I thought with all the building of puters and engineering talent here that maybe I could get some
insight in how to get this satellite dish working.
Hutch - If this is to far off topic, delete please.
First my sob story. A tree fell on my 8' Orbitron and wiped it out. I was left with the pole and the actuator.
I found a 10' fine mesh dish which I have reconditioned.
After weeks of trying I can't get any signals on C or KU band.
Here are the stats of my setup:
Pansat 2800a receiver
Uniden sq530 (used as a dish pusher - might replace with a g-box)
LNB bsc621-2d (no markings to set focal depth)
Pico-Peaker Model pp1450 (useless to me as I don't know how to work it)
Latitude - 29.1024
Longitude - -82.4838 - giving a polar axis of 29.62 and a declination of 4.20
120" dish width by 19" depth - giving a focal length of 47.36".
LNB is pointing at the center of the dish as close as I can make it with a long stick.
I went on "satsig.net" and entered some values to get the following analysis:
Items with the ??, I have no idea what they mean.
dish azimuth(deg e relative to true North 236.7??)
dish azimuth(deg e relative to magnetic North 240.37??) (how do I measure this?)
slant range(km) 37957.86? (how does this apply to me)
polarization tilt(deg) 46.91?? (I guess this means turning the LNB 46 degrees to
the right facing the dish from straight up)
polar axis 29.73 OK
polar declination 4.21 OK
dish elevation (deg) 37.73?? (Is this set with a long bar set vertically across the
face of the dish?) If so it is not the addition of 29.73 + 4.21 which equals 33.94)
No local guys to help with this as I am willing to pay for some help.
are you in Florida ?
http://www.dishpointer.com/
Hi Dedndave,
Thanks for replying.
Yes I am in north central Florida.
I know about those sites and they don't help with my problem.
I know my lat and long. and they are correct.
Also my main axis angle is correct and so is the declination.
I got those from several places like "Sigsat.net".
The LNB polarization is a probable.
No markings or directions for installing to be found anywhere.
I think the focal point is also correct.
tell us which "bird" you are trying to hit :bg
i had to do this a couple times, but i had a spectrum analyzer to see and peak the signals (i.e. i cheated) :P
it can be frustrating because, nowdays, there is a bird every 1/2 degree across the sky
according to this image, your magnetic declination is ~4 degrees,
so - the difference between true north and magnetic north looks about right
http://upload.wikimedia.org/wikipedia/commons/2/28/Mv-world.jpg
the slant range is the distance from your dish to the bird
that value is of little use, other than it is interesting
it might help if you wanted to draw the triangle or do the other calculations manually, though
it is the hypotonuse of the triangle
as for spotting north (either true or magnetic), i usually try to find some landmark that is visible from the antenna
the farther away it is, the more accurate your result
then you can use google to get the exact azimuth of that landmark from your dish
use that to "calibrate" your dish azimuth
it helps if your dish has azimuth markings on it
if not, you can scratch a few marks across the rotating parts if you want
you want to aim the dish roughly WSW (240.37 degrees from true north)
Quotepolarization tilt(deg) 46.91?? (I guess this means turning the LNB 46 degrees to the right facing the dish from straight up)
you got it - rotate the LNB ~47 degrees clockwise (as the bird sees the dish)
http://www.satsig.net/polangle.htm
the dish elevation is the angle between your dish and the ground
it may not add up the way you think (it confused me until i drew the triangle)
nice house you have, there
being in Arizona, i really miss the green trees
(http://img710.imageshack.us/img710/6809/shankle.jpg)
oh - the focal point is the distance from the center of the dish to the dipole part of the antenna
(that would be the base of the horn, roughly)
Pico-Peaker PP1450 instruction sheet (aka The Sky Peaker+)
http://www.satelliteguys.us/attachment.php?attachmentid=39604&d=1247682989
Thanks Dedndave for replying.
Spector Analyzer is Cheating :bg
Must be nice.
I am trying to pull in birds from 55 degrees to 121 degrees.
