This post was most recently updated on October 2nd, 2019
In today’s post, I shall be posting a comprehensive guide on the tips to a successful BUD installation. BUD is interpreted into different names. To some, BUD means “Big Ugly dish” while to satellite tv enthusiasts, we all know that BUD means “Big Useful dish”. Like I said in my article on the importance of a big dish, the usefulness of a BUD can’t be emphasized. We will, however, limit ourselves to those things you need to cake into consideration when mounting a BUD on a pole.
Definition of Major Terms on Tips to a Successful BUD Installation
“Q” Denotes the quality reading produced by your FTA receiver when it is on an active satellite transponder. The higher the Q, the better the Quality of the received signal. Similarly, The “S” or Signal reading is the electrical connection to the LNB
“Zenith” Is the point in the sky where the satellite arc is the greatest angle above the horizon. It will be located straight south if you are in the northern hemisphere. Straight north if you are in the southern hemisphere.
- Zenith satellite Is the satellite closest to this point, with active transponders on the “band” you are using to align your dish.
The “Azimuth” is the rotational position of the mount on the pole.
- Polar Elevation: Equal to your Latitude, with the reference of 0 on the horizon, or 90 – latitude, if your reference is 90 on the horizon.
- Dish offset angle: This is the Angle produced by mounting the dish, to the polar axis, with the top attachment longer than the bottom. determined by your required DECLINATION, (from charts)
Within the context of BUD installation, Declination is the difference between the polar elevation and the dish offset angle.
Required Specifications for Success with a BUD: Why Must your Dish’s Feed be centred?
- First off, if your feed is not centred, it will affect the angle at which the dish looks. This can be vastly different than the angles you measured to calculate to adjust the declination.
- Another reason why you, on a single mount point feed antenna. That is the button-hook or its variant. At the “zenith”, if the feed sags, it is towards the bottom of the dish, and we can compensate with the polar angle. But, The actual discrepancy is in the declination angle. When we drive the dish off of the zenith, the feed doesn’t sag to the same point on the dish.
That is to say, It’s now sagging off to the left or right of the centre bottom of the dish. This would mean the azimuth would also be off one way for satellites to the east(e.g Hotbird), and off the opposite way for sats to the west(E.g Hispasat).
The elevation is also thrown off by this asymmetric variance. There is no way to compensate for all this. As we are dealing with oo many variables!
- Also, for the feed to be centred has to to with the tripod. On a tripod-mounted feed, if the feed is up or down from center, This will effectively add to or subtract from our calculated declination. You can go to the Zenith sat, and adjust your polar axis angle to compensate for the higher or lower focus angle of the dish.
Then we do the end of the arc, and adjust the AZIMUTH. But when we return to the zenith, where we have to make a large re-adjustment to the Polar axis angle. This may then throw off AZIMUTH on the other end of the arc. At this point, we cannot compensate for the Polar axis angle. compensation must be made with the declination.
Noteworthy: Through much experience and experimentation, compensation can be made to the declination angle. But it is very time-consuming.
- Lastly, If the dish is on the left or right of the center, it will affect only the angle the dish is driven to by the actuator. A very slight re-adjustment of the polar angle and Azimuth may, or may not, be necessary to compensate for this.
2. Here are the Reasons why a Warp Big Dish(BUD) will Cause Problems
Your dish must also be “TRUE” to the size in. To perform the “trueness” of a dish’s test, run a string across the center of the face of the dish. The string must go lip to lip. Next, Run another at 90 degrees to the first string.
Do the strings touch where they cross? If yes, your dish is true. If no, your dish is warped. Now, the amount of warpage can be determined by the space between the strings at the crossing point. If this space is up to an inch, it may not degrade a C band dish performance by much. However, this would have a negative effect on the Ku band. If you want Ku with your BUD, The space between the strings should be less than 1/4 inch. If space is between 1/4 and 1 inch, it will probably work okay on C band, but Ku may be disappointing.
Also, if you realize that your big dish is warped, Weigh your options. Should you Straighten or replace it? Or is the performance “good enough?”.
Furthermore, All initial alignment is and should be done on C band alone. The beam-width of a BUD, at C band, is much wider than it is on Ku. A signal on C may start out at a Q(quality) of 10 and we can tweak the dish left, right, up and down without losing it. On Ku, we may have to be “Right On” in order to see any signal Q(quality).
Also, it is after we have gotten the dish aligned on the arc and operation of C band is acceptable that we can attempt our Ku band installation.
