Why? I have no idea... Maybe those instructions are written for a specific model of dish for which that might be true. But I just checked on 4 dishes that I have and I can tell you that that angle is different by 9-12 degrees. (checked on FortecStar 90cm, Channel Master 75cm, Dish500 and an old Muzak dish , and the angle of the arm is nowhere near the elevation of the satellites that they are receiving)
OTHER Cannot Find Galaxy 19 FTA 97 West :(
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QUESTION: Do you mean as set behind the dish and as measured on the antenna branch?
I mean that the angle I measure by placing my phone on the the arm (what they call the "antenna branch") - compared to horizontal - is quite different from the elevation of the satellite that the dish is receiving.
I have measured the following at my location:
Muzak dish aimed at 123W - the satellite is at 21 degrees elevation - the measurement on the LNB arm shows 13 degrees elevation
FortecStar 90cm aimed at 87W - the satellite is at 40 degrees, the measurement on the LNB arm shows 31 degrees
Globecast Channel Master 75E dish aimed at 34.5W - the satellite is at 28 degrees and the measurement on the elevation of the LNB arm shows 14 degrees
so what I conclude is that :
a- the LNB arm (or "antenna branch") is not in line with the elevation that the dish is aiming at
b- the difference varies from one dish to another
as far as measuring behind the dish, in most cases there's no place on most offset dish that will give you an accurate reading. The closest you'll find to an accurate reading is the marks on the dich mount - but like i said before, that can be off by a few degrees
So my recommendation here is to set that elevation using the marks on the mounts, have the receiver and a TV near the dish, tune to a known transponder for the satellite you are trying to find, set the skew of the LNB approximately to what it should be, and move the dish slowly in azimuth until you get a signal. If you don't get anything, lower the elevation by one degree and try the same again, then another degree. Then if after lowering by 5 dgrees you have not found it, move it up one degree at at time and try again, etc.
a note on dish pointing apps - they are pretty good for the elevation, and quite terrible for the azimuth, because the compass in a phone is quite innacurate and might react to metal in its proximity, so treat those apps as a rough indicator and not as a scientific tool
another note, on the finder that were discussed earlier in the thread. I have one and I love it. It's also not very accurate and won't tell you if you're pointing at a satellite or at your neighbor's tree, but it will change sound when it's receiving some energy - whether it's true satellite signals or thermal noise from a tree. So if there's no obstacle, it's a quick way of aiming the dish toward something potentially interesting. It also won't make a difference between an FTA satellite and a Directv satellite. So if it squeaks - indicating there's signal - but a blind scan finds nothing, that means it's probably aiming at DirecTV or DishNetwork. If the blind scan finds something, you look on Lyngsdat to try to figure out what satellite it is that you're receiving, and once you found one, it's usually fairly easy to hop on to the next one etc
Once you understand those limitations, it's a very useful tool for zeroing in on something
The arm elevation would be a very, very rough approximation of the elevation angle, for an offset dish that has its bottom at the vertex of the parabolic shape, and an arm mounted to the dish in a certain way. These conditions are often only very roughly the case, with offset satellite dishes.
(Sorry for the jargon, I don't expect you to understand this right now...)
You could use that very rough estimate for a dish that has no elevation scale, and/or if you have a problem of calculating the dish offset angle (by measuring width and height of the effective parabolic surface, and then apply a bit of maths).
Alas, such (extra) information is very often left out, on the internet. And sometimes the internet gives information that is really faulty.
The beauty of a forum like this is that members can add to posts of others (more info), and if necessary correct (different info, and dialogue).
By the way; I sometimes use such rough information of the arm elevation in the pictures from members, to quickly assess if the elevation of a dish is way out of what would be expected.
Greetz,
A33
Strange numbering on that lnbf to show the degress of skew but if they define it like most each line would be 5 degrees so 23.8 clockwise from behind should be about where I put the red line in my estimation.
When you look at this in real life the LNB mount appears to be ticked at every 5° up to 20°. However, the number system on the LNB itself starts at 0° and ends at 13° but the numbers are spaced in such a way that they line up with the LNB mount at every 5°. I think everyone will agree on this?Strange numbering on that lnbf to show the degress of skew but if they define it like most each line would be 5 degrees so 23.8 clockwise from behind should be about where I put the red line in my estimation.
View attachment 160523
I'm concerned about how you suggest the LNB must be rotated. The Dish Pointer app I use suggests something totally different. I attached two screenshots so you can see and thus verify if your suggestion stands as is or if a mistake has occurred.