There are no markings on my dish. It is probably 20 to 30 years old.
Still don't understand the 240.37 degrees from the north. North is 0 degrees. Right?
That's 60 degrees west of due south. Can't be. 4 or 5 degrees past 180 degrees maybe.
If you are familiar with the BSC621-2d LNB, does the mean the label is 46 degrees right
of vertical. No other marks on it. Or does that mean something inside the feed horn?
They have pictures of it plastered all over the net.
You got my house - what you can see of it.
Think I have the focal point correct. Azimuth seems to be my nemesis.
Dish elevation - where do I set that. Big bolt on back sets the angle of the rocker
arm. Axis angle at 29.73 degrees. Big bolt on front of rocker arm sets the declination (4.20).
Add the two together and that is the angle of the plate on the back of the dish 33.94.
Sigsats figures and mine differ slightly but so small I can't adjust that fine anyway.
Thanks for the pdf on the Pico Meter.
i see what you mean
reading up a little - it seems to be a strange unit
some of the guys reported it sux for Ku band
i don't think they had it hooked up right or, perhaps, they did not have a compatible reciever
http://www.satelliteguys.us/c-band-satellite-discussion/207512-bsc-621-a.html
http://www.satelliteguys.us/c-band-satellite-discussion/189414-bsc621c-2-a.html
37.73 degrees (your satsig spec) is a relatively long way from 33.94 (what you appear to have)
3 degrees will kill ya totally - lol
get it as close to 37.73 as you can - then use the meter to fine tune
of course, this will change for each bird
if you have both motors (azimuth and elevation), it may take some adjustment to get it to work right on more than 2 birds
there is a lot to getting it set up
you have to get the reciever set up correctly for the LNB you have
AND
get the motors to track the arc across the sky
i never had to mess with those, the ones i had to align were fixed
i was working for SSE Datacom (formerly Fairchild Data)
we had one dish for video conference calls and another for internet
of course, there were other guys in the company (back east) that i could get ahold of if i got stuck
seeing as we were in the business of building satellite data modems, we had a few experts on hand :P
the spectrum analyzer made it easier, of course
not only could i see changes in the signal strength, but i could identify most of the signal types by looking at the sidebands
TV signals look very different from data signals
as for the azimuth of 240 degrees, that may be correct for one of the many birds
the arc goes from one horizon to the other - there are birds all along the arc
that angle is specific for one of the birds - that is why i asked which bird it was
I'm still befuddled about the dish elevation of 37.73.
This is the procedure I followed.
1. set the rocker arm to 29.73 degrees.
2. added 4.21 to 29.73 giving 33.94.
This was the angle that the back round center plate had to be adjusted to
(using the big bolt in the front of the rocker arm) to get the declination to equal 4.21.
I know of no other way of doing it. As you see I am rather confused.
Maybe the 37.73 is measured on the face of the dish with a straight edge
and inclinator giving the correct declination?
Yes, each end point has to be adjusted for the arc.
So am I not right about the magnetic North being just 3 or 4 degrees right of true north
at my Latitude?
Yes I know about the sateliite guys site. I have a long post there titled
"can't align a 10' satellite dish" in the c-band forum. They didn't want
to come down to my level.
ok - the 33.94 degrees is probably the correct angle for some "reference bird"
that angle will change as you track the arc across the sky
when you punched in your numbers to get the values in your first post, you must have specified some bird as the target
which one ?
i know you want to get all of them, but it makes a difference - you will get different azimuth/elevation for each bird
if you want to get a visual idea of how the arc tracks across your sky,
you can get azimuth and elevation numbers for several birds (at least 3)
for us, the arc is an elipse from just south of the east horizon to just south of the west horizon
in order to set up the antenna so you can get all of them, you need to track that arc all the way across
i wish you'd invite me over for a beer - it would be much easier to explain in person - lol
your magnetic north is 3.67 degrees west of true north
so, if you start from magnetic north and go clockwise 240.37 degrees,
you will wind up at the same azimuth as if you start at true north and go clockwise 237.7 degrees
i get a different declination angle for you from diskpoint.com
it says your magnetic north is 4.8 degrees west of true north
Here is where I got my feet wet: "satellitehelp.com".
