Got a C-Band dish...now some questions
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pictures of the base on the back
Its just a couple "O" rings and a couple pieces of metal that all get put together. The back bar with the know adjusts elevation
The reason for the sandbag on the back is 38 degrees the dish seems to get a little top heave and wants to tip forward 1/2".This prevents it
Its just a couple "O" rings and a couple pieces of metal that all get put together. The back bar with the know adjusts elevation
The reason for the sandbag on the back is 38 degrees the dish seems to get a little top heave and wants to tip forward 1/2".This prevents it
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Berg, whenever you're using the polarotor, it's possible that imperfect setup might cause one polarity to get better reception that the other. But whenever you're using the DMSI, there's no reason for one polarity to be received better than the other....unless it just so happens that T5's vertical transponders are a little bit weaker (or stronger) than its horizontal transponders).
If you get generally better reception on the polarotor than the DMSI, then I think the reason for that is probably just that the polarotor's LNB is just simply a better LNB than the DMSI one.
T5 and G4 are adjacent to one another. The difference in the skew (on a stationary type mount such as yours) between those two adjacent sats is not enough to matter (in my opinion).
If I were you, I'd just use the DMSI and, when installing it, experiment to find the orientation that gives you the strongest quality DVB signal.
Are you slaving the receivers, or hooking them up one at a time? If you are slaving them, then I suggest you let the FTA receiver control the DMSI's polarity (if you use the DMSI).
Yeah, to me it looks like the signal is definitely blocked from reaching the lower one third of your dish. If you could mount the base up at the height of your railing, then that would solve that problem...but create another one in that that would make it hard for you to work on your LNB. It wouldn't be a problem for me...because I'm six foot six. But I doubt you're that tall.
If you get generally better reception on the polarotor than the DMSI, then I think the reason for that is probably just that the polarotor's LNB is just simply a better LNB than the DMSI one.
T5 and G4 are adjacent to one another. The difference in the skew (on a stationary type mount such as yours) between those two adjacent sats is not enough to matter (in my opinion).
If I were you, I'd just use the DMSI and, when installing it, experiment to find the orientation that gives you the strongest quality DVB signal.
Are you slaving the receivers, or hooking them up one at a time? If you are slaving them, then I suggest you let the FTA receiver control the DMSI's polarity (if you use the DMSI).
Yeah, to me it looks like the signal is definitely blocked from reaching the lower one third of your dish. If you could mount the base up at the height of your railing, then that would solve that problem...but create another one in that that would make it hard for you to work on your LNB. It wouldn't be a problem for me...because I'm six foot six. But I doubt you're that tall.
First and foremost you need to get your dish in a position where it's not obstructed. Although I don't think the obstuction is going to be just blocking out one polarity and not the other (that shouldn't happen) your definitely not going to get good performance that way. A table sounds like a good temporary solution (if properly secured as to be safe) but a good long term solution would be a non-penetrating roof mount of some sort.
As for your polarity issue, I'd think it's either an issue of the feedhorns not oreinted properly, or the receviers not propely controlling the polarity. If the recievers are slaved how are they slaved? Are you using a DC block on the reciever that doesn't control polarity? What about the LNB voltage? You do know that some LNBs that are made for use with feedhorns on C band dishes (and therefore generally use a polar servo to control polarity) are not rated to operate at 13V right? They're generally rated for 15- 24v. That might mean that if you had your FTA reciever connected to them and the reciever was still trying to switch polarity by switching the LNB voltage you might have issues when switching to vertical polarity or 13v. That shouldn't be the case for the LNBF since it's made for 13/18v polarity switching but could be so if your using a polar rotor feedhorn with an LNB.
Another possibility is it could just be coincidental. It could just be that on the transponders your having trouble with there are overlapping frequencies being used on an adjacent satellites and thus your getting interference from those. That's always a possibility with an undersized dish.
As for your polarity issue, I'd think it's either an issue of the feedhorns not oreinted properly, or the receviers not propely controlling the polarity. If the recievers are slaved how are they slaved? Are you using a DC block on the reciever that doesn't control polarity? What about the LNB voltage? You do know that some LNBs that are made for use with feedhorns on C band dishes (and therefore generally use a polar servo to control polarity) are not rated to operate at 13V right? They're generally rated for 15- 24v. That might mean that if you had your FTA reciever connected to them and the reciever was still trying to switch polarity by switching the LNB voltage you might have issues when switching to vertical polarity or 13v. That shouldn't be the case for the LNBF since it's made for 13/18v polarity switching but could be so if your using a polar rotor feedhorn with an LNB.
Another possibility is it could just be coincidental. It could just be that on the transponders your having trouble with there are overlapping frequencies being used on an adjacent satellites and thus your getting interference from those. That's always a possibility with an undersized dish.
Stefan, you had a great point when you said that the polarotor LNB could be underpowered for one polarity if Berg is slaving his receivers with splitters that block power from the analog receiver and PASS power from the FTA receiver. To prevent that possibility whenever he's slaving and using the polarotor LNB, he should connect things so that the LNB gets power from the analog reciver.
correct. The skew difference is probbaly 2 but its just weird that when I work across the arc it flips good polarity (G4 V is good, T5 H is good, G3 V is good, etc)7720driver said:
it is an option. The issue is I have to manually skew it and that does hinder the signal
LNB to Pansat 1500. Toshiba is slaved using the loop out. When I use the LNB with the polorotor, the Toshiba controls polarity. When I use the DMSI the Pansat controls it. Same result
thats what I figured (dammit). The kicker is getting it setup on a table (which might be another issue with the HOA).
thats a no go...no way I could put this ont he roof. I got a better chance of putting outside my garageStefan said:
no DC blocks....LNB to Pansat. Toshiba slaved via the loop out. I get Vertical fine on G4...its H that doesnt work. If I use the polorotor, the Toshiba has the wires hooked up.
