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Topic:
Satellite dish cutting out, any ideas?
This thread has 15 replies. Displaying all posts.
Post 1 made on Saturday March 9, 2002 at 09:31
Jeff406
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Hello,
I recently installed an HD dish for a customer and it ocasionally cuts out for a few minutes every day or two. I have installed several of these in the past and have had no problems until this one.

The dish has a clear line of sight and signal strenths on all transponders are all in the 90's, so its tuned in well. He has two receives (1 Sony HD and 1 Sony regular) and when it cuts out they both cut out together.

Symptoms are this:
I already tried changing the Voltage Switch unit on the dish and it did not help.

When it does cut out, it appears that half the transponers are still in the 90's and the other half are at 0 (Unlocked) and some actually swing back and forth from 0 to 90. I usually lasts for 5 to ten minutes and then it just goes back to normal.

I have not yet tried changing the LNB's

I can not find any cabling problems (not to say that none exist).

Any ideas on what can cause or not cause this kind of symptom?

I appreciate any help you can offer.
Jeff406
Post 2 made on Saturday March 9, 2002 at 11:49
ECHOSLOB
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When you have this problem it is always either the odd or even transponders going out at once. In other words you will only see evens all working or only odds working. Usually it will default to 18 volts and not switch back to 14 volts. In order of problems I have pesronally noticed.

1. Bad LNB
2. Bad cable or bad connector.
3. Bad multi-switch.
4. Bad IRD

Doubt it's an IRD because both of them do it. I have seen this before but it is rare. I would also think it is not an LNB because both IRD's are exhibiting this problem. But I have still seen this happen so don't rule them out. I would lean towards the multi-switch. I think you said you changed it but I would still look into this. I would look into a powered multi-switch as they seem to be better then the passive switches. If it is powered make sure you don't have it plugged in with fluorescent lights.
How long are your runs? Eagle Aspen makes a good switch as does Channel Master. Spawns are a lot more expensive and actually have the most problems in my experience. Make sure to check your cables and ends. It is always one of these things I have mentioned. A cable splitter will also cause this but you would have it all the time and not just intermittant. Sometimes we will switch IRD locations but since you said both are doing it I would think it is something common to both sytems. Elimnate the multiswitch and run the wires from the 101 LNB direct to the IRD's. You would lose the HD channels but at least you could narrow down the problem. Good luck but I am sure you will find it.
Post 3 made on Saturday March 9, 2002 at 13:07
EXT
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Check the timing, does it occur at approximately the same time each day? Does it occur at the same time something else happens? Had a similar problem years ago in a large office building, the computer would crash everyday between 3 and 4 PM. Finally traced it down to a large pump that was wired in with the computers power circuit. Some equipment would be drained by this pump at close to the end of each work day. Possibly you have it plugged in with something that that creates interference and turns on at the same time your equipment cuts out.
OP | Post 4 made on Saturday March 9, 2002 at 16:29
Jeff406
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I did ask the customer if there were specific times the problem would occur, but he said it happens at anytime and even during totally clear non-windy days so there does not seem to be a pattern to it.

I did try another voltage switch and it did not remedy the problem (its still hooked up) and I plan to swap the A LNB on Monday.

Question to Echoslob: You kind of doubted that the LNB is causing the problem, but if the A satellite dual LNB is hooked up to the voltage switch, and the switch locks one of the dual feeds to vertical and the other to horizontal (18V / 14V) then I would think that the LNB would still be a good candidate of the problem. If the dual LNB feeds went right to the two receivers then I would agree that the LNB would not be as suspect since the two receivers are both exhibiting the same problem.

Trying to connect straight from the LNB to the receiver is a good idea, if the LNB swap does not work then I will try this.

Thank you for the help so far and if you have anymore ideas pleas share them with me.
Post 5 made on Saturday March 9, 2002 at 17:09
Larry Fine
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Jeff, what about swapping the cables coming from the dual LNB? Wouldn't that cause the LNB to change even and odd channels, so whether the problem switches to the other numbers (even to odd, or odd to even) will tell you where the problem lies; i.e., whether the problem is ahead or after the point where you make the swap?

Larry
www.fineelectricco.com

Post 6 made on Saturday March 9, 2002 at 19:45
ECHOSLOB
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Jeff,

The reason I was leaning towards the multi-switch is because both sides of the LNB are independant of each other. You could possibly be correct though as both sides go into the multiswitch. I have seen an LNB bad on one side effect 2 IRD's but I don't remember if they were going through a muli-switch or going direct. Point is I am 90% sure it is one or the other. If you feel the new switch is good install a new 101 and see what happens. Being intermittent this will be hard to diagnose while it is working fine without changing parts anyway. I don't like swapping parts out like that without knowing for sure but in some cases like this you don't really have a choice unless you are there while it is happening.


LARRY,

Swapping cables wouldn't have an effect on the voltage. The voltage is produced from the IRD. You could have both IRD's sending 18 volts at the same time. You would need to change channels and check the voltage from the IRD to the LNB to see if it changes. I guess in a rare case a bad IRD could cause both to go out and something to look into after the LNB,switch and cables first.
Post 7 made on Saturday March 9, 2002 at 22:13
Larry Fine
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Echo, I was under the impression that a multiswitch permanently "assigns" one LNB to 14v. and the other one to 18v, and the voltage from each IRD determines which LNB each of the multiswitch's outputs switch to.