My Latitude is 29.1024 degrees. The polar angle is just a fraction more than my latitude.
29.62. The chart on satellitehelp.com shows a declination of 4.20. The face of the dish
or a flat place on the back then must be 29.2 + 4.20 = 33.82. This is slightly different than
what shows on "sigsat". Have no idea why. These settings were made when the dish is
due South and at the highest point of the arc. This for me is about 82 degrees and
satellite nimik 4. A KU bird. Can't align on a KU bird 1st as they are more sensitive than
the C-band satellites. The declination is fixed with a big bolt and doesn't change with
the movement of the dish. However the face of the dish does changes as it is moved
from west to east.
To get the figures that I got on satsig I entered -119 for echostar7 and 29.1034 and
-82.4838. I agree by entering other satellites the dish elevation changes.
The other values remain the same.
To my understanding declination has nothing to do with true north or magnetic north.
So I am still confused about azimuth. A 3 or 4 degree west of true north should be my
magnetic north. The other stuff confuses me.
I will follow this with a bunch of azimuth and elevation figures for a lot of birds.
You can have 3 or 4 beers if you just happen to be this way.
Just a short bike ride from Arizona. :bg
well - i am using the term "declination" to refer to the difference between magnetic north and true north
perhaps, in satellite lingo, the term "declination" is used to mean something else
if that is the case, i can see why you might be confused
the declination i am refering to is a kind of correction applied to azimuth
it sounds like you are applying a correction to elevation
let me look into it further tomorrow and we'll see if we can't clear it up
it is good to have a few of the birds you want - we can use those to get some points
Yes, I am having trouble with terminology. I see what you are saying and my declination
understanding is shown in the one on satellitehelp.com.
Maybe I am also having problems with the word elevation.
Here are a few birds:
bird degree elevation
intelsat 805 55 44.62
amazonus 1 61 48.97
telstar 14 63 49.86
amc6 72 54.14
echostar 1 77 55.52
nimik 4 82 56.05 (this is almost directly overhead at my latitude)
amc 16 85 55.94
nimik 1 91 54.78
galaxy 3c 95 53.36
amc 4 101 50.42
echostar 10 110 44.62
xm 4 115 40.89
echostar 7 119 37.73 ( used this one to get values on satsig)
echostar 9 121 36.11
So by putting a straight edge on the face of the dish I should be able to tell what
degree and satellite the dish is pointing at. Right? Then all I have to worry about is azimuth.
The Uniden pusher is so old that the sats are obsolete and all I have is a click count.
I probably should replace it with a G-box.
However the elevations seem backwards to me. The steepest face slope of the dish
is at its extreme west position and extreme east position. What do I know.
