Why doesn't this work?

[CenterFreq]

This sounds like a fun Thursday morning project! I can say this though, the motor that moves the dish is working and wired properly. Back when we first tried setting this up, the wires were reversed, and when I tried to move the dish a little East, I jammed it into the West limit. That was fun. I had to disconnect the rod and move the dish a few degrees by hand, then reconnect the rod. Also, I un-reversed the wires, so now *at least* the dish moves in the right direction.

BTW: Lak, can you answer my earlier question; is a signal strength of 68 strong enough to get a channel? My kid wants the Sci-Fi Channel so bad he can almost taste it. Thanks.

 

[Lak7]

Think of "Signal Strength" as an indicator that you have the RG6 cable connected correctly.
You will be looking for Quality.

Can you or Can't you move the Dish?

 

[CenterFreq]

It looks like my late Wednesday night post somehow disappeared, so I'll try again.

If the "Motor Power" wires are the ones responsible for the dish turning East and West, I can say with certainty that they are now correctly wired. They were reversed when we first started this project months ago, and I accidently drove the dish into the West limit physically while trying to turn it East from the receiver. After freeing the dish and reconnecting the rod, I un-reversed the wires and now the dish turns to the direction we tell it to.

I can try to do that continuity check, but I will have to recruit some family help. The BUD is about 16 feet up and the rod is hanging way out past the edge of the roof. I may have to do some kind of scaffold thing.

 

[CenterFreq]

Oops, I should have made this more clear:
* The dish moves fine, East is East and West is West
* The receiver makes a single clicking noise whenever I tell the dish to move
* The receiver always says the dish is pointing at 6699
* When asked to move the dish, the receiver occasionally displays "limit has been reached", but the dish is roughly in the middle of the arc
* On the limits screen, West can be adjusted, East only allows higher numbers to be entered, thereby gradually reducing the amount of East available to me

Question: On the Ku receiver, I can see "meters" for both Signal and Quality. Back to the BUD; Where do I look for C-Band Quality in the labyrinth that is the Motorola's menu system?

 

[eurosport]

Oops, I should have made this more clear:
* The dish moves fine, East is East and West is West
* The receiver makes a single clicking noise whenever I tell the dish to move
* The receiver always says the dish is pointing at 6699
* When asked to move the dish, the receiver occasionally displays "limit has been reached", but the dish is roughly in the middle of the arc
* On the limits screen, West can be adjusted, East only allows higher numbers to be entered, thereby gradually reducing the amount of East available to me

Question: On the Ku receiver, I can see "meters" for both Signal and Quality. Back to the BUD; Where do I look for C-Band Quality in the labyrinth that is the Motorola's menu system?

There are 2 other small wires for the sensor...these send a pulse signal back to the receiver- it counts the pulses to remember what number position each satellite is at. It sounds like either there is a break in these somewhere, or the sensor in the drive motor is bad, making the receiver stay on 6699.
As for the quality meter, you won't see it until you lock a digital signal. Best way is to find Classic Arts Showcase channel on G1-5, when you get it clearly, change to ch 3, and you should get a DCII lock green light and a quality reading in the menu. But this will not be possible, 'till you get the BUD moving properly.

 

[CenterFreq]

Yes, I can see that getting the positioning system to work is critical in C-Band. I wanted to try earlier, what Lak7 had suggested, but the darn dish is so high up, and the rod is sticking out over the concrete. 30 years ago, I used to love climbing up the mast of the USS Ranger to work on the 899 antenna. So high up, I could see the curvature of the earth with ocean all around me. Now I got to be careful because I've lost that youth resilience. I have rented a scaffold, as you can see in photo D89, but I didn't get a tall enough one. As you can guess, I have to stand on the thing and work with both arms extended upward.

In photo D91, you can see the detail inside the cover... now I know what a reed sensor is. I also recognised the two-gang microswitch used for the East/West limits. Now I can clearly see the color of the two wires coming off the reed sensor, and while I am back up there, I will put the ohm meter to the limit switch and try opening and closing both poles in turn, with a small screwdriver.

 

[Lak7]

It's hard to tell, but Pic #2 looks like you might be up to the Limit Switch.

