Cable modem TV antenna experiment

The other day I was surfing the web and saw an ad for a cable modem, which won't do me any good because I don't have cable, but, the thought crossed my mind, If someone hooked up a cable modem to a TV antenna, pointed it at their neighbors house where they had the same setup... Would you be able to get a network connection between those two houses?

This might turn out to be an unnecessary expense for me to try it, if it didn't work, so, I thought someone on this group might already have the equipment to try it, without incurring additional expense, or, you might already know if it will work.

I thought it would be an interesting experiment.

What do you think?

Reply to
Texas Dawg
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This will not work.

Connecting a TV antenna to your coax input on a cable modem will not bring in a neighbor's anything. It especially will not bring in another cable modem configured the same way at your neighbor's house.

A waste of time and money.

Reply to
Smarty

There are lots of ways to steal cable. That additional expense you incur might be for lawyers.

Reply to
mike

Cable TV doesn't reach this far out of town. I wouldn't be able to steel cable if I wanted to, which I don't.

I think you don't understand what I was talking about.

Reply to
alonzo

It was just a thought. I have Internet through ERF wireless, where their antenna on my roof is pointed at a tower twelve miles away at the nearest town.

My nearest neighbor lives 1000 feet away, he's old, and sick. He likes my Android tablet, so, I was thinking about getting him one, but, he doesn't have Internet. I thought maybe I could get him Internet that way, where he could watch Netflix and surf the web without him paying for Internet at $41.11 per month.

Reply to
Texas Dawg

Rather than trying to relay the cable signal via antennas (which would in effect be creating an unlicensed TV transmitter, and could cause all sorts of legal and technical grief) you'd be better off setting up an 802.11 bridge. A 1000-foot link is definitely possible with a gain antenna on each end, if you have a clear line of sight between the two houses. That sort of solution would be legal, as long as you pick 802.11 radio-and-antenna systems which have been properly certificated. Ubiquiti is one vendor of these sorts of devices.

Your neighbor would have two WiFi devices in his house (one for the bridge, with a directional antenna, and a second access point or router indoors with an omni antenna to provide a base for the tablet and any other device he wants. They would operate on different channels from one another so as to not interfere. One run of Cat-5 Ethernet cable between them, a bit of setup on each end and you'd be good to go.

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Reply to
Dave Platt

My bad. Just use a wireless modem and a cantenna or some such to increase the range.

Reply to
mike

Doing this with a cable modem would never work, for lots of reasons. If your intention is to create a wireless bridge for sharing internet service with somebody, use a wireless bridge or long-range wifi network.

Wifi can be added easily if doesn't already exist, and if distance is an issue, get a bigger antenna. I've done it: Had two neighboring farms sharing an expensive satellite internet subscription. Used two access points driving signal amps with outdoor dish antennas on poles. One end provided a secured wireless network, other was client. Wasn't overly fast, but did what was needed and it blew dial-up (only other option) out of the water. Works well aside from issues caused by severe weather (dish alignment). Put in several years back, still in use as of November.

If the intention is to steal cable internet or TV, what you suggested isn't even remotely close to being a way of doing either.

Reply to
nvic

No, for several reasons:

Cable modems expect very strong signals; far stronger than you could ever collect with an antenna.

Cable modems are two-way devices, and will not function at all if the "upstream" signal doesn't make it back to the headend. You'd probably need a several-thousand-watt "booster" and a VERY LARGE antenna to send that signal wirelessly to your neighbor.

All cable modems are "registered", and the provider knows where each and every one is on the network, in terms of how long it takes the signals to travel between the modem and the headend. No modem with a time delay or a registration they didn't have on file would ever be allowed to operate.

Isaac

Reply to
isw

I just came back from a very similar install. 800ft using two Ubiquti Nanostation Loco M5. The M5 is the 5.7Ghz version, not the 2.4GHz version. The main application was shared internet access, but also to stream a common media server for HD movies via wireless.