here are 9 birds i got from dishpointer, according to their "10 most popular" list
one of them was Nilesat at 7 degees W - you probably won't get that one :P
Address: Latitude: 29.1024°, Longitude: -82.4838°
Satellite: 91.0W - Galaxy 17, Nimiq 1, Nimiq 2
Elevation: 54.8°
Azimuth (true): 197.1°
Azimuth (magn.): 202.1°
LNB skew: 14.9°
Distance: 36797km
Satellite: 119.0W - DirecTV 7S, Echostar 7
Elevation: 37.7°
Azimuth (true): 236.7°
Azimuth (magn.): 241.7°
LNB skew: 46.9°
Distance: 37961km
Satellite: 110.0W - DirecTV 5, Echostar 10, Echostar 11
Elevation: 44.6°
Azimuth (true): 226.9°
Azimuth (magn.): 231.9°
LNB skew: 39.7°
Distance: 37443km
Satellite: 97.0W - Galaxy 19
Elevation: 52.5°
Azimuth (true): 208.0°
Azimuth (magn.): 213.0°
LNB skew: 24.2°
Distance: 36930km
Satellite: 61.5W - Echostar 3, Echostar 12
Elevation: 49.0°
Azimuth (true): 141.7°
Azimuth (magn.): 146.7°
LNB skew: -32.8°
Distance: 37148km
Satellite: 82.0W - DirecTV 3, Nimiq 4
Elevation: 56.0°
Azimuth (true): 179.0°
Azimuth (magn.): 184.0°
LNB skew: -0.9°
Distance: 36727km
Satellite: 121.0W - Galaxy 23
Elevation: 36.1°
Azimuth (true): 238.6°
Azimuth (magn.): 243.6°
LNB skew: 48.2°
Distance: 38092km
Satellite: 123.0W - Galaxy 12, Galaxy 18
Elevation: 34.5°
Azimuth (true): 240.4°
Azimuth (magn.): 245.3°
LNB skew: 49.4°
Distance: 38229km
Satellite: 107.3W - Anik F1, Anik F1R
Elevation: 46.5°
Azimuth (true): 223.6°
Azimuth (magn.): 228.5°
LNB skew: 37.0°
Distance: 37312km
one thing i am noticing here - they are not all on the same arc
things must have changed in the last 15 years :P
probably got crowded
but, i am guessing your reciever takes care of all that, assuming the dish is set up correctly
the dish should point to the lower elevations at the east and west ends of the arc
for example, the elevation for Nilesat at 7 degrees W (the antenna points just S of E) was about 4 degrees - too low to work, i am sure
it should point to the highest elevation of about 56 degrees when you point it south to get Nimiq 4
if that isn't the case, then something is terribly wrong - perhaps some wires are crossed
I can at my latitude only get the eastern most sat called intelsat 805(55 degrees) and western echostar 9
(121) degrees.
I have also noticed that with each sat the Polarization changes. That means I have the polarization
set incorrectly for two reasons. 1. I should move the dish straight up to 82 degrees and then set
the polarization to 0.87 degrees right. 2. I set the polarization to 46.91 without knowing where I
was on the arc. HOWEVER, I can't reach the LNB when it is straight up. I don't know where the
dish is pointing when I am someplace else. Also there are no instructions on how to position
the bsc621-2d on any satellite. Is the label the pointing factor or is something inside the feed
horn the pointing factor???????
Nothing is ever easy.....
well - let's start, this morning, with the documentation for the 621's
i found this page which has the basics...
http://www.dmsiusa.com/products.html#c-ku
you may want to find out which version you have:
621, 621-1, 621-2, 621-2D
although the docs for the others may be helpful
i would guess the orientation of 0 degrees skew would be where the C-band unit is at the top (this is not right - see next post)
some of the units may be electrically switched by 90 degrees
i noticed one of the units may be circularly polarized
perhaps you need to find a "best comprimise" orientation and switch it 90 degrees with the reciever
the polarization should not be nearly as critical as aiming the dish
one approach might be to tweak it for the hard-to-get birds that have content that is important to you
then, live with the results on the less important ones - the ones in between will probably be fairly good
but, if you can get one of the birds at the east or west end of the arc, you may try peaking the signal with the meter
that may verify the skew orientation
something else i noticed is the focal point is different for C and Ku bands
that could account for crappy performance reported on Ku :P
this is the home page for that site
on the left, there are a number of interesting links that may be worth browsing
http://www.dmsiusa.com/index.html
here is a pic and description of how one guy oriented his 621
QuoteOn mine, the 1/4" metal rod is Horizontal, when at True South, and the "Connection Box" is on the Lower Left side when looking down at the Dish from behind the LNBF.
(http://www.satelliteguys.us/attachment.php?attachmentid=34962&d=1236689609)
i don't know if he was on a step ladder, or if he dropped the dish at true south :bg
a few other links i found:
http://www.satmancanada.com/BSC621test.htm
http://www.satelliteguys.us/c-band-satellite-discussion/184748-questions-about-dms-didital-c-ku_lnbf-2.html
http://rickcaylor.websitetoolbox.com/post?id=3760493
here is how we adjusted ours...
