Make my own Hotspot with a few Pi's

[CJ1]

I 'd like to build my own HOTSPOT, like CLEAR or Verizon or other vendors have. I realize I will need at least 2 Raspberry Pi's One for transmitting and one for receiving.
I realize along with both Pi's they will need wireless Wifi (for Internet). I will need (I believe) a FM transceiver for both. This is not a great distance. As the crow flies (line of sight) my 3rd floor apartment (flat) is less than 2 miles. (3.2 KM).
I have seen projects for FM transmitting and also to make a Pi an access hot point. I'm just wondering if anyone has done this before and/or could guide me? Let me know the "Gotcha's" before I start. Etc.
I believe you guys (Adafruit) sell FM transceivers. If you have some for the distance I would buy them from you. If not I'd appreciate you letting me know where to buy some. I've seen some with ranges up to 40-45 miles. costly at $79 each but cost is not a factor as this is more of a proof of concept type project. Not to mention if I pay for internet at home I'd love to be using it a few meters from my apartment.

I've asked this on other forums and got an answer on how to set my Pi up as a router or Access point. I know how to do that. I want to be able to send the wireless from my flat to some where in the city (no more than 5 miles) and receive the wifi for my laptop iPad etc.

Am I asking the right information? Am I on the right track? Do I need different equipment?

Any help from anyone would be appreciated.

CJ

[Douglas6]

I'm afraid I don't have an answer for you, but perhaps I can clear up some misconceptions. 1. This forum is populated with volunteer Raspberry Pi enthusiasts, and run by the Raspberry Pi Foundation. No connection whatsoever with Adafruit. 2. FM broadcasting is licensed by the government and is not for public use. 3. You may be thinking of Lora radios sold by Adafruit. I sincerely doubt you could run TCP over a Lora radio; I could be wrong. So, those are your main 'gotchyas', I think.

[SonOfAMotherlessGoat]

I would think you could run TCP over just about anything within reason, the actual medium over which you communicate would be handled at it's own layer (fun with OSI!). Now that being said, using the LoRa over license free ISM is a possibility, but the speeds you are looking at are quite dismal. From Ada "The data rate is adjustbale but its common to stick to around 19.2 Kbps."(sic)

[Douglas6]

I would think you could run TCP over just about anything...but the speeds you are looking at are quite dismal.

That sounds about right. Maybe better than pigeons.

[SonOfAMotherlessGoat]

That sounds about right. Maybe better than pigeons.

Lol, have you ever tried to checksum a pigeon packet?

[bensimmo]

Directional Wi-Fi antenna and good alignment ?

[ghans]

Note that FM and WiFi are very distinct and incompatible
technologies. Furthermore WiFi needs transcievers on
all sides , pure "recievers" simply don't exist with WiFi -
perhaps the biggest difference to FM radio broadcast.

ghans

[scotty101]

FM is an analog modulation.

Wifi uses a digital modulation, OFDM i believe.

And as others have pointed out, you probably don't have a license to transmit, especially not with the power needed for 3.2km.

[CJ1]

I appreciate al the responses. I refer you back to Magpi Issue #17 (Page 22), October 2013 article by Matthew Hollingworth. He talks about "Long-range wireless with RPi900". He mentions being able to talk to the Pi. He also mentions the frequency it (FM Transceiver) uses are available for license-free use in most countries.

I'm not concerned with the legality I'm concerned with the "proof of concept". I'd like to be able to get it done. Then I will worry about other issues. I'm trying to google how other vendors make their portable Hot spots work. But so far no definitive answers.

As I said any help would be appreciated.

CJ

[stderr]

I'm not concerned with the legality I'm concerned with the "proof of concept". I'd like to be able to get it done. Then I will worry about other issues.

It might be difficult to continue your studies as a lifer in Sing Sing or wherever they put FCC scofflaws. In any case, people on this website can't provide how to instruction that might invite legal stricture, the potential liability and all.

[CJ1]

Unbelievable!
It would be nice if people read all the posts.
I stated in the post and he states in the article the FM Transceiver he uses uses are available for license-free use in most countries. The USA being one of those countries.
RPI900.COM is the web site. Or refer to the article. I'm sure the Pi foundation would not post an article allowing federal laws to be broken!

Let's be an adult and take in all the facts before making a childish remark!

[CJ1]

From the web site:

The DNT900 is a 900 MHz, frequency-hopping spread-spectrum radio transceiver with maximum transmitting power of 1 W and a range of up to 40 miles. Data transmission rates of up to 500 kb/s are possible, depending on range. Point-to-point links between two radio are easy, as are more complex networks of multiple remotes. The radio also includes analog and digital I/O for sensor applications. It operates in the ISM band and is FCC certified for unlicensed operation. At $70, this radio is probably the most affordable in its class.

[ghans]

Make sure that the seller provides instructions on how
to configure them under official Raspbian images
and/or provides upstream Kernel drivers. It is not your
job to cobble either of that together yourself , but the sellers.

You might want to research on the keywords "Bridging" ,
"iptables" , "pppd" and "hostapd" too.

ghans

[CJ1]

@ghans

Thanks for the feedback. I'll keep that in mind. Much appreciated.

[stderr]

I stated in the post and he states in the article the FM Transceiver he uses uses are available for license-free use in most countries. The USA being one of those countries.

In the US, you cannot transmit high enough power on the FM broadcast bands, which is known as "FM" to most people, to go 45 miles without getting a visit from the FCC, which is what I was responding to. You might be able to transmit so you could hear your content on small radios inside your house and perhaps a bit more but not anything like you are going on about. They, however, do sell higher power FM radios. They are not legal in the US!

Now you seem to be talking about something that isn't using broadcast frequencies, rather ones that offer unlicensed operation with certain restrictions. If you change what you are saying to something entirely different, then things can be entirely different. You still can't ignore the law. Furthermore, you continue to refer to what you want to do as "FM", so you aren't even really walking back your original assertions.

[CJ1]

I didn't make this up. Its from MagPi issue I mentioned and his webpage project and manufactures website.
It mentions up to 40 Miles transmission line of sight and FCC and Canadian IC Certified for Unlicensed Operation.
http://www.digikey.com/catalog/en/partg ... -kit/30658

and spec sheet.

http://wireless.murata.com/RFM/data/dnt900dk.pdf

I'm through answering anything but constructive posts.

[bensimmo]

Note that FM and WiFi are very distinct and incompatible
technologies. Furthermore WiFi needs transcievers on
all sides , pure "recievers" simply don't exist with WiFi -
perhaps the biggest difference to FM radio broadcast.

ghans

I know the difference, it was an alternative method to create the link from the home network to the other place network. By WiFi I was leaving it open to WiFi type technologies. Line of sight would be needed afaik.