Larry
www.fineelectricco.com
Post 8 made on Sunday March 10, 2002 at 09:13
ECHOSLOB
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Most multi-switches do more then 2 ird's that is the whole point point of having them other then combining 2 or 3 birds. If an LNB was locked on one voltage you would only get half the channels. High and low voltage switch between the odd an even transponders. A 22khz tone switches the sats when you have 2 birds hooked up to one multiswitch. I have 2 powered ones in my home using powered pass-throughs and you can hear them clicking all the time switching voltages.
Post 9 made on Monday March 11, 2002 at 10:19
Makai Guy
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Since I have only a basic dual-lnb setup I don't speak from experience, but here's my understanding.

A multiswitch keeps each lnb half permanently set to a single polarity (i.e. odd or even transponders) by sending it a constant 14 or 18 volt signal. Thus ALL transponders are available at the switch at all times. The switch just flips each receiver to the appropriate odd-or-even lnb half as needed.

When you get into more complicated setups caused by viewing multiple satellites, etc., the switching requirements as to which lnb you connect each receiver to get more complex, but the basics of keeping each lnb (or dual lnb half) permanently set to a single polarity remains true.
Post 10 made on Monday March 11, 2002 at 12:53
ECHOSLOB
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If thats true I stand corrected but the IRD will still send out 14 or 18 volts back to the switch depending on the transponder for a given channel. I was always told even through a multiswitch the LNB's changed voltage but the way you have explained it seems to make more sense.
Post 11 made on Monday March 11, 2002 at 13:10
Larry Fine
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Makai explained it exactly as I believe it to be. The IRD sends the appropriate voltage to the switch, so each switch output can be connected to the proper LNB for the channel selected. The relay clicking heard is the switches output being switched back and forth from one LNB to the other.

The reason I suggested swapping the coaxes at the switch inputs is to see if the dropouts switches from one set of channels to the other.

The benefit of using a power supply for the switch is that, especially with long coax runs, the switch receives plenty of power to operate the relays, but more important, that both LNBs receive the proper voltage at all times.

So, refering back to the original post, it sounds like the voltage being received by the LNBs is marginal, and at certain times, drops just enough that the LNB in question is being starved for power. The solution: get the power supply (wall wart) that the switch needs. (Jeff, is there a multiswitch?)

I noticed that Jeff didn't mention a switch, and only two receivers would not require one. With two receivers and a dual LNB, the setup is basically two independent systems: each IRD has its own LNB, so the cutout affecting both receivers is strange.

Larry
www.fineelectricco.com
Post 12 made on Monday March 11, 2002 at 19:02
ECHOSLOB
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LARRY,

He is calling what I believe to be multiswitch a voltage switch and he said he switched it out with no difference. If you guys are right about one side of the LNB being 18 and the other 14 when using a switch then I would have to agree it is looking more and more like the LNB. Could also be a bad cable or end on one of the sides that is shorting to ground intermittently. It's funny but my multiswitch clicks all the time even when nobody is watching TV. It would make sense when changing channels but I wonder why it does it when not watching TV?
OP | Post 13 made on Monday March 11, 2002 at 20:43
Jeff406
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Hey Echoslob, if I called it a Multiswitch it was a typo (sorry), in a nut shell, the customer has a HD antenna that has a 2 dual LNB's that must be fed into the proper voltage switch that has 4 inputs and this one has four outputs that go to the receivers of which he only has 2 so I have 2 unused outputs on the voltage switch.

Today I tried swaping the A and B LNB's since I don't have a replacement at the moment. I also replaced the 4 cheap cables that came with the dish that connects the LNB's to the voltage switch mounted on the back of the dish and reconnectorized all other connections. It's kind of a waiting game now, if it is the LNB then I expect him to have problems with the HD channels now.

Let's wait and see.

Thanks for the help so far.
Post 14 made on Monday March 11, 2002 at 22:40
ECHOSLOB
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HEY JEFF,

Possibly not. It is called a multi-switch not a voltage switch. The one you are using is passive as it uses the ird's voltage to switch instead of an external PS. Like Larry said on long runs a powered switch is always better but once again this may not be your problem. The 2 lnb's are looking at 2 different birds. If you have a bad LNB on the 101 side it will not effect the HD channels. What we were talking about sides in reference to a dual LNB was a 14 volt side and an 18 volt side but both coming out of the same LNB. If you have an LNB problem and you swapped LNB's at the dish then yes if the LNB was bad then you would have problems with the HD channels if it originally was bad on the 101 side but just swapping the wires will only change which channels or I should say transponders are effected from the same LNB unless of course if you have a bad wire.

Here is what you can do. If it happens again have the custy go into the setup menu and see which tranponders aren't getting signal odds or even's. If you swap the wires and the opposite channels don't work the you have isolated the bad side so it could only be the lnb or the wire from that side. If the channels didn't change after switching wires then I would look at the mulitswitch and also check the voltage out of both ird's make sure they are both switching.
OP | Post 15 made on Saturday March 16, 2002 at 08:16
Jeff406
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I forgot to write yall back,

Well, it ended up being an LNB failure, I had replaced a lot of the cabling, but I also had swapped LNB's A to B and B to A and now the HD channels are cutting out every once in a while and the regular programming has been steady as a rock all week (opposite of where I started) so I got a replacement LNB for the bad one.

Thanks for the info and help from everyone
Jeff
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