(http://img697.imageshack.us/img697/812/losa.jpg)
don't drop that wrench !!!
attached is an updated list of 18 birds
i added the ones from your list that my list did not have
and i re-ordered them by location
it does appear to be a single arc, afterall :bg
now for declination
it is indeed a different term - i appologize if i introduced confusion
i should have qualified my use of the term as "magnetic declination"
http://en.wikipedia.org/wiki/Magnetic_declination
for satellites (and for star-gazing), the term "declination" is used quite differently
http://en.wikipedia.org/wiki/Declination
from what i can interpolate from the tables, the "modified" declination correction angle for your latitude should be 4.23 degrees
that is even more confusing because it isn't far from the magnetic declination for your location - lol
here are a couple pics and some useful links to help understand...
(http://www.mbcsatellites.co.uk/wp-content/uploads/2008/10/drawing.jpg)
(http://img405.imageshack.us/img405/9043/adjarcsr.jpg)
http://www.geo-orbit.org/sizepgs/decchartp.html
http://www.mbcsatellites.co.uk/tag/motorised-dish/
http://www.geo-orbit.org/
http://www.geo-orbit.org/sizepgs/tuningp4.html
Magnetic Declination
here is a java script from NASA for determining the magnetic declination angle for a given location and date
http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp
for your location, it is currently 5° 2' W, changing by 0° 5' W/year
or 5.03 degrees W of true north
Thanks for all the pointers.
Some I've seen before and some I haven't.
I got dizzy just looking at those guys up on that tower. :bg
I doesn't do me any good at my latitude to point the dish straight up and try to get
a signal on nimik 4 (82) as it is KU as I haven't been able to get any C-band yet.
Tried the Pico there and it sat at the right.
Got to be the bloody LNB settings. I got the focal point of the lnb set to 46+ inches
from the center part of the dish. One of your references got me confused again.
They talked about f/D. In my case that's 47.36"/120" = .39. I interpreted this as
moving the lnb .40 inches past the scalar ring. Never heard of this before and I haven't
tried it yet.
As of right now I am nowhere.
i don't know if you saw this or not
it shows the focal points for the 2 bands
one of the guys i saw wrapped some tape around the focal point to mark it
then aligned the tape with the scaler ring
(http://img6.imageshack.us/img6/1874/focalpt.jpg)
if you can get 2 birds at the ends, but nothing in between, it might suggest a declination problem
but - that does not mean that the elevation is not also set wrong
another comment that i have seen more than once...
once they get it set up, moving the LNB in toward the dish slightly seems to help
that is probably because the aim is not quite as critical if the feedpoint is not at the focal point
moving the LNB in like that has the effect of widening the "beam" a little
you capable of creating a satelite that flys in space dave? :bg
lol - i have worked on a few little satellite pieces here and there (microwave)
and earth-bound high-speed satellite data modems
i also did some work on the space shuttle electronics at Sperry
a box we called "SRB/MDM" - solid rocket booster multiplex-demultiplex
no - it had nothing to do with the O-rings :P
we were sweating a little during the investigation, though
NASA design and quality specifications are far more stringent than military specifications
i don't like working on either - because of all the bureaucratic bs
My latest blunderings today.
Think I finally got the bsc621-2d lnb installed correctly.
Thought that would solve my problems
DMSI painted the polarization mark the same color as the rest of the lnb. Brilliant..
Very hard to see if you don't know where to look for it.
Still can't bring in a single thing.
I beginning to wonder if maybe the bsc621-2d is not compatible with the Pansat 2800a receiver.
