true south(g10r) & south san francisco

[ajm]

equipment: pansat 2500a,fortec 80cm dish with hh motor

what tp. (strongest) should i use to get a hold of g10r?

[ajm]

having trouble getting my true south sat ... which is g10r... using 31" fortec dish...need your advice of trouble shooting must in do?

[wejones]

Originally Posted by ajm

having trouble getting my true south sat ... which is g10r... using 31" fortec dish...need your advice of trouble shooting must in do?

It would help if you'd say what you have done, otherwise all that can be said is to follow the instructions on the Sadoun web page. Re G10r , just tune to one of the active known transponders, like the 11720/27692 transponder.
Usually the true south sat is relatively easy to find. Just make sure that you keep the latitude adjustment on the motor relatively close to the theoretical, which means that the angle of the shaft that goes through the motor (not the bent part) should have an angle with respect to the ground of approximatey your latitude plus about 0.6 degrees, if you can do it that accurately. With a big dish, it is usually best to set your declination first, then find the sat using the latitude adjustment, but I think with these little dishes, that it's probably best to do the opposite, ie set the latitude adjustment then find the sat with the declination adjustment, which is the angle set on the dish mount.

[ajm]

dish a 80cm fortec dish mounted on tripod with pansat pm900 motor... i live in south san francisco, ca 94080

[ajm]

what is the lat. value of location?

[wejones]

Didn't you go through this exact problem back in Nov/2004, and didn't you get all sorts of help then got the thing working then? What has changed since it was working?

[ajm]

i moved and its on a tripod now...not on roof

[wejones]

Originally Posted by ajm

i moved and its on a tripod now...not on roof

Since it doesn't sound like your location hasn't changed much,
it would seem like all you'd have to do would be to make sure your pole on the tripod was plumb, and rotate it to aim south. Unless you have made some changes to the angles.

[ajm]

where i'm getting confused is the motor and dish angles ...everything else is cake...

[wejones]

Originally Posted by ajm

where i'm getting confused is the motor and dish angles ...everything else is cake...

The angle at the motor should be approximately your latitude. You can adjust the other angle until you get reception, but unless you've changed it, it should be the same that you had before.

[ajm]

first i'd like to thank u for all your advice...so if my lat. is 37.6 then go to 38...my long. is 122.4... what would be my dish elevation?...this what is confusing...

[wejones]

Originally Posted by ajm

first i'd like to thank u for all your advice...so if my lat. is 37.6 then go to 38...my long. is 122.4... what would be my dish elevation?...this what is confusing...

I'm not familiar with the markings on your dish, however the actual angle you are trying to obtain is approximately -5.4 degrees, if the angle has been set properly on the motor, and maybe closer to -6.0 if not. However the markings on your dish may or may not allow setting of this angle, so you'll probably just have to experiment. However the experimentation should probably be started toward the lowest elevation settings available.
What gets confusing, and this might be different for different mounts, is that the latitude angle is really a 90-lat angle for the aim of the dish relative to the horizon or is just the approximate latitude when measuring the angle of the motor shaft relative to the ground, so it depends on how you measure it. Ie if you are on the equator, the elevation of the dish aim should be 90 deg relative to the horizon or the motor shaft should be zero deg relative to the ground, etc. However, they usually have the markings on the mount so that you can just set it to your latitude. For your latitude, you actually want the shaft through the motor (not the bent part) at an angle of (90- 38.4)=51.6 degs relative to the aim vs the horizon. You then need a declination angle of about -5.3 degrees, which is a negative elevation, ie if the dish was on a vertical pole rather than the motor, the dish would be aiming down. The dish elevation markings won't go negative, however the shaft that comes out of the motor has an angle to it which will help you obtain the proper declination angle, however how you do this is apparently different for each dish/motor combination. You are best off going to the Sadoun installation page http://www.sadoun.com/Sat/Installati...stallation.htm where I think it describes different combinations, or perhaps someone else here has the dish/motor combination that you have.
The angles are further confused because the dish itself aims something like 22 deg or so higher than it appears to aim, so unless you know that angle, you can't easily check your results with an angle meter.
Bottom line is, that you set the motor markings approximately to your latitude (actually should be about 0.6 degree lower), then set the dish elevation by trial and error, peaking to the best signal, although it helps if you are pretty close to start with.
But basically, for your location, the sat is at an elevation of about 46.3 degrees. The 90-38.4 deg latitude setting on your motor gives you an aiming angle of 51.6, which is too high, but subtracting the 5.3 deg declination angle brings you down to 46.3 . But the trick is combining the angle on the shaft of the motor with the settings on the dish mount to get the proper declination angle, and that can be confusing.