Using the internal Ubiquiti benchmark tests, I was getting about

150Mbits/sec thruput in both directions (one at a time) and splitting it in half for full duplex simulation. When the radios were both on the setup bench, I was getting over 200Mbits/sec. Using Jperf, I was only able to get about 120Mbits/sec in TCP, half duplex. Some tweaking should bring it up. Note that is two MIMO streams, one vertically polarized, and the other horizontally. This is MUCH better than what I typical get with 2.4Ghz links. Highly recommended. Hint 1: Make sure all the radios are running the same firmware or nothing works right. Hint 2: With bridging, make sure there's exactly one DHCP server running on the network. You're life will be miserable if there is more than one. Hint 3: The mounting bracket does NOT come with the package. The 24v PoE box is included.

Drivel: Every muscle aches, my cold/flu/crud is far worse, I left my ladder at the site, got involved in some brush removal to improve the LOS, and spilled much of my toolbox all over the hillside. I didn't know that poison oak was active in January. There's a Motorola SP10 walkie talkie somewhere on the hillside. No photos because I left my camera at home and my Droid X micro-SD card was full. The setup was fairly easy. The physical installation, not so easy. Sometimes, I wonder if internet connnectivity is worth the effort.

Nope. The Ubiquti Nanostation Loco M5 supports WDS (wireless distribution service), where the radio supports both access point features and store-and-forward repeater features. More specifically, WDS is bridging. I was connecting through the local bridge radio, with my dual band wi-fi equipped laptop, to the other end of the link. Running bridging, where everything runs at the MAC address level (layer 2), made connectivity to everything quite easy. They were rather pleased when I was able to print to a remote laser printer, and not so pleased when I connected to their Roku streaming media player, iPod, iPhone, etc via the network. The VLAN configuration is the next step in order to isolate parts differnt parts of the network (and reduce broadcast traffic across the wireless link).

Yep. Note that section "E" shows the setup as "access point WDS" which Ubiquiti lingo for bridging. That should be the device closest to the main internet router. The client end(s), should be setup as "station WDS". With this arrangement, you can also have more than one station.

As for the cable modem antenna idea, it won't work. It will be spewing the entire 40-1000Mhz CATV spectrum and not just the channel that you're watching. It's like watering your lawn with a fire hose at full pressure. Colateral damage (interference) is inevitable. The cable also works both directions. Ingress (where the cable picks up over the air radio stations which mix in the cable amplifiers, is a major problem for the cable company. Ingress will show up on the management software or fly-over survey, making discovery of your abomination quite likely. It's futile anyway, because you'll need a legal cable box to watch digital channels. Analog TV channels are slowly going away. Also, the signals on the cable are such a low level, that you'll need an RF power amplifier in order to transmit more than a few inches. Building a suitable RF power amp with sufficient linearity to not trash the video is not a trivial exercise.

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Reply to
Jeff Liebermann

The simplest solution is to find someone with a wireless router who hasn't done anything to prevent unauthorized access.

By the way... It's possible (and quite easy) to set up your local network so that it will communicate only with devices that you've supplied the MACs for. This isn't 100%-foolproof, as it's possible for someone to read the MAC when it's transmitted, then mimic it. But for the average user, it makes your network effectively inaccessible.

Reply to
William Sommerwerck

Maybe I just missed it. Could you repeat the total customer cost number for the install including the links at both ends and installation?

Reply to
mike

1000 feet is gonna be more than you want to deal with. But more importantly, how far to HIS nearest neighbor. Maybe it's more feasible for him to steal their netflix and internet.

For movies, you can load the movies onto a flash card and deliver it to his tablet.

Reply to
mike

Actually, I haven't added it up yet. Note that this system is for sharing internet, not remote video.

Prices are off the top of my head as I'm too lazy to look them up and the pile of receipts are scattered all over my office.

Quan Item Unit cost Exten cost 2 Ubiquity Nanostation Loco M5 $ 90 $180 2 Mounting brackets $ 8 $ 16 1 100ft CMXT (gel filled) CAT5 $ 10 $ 10 2 Through the wall hardware $ 10 $ 20 1 Linksys E2500 wireless router $ 35 $ 35 1 Power strips, wall plates, RJ45 plugs, $ 20 $ 20 sinkers, "P" clamps, etc. 1 Satellite TV "J" mount $ 20 $ 20 =========== Total $301 Add about 12% for sales tax and shipping. Add about $40/ea for Nanostation M5 HP, if you need more range. The Linksys E2500 is for redistributing the internet inside the house on both 2.4 and 5.6Ghz. It is setup as an access point, not as a router. Price is for a refurb on eBay while retail would be about $65.

