C-Band, 5' Prime Focus Disshues!

[AmericanZ28]

Im having Disshues setting up an old ECHOSTAR 5' Prime Focus dish with new WSI C-Band LNB, and Coolsat 7000. Using the same LNB, 90cm Offset Dish and WSI Conical Scalar Ring, I manged to BLIND Scan in about 8 channels, 4 of which were duplicates and came in @ 65% quality.

I dont know anything about the dish itself. I bought this dish from an uncle and removed all of the actuator arm hardware as im only trying to pick up one bird (Satmex 5 @ 113). I made sure the mast was plumb, and using an anglefinder at the center of the dish, I set the elevation the same as the OFFSET dish (~71 degrees). Using the default "universal" settings for the LNB on the CS 7000, I tuned it to the channel with the best signal on the previous dish and started to turn the dish side to side (azimuth) to try and find the satellite with absolutely no luck on the quality side. I Calculated the F/D and I think I got that dialed in right.

I kept trying to tweek the elevation, F/D, and Azimuth with no luck. Below are some pics of my setup. Any ideas?

Angle Calculator call for these settings: Satmex 6 @ 113 w
Elevation: 48.7
Azimuth: 156.8 (mag)
Skew: -8.2

Current CS 7000 Settings:
Satmex 6 113 W
LNB Type: Universal (all settings default)

 

[SatelliteAV]

Set the LNB type to Standard, LO 5150 (to eliminate the duplicate channels).
Use the flat scaler and adjust the FD to peak the Signal Quality.

I have played with receiving the SatMex channels with an offset GEOSATpro 1.2M here in Sacramento. Able to lock on several channels, but the FD adjustment was highly critical. Most channels were borderline on the threshold and would not lock in on a Fortec Star Mercury II. Swapped out to the GEOSATpro DSR200c with a more sensitive tuner and maintaining lock.

A larger dish would be useful to provide reliable reception especially during inclement weather.

 

[turbosat]

SHouldn't you be adjusting your elevation too? 71 sounds way too much for that satellite, in fact your calculator listed 48 for the target satellite. Or did you do that already? Remember the prime focus dish is looking about 20degrees or so lower than an offset dish.

 

[AmericanZ28]

Thanks for the advice! Ok, I was confusing the elevation of my GEOsat pro dish with the Prime Focus Dish. I was setting the elevation of the Prime identical to that of the offset using an inclinometer. 71 minus the 24 degree offset of dish puts me close to what the elevation calculator asks for, on the offset dish.

I didnt know I could simply place the inclinometer on the center of the prime focus dish and adjust to exactly 48.7 degrees.

Nonetheless, I raised the elevation some 25 degrees until the inclinometer read 48.7, set the LNB type to Single and LNB Freq. to 5150, and ballparked the azimuth. Ran a blind scan still with no luck. Signal reads 81, so that means the LNB is working, right? Im beginning to hate this C-Band stuff:rant:

Any other tips/tricks?

 

[Tron]

Can you bring your receiver and a small TV or video monitor out with you to the dish site? I find this is the best way to tune dish alignment, if sometimes the most cumbersome. Many battery-powered portable DVD players have video inputs and function very well as monitors. You'll still need to run an extension cord out to the dish to power the receiver though.

The quality meter on most receivers works well for dish tuning. You must select a known, active transponder first, or you will see no quality. I usually do this manually adding the desired transponder, inputting the published frequency and symbol rate. Tune to the newly added transponder while aiming, and you'll soon see quality. I went through this process last week, when I moved PortaBUD over to its new home on 87W, AMC-3 ...

 

[AmericanZ28]

Can you bring your receiver and a small TV or video monitor out with you to the dish site? I find this is the best way to tune dish alignment, if sometimes the most cumbersome. Many battery-powered portable DVD players have video inputs and function very well as monitors. You'll still need to run an extension cord out to the dish to power the receiver though.

The quality meter on most receivers works well for dish tuning. You must select a known, active transponder first, or you will see no quality. I usually do this manually adding the desired transponder, inputting the published frequency and symbol rate. Tune to the newly added transponder while aiming, and you'll soon see quality. I went through this process last week, when I moved PortaBUD over to its new home on 87W, AMC-3 ...

I locked in a few channels with my 90cm mini BUD setup, and used that stored info to try and home in the signal with the prime focus.

Im still confused about the elevation though. There is little information about setting the elevation on a stationary dish here on this site. Seems like everyones talking about true south, and declanation angles, and latitude, but i think thats for motorized setups. Can I set my elevation by simply putting an inclinometer on the back center of my dish and matching it to the elevation of the sat Im looking for? Satfinder says elevation is 48.7 degrees for satmex 6. So as long as my inclinometer reads 48.7 at the back center of the dish, am I in the ballpark?

Thanks in advance!

 

[Tron]

Go to Dishpointer and enter your location and the satellite you are interested in receiving. You will get a Google satellite view of your site, the direction to aim the dish, and an info box that will list the elevation. Using that elevation figure, place the angle finder on the center plate of your dish (Pic #5 in your above post, the part with "Echostar" stamped on it). That should get you the proper elevation reading (or VERY close to it)...