In addition, If the dish is to be reassembled as it was, don’t swap the positions of panels/petals. or sections of the dish. If it has a “Button-hook” feed, a single-pole from the center of the dish, to mount the feed, mark its position, both distance from dish and what is aimed towards the top of the dish.
3. Focal length(F) and Focal diameter(f/D) Calculations
What is a dish’s Focal Length?
A satellite dish is actually a lens, just like in a camera. The antenna is actually in the feed. Now called a “probe”. If you have no clear indication of where the original feed was located, you will have to calculate the focal length and f/D ratio. The image below illustrates how to calculate the F/D or a dish
- f/D example: 10 ft dish, f calculates to 48 inches (4 ft) 4/10=.4. Assemble the feed scaler ring assembly aligning the f/D ratio you calculate, to the corresponding f/D mark on the feed, to the front, or rear face of the scaler. (Refer to manufacturer’s instructions)
- Now, Assemble your feed mount so that the distance from the center of the dish to the feed is the calculated Focal length, MINUS 1/4 inch. Next, get it centred, If your dish is a “buttonhook style, adding struts may be necessary. Aim it for the center of the dish. We want to use all of the dish, not just to one side.
- Refer to the feed manufacturers documents to properly set the LNB skew. Usually, there is a mark on the feed to align the LNB vertically, or horizontally, with the dish. Most feeds with a servo for polarity, require the servo to be 45 degrees to the west of vertical in the northern hemisphere(or 180 degrees from there) or East of vertical in the southern hemisphere
4. Tips to a Successful BUD Installation: The Declination Chart
We must assemble the big useful dish(BUD) with the proper DECLINATION. The important thing we have to know to properly assemble the BUD is your Latitude. North or south of the Equator makes no difference.
Use the chart below to find your Latitude and the Declination angle.
5. Assembling the Declination
Whenever you measure the angles of the polar axis or the dish offset, always use the same reference. Either 0 for horizontal, or 90. It doesn’t matter If you want to measure from the pole just make all measurements from the same reference point.
Personally I prefer horizontal as 0, Once we know what our DECLINATION should be, we can measure our polar angle, Dish mount plane angle, and calculate our declination.
- Furthermore, you should measure the Dish mount plane angle at ZENITH With your dish on the pole. Then, drive the dish to the center of its rotation about the polar axis with the actuator, This is the dishes highest angle above the horizon
- We Then adjust the Declination assembly so that the Polar mount angle and the Dish mount plane angle as seen in the Declination chart angle different.
Note in the figure above that length A is greater than B
- Note also that you may find it easier to place a 2X4 up and down, spanning the face of the dish to measure the Dish mount plane angle. Just remember to use the same reference for both angles. That is; Polar elevation, and dish mount angles. It is the difference, between the two angles, that we adjust to the declination chart angle.
6. Adjusting for the Zenith Satellite on the Big Useful Dish
Zenith is the highest point, from your horizon to the satellite arc. This will always be to your true south if you’re in the northern latitude. Similarly, it will be true north if you’re in the southern latitudes.
Note: In the following, to “drive your dish” means to use the actuator or other the device you use to rotate your dish about the polar axis.
From here on, North and South can be inter-changed, along with East and West.
First off, Drive your dish to the centre of its rotation on the polar axis. Next, adjust your Polar Axis angle according to your Latitude as shown in the following fig.
Important Notice: As a reminder, your horizon can be 90 or 0. Either is correct, just the reference is different. If your horizon is measured as 90 degrees, you need to adjust Polar axis angle to 90 minus your latitude. To explain further:
-IE: lat = 40 90 – 40 =50 Polar axis angle = 50 degrees
-Adjust it to latitude if your horizon is 0 degrees.
7. Tips to a Successful BUD Installation: Finding the ZENITH Satellite
By definition, the AZIMUTH of a dish is the rotation of the mount on the pole. The ELEVATION is the angle of the Polar axis. Polar Axis is the axis of rotation of the dish provided by the actuator.
Now, to search for “Q” on a known active transponder, on your zenith sat, rotate the mount on the pole, slightly east or west, looking for a maximum signal quality reading.
Most receivers will require you to pause after each rotational adjustment, for the Q reading, to be acquired or stabilized.
NOTE: If your Zenith satellite is more than a few degrees East of West from your longitude, you can “fudge” a little, I.E: drive your dish a little east or west.
However, if you are unable to get any Q, slightly adjust the Polar angle up or down and repeat the above.
When you have maxed your Q with slight rotations of the mount on the pole, adjust your polar elevation for maximum Q. This is usually a large turnbuckle or nut and bolt arrangement on the backside of the mount.