To add remote video, add a Slingbox for $180: and a 2nd CATV digital receiver for whatever the local cable company charges. Currently, video from the DLNA video server is being watched on a Roku 2 XS streaming media player:

The internet connection is wireless via Etheric networks in an area where both cable and DSL are not available. Previous experience with satellite internet was deemed a waste of money: At about $180/month, sharing the cost is certainly a good idea.

I haven't worked out the charges yet. Ignoring several diversions and stupid mistakes (including getting a cardio workout by chasing the escaped house cat through the bushes for about 15 minutes), and since the owner did all the endpoint preperation, I'll probably only charge for 3 hrs at $75/hr = $225 in labor. About half of that is preperation, ordering, travel time, and RTFM, which were not directly involved in the actual installation.

I'll be going back later to add some ethernet lightning arrestors which did not arrive in time. When the smoke clears, I would guess that the total will be about $600 for everything including the inside network, wiring, configuration, SNMP monitoring setup, "training", system documentation, backups, and of course testing by watching about

15 minutes of a movie on Netflix.

If you do it thyself, it can be done with zero labor cost, scounged hardware, wire scraps, and used equipment for some savings.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

I have 5.7GHz links that are 1.0 miles, 1.5 miles, and 3 miles. They run a mix of Ubiquiti hardware. Zero problems with the link part of the puzzle. In the past, I used 2.4GHz links, with bit 24dBi barbeque dish antennas. Add some interference, and it simply didn't work.

5.7Ghz fixed that. 1000ft (1/5th of a mile) is a no brainer.

If he can get a wireless or wired bridge running, one of these should be able to provide the necessary video:

I know very few people who a willing to watch an hour or two long movie on a tablet screen. Large screen LCD TV's are more common. Plugging the big LCD TV into the iPad or Android tablet via an HDMI cable works. At that point, might was well get a streaming medial player from WD, Netgear, Roku, and others, instead, and leave the tablet for other things.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Actually, it's trivial to hack into a wireless router with MAC address filtering enabled. Just sniff the traffic to/from that wireless router and collect the MAC addresses that are being used. The MAC addresses are NOT encrypted. Then, just change the MAC address of your computer to one of them, and you're on. MAC address filtering might be effective for the clueless user, but the average user usually knows someone more knowledgable who can help.

For a wireless router, the only real and effective security is WPA2 encryption. All else, including MAC address spoofing, IP filtering, SSID hiding, and the disgusting guest mode, are only minor additional obstacles, which can eventually be circumvented with minimal effort.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

I submit that "no brainer" for you is way more than he would want to deal with. Spending $600 to redistribute ethernet service and netflix service in violation of TOS seems like a lot to deal with.

And, with these threads, there seems to always be a gotcha.

50 posts into the thread the OP volunteers, "There's a huge ass metal building in the way...does that matter?"

I'm just too cheap to comprehend stuff like this. My wireless bridge is a $1 WRT54G with tomato firmware. I expect 1000 feet would be a stretch. But I can't see more than about 200' without running into a forest or a big ass metal pole building.

I administer my neighbor's system. I have many ways to steal his netflix, with or without his permission...but it puts him at risk and it's just wrong.

Reply to
mike

You are fortunate. Around here, the providers prohibit redistribution of their service. I could save a bunch of money by hooking up the whole cul-de-sac to one cable connection.

Reply to
mike

That's assuming there's no data encryption. I use both encryption and MAC filtering.

Nevertheless, I appreciate this information, as the book I read indicated that you needed hardware to spoof a MAC address. (Perhaps the author was talking about what was required to sniff it.)

A friend of mine remarked that both he and I were relatively safe from such attacks. "Why would anyone be interested in accessing //our// computers?" Indeed. This is true for most users. Of course, it's no excuse for not taking simple steps to protect yourself.

Reply to
William Sommerwerck

William Sommerwerck udtrykte præcist:

Changing the macadress is usually no problem.

Often, it is not your computers which are interesting. More often it is your connection, so somebody will break into your network will use it just for not having to pay for internet access, or worse, to break into other computers, to do illegal filesharing or to down/upload kiddyporn. Which could get you in trouble if it is traced back to your network. On the other hand, it could be your defence, because "Judge, it could be anybody, because my network is not encrypted".

Leif

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Reply to
Leif Neland

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