View Full Version : Antenna to fibre optic extender?


flexible
01-10-07, 05:30 PM
A colleague asked me a question that I had no advice for. Not surprising, but I know where the experts live (here).

He is a high tech guy that lives in a private valley in California. He owns the hills and the valley where his house has just been built.

While he can easily put in a Dishnet or DIRECTTV antenna and get satellite signal, he wants to try an OTA antenna first. (One of the only people I know that just wants OTA instead of all that satellite can bring.) The cable run from an antenna that he would put on the closest hillside to the house would be up to 1500 feet. Accordingly coax is out of the question.

He wants to know if there is a unit that he can put at the antenna to convert the signals and send over fibre optic cable to the house and feed a yet-to-be-obtained plasma TV.

I've checked antennaweb.org and it looks like he will be able to get a variety of OTA stations analog, but only two of them digitally.

Is something like this even possible? Whether or not it makes the best sense is not the question here. He is a tinkerer and inventor.

If the signal can be converted at the antenna and transmitted over fibre to the house, then what would be required (if anything) before going into that yet-to-be-purchased plasma TV.

Recommendations on equipment and feasibility are appreciated.
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rlj5242
01-10-07, 06:23 PM
Shouldn't be a problem. The satellite companies snag the OTA signals and send them to the uplink facility all the time. $50k to $100k of equipment (just a guess) should cover it.

-Robert

flexible
01-10-07, 07:54 PM
Shouldn't be a problem. The satellite companies snag the OTA signals and send them to the uplink facility all the time. $50k to $100k of equipment (just a guess) should cover it.

-RobertLet's hope hope that's a bad guess. $50k for OTA is a problem for "free" signals.

atperson100
01-10-07, 11:20 PM
He could put some tuners up on the hillside, then send the transport stream down the hill using ethernet or 802.11. Then you'd just have to worry about powering the receiver, but I suppose some solar panels might do the trick

flexible
01-11-07, 08:17 AM
He could put some tuners up on the hillside, then send the transport stream down the hill using ethernet or 802.11. Then you'd just have to worry about powering the receiver, but I suppose some solar panels might do the trick
Right. This was an idea that he and I discussed originally. Question is, what kind of (weather-proof) tuner can you mount at an antenna?

We actually have done some outdoor wireless 802.11 work on the property independent of this.

Rick0725
01-11-07, 08:27 AM
Small enclosed shed next to the tower with equipment rack and monitor

dr1394
01-11-07, 08:40 AM
You could try the "passive antenna repeater" approach.

1) Hook two antennas together with a short piece coax.

2) Place them on the hilltop. Point one antenna at the TV stations and point the other antenna at the house in the valley.

3) Use a third antenna at the house aimed at the passive repeater on the hillside.

Sounds wacky, but this has been used in commercial two-way applications. Whether it actually works will be a function of signals levels on the hillside and antenna gain. If you can get power on the hillside, an amplifier between the antennas will help.

Ron

flexible
01-11-07, 08:50 AM
Someone on a different board where I posted the same query posted this solution.
http://foxcom.com/sdtv/hfc.asp

Looks like the right equipment. No clue what the costs might be yet for the components.

Rick0725
01-11-07, 08:59 AM
have him try a 91xg mounted on the roof of the home, aimed at the towers, angled up to the ridge/horizon, and see what he receives. then go from there. he may not need to go through the expense of installing equipment 1/3 of a mile away from his home.

Then if the antenna on the roof is not successful, hire a local consultant with the proper equipment, instrumentation, expertise, site survey the situation, get a quote, order the parts, have it professionally installed. and do it right!

this is not your everyday antenna reception situation.

"looks like the right equipment"... you got to be kidding me!

you are going to get AMATEUR ideas at the forums unless a hotshot out there actually knows what he is talking about and has experience with the process you are "shopping around" for.

flexible
01-11-07, 01:42 PM
have him try a 91xg mounted on the roof of the home, aimed at the towers, angled up to the ridge/horizon, and see what he receives. then go from there. he may not need to go through the expense of installing equipment 1/3 of a mile away from his home.

Then if the antenna on the roof is not successful, hire a local consultant with the proper equipment, instrumentation, expertise, site survey the situation, get a quote, order the parts, have it professionally installed. and do it right!

this is not your everyday antenna reception situation.

"looks like the right equipment"... you got to be kidding me!

you are going to get AMATEUR ideas at the forums unless a hotshot out there actually knows what he is talking about and has experience with the process you are "shopping around" for.

