passive satellite repeater

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Rikkitic

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Topic # 94331 8-Dec-2011 09:16

I can't figure out where else to post this. Does anyone have experience with passive dish repeaters? I'm trying to get Asiasat 3s/7 but the look angle is way too low at my hilly farm. I'm wondering if I could put a big dish on one of the hills and link it to a smaller dish pointing down to the house. The distance is probably about 400 metres or so. Would this have any chance of working? How would I hook it up? Just connect the two LNBs together? Don't they change the frequency? Would a standard dish still work for that? I'm a little out of my depth here. Any tips would be much appreciated.

[Mod (Net): Moved to Freeview forum as closer to what you are talking about then HTPC]

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Reply # 555341 8-Dec-2011 09:57

Hi, no I dont think you have a chance of doing what you want. A more practical solution is to run 400m of RG11 and a launch amp and a couple of distribution amps on the way, alternatively you can get fibre systems to cover that distance.

Cyril

Zeon

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Reply # 555357 8-Dec-2011 10:22

Another option could be to put the receiver unit next to the dish and run it into one of those IP based HDMI senders. You could then run a Ubiquiti wireless bridge back to your house and with the other end of the IP-HDMI module plugging into your TV. May be almost 1k for all that equipment though?

Don't quote me on this but if you have a high enough gain antenna on the hill, could you not have another dish pointing back to your house e.g.

BigSatellite Disk -->Coax-->Smaller Dish ------------------------------------>>air ------------------>smaller dish-->house

cyril7

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Reply # 555364 8-Dec-2011 10:30

Good idea Zeon.

Cyril

Rikkitic

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Reply # 555415 8-Dec-2011 12:25

if you have a high enough gain antenna on the hill, could you not have another dish pointing back to your house e.g.

BigSatellite Disk -->Coax-->Smaller Dish ------------------------------------>>air ------------------>smaller dish-->house

Sorry, I thought that was what I was asking. Can I just hook two dishes together to redirect the signal from one down to the house without any amplification or other electronics in-between? How would I do that? Do I just connect the LNBs on each dish together?

Somewhere I read a comment that something like this ought to be possible if each dish is set to a different polarity to avoid interference. I have enough skills to set something like this up if there is a reasonable chance of it working, but I don't really understand the technical issues involved.

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cyril7

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Reply # 555427 8-Dec-2011 12:55

Hi, what Zeon described is not what you proposed, in his idea you are simply putting the STB at the remote dish, then using an IP wireless network to re encode the video and shift it to your house, that is quite different to a passive reflector.

Cyril

nickb800

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Reply # 555440 8-Dec-2011 13:11

Rikkitic:
if you have a high enough gain antenna on the hill, could you not have another dish pointing back to your house e.g.

BigSatellite Disk -->Coax-->Smaller Dish ------------------------------------>>air ------------------>smaller dish-->house

Sorry, I thought that was what I was asking. Can I just hook two dishes together to redirect the signal from one down to the house without any amplification or other electronics in-between? How would I do that? Do I just connect the LNBs on each dish together?

Somewhere I read a comment that something like this ought to be possible if each dish is set to a different polarity to avoid interference. I have enough skills to set something like this up if there is a reasonable chance of it working, but I don't really understand the technical issues involved.

I dont know if that would work, but if it did work, then I think you would need to supply power to the LNBs on the hilltop to control the polarity - something like this perhaps http://www.dipolnet.com/diseqc_1_0_generator_viper_s_115_R85254.htm.

RunningMan

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Reply # 555469 8-Dec-2011 13:50

Zeon's first idea will work - having the sat receiver up by the dish. If you use one of the various linux based boxes, you can then just stream the video over IP back to the house without an HDMI converter etc. 400m should be fairly easy to cover with decent WiFi gear, and 802.11g would be fine for SD streams, and possibly HD streams if you have a decent connection.

You can't use a sat dish & domestic LNB setup as a passive repeater, as these LNBs are a receive only device.

I don't know exactly how far you can transmit the sat signal down a cable before it becomes unusable, but suspect 400m would be pushing the limits, even with amplification.

Do you have power at the remote site? It will likely be a problem if you don't...

cyril7

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Reply # 555474 8-Dec-2011 13:55

Hi, I have done over 300m on RG11 and it still had sufficient C/N to be usefull, however I was starting with a 90cm dish on Optus D1 so good input C/N. As I mentioned there are fibre systems to doing this and can go 10's of kms.

Cyril

Rikkitic

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Reply # 555508 8-Dec-2011 14:58

Right. I get it now. I was also thinking of something like that, using WiFi, as a possibility. My biggest problem is finance and I was hoping to find a 'clever' cheap as solution. That's also why I'm not too keen on 400 metre cable runs.

