Help Needed -- John's "Bring it Back from the Dead" C-Band Project

[jnastasi]

Well everyone, I'm just about out of ideas about what could possibly be wrong with my old C-Band dish. I've run the gambit without much success. Hopefully someone here can chime in with an idea or suggestion .

Background...

Originally installed in the mid 80's, I'm attempting to revive a 10 foot fiberglass dish that has been inop for several years now.

Replaced the froze up actuator with a Thomson Saginaw 24" ball screw, which works like a champ. Replaced the feedhorn with a Corotor II Plus wideband version. Also replaced the Cal Amp C-Band LNB with a Norsat 8115 and Norsat 4106A.

On the inside I've replaced the Houston Tracker V analog receiver with a DSR-922. The Motorola has just been repaired, and had a new battery installed, so should be good to go.

Also ran a fresh home run of Belden 7915A RG-6 into the house, because it looked like the satellite ribbon cable coax might have been sub par. Lastly ... took down a small tree that had managed to grow up in front of my true south satellite over the past 10 years.

Today...

With the DSR-922 back in from ATS Electronics, I decided to hook everything up today and give it a try. The C-Band LNB was connected to the DSR-922 in the house ... and the Ku-Band LNB was connected to my Fortec Dynamic outdoors.

I tried panning back and forth across my true south (Galaxy 17) but never could pick up anything on the DSR-922 or on the Fortec. I had the Fortec on a working G17 transponder when I disconnected it from my FTA dish. Had it set for LO 10750 ... so that shouldn't have been a problem. Also tried switching polarity 90 degrees on the DSR-922 ... which didn't make any difference.

What's weird ... is that my DIGISAT II meter shows a fairly strong signal anywhere I point my dish. It never changes. Likewise ... the DSR-922 always registers in the 60 range ... no matter where I aim. The Fortec stayed at about 40 ... with quality stuck at 0.

Any clue what I could be doing wrong here? And likewise, any suggestions for next steps that would be used to troubleshoot the setup?

I'm thinking ... possibly ...

* Some type of issue or mismatch involving the wideband feedhorn or LNBs?

* The BUD guy that came out a few months back perhaps didn't position the feedhorn (in/out, rotation) correctly?

* The dish itself has gotten terribly out of alignment?

Thanks for any insight you guys might be able to provide. I've attached a few photos just to give an idea of what the setup looks like.

John

 

[stogie5150]

My first step on a dish like this is to string it. Make sure its still holding its shape. If that works out, I'd bring my FTA receiver out to the dish with a TV, and check it out. That's how I did all mine and to me its them best. A lot of the meters, well, they won't tell you a whole lot, unless you have a high-dollar one.

Second, I'd measure from the scalar edge to the edge of the dish in four places 90 degrees apart, to make sure the feed is centered correctly. Other calculations would have to be made to check the in/out, unless you know the make of the dish.

My hunch would be, after all these years, it probably needs a re-aim. Digital is a LOT less forgiving than analog.

If you live close enough, I'd be glad to have a look at it, if you'd like...:up

 

[GreatFTA]

Check the plumb of your pole. Need to be absolutely straight or the dish won't track correctly.
If that pole been there for years, the weight of that dish can make it lean. Plus the winds of storms and hurricanes can do that too.

 

[Lone Cloud]

That bracket your motor attaches to looks strange. It doesn't look centered on the dish. Maybe it's the photo. Did you use different bolt holes when you put it back together?

Also, that button hook holder for your lnb looks weak . Maybe after all those years it got knocked off center. Maybe in your new installation you moved it.
Have you measured from the edge of the dish in a few places to see if your lnb is centered? If so, flex it back to center and try again.

 

[Newbie_McNoob]

Take a receiver and TV out to the dish. That way you can tell if the servo motor is moving.

Also, make sure you have the cables from the LNBs connected to the right input on the receiver. I've made the mistake more than once of connecting the Ku cable to the C input of the receiver and wondered why I couldn't get anything.

 

[jnastasi]

My first step on a dish like this is to string it. Make sure its still holding its shape. If that works out, I'd bring my FTA receiver out to the dish with a TV, and check it out. That's how I did all mine and to me its them best. A lot of the meters, well, they won't tell you a whole lot, unless you have a high-dollar one.

Second, I'd measure from the scalar edge to the edge of the dish in four places 90 degrees apart, to make sure the feed is centered correctly. Other calculations would have to be made to check the in/out, unless you know the make of the dish.