It is already confirmed to be dead air at the house in the valley.

He wants ideas, amateur or otherwise. He can get a pro if he wants one. He doesn't want one, yet. He knows he can solve it simply with consumer satellite service. He does not want that except as a last resort for his own reasons. I personally think making his life difficult for not taking the easy route.

Targus
01-11-07, 01:53 PM
Since you'd have to run cable from the house to the antenna location, to power any amplifiers or "conversion" equipment, why not just run coax to the house.
Use 1/2" rigid line, that cable companies use for trunks.

taz291819
01-11-07, 03:46 PM
A job like this would be extremely expensive. He would have to use heliax (sp?). A cheaper alternative would be to build a shed (with power) beside the tower, and use a PC with a MyHD card at the shed. Then run some ethernet cable to his house (may need repeaters), and use another HTPC to view the programming. This is by far the cheapest route to go, and he'll get some good HTPC use.

Targus
01-11-07, 04:26 PM
He would have to use heliax (sp?).

Why?

Why don't cable companies have to use it?

flexible
01-11-07, 05:39 PM
A job like this would be extremely expensive. He would have to use heliax (sp?). A cheaper alternative would be to build a shed (with power) beside the tower, and use a PC with a MyHD card at the shed. Then run some ethernet cable to his house (may need repeaters), and use another HTPC to view the programming. This is by far the cheapest route to go, and he'll get some good HTPC use.
This is very interesting. He is a Linux guru and might like this. I see a Linux HTPC howto and info about MythTV.

flexible
01-11-07, 05:41 PM
Ok. Just got some additional info. There is already 120V ac power and fibre run to the ridge. So those two aspects go away as problems.

dr1394
01-11-07, 09:22 PM
Some numbers for the passive repeater. Let's assume that three 91XG antennas are used. The gain of the 91XG is around 15 dBi at channel 44, or 650 MHz.

The free space path loss with d(istance) in meters and f(requency) in hertz is:

FSL(dB) = 20log10(d) + 20log10(f) − 147.5

1500 feet is 457 meters, so the path loss at 650 MHz is 82 dB.

The three antennas give you 45 dB of combined gain, so the overall attenuation is 82 - 45, or 37 dB. If you placed a 37 dB amplifier (or two 20 dB amplifiers in cascade) between the two hilltop antennas, the performance of the system would be equal to a 0 dBi antenna and receiver located at the hilltop.

Ron

bfoster
01-11-07, 10:57 PM
Here is what you need...

http://www.buysellcable.com/item-details/5176-SA-OPTOELECTRONIC-TRANSMITTER.html

http://www.buysellcable.com/item-details/5182-SA-OPTOELECTRONIC-RECEIVER.html

Used S/A system 60 opto gear, 750, stand alone (no seperate chassis or power supply required) . This is older gear from a refurb shop. Might want to get an optial attenuater though, the laser is a 9.5 dBm laser and your link has less than a half dB loss!

atperson100
01-12-07, 12:29 AM
This is very interesting. He is a Linux guru and might like this. I see a Linux HTPC howto and info about MythTV.

There's also a product called the HD Homerun. No PC required at the receiving end! Its a box with 2 tuners and an ethernet connection. If his 802.11 reception is reliable enough and you get good throughput, you could hook it up to a bridge.. otherwise, run the ethernet down the hill. This could be more economic than a pci tuner in a pc for power consumption reasons.. And it's smaller than most pcs, so you might have an easier time to putting it in a weatherproof box.

Rick0725
01-12-07, 07:58 AM
After installing all that stuff, what are ya going to do if the reception stinks, is difficult to operate or not user friendly, not dependable remotely, and is difficult to maintain.

Many people out there have a hard enough time operating equipment in the next room, upstairs, let alone 1/3 of a mile away for that matter.

All the above really sounds like a royal pain in the ass.

You are his friend, talk him into satellite or cable . The above is why they invented cable and satellite in the first place.

flexible
01-12-07, 11:58 AM
There's also a product called the HD Homerun. No PC required at the receiving end! Its a box with 2 tuners and an ethernet connection. If his 802.11 reception is reliable enough and you get good throughput, you could hook it up to a bridge.. otherwise, run the ethernet down the hill. This could be more economic than a pci tuner in a pc for power consumption reasons.. And it's smaller than most pcs, so you might have an easier time to putting it in a weatherproof box.
Now *that* was a useful post! I had not heard of that product.

kenglish
01-13-07, 01:16 PM
http://www.blondertongue.com/FiberOptics