Have no idea how to find out.
with the "-2D" version, you cannot use 22 KHz to switch bands - the "D" stands for dedicated
that means you need an external coaxial switch to switch bands
on the plus side, it should provide a little better performance
it does use 13 or 18 volts to rotate polarity 90 degrees
i am going to guess your problems are still in correctly aiming the dish
Don't think I ever had a 22 khz switch. My previous setup had 2 norsat lnbs, c/ku and worked
but not great.
Yes, I am still having problems aiming the dish. The Pico isn't helping much.
There is a gentleman in Ca. that has an arc set he sells to put your dish on the arc.
I haven't bought one but he told me that if I went west till the face of my dish is 52.25
degrees that would put me on the arc. Trouble with western sats is there is no C band there.
And it's far to early for me to be looking for ku. I'm talking about echostar 7 at 119 degrees.
Two questions that might solve my problems.
1: Focal Point
dish width = 120" - D
dish depth = 19" - d
DxD= 120"x120" = 14400
16xd = 304
f = 14400/304 = 47.36"
f/D = 47.36/120 = .38"
should the lnb be set to 47.36" from the center of the dish?
OR
should the lnb be set .40" past the scalar ring?
2: elevation of the rocker arm
my latitude is 29.1024
my rocker arm is set to 29.62 (at the present time)
declination - 4.21
29.62 + 4.21 = 33.83
should it be set to 90 degrees minus 33.83 = 55.17?
I have read conflicting directions and it is very confusing.
1. Focal Point
Refer to the picture in this post:
http://www.masm32.com/board/index.php?topic=13760.msg108295#msg108295
Notice that the focal point for C-band is a couple inches back from the front of the horn.
That point on the LNB should be 47.368 inches from the deepest (center) point of the dish.
I have seen a few threads where they report slightly better results
with the LNB moved in toward the dish slightly from that point.
That could be for a number of reasons, for example, they do not realize
that the focal point on the LNB is not at the face of the horn.
It could also help to acquire signals when the aim is off a little.
Although, tweaking this on one bird may not be a good idea.
If the dish is aimed correctly, you should get pretty
good results by adjusting it as we have calculated.
Keep in mind, these satellites do change position along the arc slightly over time.
Moving the LNB in slightly toward the dish could also help overcome this.
2. Declination Angle
Refer to the first picture in this post:
http://www.masm32.com/board/index.php?topic=13760.msg108279#msg108279
Right away, I do see a discrepancy between what that example demonstrates and
what makes sense to me. So, don't feel bad if you are confused.
First, the motor should point true south. The example shows a motor with a
30 degree bend in the pole. I don't know if that is what you have, but let's use it.
The example says the motor must have an elevation angle of (90-Lat) = 60.8976 degrees.
That seems a little off to me. If you were on the equator, the motor would need to
have an elevation angle of 90 degrees, yes. But, as you travel away from the
equator, there has to be a slight correction, so I don't agree with that formula.
We know the center (true south) elevation angle of the arc at your location is 56.1
degrees. We also know what the adjusted declination angle is for your location.
To me, the 56.1+4.23 = 60.33 degree value makes more sense.
Adjust your motor angle to 60.33 degrees elevation and make sure it points true south.
This is assuming you have a 30 degree bend in the motor pole.
If the motor elevation is 60.33 degrees and the declination is 4.23 degrees, the dish
elevation will be 56.1 degrees when it is aimed true south.
Go to www.sat-toys.com and become a member, instruction to align dishes are there with pictures/examples. Also has automatic calculators based on zipcode to align the dish. Sat-Toys has private boxes to watch direct tv / dish, etc at low one time costs.
Hi Guys,
Thanks for responding.
I have attached a small picture of the rocker arm.
It is in zip format of a .jpg image.
To the best of my knowledge I don't have a motor mount.
Am confused by the term. No 30 degree bend.
Today I will set the rocker arm to 56.17 degrees and the inclination to 4.21
and use the good old trial and error method and see what happens.
I will not mess with the Focal Point yet.
Thanks for the sat-toys site. Will check it out.
great pic :bg
step back so that most of the dish is in the pic and take a few more for us one from the front, side, back
it would be helpful to know what you have
or - maybe you can find a set of drawings of it online
Will send two more pictures as I think they would exceed the limit if sent all at once.