To work on it, you could loosen the Mount bolts and spin the Dish on the pole. Just mark the position before hand.

 

[CenterFreq]

From close up, I can see that neither limit is being reached, although one is much closer to hitting one of the little prongs on the microswitch than the other. I assume the closer one is the West limit, based on observed current antenna position. Both poles of the microswitch are currently resting at normally open position, so I can easily slip a small screwdriver under either one to simulate reaching the limit. Now I have to go up and check out these three things:
1. is the microswitch functioning properly
2. is the reed sensor generating any pulses
3. do the wires pass a continuity check
---------------------------------------------------- up the scaffold ------------------------------------------------
Ok, we're back down. I went up the scaffold, youngest son went up the ladder to the point where I connected new wires several months ago. The box was still two feet over my head, but we cut the blue wire at his ponit and got good continuity on the reed sensor wires. Everything else was difficult because the scaffold is too low. I will be going back to Mr. Scaffold Monday morning, and I'll rent another section for height. While waiting for Monday (and re-enforcements: my middle son will be home), can anyone tell me what instrument to use in order to measure the output from a reed switch? Here's what we tried:
1. disconnected both leads from the reed switch
2. hooked up extension wires to bring the work down to my level on the scaffold
3. hooked my Sperry digital multimeter to the wires, set for 20 volt DC scale
4. called my son on walkie-talkie to move dish East - no noticeable reading
5. set scale to 2 volts DC, tried again - no reading
Okay, the reed sensor probably doesn't make DC
6. set scale for 200 volts AC, tried moving dish again - still no reading, scale too high?
7. I have no lower AC volt range so, what the heck, it's out of the circuit, set to 200 ohms scale
8. called my son to move dish West, did I see a change in resistance? This can't be right
9. called my son, moved West again. It must be the loose connections

What the heck does the reed sensor generate? What are the "pulses" made of?
Do I have to rent an O'scope?
Can somebody give me some guidance on this reed sensor thing? Thanks!!

 

[eurosport]

what the heck, it's out of the circuit, set to 200 ohms scale
8. called my son to move dish West, did I see a change in resistance? This can't be right
9. called my son, moved West again. It must be the loose connections

What the heck does the reed sensor generate? What are the "pulses" made of?
Do I have to rent an O'scope?
Can somebody give me some guidance on this reed sensor thing? Thanks!!

It's a pulse ...while the motor is running. every time a magnet on the little wheel passes the reed switch, it closes the contacts for a split second. This is how the receiver counts to remember the dish position. You should see a resistance drop from an open circuit to a very low resistance with each pulse of the sensor.

 

[CenterFreq]

Wow. That explains why I saw no voltage changes with the reed sensor wires lifted out of the circuit... it was just a momentary closing of a switch. That also explains why I did see a quick change of numbers on the ohms scale. The little wheel rotates very fast; it looks like a hundred rotations for every one on the limit switch assembly. With the little wheel flying around like that, the ohmmeter barely had time to react to the closing of the switch, because it instantly opened again. It all makes sense now. So if I really want to verify the reed sensor, I would need to disconnect the rod and slowly turn it by hand. Then the magnetized segment could be brought right under the reed and the ohmmeter would show zero ohms.

From what I've seen, I'm pretty sure the reed sensor is pulsing properly, so that narrows it down to the wiring or a faulty circuit in the receiver. When I get the additional section of scaffolding, I will be able to see and reach easier into the junction box. While I'm in there, I will disconnect the limit switch leads, and put the ohmmeter to the switch contacts. Using a small flat blade screwdriver, I can then push on the little tabs one at a time to see if the limit switch closes at both extremes.

Thank you so much, Euro, for the explanation of the reed sensor mechanism. I would not have known that there is a little piece of magnet imbedded in that small wheel.

 

[Lak7]

Just to confirm, you can move the Dish East?

 

[CenterFreq]

Yes, the dish can be moved from the receiver, East and West, no problem.

I believe, from a message that keeps appearing on the screen, that we are pointed at G1. I am not in the room with it right now, but as I recall, the message shows up on channel 14, or something just below 14. Signal strength at the current position is 82.