It would be fun to experiment with all these possibilities, but I just can't afford a major investment without a guarantee that it would work in the end. Even if a passive repeater could be made to do it, we're still taking about one big dish, plus two smaller ones, plus whatever would be needed to boost the signal and connect the two dishes together. That's already $500+, maybe a thousand. And no, there's no power on the hilltop. If the rest could be made to work, it would also need a battery with small solar and wind generators. That would certainly bring it up to $1,000.

How depressing. The thought that Rupert Murdoch may be the only answer, I mean.

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RunningMan

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Reply # 555888 9-Dec-2011 13:12

Just skimming through TradeMe, I saw this. It appears that the LNB is also capable of transmission, which is what you are looking for.

I do not know what is needed to drive this through.... might be worth investigating.

B1GGLZ

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Reply # 555931 9-Dec-2011 14:27

RunningMan:
It appears that the LNB is also capable of transmission, which is what you are looking for.

A LNB cannot transmit. It's only a Rx amp and convertor to feed a low level intermediate frequency down the coax to the STB.
What is transmitting in the Trademe ad is the BUC (Block Upconvertor) also connected to the dish for a 2 way satellite broadband system.
You may be able to make it work if the BUC was connected to a separate dish pointing at the house. Would still require power supply and equipment on the hilltop.
IMO the whole idea is barely feasible and rather expensive.

RunningMan

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Reply # 555942 9-Dec-2011 14:40

B1GGLZ:
RunningMan:
It appears that the LNB is also capable of transmission, which is what you are looking for.

A LNB cannot transmit. It's only a Rx amp and convertor to feed a low level intermediate frequency down the coax to the STB.
What is transmitting in the Trademe ad is the BUC (Block Upconvertor) also connected to the dish for a 2 way satellite broadband system.
You may be able to make it work if the BUC was connected to a separate dish pointing at the house. Would still require power supply and equipment on the hilltop.
IMO the whole idea is barely feasible and rather expensive.

Thanks B1GGLZ, I didn't quite get the terminology correct, but aware of the function of an LNB.

I think the question is what would need to go between the LNB on the primary receive dish, and the BUC on the transmit dish? It clearly needs to be an active device of some description, but I do not know if this would be something as simple as an amplifier, or if creating the transmitted signal is more complex than this.

Whatever it may be is probably moot anyway, seeing as the OP has no power at this location.

Rikkitic

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Reply # 556062 9-Dec-2011 20:07

Thanks again for thinking with me on this. I really appreciate it. I just wish I was an engineer. I don't have the knowledge or maths skills to work out the details of ideas like this. The only course open to me is trial and error (and helpful suggestions from others).

In the meantime, two new 'brilliant' (read desperate) ideas have occurred to me. I am ringed by hills. So what about putting a big sheet of metal or other reflecting material on a hill behind me that would reflect the satellite signal in my direction and then pointing my dish at that? Would the reflected signal be so attenuated that there wasn't a hope in hades of detecting it, or could this possibly work if someone who actually knew what they were doing tried it?

Wild idea #2: Put a dish on the hill with some means to power the LNB, add a signal booster and connect that to a home-made Yagi cut to the LNB frequency and point it at the house. Use another Yagi to receive the signal and, if necessary, another booster before feeding it into the STB. Does anyone think this might work? (I thought of it before the BUC suggestion, principle is the same).

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B1GGLZ

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Reply # 556123 9-Dec-2011 22:00

Rikkitic:

In the meantime, two new 'brilliant' (read desperate) ideas have occurred to me. I am ringed by hills. So what about putting a big sheet of metal or other reflecting material on a hill behind me that would reflect the satellite signal in my direction and then pointing my dish at that? Would the reflected signal be so attenuated that there wasn't a hope in hades of detecting it, or could this possibly work if someone who actually knew what they were doing tried it?

Not such a wild idea. Don't know if its still in use but this is how TVNZ in Dunedin got their signals between the Studio in town and the Transmitter on Mt Cargill. There were high buildings to the North side of the building so the dish on the roof pointed at the wall of a tall building over the road to the south (suitably clad with metal sheet over the bricks) and bounced the signals to and from Mt Cargill. Worked very well. They probably use optical fibre now I guess.
In your case though, given the distance to the hilltop and low signal strength, it would have to be a massive reflector and alignment would be a nightmare.

hdinsider

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Reply # 556693 11-Dec-2011 19:57

The TVNZ reflectors worked because the signal level was relatively high. I think reflecting a satellite signal would be very difficult as the levels are so low. I've seen satellite amplifiers for sale that boost the L-Band signal. Putting one of these half way down your cable run might do the job.

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