Also I have discarded the setting of the rocker arm to 57 degrees. It would push
the dish into the ground and be way in the trees. This can't be right. I did set the
lnb to .40" out from the scalar ring but still can't get anything.
1 picture attached.
2nd picture.
3rd picture
that last pic helps a little
do you have the manufacturer and model number of the dish ?
EDIT - not the dish, so much, as the mount/motor for it
Don't know what manufacturer made the dish. All I can say about it is it's like that thing
Noah used - ancient 20 to 30 years old.
I actuator is a pro brand ball screw superjack (24")
Woks fine.
i may have found part of our problem
i got the declination angle by interpolating from the table posted above
it must be an old table - lol
dishpointer.com says your declination angle is 4.8 degrees
i used a program from al-soft called Satellite Antenna Alignment and come up with ~4.85 degrees
attached is the report...
you can d/l the program yourself
http://www.al-soft.com/saa/satinfo.shtml
when it installs, it installs some adware called "Relevant Knowledge"
i blocked the adware from installing
i am going to take a closer look at your pictures and see if i can determine what some of the angles are
i will get back to you.....
here ya go
near as i can measure, it looks like you have the inclination angle at about 32.5 degrees
i can't tell for sure - the picture is not square with the bracket, and the top of the bracket may not be level
the angles in the picture are what i think they should be
the inclination angle (top of the polar support) should be 29.1 degrees from level
(http://img97.imageshack.us/img97/7334/anglesc.jpg)
Downloaded the report. Thanks.
The two satellites that I need to get me started are "nimik4 and satmex 5"
Nimik4 ku 82 degrees w
This one is very near the top of my arc here.
I have no idea what azimuth 179.005 is. I need how many degrees west of true north 0 degrees.
Should be 3 or 4 degrees west of true north.
Elevation 56.048. Is this a measurement on the face of the dish?
Satmex 5 116.8 degrees w is the lowest bird I can get that has c-band. The other birds that
are a little lower are worthless ku birds.
I have no idea what azimuth 234.58 is. I need how many degrees west of true north 0 degrees.
Should be 3 or 4 degrees west of true north.
Elevation 39.528. Is this a measurement on the face of the dish?
At the present time the LNB is set past the scalar ring .40" (might be wrong also)
For polarization it is set about 9:30 o'clock. (when dish is straight up)
according to NASA, true north is currently 5.03 degrees clockwise from magnetic north for your location
in the daytime, you may be able to use the sun to find the true heading - there are astronomy websites for that
astronomers use Polaris (the north star) to find true north - that might be another approach - don't trip over the garden at nite :P
56.048 degrees is the elevation above the southern horizon to sight the bird
so, that is 90 degrees away from the vertical face of the dish'
when the dish is straight up and down, the isolation bar should be level across the cavity
you should be able to acquire signal, even if the polarity is off
some of the birds have horizonal polarity - some have vertical - it should not be that critical
The figures on the image are very close to how I have them set. Hard to measure
fraction of a degree with an inclinometer.
Never thought to check bracket A for level. Will do that tomorrow. I checked the sides
of the polar mount for level with the inclinometer.
Still have problems with terminology.
How and where do I set the 56.048 elevation? Or is this something that occurs
as I rotate the dish?
What is the "Isolation Bar"?
Think I can now hack the magnetic North . Thanks.
I know the questions are elementary to you but I am a true novice at this.