When looking up at the dish, it appears to be sitting 20 or so degrees West of due South. We are located in North Las Vegas.

 

[CenterFreq]

Can anyone tell me if the braided ground wire needs to be connected? As you can see if you enlarge the photo, the cable coming into the box has a braided conductor that is trimmed back to the plastic covering. The reed sensor is only a switch, so it shouldn't care about grounding, but what about the limit switch assembly? Does the receiver need a ground in order to know whether it is the East or the West limit that has been reached? Thanks.

 

[Lak7]

That Grounding wire is connected to the Ground Term on the back of the 4DTV.

 

[Lak7]

Have you been able to get G1 yet?

 

[CenterFreq]

I'm not sure. It may be pointing at W7, based on the static and signal strength. But at least by connecting the ground wire, everything now works as it should, as far as movement and the receiver knowing that the dish is moving.

How does the receiver "know" which bird it's looking at? Remember, this receiver was connected to somebody else's BUD, and had a whole bunch of settings already in when I hooked it up here. Also, as I clumsily poked around in the setup menu, I somehow got the receiver to think that many of the satellites are at 6699, which was also my West limit.

Now the receiver thinks that the West limit is 6700, the East limit is 5874, and the BUD is pointing at 6632. How do I get it all in synch? As I said in an earlier post, the dish appears to be pointing about 20 degrees West of due South. Signal strength is about 86, so I believe I am pointing right at a bird.

There is no picture, just static and snow.

 

[Lak7]

How does the receiver "know" which bird it's looking at?

It doesn't, "you" have to set all that up.
First thing to do is locate G1 (Galaxy 15 @ 133 west) Channel 5. Channel 5 is the "Classic Arts" analog channel, pretty easy to find.

Signal strength is about 86, so I believe I am pointing right at a bird.

Cycle through the Analog Channels, 1-24, see if something pops in.

If nothing, drive the Dish East until the next increase in signal and cycle through the Anaglog Channels again, 1-24, repeat that until you find a channel or the Dish is pointing due south.
Post any Channel you find.

 

[CenterFreq]

I just realized that I may have messed up anyway. All along I have been saying that the BUD and the receiver were new to each other, and that was all I would have to adjust. Then I did something stupid. Taking a cue from the Ku forum, where they often recommend bringing a small TV up to the roof, I took the actuator assembly off the arm and brought it down to my receiver.
That seemed like a great idea. I could see the reed sensor working, I could watch as the limit wheel slowly brought a high spot around to push up on the microswitch tab. I could see index numbers changing on the TV, and all the while the BUD was just sitting up there not moving.
Now it occurs to me, the original installer must have had to align the physical limits by making sure the BUD was all the way East when the East high spot pushed up on the tab of the "East limit microswitch" (for lack of a better name). Once this was accomplished, and assuming West would then also be in the correct position, about 150 degrees away from East, the user never had to worry about *physical* limits, they were already set by the installer.
Since I removed the actuator, and had it spinning all over the arc on my workbench while the BUD sat motionless up on the roof, I have managed to undo the physical part, the installer's part, of the limits alignment.
I will forever be a Newbie. This will be tough to fix.

 

[Lak7]

I'm not following.
Did you remove or Reset the gray Cams that contact the Limit Switches?

 

[CenterFreq]

I had actually removed the entire actuator assembly, right off the arm. But it's okay. To fix the problem, I disconnected the BUD from the arm, ran the actuator all the way West until the limit switch stopped me, reconnected the BUD to the arm, and THEN I accepted whatever index number was offered to me as the West limit. Why not? I was physically, actually now at the West limit.


So now, my new limit numbers are something like East, 6100, West, 7300. If they are *only* index numbers, like relative compass points on a ship, then it should be ok. If I have to deal with true bearings, I'm going to need a better compass.

The BUD is now pointing at around 100 degrees. From out back, that looks more East than West. The receiver thinks I was aiming at W7, but I know that's wrong. And I am getting a whopping set of color bars on channel 8. What bird am I really aiming at? There are no other channels showing up. The problem now is my total lack of experience running a C-band receiver, even though the movent issues are solved.