Satellite Signalling at 2 Locations for each Satellite why?

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jsattv

Thread Starter
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Jul 4, 2006
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Guys for almost all Satellites that I can currently find on my 12 foot mesh dish - especially the Ku Band ones, I can see Signalling in 2 locations, that is for example 74.0W (ONN), I have locked it in on count 744 on my VBox III at approx 62% Quality, but I can also go back to Count 732 and find 74.0W again - but with only 37% Quality?? Is this a calibration thing?? I have been reading the "How to point a satellite dish and use a spectrum analyzer" info recently contributed by Linuxman, but when I got to the Section on - PEAKING UP, it is very hard to understand! That is swinging the Dish either side of 2 Points till you lose the Signal - then set it in the middle, is this what I should be doing? Any replies would be appreciated.
 
Corrado

Corrado

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Apr 2, 2007
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Is there any free play or lost motion in the pivots or actuator? Perhaps the dish isn't really moving much but taking up slack in the mechanism.

Is it Ku only or both C+Ku?

I find with my BSC621 LNBF, the Ku is a click east of the C band. I think due to the difference in the probes inside the housing. No amount of tweaking gets rid of it.
 
gabshere

gabshere

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Aug 20, 2006
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are you moving the dish and just comming back to lets say this satellite 74W ?

i've always had problems with my count going from a west satellite to a east satellite. I blame it on the v-box III but its actually a combo of the v-box and actuator ( not having a high count). I did find a thread on it " V-Box III Accuracy " also my problem of drift DRIFT Thread
 
J

jsattv

Thread Starter
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Jul 4, 2006
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Thanks for the replies Corado, Lak7, and Gadshere.

Corado the dual appearances are mostly on the Ku Birds, ie. 74.0 and 79.0. Haven't noticed it much on the C band Satellites as they are usually stronger signals.

Lak 7 haven't tried the string test - would need a ladder to reach to the top and that looks almost impossible to do on the big 12 footer without risking a fall!!

Gadshere thanks for the references re the V Box III I'll study them. One other thing you reminded me of is that this Dish seems to have some kind of a BACKLASH in that when I zero in on a Satellite going to it in the West direction it is easily tuned in, BUT when I am coming back from West to East ie. from 127 back to 101 the Satellite reception and Quality isn't as good until I click back and forth on the V Box III. Is this Backlash, and is it normal on a big 12 Ft Mesh Dish??
 
Covack

Covack

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Oct 4, 2004
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sounds like a tracking problem
I had to add shims,
the problem was pole mount
I used a hacksaw blade and broke it, I drove in between the pole and the mount( worked great)
I was having problems on Hor.2 and also G18 KU
 
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Lak7

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Feb 28, 2008
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haven't tried the string test - would need a ladder to reach to the top and that looks almost impossible to do on the big 12 footer without risking a fall!!
Can you throw the string over the top and tie it to the mount?
 
gabshere

gabshere

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yeah i would be a click or two off ( in the center of the arc & the east) when i went all the way west and then back to the east. you can try all the suggestions the guys give ( they won't hurt ) but really sounds like and i didn't call it backlash but just a plain ole counting problem.

got to your east satellite and tune it in ( with the v-box ) and remember your # on the v-box III, then go to your west satellite. now go back to the same east satellite. it should stop at the same # ( mine did ) but the second time i would get to the east satellite it would again be off about 2 clicks in tuning. I blame this on the v-box & the actuator. the v-box III isn't as good as a g-box ( from what i understand) plus i suspect the actuator isn't counting enough for the v-box to be very accurate.

i have been trying to add a second reed switch to the actuator to see if i can double the counting up and get a more accurate count. hopefully i will be able to get on this project soon and see if i can correct my counting problems.

my only cure was just to retune ( the v-box) each time i went east.
 
J

jsattv

Thread Starter
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Jul 4, 2006
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Can you throw the string over the top and tie it to the mount?

Lak7, the dish is so high off the ground that a rope would probably be a better option. Will that work?
 
