Acoustic Modem - use your mobile radio to log in to your buddy's lap top secure

Originally posted by dainoyfb
reply to post by Rocketman7

 

So, now you don't need the modem but you need six radios?

Why not just buy two EnGenius EOC56110p bridges for $100 each and plug them directly into your laptops with a piece of cat5. They are rated for 30 Kilometers, have double encryption and 50mbps bandwidth.

Got a link to that?

reply to post by Rocketman7


Google does.
EOC5611p

I followed your ongoing debate, and I see the modem as a far better option. Not only do you get the duplex benefits built in, but you could even potentially set up a "mini internet" which would be pretty useful. Not to mention if you secured the modem, it'd be far harder to crack for a low level person who means harm, whereas, with the radios, anyone with a radio could listen in...

Correct if necessary.

Originally posted by GuestStarConspiracy
I followed your ongoing debate, and I see the modem as a far better option. Not only do you get the duplex benefits built in, but you could even potentially set up a "mini internet" which would be pretty useful. Not to mention if you secured the modem, it'd be far harder to crack for a low level person who means harm, whereas, with the radios, anyone with a radio could listen in...

Correct if necessary.

Well the EnGenius bridge option has a faster data rate, much faster. But it would require probably a big antenna and a generator. To get some real distance.

And that might be 50 km line of sight. If you are in a city, you might get two blocks. 2 blocks won't help you. They are designed for an Internet cafe to broadcast to an outdoor patio, or a hotel or motel to broadcast to rooms, or to the pool area.

Now maybe it might work, if you set up your bridge on a roof top of a tall building, but then you need to connect it to a lap top right there. The video from that link, showed that you need to attach an RJ45 cable to the bridge, and a power cord that is 24 volts. Now you can get a 24 volt battery, but if it is sending a powerful signal, who knows how long that will last.

So lets say, that since it is the apocalypse, and you don't really need major bandwidth, you just want to maybe send a couple pictures because cell phones aren't working or transmit a document on how to dress a deer.

Thats not much bandwidth needed if you are not sending large files or video.

You can get by with 9600 baud. The acoustic coupler is 24,000 baud.

You know a typical dial-up connection might be 9600 baud.

So I guess the acoustic coupler has the benefit that you could connect any radios you want. Now that means the expense of connecting expensive radios if you want long distance.

Lets suppose you still want it. So you get 2 FT-817ND Yeasu radios, and you go camping with your acoustic coupler and your lap top. You are camping on a hilltop.

So your two radios at $600 each have cost you 1200 bucks. But they are portable and can reach almost any country in the world.

With this Yeasu antenna for the FT-817

Ok, it requires that someone at the other end has 2 radios and a third for voice unless you use one of the 2 to set it up with instructions prior saying give it 15 minutes to work, then stop and go to voice. etc.

However, if you are using ham radio, you know you will need filters and the signal is not very good. But then you may be able to get it to work around the world if conditions are perfect.

Still if all you need is 200 miles, or 30 miles around a city, maybe this would work, I don't know.

I suppose the question is, what kind of radio equipment, is guaranteed to give a good clear voice signal, in a city, through buildings, because that is the critical part. The acoustic coupler can connect the radios to the lap tops.

So, what portable radios can you get cheap, that will go right through buildings for 30 miles?

The Bridges are only 600mw so the will be comparable in power draw to an FRS/GMRS radio. You will not need a generator to realize their full range. Your range will, in most circumstances be far greater than what you will get from a FRS/GMRS radio and with a fraction of the complexity. I know that FRS/GMRS radios claim long distances on the box but if your read up on it and in my experience you will be lucky to get 3km from them. Also to try and keep the batteries going and everything working together with 6 radios at a time is going to be a nightmare compared to a single piece system that is made for the job. Your OP was about short distance hops and the EOC5611p is perfect for that. Your latest post about linking at much greater distances including around the world is drifting far from goals of your OP but for that you may consider exploring other longer range (all be it more expensive) solutions such as the Amature radio band units now coming out (yaesu has one) that have network data functionality built in.

Originally posted by dainoyfb
The Bridges are only 600mw so the will be comparable in power draw to an FRS/GMRS radio. You will not need a generator to realize their full range. Your range will, in most circumstances be far greater than what you will get from a FRS/GMRS radio and with a fraction of the complexity. I know that FRS/GMRS radios claim long distances on the box but if your read up on it and in my experience you will be lucky to get 3km from them. Also to try and keep the batteries going and everything working together with 6 radios at a time is going to be a nightmare compared to a single piece system that is made for the job. Your OP was about short distance hops and the EOC5611p is perfect for that. Your latest post about linking at much greater distances including around the world is drifting far from goals of your OP but for that you may consider exploring other longer range (all be it more expensive) solutions such as the Amature radio band units now coming out (yaesu has one) that have network data functionality built in.

Yeasu APRS
But then you need a HAM license. And all it does is show your location on a map. Is that what you mean?


I suppose the two options, the Bridge using hi speed data transfer would work, if a person was tech savvy enough to set it up and you could get enough power and maybe an external antenna set up.