 

[SatelliteAV]

Correct! On a fixed prime focus dish, set the elevation angle of the dish face to the stated angle of the satellite. Your declination angle calculation is not necessary as the dish will not be moving and tracking the arc. Either place a vertical straight edge on the edges of the dish or determine what surface on the rear mount will provide the same angle as the face. The rear angle is only correct if the dish mount is locked in the top (apex) and the declination is set to 0 (zero). This is why I suggest using the vertical straight edge on the face of the dish.

Remember, the elevation angle is approximate, so the dish will need to be fine tuned.

Have you tested the dish to make sure that it is not warped? Stretch two strings from edge to edge, one vertical and one horizontal. Do the strings touch in the center or is there a gap between the strings?

Is the Scaler and Feed horn aimed at the exact center of the dish? Mark the exact center of the dish with a permenent marker. I place a laser level with the beam centered in the scaler opening to first flatten and aim the scaler into the exact center of the dish. Then insert the feedhorn and place the beam in the center of the throat with the level laying on the feedhorn edges and center the laser in the same exact center of the dish

Do you have a clear line of sight to the satellite? I notice that the C-band dish is lower and in front of the 90cm. Are you shooting over the top of your home? Single story or 2 story? Could the structure be blocking the C-Band dish, but not the 90cm? Maybe provide a photo from the dishes looking South?

If you originally had Blind Scanned the channels when playing with the Micro-BUD with the receiver's LO type as the Universal setting and now changed the LO setting to the correct LO (Standard type), the scanned channels will no longer be the correct frequency. So for now, return the receiver's settings to match those used in the Micro-BUD experiment.

Locking onto a C-band signal with this larger prime focus dish should be simpler than with the micro-BUD set-up. I am sure that you will find that it has something simple and when you find the satellite, there will probably be that "DUH MOMENT"!

 

[AmericanZ28]

Thank you so much Tron, and SatAV! Theres nothing obstructing the view of the satellite, it was pointed that low because I was trying to match the angle with that of the KU dish.

So I placed the angle finder in the middle of the dish and adjusted accordingly, defaulted receiver, set correct freq. and LNB type and ran a blind scan. I got one channel It got late and cold outside so I couldn't play with it more, but it was such a relief! Now I have something to go by, and this weekend I will check the dish to make sure its structurly sound and take it from there.

Thanks you guys so much for your help. I searched for hours here and couldn't find the simple answer I was looking for. I will do my part and post a "HOW TO Thread" once i get a chance to take pictures. Thank god you guys set me straight on the LNB freq too, thats something else I wont have to pull my hair out for later!

 

[John Popper]

Thank you so much Tron, and SatAV! Theres nothing obstructing the view of the satellite, it was pointed that low because I was trying to match the angle with that of the KU dish.

So I placed the angle finder in the middle of the dish and adjusted accordingly, defaulted receiver, set correct freq. and LNB type and ran a blind scan. I got one channel It got late and cold outside so I couldn't play with it more, but it was such a relief! Now I have something to go by, and this weekend I will check the dish to make sure its structurly sound and take it from there.

Thanks you guys so much for your help. I searched for hours here and couldn't find the simple answer I was looking for. I will do my part and post a "HOW TO Thread" once i get a chance to take pictures. Thank god you guys set me straight on the LNB freq too, thats something else I wont have to pull my hair out for later!

Please do, cause Im trying to set up a 7 footer I have on a very narrow roof and the whole elevation, azimuth, declination stuff is so difficult for me to understand being that this will be the first time I do it and I have such a small area to play with.

 

[Anole]

I usually recommend this page and its sister pages on the Geo-Orbit web site.
After staring at it 'till your eyes bleed, you'll eventually absorb the secrets.

 

[Tron]

It is always amazing to see a prime focus dish and an offset dish aimed at the same satellite, since the difference in elevation is very noticeable. It is also strange to see an offset dish apparently aimed at a building or rooftop, when it is receiving signal from a satellite above the obstruction.

 

[AmericanZ28]

What a weekend! I spent all weekend "Ghetto Moving" my dish and playing with everything to chase that mythical beast that is Signal Level. So I found that setting the elevation is as simple as taking the elevation setting that you get from a Sat Locator, and elevating the dish till the inclinometer (set on the center base of my dish) reads the requested value. No need to calculate and adjust declanation. JUST LIKE YOU ALL TOLD ME!

For anyone looking to get SATMEX5, these two transponders were the strongest;

Freq: 3858
Pol: Horizontal
Symbol Rate: 2803

Freq: 3779
Pol: Horizontal
Symbol Rate: 6528

I also had to remove the 2 lower scalar ring support arms as they were tweaking the LNB into a weird position that wouldn't allow for peak signal. The bottom of my dish is banged up and dented, so Im guessing this kept the LNB assembly from being parallel with the dish face.

Note in the pictures the difference in elevation between an offset and prime focus antenna. Both are pointed at the exact same satellite.

 

[AmericanZ28]

Ok, posted some how to's for newbs like me here:

http://www.satelliteguys.us/c-band-...ng-elevation-stationary-prime-focus-dish.html

And for Azimuth, this is my tecnique:

http://www.satelliteguys.us/c-band-satellite-discussion/201630-how-setting-azimuth.html

 

[Tron]

Yep, pic #1 says it all. I'd been accustomed to setting up offset dishes for the past 5 years. Then, for the first time, I set up a prime focus dish (my 6 footer). The difference is amazing.

 

[John Popper]

excellent info z28!