J

jsattv

Thread Starter
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Jul 4, 2006
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yeah i would be a click or two off ( in the center of the arc & the east) when i went all the way west and then back to the east. you can try all the suggestions the guys give ( they won't hurt ) but really sounds like and i didn't call it backlash but just a plain ole counting problem.

got to your east satellite and tune it in ( with the v-box ) and remember your # on the v-box III, then go to your west satellite. now go back to the same east satellite. it should stop at the same # ( mine did ) but the second time i would get to the east satellite it would again be off about 2 clicks in tuning. I blame this on the v-box & the actuator. the v-box III isn't as good as a g-box ( from what i understand) plus i suspect the actuator isn't counting enough for the v-box to be very accurate.

i have been trying to add a second reed switch to the actuator to see if i can double the counting up and get a more accurate count. hopefully i will be able to get on this project soon and see if i can correct my counting problems.

my only cure was just to retune ( the v-box) each time i went east.

Thanks a lot George, well its not so much a counting problem as the Dish always goes back to the same count I previously saved or stored for a particular Satellite on the V BoxIII. (I'm using the 8 magnet Von Weise Actuator you advised me to try). The problem is that it seem like the sheer momentum of the 12 Ft dish is such that when it stops when going from East to West - the Satellites have about 10 to 15% better Quality then when I come back the other way ie. from West to East.

Also definately noticed with the very cloudy and at times rainy weather tonight that the Dish is definately not tracking as well on the Westerly Satellites on Both C and Ku Band as it is on Satellites in the Easterly Side. So it's back to the drawing board again ie. start all over again?
 
J

jsattv

Thread Starter
SatelliteGuys Pro
Jul 4, 2006
1,061
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sounds like a tracking problem
I had to add shims,
the problem was pole mount
I used a hacksaw blade and broke it, I drove in between the pole and the mount( worked great)
I was having problems on Hor.2 and also G18 KU

Thanks Covak you are probably completely correct, as tonight I noticed the Satellites on the Westerly side - BOTH C and Ku Band are not tracking as well as the Easterly Satellites. I'm just not sure how to correct this?
 
gabshere

gabshere

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Aug 20, 2006
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Rison , Arkansas
So it's back to the drawing board again ie. start all over again?

well i do know that the 7 1/2 ft dish is a lot easier to set up and track the arc if you have to go that route. where the 12 fter will help is the high FEC channels and probably some ku signals. since you have a stand alone ku dish you might want to put up the 7 1/2 fter for the winter and pick up c-band with it.

you've almost come full circle and back to winter time. which makes it harder to work on the dish :( i've been re tuning my 10 ft dish for about 3 months ( i haven't got a lot of time to work on it) so i know how slow progress is ...
 
J

jsattv

Thread Starter
SatelliteGuys Pro
Jul 4, 2006
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well i do know that the 7 1/2 ft dish is a lot easier to set up and track the arc if you have to go that route. where the 12 fter will help is the high FEC channels and probably some ku signals. since you have a stand alone ku dish you might want to put up the 7 1/2 fter for the winter and pick up c-band with it.

you've almost come full circle and back to winter time. which makes it harder to work on the dish :( i've been re tuning my 10 ft dish for about 3 months ( i haven't got a lot of time to work on it) so i know how slow progress is ...

Thanks George, yes its almost been a year since the 12 Footer was installed on my 7.5 Ft Tripod. I sure appreciated that excellent buriable Satellite Cable you sent me - it was trenched in and sure put to good use and was just long enough.

Think I saw a picture of your 10 footer Mesh?? Dish in the posts you provided yesterday, so its likely no easy task to set it up. Good Luck!!

As far as installing the other 7.5 Footer Unimesh I have in the garage in 2 sections right now........you are correct - it would likely be easier to calibrate and set up, but the task of taking down the 12 footer and re mounting the 7.5 footer on the Tripod seems to be too much work, unless I can import Thomas's Crane up here to Canada!! LOL. Also what do you mean by the high FEC Channels?? So for now I'll keep trying for a while longer with the 12 Footer, and maybe take a chance and climb the ladder and fire up the 39 inch Fortec Dish and Motor on the roof when this lousy cloudy/rainy weather gets better. Thanks.
 
truckracer

truckracer

SatelliteGuys Pro
Sep 17, 2004
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351
Charleston wv
My v-box never seems to stop in the same place twice (v-box 4)

I have a good dish with tight polar mount and no slack in any of the pivot points.
I have a good 36" actuator with a lot of pulses per inch, (can't remember how many pulses).

It still loses positions. My other dish is controlled by an analog receiver and it never needs re-syncing.
 