But is it completely portable?

then with the layperson system, you have
the 6 mobile radios, at $120 for 6, which you could also distribute to a group for voice communications.
Or give 3 to one person for data communications.

Then you need 2 acoustic modems, 74 bucks each, thats $150 .

Then your lap tops.

So if you already have your lap tops, then your cost is about $270

And it may be easier to set up for a layperson than for them to set up a WAN. (Wide Area Network)

I am savvy enough to be able to do both, so I might be interested in buying a bridge if I can get one for 99 bucks and if it is portable.

I am not sure what kind of antenna would work, but maybe a whip antenna for a car? 12 foot?

But do you have to have it connected to a lap top right there? Through the RJ45? So if you put it on a roof, you need a lap top there, the bridge, an antenna and a truck battery and voltage converter?

There is a Yaesu that has data networking too I think. It was mentioned on a thread here recently. I'll try and find it.

The Layman system is not a layman system because it requires linking between the modem/laptop that is not trivial unless you plan on using a acoustic coupler at each end. The radios will also most likely lack the audio bandwidth required by the modem. also be aware that you'll go through the small internal batteries on the radios quickly if you are transmitting continuously. Also, I don't know if most FRS/GRMS radios are designed with heat dissipation for continuous transmission.

Also, now that you are talking licensing and keeping things legal. Digital transmissions on the FRS/GRMS
frequencies are not legal. Encryption on amateur bands is definitely illegal.


The bridges have POE rated at 50 meters so you only have to have the bridge itself at rooftop. The power is injected onto the cat5 cable so the power supply and computer can be up to 50 meters away.

A 12 foot antenna will not work for network bridges. They run at 2.4 Ghz an 5Ghz so antennas for them generally have elements on the order of a couple inches long.

Ok rough and dirty in the field apocalypse Internet you make yourself.

Scab one radio onto your mic on your lap top with some duct tape.
That will receive data.

Scab a second radio to your lap top speaker with yet more duct tape and tape the button down.
That will send data.

Seal around the radios with some yes you guessed it, duct tape. To try and limit the external noise.

Then using windows, ok, this is where I am stumped. Using terminal server or some communications program to reroute your audio in, to your com port so that the data coming in to your mic and going out your speaker can be sent through the radios.

Is there a handy man in the house who knows how to do that?

The bridges are already set up for bridging and just need very basic configuration like password, etc. Took me 15 minutes the first time. 2 minute after that. Advanced knowledge of networking is not needed.

Originally posted by Rocketman7
Ok rough and dirty in the field apocalypse Internet you make yourself.

Scab one radio onto your mic on your lap top with some duct tape.
That will receive data.

Scab a second radio to your lap top speaker with yet more duct tape and tape the button down.
That will send data.

Seal around the radios with some yes you guessed it, duct tape. To try and limit the external noise.

Then using windows, ok, this is where I am stumped. Using terminal server or some communications program to reroute your audio in, to your com port so that the data coming in to your mic and going out your speaker can be sent through the radios.

Is there a handy man in the house who knows how to do that?

This isn't strait forward either. You will need modems to handle things like propagation delay, dropped bits etc. This is why there is always a modem of some kind. Alternatively you can write software to handle these types of issues as well if that is a skill you have.

I'll have to continue this tomorrow.

Originally posted by dainoyfb

Originally posted by Rocketman7
Ok rough and dirty in the field apocalypse Internet you make yourself.

Scab one radio onto your mic on your lap top with some duct tape.
That will receive data.

Scab a second radio to your lap top speaker with yet more duct tape and tape the button down.
That will send data.

Seal around the radios with some yes you guessed it, duct tape. To try and limit the external noise.

Then using windows, ok, this is where I am stumped. Using terminal server or some communications program to reroute your audio in, to your com port so that the data coming in to your mic and going out your speaker can be sent through the radios.

Is there a handy man in the house who knows how to do that?

This isn't strait forward either. You will need modems to handle things like propagation delay, dropped bits etc. This is why there is always a modem of some kind. Alternatively you can write software to handle these types of issues as well if that is a skill you have.

edit on 13-10-2011 by dainoyfb because: To clarify.

I guess that is where the acoustic modem comes in. By getting the data and then just patching the data into your com port through the RJ11 Windows automatically assumes it is dial-up communications and then you can just use any com software for a modem, and select the modem you have in this case the acoustic modem, maybe you need to provide a driver to the com software if it does not recognize it, but once that is done, you are able to use your modem to communicate.

Now I know that somewhere there is a whiz who could do all that without the acoustic modem, using Windows and probably some terminal service or com port redirection. Emulated modem software or emulated serial port or emulated com port software etc.

However I am not that much of a computer geek to know where to start to do that with Windows.

It used to be easy to redirect ports with DOS. And even in Windows 95, you could just redirect a port quite easily by providing the port address.

But now its a complicated thing and I have no clue.

So I guess for me, the quickest rough and ready network solution in the field, is still to have 2 acoustic modems.
One to give to someone.