Attachments
I'm simply going by what you said in post 25 as quoted below:
If you are behind the lnbf with the small side (neck) facing then you are looking at the face of the dish. You said you need to rotate the lnb clockwise. If that is the case then what I posted is indeed clockwise 23.9 degrees and you would rotate the lnbf until the 0 mark on the holder lines up with the red line. We can only give advice based on the information we are given.
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Something here is lost in translation. Your red mark is to the left of the ZERO meaning you turned counterclock wise. If your red mark was to the right of the ZERO on the LNB then you would be tuning clockwise. What am I missing????I'm simply going by what you said in post 25 as quoted below:
If you are behind the lnbf with the small side (neck) facing then you are looking at the face of the dish. You said you need to rotate the lnb clockwise. If that is the case then what I posted is indeed clockwise 23.9 degrees and you would rotate the lnbf until the 0 mark on the holder lines up with the red line. We can only give advice based on the information we are given.
Also, The "0 mark on the BLACK holder " does not rotate. This is getting confusing......
You must turn the lnbf in it's holder. Maybe this crude drawing will help.
What would you call "the smaller side"?
Skew is calculated as positive value = clockwise direction, when looking towards the satellite.
(This would normally be for satellites that are located 'right' from due south, when you are on the northern hemisphere.)
Your dish is a kind of mirror, so when looking into the dish, a positive skew value means rotating the LNB counterclockwise.
I hope this helps, a bit.
Greetz,
A33
OK! This is a much better explanation. Thanks for expounding upon your methodology. I'm happy to see we agree in what direction we rotate the LNB and set the skew!
I believe we are in agreement that the numbereing systems used on both the LNB and LNB mount appear to be evenly separated by 5°. EG the tip of the ▲ on the LNB mount lines up perfectly with a number on the LNB.
With this point in mind, if 20° on the LNB mount is indeed twenty degrees this means to me that an additional clockwise rotation would increase the skew to nearly 45° (20°+23.9°=43.9°)
On the otherhand, if we simply ignore the numbering on the LNB mount and instead simply focus on lining up the 0's on the LNB mount and LNB so everything is centred on zero then using the numbering on the LNB only we can move the correct amount of degree's away from zero. In this example, we would rotate the LNB clockwise and stop just before -5 lines up with '0' on the LNB mount.
After having looked things over, I belive I should focus on the numbers on the LNB and rotate as described above. EG:before -5 lines up with '0' on the LNB mount.
Thoughts?
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I believe the confusion stems from the weird numbering on that lnbf. Most either have just small and large lines (small line equals 5, large equals 10). I've seen a few with actual 10, 20 etc on the large line with the 5 degrees in between just being a small line. I've seen others with just a single mark in the middle which you move using the scale on the lnbf holder (like the numbers on your holder). I've never seen one numbered 1, 2, 3, 4, etc like yours before.
In any case, yes focus on the 0 (▲ mark) of your lnbf holder as being the spot you want to rotate your lnbf to to get your desired skew. So, if you rotate the lnbf in it's holder so that the red line I put on your drawing lines up with the 0 on the holder then you will have it skewed clockwise to 23.9 degrees like you mentioned was needed in post 25.
Skew itself can be very confusing when starting out. I've seen many sites use different ways of doing and referring to it. Some skew it facing the dish, some skew it as looking from behind. Some say skew left/right, others clockwise/counter-clockwise... The whole thing can become a mess of conflicting info in your head.
According to me, the LNB in the left picture of message #27 would have a skew of about minus 15 degrees.
As I have no idea what you meant with "smaller side", I don't know if that is contrary to what you or FTA4PA said, or not.
Are you east of 97W, or west of 97W?
As I have no idea what you meant with "smaller side", I don't know if that is contrary to what you or FTA4PA said, or not.
Are you east of 97W, or west of 97W?
Hey man!
Let's not get all uppity over skew. It's a bit easy once you get a grasp. Tear out and go look at any dish mounted on a house around you. See the angle it's tilted at? There's your correct skew direction, Mister.
The difference in your setup and theirs is the whole dish is turned because the lnbf is mounted stationary. It is mounted permanently at 0 degrees in relation to looking at the front of the dish as if it was completely level.
Yours is bolted to the pole with the lnbf arm perpendicular to the pole. Yours (dish) doesn't rotate.
To get your skew angle, you spin the lnbf in its holder. If your neighbors dishes are cocked clockwise looking at the front of them. Your lnb will spin in the mount in that same direction.