My hunch would be, after all these years, it probably needs a re-aim. Digital is a LOT less forgiving than analog.

If you live close enough, I'd be glad to have a look at it, if you'd like...:up

That's what I'm saying :up The local BUD guy who came out a while back mounted the scaler ring, turned the feed and went "that looks about right". For some reason I was thinking it needed to be a little more precise.

If you plan on making a trip over to Baton Rouge anytime soon, I'd be happy to take you up on that

 

[jnastasi]

Check the plumb of your pole. Need to be absolutely straight or the dish won't track correctly.
If that pole been there for years, the weight of that dish can make it lean. Plus the winds of storms and hurricanes can do that too.

It's funny you mention that. Looking at the pole you would swear it was leaning ... but I've checked it out on three sides with a Johnson angle locator and it seems to be ok.

 

[jnastasi]

That bracket your motor attaches to looks strange. It doesn't look centered on the dish. Maybe it's the photo. Did you use different bolt holes when you put it back together?

Also, that button hook holder for your lnb looks weak . Maybe after all those years it got knocked off center. Maybe in your new installation you moved it.
Have you measured from the edge of the dish in a few places to see if your lnb is centered? If so, flex it back to center and try again.

There are two holes on the frame that you can connect the end of the actuator to, and Dad couldn't quite recall which one he took the old motor came off of. Other than that I think it's ok.

Agreed on the button hook holder. I'm told that a tree limb whacked it during one of the hurricanes, and that the pole was bent back into shape. I'm curious as to whether or not that center pole and feed mount are bent slightly out of alignment. That might be worth checking :up

 

[stogie5150]

There are two holes on the frame that you can connect the end of the actuator to, and Dad couldn't quite recall which one he took the old motor came off of. Other than that I think it's ok.

Take lots of GOOD, clear pics of the back of the dish and post them, someone will be able to tell ya if the actuator is mounted correctly.

Agreed on the button hook holder. I'm told that a tree limb whacked it during one of the hurricanes, and that the pole was bent back into shape. I'm curious as to whether or not that center pole and feed mount are bent slightly out of alignment. That might be worth checking :up

I will almost GUARANTEE you that if it was bent, it isn't right. Buttonhooks are notorious for being out of alignment, mostly by sagging over time, but damage too. Easy way, like I posted earlier, measure with a tape measure from the scalar ring to the outer edge of the dish at four places, 90 degrees apart...scalar to top, scalar to bottom, scalar to left, scalar to right, that will tell you QUICKLY if its where it should be.

As an aside, your feed installation issue, I am not sure of the proper way to put those old 'steam' LNB/feedhorn/servo combos when installing, I use voltage controlled LNB'S on both of my dishes, so they HAVE to be right, on your setup, you have the motorized skew to adjust it out for best signal. Maybe one of the guys that use these type setups can help ya better.

Keep at it! :up

 

[14karat]

Eeew... fiberglas...
Maybe it's just me - but from the photos, the feed seems to be way too close to the dish... but if you're using the original buttonhook, it must be ok... just really, REALLY looks too close...
Must just be a short focal length I guess... but I'm still suspicious...
I'd check all your angles, also focal length.
Make certain the feed is centered perfectly. If you have problems with the buttonhook either out of alignment or wobbling, you can fix that with guy wires to the dish - use turnbuckles for fine tuning.
String test the face of the dish, make sure it's not pouting... if it is, you may be able to pull it back into shape by stringing guy wires across the dish face...
On another note, has the dish ever been used for Ku? It may not be Ku compatible...
For initial setup, I'd forget Ku - just try to get C-band peaked then go after Ku... you'll be pulling your hair out before you get Ku peaked... or it'll just start falling out, like mine...

 

[jnastasi]

Thanks guys!

Will get some better photos of the back side. I was using the BlackBerry that day and my pictures weren't the best.

I'm willing to bet that center pole is a little bent as well. It does look like it's sagging down a tad. Will get the string and tape measure out, and make sure everything is centered.

You could also be right about the F/D 14k. Will check it out. The fact that the signal never changes across the arc has me thinking that the feed is way too far in or out. Will test.

Never been used for Ku-Band. I replaced a legacy Corotor and Cal Amp with a new dual LNB setup.

I'll be out there on Friday ... will check the plumb, take some measurements, check to see if the feed is centered and F/D is correct.

Props to all for the great feedback! :up Will report back after I've checked these things out.