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Long haul grounding issue? Switch to MFH-3?

935 Views 5 Replies 3 Participants Last post by  AntAltMike
This is going to be a long post, so bear with me. The short version is does anyone know of any sub-$10k solution for putting DTV signal on fiber? I'm talking point-to-point, not for a big distributed system. Looked at MFH-3, but it seems like the cost for my setup would be well north of $25k, which is just nuts.

Background: Large farm and main house has NO good place to put a dish that will get signal thanks to trees and topography. Barn has great place, but is 500' away. Several years ago we put a three LNB dish on the barn. There's a multiswitch there because there's one receiver in an apartment in the barn itself. The signal then goes to an amplifier and then to four very large coax cables pulled to my house (I forget the designation, but they're 5/8" in diameter or so...big mommas). They go to a big multiswitch for my house, which has something like 10 receivers in it.

I used to also have an analog phone switch in the barn with extensions in my house connected via twisted pair copper that ran underground between buildings with the DTV coax. We used to REGULARLY lose a lot of equipment in big thunderstorms and finally narrowed it down to the fact that the soil in our area is very bad at grounding with traditional ground rods. We had huge potential differences in the grounds at each building. So we spent a lot of money on a much better grounding "system" (involves boring deep holes, putting in large spikey ground rods, and topping off with salt a couple times per year so each one has an access hole). Each building has several of these rods, too. All the equipment is tied to these rods VERY well.

This system worked GREAT for a long time, though we did very occasionally lose fuse protectors on the phones, but those were relatively inexpensive to replace so we lived with that. Eventually for a lot of reasons we went with a digital phone system that now runs across the multimode fiber we were already running our data over that's also buried between buildings. That stuff is all gigabit and run with higher end Cisco managed networking gear.

So now the ONLY thing we have running across any physical wire between buildings is the DTV. It was fine that way, too, until we had to get new multiswitches and a new dish for the 5 way stuff. Now we're very regularly losing ports on the multiswitch in the barn. Every time there's lightning close by, we lose all four connected ports on that switch, but USUALLY nothing more (we've once lost an entire switch, but we've now gone through probably 24 total ports otherwise). We use a 16 way switch there. We've tried a couple different brands with the same story, and we've tried various combinations of grounding and not grounding each side, same story.

I'd dearly love to get this signal hauled by fiber instead. Anyone know of any sure fire way to do that? Short of that, is there any better way to protect this stuff so this doesn't happen? Everything we've looked at so far has been north of five figures, which is a little crazy...I could by multiswitches for a pretty long time for that. *sigh*

I can get more data on what exact types of equipment we use and what the flow looks like if needed, but I thought I'd throw this out there. If fixing my existing solution is possible and this is just the wrong forum, that's fine...let me know and I'll post elsewhere. But I would really love to go to a model that let me use fiber instead since I *know* I won't have this problem there. I don't even mind if I have to pull new singlemode fiber or something. We have plenty of space in the conduit, particularly if we can remove that big coax.

I'll also add that my multimode fiber and data network is distributed to three shops and four OTHER residences, so there does exist the potential to use something like MFH-3 at all those locations if the cost got more reasonable. We can't get cable or DSL where the farm is, so I already provide internet and phone to those residences and shops via three T1's (two data, one voice).


--Donnie
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Dishes are cheap. You should have one dish for the barn and another to source the house. You would line power the dish for the house so it will be electrically isolated from the barn electrical system.
Please reply to me with a private message with the specs for each building and I will give you a parts list and pricing from a wholesaler for the fiber gear. Yes it is going to be under 10000.

Dan
AntAltMike said:
Dishes are cheap. You should have one dish for the barn and another to source the house. You would line power the dish for the house so it will be electrically isolated from the barn electrical system.
At first I was like "what is this idiot talking about...I said I couldn't put a dish on the house" and then I realized what you mean. Two dishes on the barn. One for the barn itself, and one for the house and the house dish gets power fed back from the house, thus isolating it. Excellent idea. Can't believe I didn't think of that. Apparently I'm the idiot. :) We've got the room for the extra dishes (and in fact, just for signal strength and quality I was getting ready to split my triple into three singles when I found out we were going to have to go to the five way system).

I'll PM the other fellow about the fiber system, too.

--Donnie
We tried today to see if we could power the dish from that far away over the RG-11 and it worked. Seems like we've got plenty of signal on all five satellites. So tomorrow we're going to add a second dish to run the stuff in the barn and we should be set.

I'd still rather have it all over fiber, but this solution may mean that can wait until prices on that kind of thing come down. Thanks for the suggestion, AltAntMike! We're actually running it without an amplifier set that we used to run, too. The signal must be a good bit better direct off the dish than it is coming out of a multiswitch.


--Donnie
You might want to tap into the "evens" coaxes at the point at which they enter the LNB to measure the actual DC voltage drop across the LNB. You can do that with an HF splitter that passes power on both ports. If it is close to 15.5 volts, your system would be vulnerable to losing the highs if it ever dipped a few tenths. If it is close to 15.5 volts, you might want to rig up a DC power inserter that is a little stronger than 18 volts to better sustain the voltage. The voltage of the 13 volt lines is not critical. In fact I thing that the ports will put out the odds at full strength on them even if they see no voltage whatsoever. as long as there is 13 volts or more on any other port.
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