After locating our ZENITH sat by rotating the mount, adjust the elevation. for maximum Q, we would like Q to be 40 or more. At this point, do not rotate the mount on the pole (AZIMUTH) at ZENITH again.
From now on, the actuator moves the dish E-W. at ZENITH. So, there is no need to adjust AZIMUTH (E-W), the actuator does it. Consequently, we only need to adjust ELEVATION at ZENITH from now on.
Note: If you are unable to get Q, and assembly of the dish is as outlined, double-check your satellite receiver’s receiver programming. You should also double-check the feed measurements. If that is also correct, suspect an electronic failure.
If you have switches(e.g diSeqc, splitter and so on), remove them, and run the coaxial cable directly from the LNBf to the receiver. Check all connections. Swap out the receiver for a known working unit. You can as well swap out your LNB in some extreme cases.
8. Tips on how to Adjust the Azimuth on a Big Dish
The azimuth of a dish is also often referred to as “the end of the arc”.
To adjust the azimuth, you need to drive your dish so that the actuator retracts/shortens.
Also, watch out for Q on known active transponders on satellites in East or West of your ZENITH sat to determine which direction it is when you retract your actuator.
When you don’t see another Q reading, go back to the last Q indication you had. Peak the reading with your actuator. Take Note of the Q reading. You can also manually rotate the mount slightly East or west.
Along the line, if the Q you had dropped or rotate in the opposite direction. maximise the Q indication by alternately rotating, then driving the dish back and forth with the actuator.
However, if you can’t get Q back to where it was, it means you rotated the mount (AZIMUTH) in the wrong direction.
Repeat as necessary until you get no more improvement. Then repeat this whole paragraph until you’re at the end of the arc.
- When you are not at your ZENITH sat, don’t adjust the polar elevation. Moreover, When we are not at ZENITH, the actuator moves the dish up and down. The further the dish moves from zenith, the more up and down. We, therefore, only adjust the AZIMUTH.
- Secondly, When we have the arc aligned, tighten up the AZIMUTH bolts and drive the dish back to ZENITH and find the ZENITH sat again. If at this point the Q dropped slightly, re-adjust the polar elevation angle. There should only be a very slight adjustment.
- Furthermore, if the Polar Elevation angle changed by more than a degree or two, after returning to ZENITH, you should suspect an off-centre feed, improper declination, loose or sloppy polar axis pivots, or some other mechanical problem.
9. Tips on Feed tweaking for Maximum Performance or Using with Ku Band
Now that you are tracking the arc on C band, If you think it will benefit you, you can try to “Fine Tune” the focal length and readjust the f/D on the scaler.
Experimenting with the F/D for Max performance
This could be time-consuming. Using the calculated focal length, and calculated f/D usually results in very acceptable C band performance.
However, the adjustment made usually isn’t enough to make a significant change to the f/D setting of the scalar ring. This can be accomplished by only moving the feed, in or out, in the scaler.
- If it is a large change, you may want to use spacers to move the feed closer, or further from the dish and readjust the f/D setting on the scaler.
This could be caused by the dish not being a perfect parabola. If it was stored, many years, face down or up, on the ground, the center area could have become “Flattened”. Besides, this could also cause Ku operation to become hard to get working.
- Secondly, if you have a C-Ku feed on your BUD, this could be very beneficial on Ku.
Wire in your band select switch, DiSEqC or 22khz, whatever you use. Program a Ku sat accordingly, and look for signal quality on an active transponder. This is easier if the sat is C and Ku with active transponders on both.
Next, drive the dish E or W slightly, as many BUDs may focus Ku off of where C is focused. Adjust feed in or out for maximum Q. Adjusting the feed is easier if the satellite is close to the horizon. The feed is closer to the ground in most instances.
Also, Polar elevation and Azimuth may have to be “tweaked” slightly. It is of utmost importance that an adjustment on Ku will usually be 1/4 of that you made while tuning/aligning the BUD on C band.
The BUD “sees” the sky 1.5 to 2 degrees up/down/E/W of where it is pointed at on the C band. While on Ku, it may only be .3 degrees or less. This, in all, may decrease your C band performance somehow.
Ultimately, It’s up to you what you determine as acceptable performance.
Articles for further reading
- Beginner’s Guide to how the Satellite TV Works and it’s Scope
- Ways to Fix Satellite Dish Signal loss During Bad Weather – Such as Rain, windstorm, snow
- List of the Latest Free-To-Air Satellite Tv Channels and Frequencies
- How to Manually Track a Satellite Dish Network & Frequencies
- Predetermine the size of dish/antenna to be used for any Satellite TV packages