Tony, I think the last poster meant a non-penetrating roof mount
(not necessarily mounted on the roof). NPRMs are frameworks of angle iron that are weighted in place with cement blocks or other ballast, with a mast somewhere in the center of the structure. They are generally meant for installation on flat surfaces and weighted down. If your difficulty in clearance is because you don't have it high enough, consider making your own rigid "table" out of a mix of 4x4 timbers and larger construction lumber such as 2 x 10 inch, through bolting it all together with at least 3/8 inch if not 1/2 inch carriage or machine bolts and fender washers under the nuts.
The 6 as well as the 8 foot fixed mount antenna leave a lot to be desired for stability, in their tubular frame mount, which is very top heavy. But you need to clamp it securely into a flat surface such as the elevated "picnic table" suggested above, turn to the proper azimuth, and weight the whole thing down with cement blocks.
10 or more 40-pound blocks would be the minimum for your 6-footer, if the deck can hold it. If you don't weight this whole thing down (and secure with a heavy cable in case it breaks loose or tries to tip over in the wind), it will easily catch the wind and lose its proper pointing postion (or worse).
Good luck!
Mike
(not necessarily mounted on the roof). NPRMs are frameworks of angle iron that are weighted in place with cement blocks or other ballast, with a mast somewhere in the center of the structure. They are generally meant for installation on flat surfaces and weighted down. If your difficulty in clearance is because you don't have it high enough, consider making your own rigid "table" out of a mix of 4x4 timbers and larger construction lumber such as 2 x 10 inch, through bolting it all together with at least 3/8 inch if not 1/2 inch carriage or machine bolts and fender washers under the nuts.
The 6 as well as the 8 foot fixed mount antenna leave a lot to be desired for stability, in their tubular frame mount, which is very top heavy. But you need to clamp it securely into a flat surface such as the elevated "picnic table" suggested above, turn to the proper azimuth, and weight the whole thing down with cement blocks.
10 or more 40-pound blocks would be the minimum for your 6-footer, if the deck can hold it. If you don't weight this whole thing down (and secure with a heavy cable in case it breaks loose or tries to tip over in the wind), it will easily catch the wind and lose its proper pointing postion (or worse).
Good luck!
Mike
so true especially "Up North" where our TS is 38 degrees. I have a 70# sand bag on the back end of it to keep from leaning forwardmikekohl said:
Berg, you said you didn't like having to manually adjust the DMSI's skew. Well, you only have to adjust it whenever you move to a different satellite. I doubt that you'll be moving that dish from sat to sat a lot. I mean, that dish doesn't have a polar mount. So moving it from sat to sat takes a lot of time to get the azimuth and elevation right.
So, if you really want to move it from sat to sat, why don't you make a polar mount for it. With polar mounts, moving from one sat to another requires only one adjustment, not three (azimuth, elevation and skew). If you made yourself a polar mount then you wouldn't have to worry about skew. Skew, would in essence be automatic.....thus you could use the DMSI and the skew would always be correct.
Now, making a polar mount for that dish would not be easy, but I'm confident you could do it. I would not put a motorized dish postioner on it (although you could). I'd prefer to just use a hand crank.
Hey, maybe the manufacturer makes a polar mount "kit" for that dish?
So, if you really want to move it from sat to sat, why don't you make a polar mount for it. With polar mounts, moving from one sat to another requires only one adjustment, not three (azimuth, elevation and skew). If you made yourself a polar mount then you wouldn't have to worry about skew. Skew, would in essence be automatic.....thus you could use the DMSI and the skew would always be correct.
Now, making a polar mount for that dish would not be easy, but I'm confident you could do it. I would not put a motorized dish postioner on it (although you could). I'd prefer to just use a hand crank.
Hey, maybe the manufacturer makes a polar mount "kit" for that dish?
I'll probably put the DMSI one back on and see how that works. I know I wont need to skew it after I mount it there but its weird. If I use that one or the older LNB with the polorotor, I get the same results.
I'll keep working on it.
I'll keep working on it.
Bryan
So the fact the lower portion of my dish has a LOS issue is the reason why I get one polarity (and they flip as I move across the arc)?
I'm going to try tonight to see if I can get the NBC stuff on AMC4. They are Horizontal so using my theory, I should get it but not any of the V stuff
So the fact the lower portion of my dish has a LOS issue is the reason why I get one polarity (and they flip as I move across the arc)?
I'm going to try tonight to see if I can get the NBC stuff on AMC4. They are Horizontal so using my theory, I should get it but not any of the V stuff
In this case, your dish does not see the sat fully, therefore you don't get good signal strength/quality.
As stated before, dish is just a reflector that gathers the signal. Polarity is taken care by the skew motor. It's not like "upper half gets H and lower half gets V"....
FTARock
As stated before, dish is just a reflector that gathers the signal. Polarity is taken care by the skew motor. It's not like "upper half gets H and lower half gets V"....
FTARock
Iceberg said:
Iceberg, is there any way you could temporarily (just for a couple of hours or so) move the dish away from the back of your house? I know you don't want HOA problems, but if you could just put it in the yard and then do a quick test, it'd answer a lot of issues. Even though its only a 6' dish, the fact that its solid and not mesh should be a plus. I'm sure its capable of far more than its getting...
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