Actually my 2nd time. How I ever did it the 1st time is a mystery. It was an
Orbitron 8' with a manual. I am not looking forward to doing this the next
time a hurricane passes by. Maybe another tree.
we can make fairly accurate measurements with the camera
if you put a bubble-centered level in the picture nearby, we can use that as a reference line
it is important that you put the dish at the center of the arc (high point)
it is also important that the camera is perpendicular to the polar mount and at the same height from the ground
if the camera is tipped (rotated cw or ccw) a little, that won't matter
we can use the pixel x,y positions to calculate precise angles with a little trig
oh - don't get too far away - the more pixels, the more accurate the calculations
don't get too close, either - i need to find a few points
if we wanted to get fancy, by knowing the turns per inch of the adjustment bolts and a few other measurements,
we could calculate how far to adjust the bolts (how many turns) to get the angles we want
the 56.05 degree elevation is the angle of an imaginary line from the center of the dish to the satellite
the angle of that line above the horizon (i.e. level line) is the elevation of the bird
if you add the angles together in the pic, you can come up with 56.05 :bg
calculate the angle of the back of the dish: 29.1 + 4.85 = 33.95 degrees
that angle is 90 degrees (perpendicular) from the imaginary elevation line, so 90 - 33.95 = 56.05 degrees :U
something to notice about the declination angle - not important to know, but interesting
for imaginary "birds" on the east and west horizons, the declination angle is the diff between e/w and the resulting azimuth
so, if there was a bird at the east end of the arc, on the eastern horizon, and you pointed the dish at it,
the resulting azimuth of the dish would be 90 + 4.85 degrees (4.85 degrees south of true east)
likewise, at the western horizon, the resulting azimuth would be 270 - 4.85 degrees (4.85 degrees south of true west)
in the center of the arc, the elevation is 56.05 degrees and true south
those 3 points define the arc
also interesting - they call the band of satellites the "Clarke Belt"
it was Arthur C. Clarke (one of my favorite authors) that theororized that satellites at a precise altitude would be geo-stationary
he said that 3 satellites at 120 degree points around the earth would give full coverage
not bad for a science fiction writer in 1945, eh ?
it was Arthur C. Clarke and Stanley Kubrick that wrote "2001: A Space Odyssey"
the isolation bar is inside the LNB - refer to the pic in this post:
http://www.masm32.com/board/index.php?topic=13760.msg108262#msg108262
he also said that, as he stood in front of the dish, the Ku band convertor was at 45 degrees down and left
this adjustment was made with the dish at the center (high point) of the arc
getting the focal point right is far more important than getting the polarization right
Ok, I'll drag out the camera tomorrow and try to follow your instructions.
I'll also put the lnb back to 47.36".
I guess a good distance from the polar mount would be 5'.
Chuck's site won't let me send a pic with to many pixels in it.
I've been cutting them down on purpose.
Can't get to the lnb when it's pointing straight up.
When it was straight up I put a mark at the bottom of the scalar ring.
That orients the lnb at about 9:30 when pointing straight up.
Lined up the polarization that way. Might be off a tad.
i will send you a PM with my e-mail address
you can e-mail me the pictures
some of the pics i post in here are on my imagehost
for that, i use:
http://www.imageshack.com
you can create an account there (for free) and host large pics that way, too
i got your e-mail, Jack
you forgot to attach the pic :P
don't feel bad - i do it, too
Jack and I weren't having much luck with the photographic method, sooooo......
this is another method
you can mark Point C in the grass with a nail or something
(http://img341.imageshack.us/img341/2289/newmethod.jpg)
let me know if further explanation is required, Jack
once you understand this method, it can also be used to measure the declination angle :U
for your location, Angle P should be (90 - 29.1) = 60.9 degrees
I have junked my 10' c/ku dish.
It evidently was just worn out and causing alignment problems no end.
I have another 10' c-band hook feed dish in what looks like good shape.
The mesh on this c-band dish looks about the same as the 10' c/ku dish.
Hate go to the trouble of hanging it and then finding out the mesh is to
large for KU reception.
So, how about this idea.
Take the mesh from the old 10' c/ku dish and wire it somehow to the c-band dish.
Wiring ideas would be appreciated. Is this feasible? Not sure how taking the
c-band dish apart will effect the hook feedhorn.
for Ku band, the holes should be under 1/4"
but, if you can't get C band working, that isn't the issue