[ajm]

thank you... i'll go ahead with your advice

[stockgurubear]

I am in San Jose. 37 is the lat, so the table says that the Elevation on the motor needs to be 53 or set the latitude to 37 and it will be the same thing. The Dish elevation will need to be 30-declination angle, which in this case for your latitude is 5.9. So the dish elevation should be 24.1. Let me know if that helps. I'm new to this and I am just setting mine up. Let's keep in touch in case we have questions for each other.

[ajm]

i will...thanx for your reply

[wejones]

Originally Posted by stockgurubear

I am in San Jose. 37 is the lat, so the table says that the Elevation on the motor needs to be 53 or set the latitude to 37 and it will be the same thing. The Dish elevation will need to be 30-declination angle, which in this case for your latitude is 5.9. So the dish elevation should be 24.1. Let me know if that helps. I'm new to this and I am just setting mine up. Let's keep in touch in case we have questions for each other.

The above looks to be very helpful, but I have 2 minor comments. First, I'm not sure if the original poster ever said exactly which motor/dish he was using, so the 30- declination equation may not be the one to use, since it apparently is different for different motor/dish combinations (although not having one of these small dishes, I'm not exactly sure why). So I'd make sure I had the same setup before using that equation

The second comment is something I hadn't noticed before, and that is that the declination angle chart on the Sadoun site does NOT seem to be correct, with respect to the proper declination angle to use, unless there is something built in to the markings on the dish elevation scale to change them. However, the declination angles listed there are close enough to work in most cases, so for a beginner, it is probably better to follow the Sadoun instructions. However, for those who would like to try getting more exact tracking I thought I'd discuss a slightly better option.
The declination angle listed in the Sadoun site is the actual declination of a sat to the observer's south, and if you use that angle plus the motor elevation angle for your latitude, you will receive the sat to your south perfectly. However, as your dish moves to the east or west horizon, the declination angles to the sats are approximately 0.6 degrees less, so you will be off on your aim by approximately that amount. Since the resolution of one of these small dishes is only about 2 degrees in the Ku band, this 0.6 degrees can, and often is ignored. However to get perfect tracking, within less than 1/100th of a degree and maybe better, if you use a declination angle that is about 0.6 degrees less, ie about 5.3 instead of the 5.9 angle mentioned in this example, you will be better off. This would seem to just make your aim off on the sats to due south, but what you also do is increase the angle on the motor by the same 0.6 deg. Basically the aim to sats to the east/west are not affected much by changes in the latitude adjustment, but are affected by the declination adjustment, so this minor change to the setup can make tracking virtually perfect.
As I said above, this may not be a big enough improvement to be really necessary for a small dish on Ku or a big dish on C band, but it is essential on a big dish on Ku, and it can be a slight improvement for small dishes on Ku, particularly if you are having problems receiving sats near the east/west horizons. The problem, however, is that it may not be possible to actually measure or set angles to the 0.1 degree accuracy requirred to apply this angle, so what I would recommend is to just round off toward the next degree. Ie when setting your latitude, tend to set it closer to the marking for the next degree bigger, and when setting the declination, tend to set it for the next degree lower (when taking into account the sign of the declination in the calculations, ie change it so the dish is aimed a tiny bit higher) . Anyway, I just posted this mainly for educational purposes, and to settle confusion in advance for those who happen upon other web pages that have declination angle tables, such as :
http://www.geo-orbit.org/sizepgs/decchartp.html , which is an excellent web page, and explains the relationship between these angles better than I have. This page is aimed at big dish owners, but can help expain things to those with small dishes.

[stockgurubear]

Sorry, I have a 80CM Forect Dish, Fortec Lifetime Ultra, and SG2100 motor, which in the instruction state the angle should be 30 minus 5.9 for a Lat of 37.2. I'm still learning and I think I foudn true south as I peaked Echostar 121 since it is the closest to my Longitude of 121.77.

[stockgurubear]

AJM, any luck? Also, can you tell me your most Westerly satellite and most Easternly satellite that you can get? This way, it will save me some time. :mozilla_smile:

[ajm]

no...just got back from vacation...going to start oputting it up sometime this maybe even tonite...hehehehe..