Yeah?
As far as offset angle goes. It was mentioned that if your dish were oriented so that if you look at the side of it on the pole, and the reflector face was perpendicular with the ground. It's already really "looking" at the advertised 24.62 degrees up in the sky. So if dishpointer tells you a sat is (97W) 37 degrees elevation.......
And you took a regular construction transit leveled and zeroed and calibrated to true north, set the azimuth where dishpointer tells you to. And spin the optics up in the sky.....37 degrees. And squint real, real hard. There's 97W right in the crosshairs.
BUT. Your dish is already looking up in the air 24.62 degrees with the face of it....take a string with a weight on one end. Put the string over the top of the dish and it should just touch the bottom of the rim closest to the ground.
Look at the scale on the side of it. Does it say 0 or does it say 24 degrees?
24 degrees?
So if you parked the satellite across your yard dead nuts the same height as the dish center.
You would have to tilt the whole dish negative 24 degrees with the lnb pointing more towards the dirt.
If your scale says 24 degrees, do the math. You're already pointing up in the sky by that amount.
So you need to go up how much more to aim an actual 37 degrees???
If the scale says 0. You got it. tilt it back to the actual dishpointer angle. But still consider it a politician protractor. They all lie as much as they can get away with.
Skew later on will help you to peak your signal. As long as you're real close to what it's supposed to be at first.
Your big job will be signal searching, Tilt up, turn it left and right.....slowly in minute amounts. Tilt down, do it again. Tiny changes. BTW. 99W has screaming strong transponders for the AFN stations. A good place to try to snag a signal while figuring out where 97 is.
Let's not get all uppity over skew. It's a bit easy once you get a grasp. Tear out and go look at any dish mounted on a house around you. See the angle it's tilted at? There's your correct skew direction, Mister.
The difference in your setup and theirs is the whole dish is turned because the lnbf is mounted stationary. It is mounted permanently at 0 degrees in relation to looking at the front of the dish as if it was completely level.
Yours is bolted to the pole with the lnbf arm perpendicular to the pole. Yours (dish) doesn't rotate.
To get your skew angle, you spin the lnbf in its holder. If your neighbors dishes are cocked clockwise looking at the front of them. Your lnb will spin in the mount in that same direction.
Yeah?
As far as offset angle goes. It was mentioned that if your dish were oriented so that if you look at the side of it on the pole, and the reflector face was perpendicular with the ground. It's already really "looking" at the advertised 24.62 degrees up in the sky. So if dishpointer tells you a sat is (97W) 37 degrees elevation.......
And you took a regular construction transit leveled and zeroed and calibrated to true north, set the azimuth where dishpointer tells you to. And spin the optics up in the sky.....37 degrees. And squint real, real hard. There's 97W right in the crosshairs.
BUT. Your dish is already looking up in the air 24.62 degrees with the face of it....take a string with a weight on one end. Put the string over the top of the dish and it should just touch the bottom of the rim closest to the ground.
Look at the scale on the side of it. Does it say 0 or does it say 24 degrees?
24 degrees?
So if you parked the satellite across your yard dead nuts the same height as the dish center.
You would have to tilt the whole dish negative 24 degrees with the lnb pointing more towards the dirt.
If your scale says 24 degrees, do the math. You're already pointing up in the sky by that amount.
So you need to go up how much more to aim an actual 37 degrees???
If the scale says 0. You got it. tilt it back to the actual dishpointer angle. But still consider it a politician protractor. They all lie as much as they can get away with.
Skew later on will help you to peak your signal. As long as you're real close to what it's supposed to be at first.
Your big job will be signal searching, Tilt up, turn it left and right.....slowly in minute amounts. Tilt down, do it again. Tiny changes. BTW. 99W has screaming strong transponders for the AFN stations. A good place to try to snag a signal while figuring out where 97 is.
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A picture is worth 1000 words. Please post a picture of your dish pointed to where you think 97W is. Here is my dish. 97 is a strong bird. Don't work about skew. +/- 20% will get you a signal.
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Ahh cool. You have a polar mount, so the dish skew shown in the pic may blow the OP's cookies.
Do you happen to know or have resources to who made your dish? I take it you don't have the degree scale still on it and if you do (unlikely) what it's reading?
It's a Prodelin .98M dish modified to a polar mount. The .98 meter reflector contains a 16.14° elevation offset look angle. 97W here has a elevation of 35.2. Hey OP, post a picture!
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