same.

If the dish is too high on the sides (arc ends), but fine in the center, the declination angle is too low so increase the declination and decrease the elevation angle the same amount. The two adjustments will cancel each other in the center of the arc while tracking lower on the sides.

Conversely, if the dish is too low on the sides (arc ends), but fine in the center, the declination angle is too high so decrease the declination and increase the elevation angle the same amount.

Hope it helps you!

Fred

 

[gabshere]

ok i will print this out , and give it a try tomorrow (if its warm enough) but i also have to check to see if the feedhorn is level and centered. i have the same level you have so maybe i can adapt it to something that will show me the center

 

[gabshere]

i will follow up with some reading on setting up the mount. initally when i set it up i actually tuned it to g10 first ( and it tracks the arc fairly well just not perfect) but now i will go back and make sure the mount is actually set up north/south and see if its off any there first. then try to to verify the arc on the east and west satellites. the rest should fall into play after this is done correct? lol we will see .......

also i don't know how much of a factor its playing but one of my lnb support arms is slightly bent .... but with it receiving fairly good signal in some places and not in others i will also attempt to straighten this arm.


don't know if i will get any time to work on the 10 ft dish until i get this one closer to correct tracking.

 

[gpat]

i will follow up with some reading on setting up the mount. initally when i set it up i actually tuned it to g10 first ( and it tracks the arc fairly well just not perfect) but now i will go back and make sure the mount is actually set up north/south and see if its off any there first. then try to to verify the arc on the east and west satellites. the rest should fall into play after this is done correct? lol we will see .......

also i don't know how much of a factor its playing but one of my lnb support arms is slightly bent .... but with it receiving fairly good signal in some places and not in others i will also attempt to straighten this arm.


don't know if i will get any time to work on the 10 ft dish until i get this one closer to correct tracking.

George
in our area of the country (east coast) its best to set the arc by the most western sat.
You are in the central states so I dont know which sat you view thats lowest on the horizon but thats the one I would pick.
If you do the southern sat your rotation can be off much more and still get a signal.
Go the furthest west(or east) depending on your sat choice,then do the opposite .
Your southern sat will be hit by correct elevation and positioner.

 

[gabshere]

ok heres the problem i'm having . i did adjust west ( and this is why) caus with the limit of my motor i can't get the dish over to 137W the motor is fully retracted so i thought aligning the dish westward would help gain this satellite . wrong it pushed me off my arc lost signal across the board.

everything i've read says north sout axis and mine is very close to that when starting..

so i rotate the eastward maybe 1/4 inch and signals go up across the board.(i'll post some #'s soon)

i will try a bit more but ..... how do i correct the not being able to go further west..... i will have to look at the motor mount location ........

 

[linuxman]

how do i correct the not being able to go further west..... i will have to look at the motor mount location

There are two ways to correct the situation.

The best way is to loosen the clamp that goes around the actuator, and slide the whole actuator into the clamp just enough to allow access to 137W. This will limit your eastward movement by how ever much you move the actuator in.

The second way is an internal thing, by taking the far end bolt (next to dish) on the actuator loose, and hand turn screwing it in to see if there is still room for inward movement.

I would opt for the first way and see what that does for you.

Fred

 

[gabshere]

great fred i was looking at this when i went back out

 

[gpat]

Fred Ive had problems in the past by manually screwing in the jack,
I dont remember exactly what it was but it caused it to freeze up.
Also I think once I had the thing that holds the limits on fall off.
I also opt for moving the clamp arm a little but keep in mind if it does an
auto tune it will want to go about 15 clicks past the sweetspot. It will give you an error
message of physical limits reached.
What I would do is this:
Find the sat and measure the angle its at,extend the actuator 15 clicks out from the internal
stop,then loosen the clamp and slide the mount to the same angle you found that sat at before.Tighten the clamp and your all set.
Bad news is all of your sats are out of position so youll have to re enter them.
If you went thru them all before you moved the actuator you can figure out how much it moved and add/subtract to get close.
The DSR 920-22s will do a correction for all but Ive had it mess things up before when doing this.Dont feel bad Ive monkeyed with mine so much in the last couple weeks,standing on my head to scratch my a** trying to find a Ku signal ,changing dishes etc. that I need to do a MR and start all over with my sat map. Good luck with it.
Now Im off to see if I can figure out the Coolsat.

 

[linuxman]

Find the sat and measure the angle its at,extend the actuator 15 clicks out from the internal stop,then loosen the clamp and slide the mount to the same angle you found that sat at before.Tighten the clamp and your all set.

That's good advice if you do use the auto tune. I've never had much success with it. I have always just manually tuned in every satellite. Course you see how picky I am.

I have hit the button accidentally once or twice, and you are right it will swing a ways each way.

Fred

 

[gabshere]

its ok i can reset the v-box so its centered again and i think i can reload my channel list with the locations and they will be close lol got to try it anyway

 

[gpat]

That's good advice if you do use the auto tune. I've never had much success with it. I have always just manually tuned in every satellite. Course you see how picky I am.

I have hit the button accidentally once or twice, and you are right it will swing a ways each way.

Fred

I use the auto tune to get close and the auto skew then manually peak them both going back and forth a couple of times.
My old GI analog which I still use in a pinch would save each setting for each channel and I found that the skew was off on some vs others.

 

[gabshere]

ok after i tweaked the dish today , i rotated the whole dish toward the east and you won't beleive how much the adjustment was.......3/32 of an inch .... lol ok but i added another update to the readings

......................................Coolsat 5K...Traxis ( before) Traxis (after)Coolsat 5K..... Coolsat 5K
........................................................................adjusting feedhorn.......................after dish adjustment
gained 139W ** got weird tp on this on high SQ but not listed at lyngsat
gained 137W .........................................................................................................at 87%SQ
G27 - 129W 11964 H Ku.....69% SQ........68% SQ.......63% SQ........ .....n/s............66%SQ
G10 - 123W 11720 V Ku.....91% SQ........73% SQ.......73%SQ.........88%SQ ..........90%SQ
G10 - 123W 3841...............94%SQ..........80%SQ........80 %SQ........94%SQ............94%SQ
G11 - 91W 3721 H C-Band 91% SQ.........78% SQ.......80%SQ.........94%SQ ............94%SQ
G11 - 91W 12059 V Ku........n/s................n/s...............17%SQ..n/c..63%SQ..............63%SQ
AMC3 - 87W 12144 H Ku ......n/s.............n/s................17%SQ..n/c..63%SQ.............63%SQ
AMC2/16 - 85W 12195 H Ku 63%SQ........17%SQ...n/c.23%SQ...n/c.. 66%SQ..........69%SQ ** gain**
G17 - 74W 11734 H Ku.........90% SQ........72% SQ......80%SQ.......94%SQ...............96-97%SQ ** gain**
AMC6 - 72W 12053 V Ku.......69% SQ......65-67% SQ.....67%SQ.......69%SQ............88-90%SQ ** big gain**
AMC6 - 72W 4040 V C-Band..87-90% SQ....71% SQ........72%SQ.......90-91%SQ......91-93%SQ ** gain**
gained 58W C-band 4125 H ........................................................................................ 94-95%SQ

well i gained almost across the board the center is still off... i will go out tomorrow ( hopefully if its warm) and check the dish (push pull lift & push down on it) at the east west and center of the arc to see where i am it is closer than it was.

 

[linuxman]

Hey George,

It's looking a lot better.

WooHoo!!

Congratulations!!
Fred