walky talkies hacked to be used for data transmition?

noobmuncher

Hey so i saw these online 99$ 45 km radios and even thought the reviews all they that they really are only good up to 5 km (3.1 miles) is there a way that i could hack these to transmit code over that distance? If so i think i could probably double the 5 km range by using a stationary antenna. Especially considering these are rated up to 45 km!

Any ideas i am happy to hear them!

Post Edited (noobmuncher) : 11/25/2008 6:21:18 AM GMT

Phil Pilgrim (PhiPi)

The Canadian Tire site asks for a postal code to enter. For non-Canadians, just type in V6B2R4.

GMRS radios (which require a license to operate) and FRS radios (which don't require a license) are prohibited by law from transmitting data. Only voice and paging tones are permitted. It's easy enough to get an amateur Technician Class license, though, which permits data transmission in the VHF/UHF ham bands. The equipment tends to be a little pricier, however.

See Ken Gracey's thread regarding data transmission in the 2-meter ham band. I'm currently finishing up some modem software for the Propeller, which will interface with radios such as Ken's.

-Phil

P.S. noobmuncher: Could you please insert your url text into a [noparse][[/noparse]url= ...] [noparse][[/noparse]/url] tag pair, please, to create a descriptive link? The url text is so long it's causing this thread to scroll horizontally. Thanks.

Post Edited (Phil Pilgrim (PhiPi)) : 11/24/2008 9:14:17 AM GMT

Jay Kickliter

Phil, are you doing an AFSK implementation? Or an object to interface with an external modem? I've been hoping for AFSK so I can turn the propeller into an APRS transmitter.

Phil Pilgrim (PhiPi)

Jay,

It's AFSK, 1200 baud (Bell 202). It requires a few external passives for filtering and a transistor for PTT.

-Phil

Fe2o3Fish

Phil Pilgrim (PhiPi) said...

GMRS radios (which require a license to operate) and FRS radios (which don't require a license) are prohibited by law from transmitting data.
Only voice and paging tones are permitted. It's easy enough to get an amateur Technician Class license, though, which permits data
transmission in the VHF/UHF ham bands. The equipment tends to be a little pricier, however.

Be careful Phil! The FRS rules/regulations have been modified a time
or two. Yes, the original FRS rules dictated no data. I thought the
same way 'til I started seeing FRS units with built-in GPS. Apparently
Text messages can be sent via FRS now but, per the rules, have to be
manually initiated.

That's my bolding in the text below:

Sec. 95.193  (FRS Rule 3) Types of communications.

    (b) Non-voice communications. 
         (1) The FRS unit may transmit tones to make contact or to continue
              communications with a particular FRS unit.   If the tone is audible
              (more than 300 Hertz), it must be transmitted continuously no
              longer than 15 seconds at one time. If the tone is subaudible
              (300 Hertz or less), it may be transmitted continuously only 
              while you are talking.
         (2) The FRS unit may transmit digital data containing location 
              information, or requesting location information from one or
              more other FRS units, or [b]containing a brief text message to
              another specific FRS unit.[/b] Digital data transmissions must
              be initiated by a manual action or command of a user, except
              that an FRS unit receiving an interrogation request may
              automatically respond with its location. [b]Digital data transmissions
              shall not exceed one second,[/b] and shall be limited to no more than
              one digital transmission within a thirty-second period, except 
              that an FRS unit may automatically respond to more than one 
              interrogation request received within a thirty-second period.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
-Rusty-
--
Rusty Haddock <=> AE5AE
**Out yonder in the Van Alstyne (TX) Metropolitan Area**
Microsoft is to software what McDonalds is to gourmet cooking

Post Edited (Fe2o3Fish) : 11/24/2008 6:51:28 PM GMT

Phil Pilgrim (PhiPi)

Rusty,

Thanks for pointing this out. I was aware of this exception (apparently initiated by Garmin), but the "one second in thirty" rule and the requirement for manual initiation seemed too restrictive for general-purpose back-and-forth data communication.

-Phil

noobmuncher

Thanks everyone feel free to let this topic run, but I am going to look into ham radio transitions, lol already i have plans to put my dorm room into security mode and clean itself with my robot from miles away lol! Not to mention control a UAV lol.

john_s

How do the FRS rules/regulations apply to DTMF method od data communication over the air?

Fe2o3Fish

John,
The way I'm reading the reg's, it doesn't appear that DTMF would be a permitted for data
comm in the Family Radio Service. But, IANAL either.

Noob,
Good luck with getting your ham license. You shouldn't need more than a Tech class
license for VHF and above (50-MHz and up) operations.
UAV --> Unmanned Amateur Vaccuum -- for remote dorm room cleaning!

Phil,
I totally agree. And we can thank our friends at Radio Shack for having the FCC to create
yet another CB and thusly the FRS!

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
-Rusty-
--
Rusty Haddock <=> AE5AE
**Out yonder in the Van Alstyne (TX) Metropolitan Area**
Microsoft is to software what McDonalds is to gourmet cooking

noobmuncher

Ha ha thanks, actually in the network i am setting up one of the things attached is in fact one of my first robots which is a AUV (vacuum cleaner) lol! But obviously i ment it as Autonomous Ariel Vehicle lol.