Now the advantage to some wizard remapping the ports is that you could have 10 people give them radios, since those are easy to come by, and spare batteries or a car battery and converter to use the radios (heat problems aside) and lap tops and they could all network. Acoustic modems are a fading relic from the past.

The other alternative, is to take a bridge, EOC5611p or similar and an electric scooter, that has a 24 volt battery, like my Kaishan,
and some solar panels and drive the thing up a mountain or hill to the highest ground near where you are, and try to hide it or camouflage it and set up a lap top. Make sure the thing is protected from the weather.
Now since it is up high, it should have line of sight for maybe 30 km.

If you are in a building, in the city, you might need to move around or get up high, to be able to use the network.

The advantage is that you can set up the lap top with Windows Server. So that many of your group could all use the network.
What do you think?

You see the problem is, without a source of power, your lap top on that hill is only going to last 5 hours.

To get it to stay on all the time, you need 4 truck batteries, a voltage converter, and 10 expensive solar panels to continually charge those batteries.
Or something huge and expensive like that.

The alternative where you have your car or truck, and make it mobile, so you can plug in your lap top, at least provides you with a source of power. Something you don't have on a roof top installation.

Originally posted by dainoyfb
I'll have to continue this tomorrow.

Thanks for your help so far. I will look for your reply tomorrow.

why not just use a parabolic reflector and a wifi dongle?

theres instructables where people build them out of soda cans and cardboard, its really simple stuff.

you would need reasonable line of sight though, but if you spend a few bucks im sure you can get a high powered transmitter and some old satellite dishes for very little money, and set up a long distance wireless network with out alot of effort.

its not like you would be subject to fcc violations in such a scenario.

reply to post by Rocketman7


will not work - as the radio handset you link to does not allow duplex traffic

reply to post by Rocketman7


still wont work - the audio jacks cannot be assigned a com # port

Originally posted by snarfbot
why not just use a parabolic reflector and a wifi dongle?

theres instructables where people build them out of soda cans and cardboard, its really simple stuff.

you would need reasonable line of sight though, but if you spend a few bucks im sure you can get a high powered transmitter and some old satellite dishes for very little money, and set up a long distance wireless network with out alot of effort.

its not like you would be subject to fcc violations in such a scenario.

Parabolic reflector. What size?

You see the problem is that you need lets say 25 km. But you can't go through buildings to 25 kilometers.

FM radio stations can. But they have enormous power output.

So then we can go maybe 3 km in a city. 2 miles at most. Thats nothing. That will get you killed and nothing more. You will lose contact with your group or your partner.

So then lets suppose you get up high and put a lap top up there with a network bridge and so then you need to power it. Like I say you go up a mountain or a hill or on a roof, but maybe better on a hill so you can hide it.

Then you need to power it. And I just read some reviews on solar panels and I wasn't too far wrong. 10 panels, 4 truck batteries to charge an electric bike. Same for a lap top and router and a light.

What about a simple repeater? Can you just put a repeater up high, with a car battery and expect it to be powered up for a month? Is there anything that will just take a signal and amplify it in all directions?

Could you put 4 of them on roofs in the city and make a wan with a lap top in a vehicle running off a battery or somewhere with solar panels?

Originally posted by ignorant_ape
reply to post by Rocketman7

 

still wont work - the audio jacks cannot be assigned a com # port

Well what about the sound card?
Can't you just provide the sound card address as a com port?

Right click on my computer - properties- hardware - Device Manager - com port - com 1 - resources - change the irq address?

You would have to convert analog to digital though. So the best thing to do might be to write a little program, that takes the audio and dumps it to disk, and you take the peaks of the signal or somehow get the digital out of the signal.

Its probably easy once you know how.

However it is even easier, to spend 74 bucks and use the acoustic modem to do that.

But! If, you are in an apocalypse, you won't have one or you won't have many of them. Thats why it would be really cool if someone knew how to take that sound card data and convert it to com data and just redirect it to com 1.

Then you could put that little program on a thumbnail drive and just give people the program, a couple radios, some duct tape a lap top and they could connect to the network in their bunker. Locally at least until someone climbed a tree and built a tree house with an FT-817ND radio and became a hub for the larger area say state wide or country wide. But then again they would need two Ft-817ND's and in every local area you would need a guy in a tree with 2 FT-817ND's to connect that locale to the larger network.

Locals connect to the guy in the tree, with radios stuck on their lap top, and he is a hub, he connects to other hubs, and together you have a rough and ready Flintstones Internet.

That still won't work.

The locals would have to connect to the guy in the tree via a bridge, so he can run Windows Server and with their lap tops they log onto the wireless network. HE then uses his two FT-817ND radios to connect to another guy in a tree 200 miles away who is a hub for that locale.

So the locals use wireless through a bridge, but the hubs go long distance using Ham radio.
You can use packet radio, with a radio modem, but thats not easy to set up so maybe 2 FT-817NDs would be easier I don't know.

If it is just two people. Then they can use radios and their lap tops. As soon as you get into a larger network scenario, you need to run windows server to handle the simultaneous traffic and that is where wireless comes in.