J

jsattv

Thread Starter
SatelliteGuys Pro
Jul 4, 2006
1,061
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My v-box never seems to stop in the same place twice (v-box 4)

I have a good dish with tight polar mount and no slack in any of the pivot points.
I have a good 36" actuator with a lot of pulses per inch, (can't remember how many pulses).

It still loses positions. My other dish is controlled by an analog receiver and it never needs re-syncing.

Thanks Truckracer. Yes there are times when I need to reset the Dish a couple of clicks East or West for a better Satellite Signal, but if I go into Installer / Save Position / on the Motor Settings on my Sat Receiver then the V Box III always returns the Dish to the same count. And if I forget to do this, then the V Box returns the Dish back to the previously saved count (when coming back from another Satellite). Found out my Polorotor is not working properly for skew today, so I'll have to check the connections at the Feedhorn tomorrow since the connections to the back of my Uniden 9900 Receiver are okay.
 
ACRadio

ACRadio

SatelliteGuys Pro
Apr 25, 2006
794
2
Near Asheville NC
Thanks ACRadio, can you please explain what a sidelobe problem is?

A trait of all parabolic dishes is that when measuring received signal strength they have the main lobe where the dish is pointed directly at the satellite, and on either side of the main lobe are what is called sidelobes, where the signal is received again albeit much lower in strength. The sidelobe is at different places with different models and sizes of dishes, but will usually be somewhere around 1 to 2 degrees off axis. This will look just like your example in that when moving the dish you will pass by the main lobe with big signal, then just past the main lobe you will see the signal return but with a much lower strength. One sidelobe can be stronger than the other, and it is more noticeable with bigger dishes since they have more collection area and can collect enough signal for the sidelobe to actually lock a digital signal. Other contributing factors that can increase a sidelobe problem is a slightly warped dish, feed not being centered, monopod feed support arm being in the down position, etc.
 
eurosport

eurosport

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A trait of all parabolic dishes is that when measuring received signal strength they have the main lobe where the dish is pointed directly at the satellite, and on either side of the main lobe are what is called sidelobes, where the signal is received again albeit much lower in strength. The sidelobe is at different places with different models and sizes of dishes, but will usually be somewhere around 1 to 2 degrees off axis. This will look just like your example in that when moving the dish you will pass by the main lobe with big signal, then just past the main lobe you will see the signal return but with a much lower strength. One sidelobe can be stronger than the other, and it is more noticeable with bigger dishes since they have more collection area and can collect enough signal for the sidelobe to actually lock a digital signal. Other contributing factors that can increase a sidelobe problem is a slightly warped dish, feed not being centered, monopod feed support arm being in the down position, etc.
...I remember this from the old analog days of my C-band dish. As it was getting near the selected sat you'd see a sparklie picture, then gone a split-second, and then crystal-clear as it stopped at the bird!:)
 
J

jsattv

Thread Starter
SatelliteGuys Pro
Jul 4, 2006
1,061
8
A trait of all parabolic dishes is that when measuring received signal strength they have the main lobe where the dish is pointed directly at the satellite, and on either side of the main lobe are what is called sidelobes, where the signal is received again albeit much lower in strength. The sidelobe is at different places with different models and sizes of dishes, but will usually be somewhere around 1 to 2 degrees off axis. This will look just like your example in that when moving the dish you will pass by the main lobe with big signal, then just past the main lobe you will see the signal return but with a much lower strength. One sidelobe can be stronger than the other, and it is more noticeable with bigger dishes since they have more collection area and can collect enough signal for the sidelobe to actually lock a digital signal. Other contributing factors that can increase a sidelobe problem is a slightly warped dish, feed not being centered, monopod feed support arm being in the down position, etc.

Wow, what a great detailed explanation, thanks a lot ACRadio. I've actually had occasions on ONN at 74.0W where its signalling appeared at 3 places with approx 10 clicks difference. And as you mentioned there was always one spot where the Satellite Tp Signalling is a bit better. So then to correct this I guess one of the things to try would be to reset the LNB's in the FeedHorn or their Focal Length positioning??

I also discovered today that my Polorotor control wasn't working properly and found out that there was some water dripping out the bottom (after I shook it a bit) of the Blue cap cover on the bottom of my Corotor II Feedhorn. We have been getting some frost at night here lately so I'm wondering if it may be freezing up, which doesn't bode well for our upcoming 30 degrees below zero winters in Jan and Feb. Guess I may have to put the LNB cover on the Feedhorn and LNB's to keep the snow and rain out??
 
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