Just a correction, transmitting on GMRS radio frequencies does require a license. It’s not a “proof of competence” license like a ham license; the only test is whether or not the FCC can cash your check.

There are interesting things you’ll learn once you get your license, though. For example, it’s illegal to use GMRS channels 19 and 21 north of the 49th parallel from Washington to Minnesota, and other points sufficiently near the Canadian border (apparently they conflict with some Canadian military frequencies.) The thing that always puzzled me was why Garmin didn’t encode that line in the internal map, and shut off those two channels in the “forbidden zone”.

Posted at 1:38 am on Nov 19th, 2007 by jaded

How about making it into a cheap wireless modem. You could run the audio out from a modem into the microphone jack. You could have another running into a phone line or another computer.

Posted at 1:54 am on Nov 19th, 2007 by Max

I am not sure that I like this idea the more I think of it, but I’m going to mention it anyhow… Make a “gaydar”-style social networking thing. Have a server elsewhere that maintains a list of your interests, what you are looking for, etc. As you travel around it tracks you and it’s other users and when one that it feels is an appropriate match is in the immediate vicinity, it notifies the two of you so that you might meet face to face.

Posted at 1:59 am on Nov 19th, 2007 by Blind

you do realize that gmrs radios require a license, don’t you? also they must be fcc type accepted to operate on the frs/gmrs bands, therefore no ‘hacks’. the rhino also was a rare exception and granted special permission to transmit data within the band.

Posted at 2:01 am on Nov 19th, 2007 by a

this is what i get for posting when it’s late and I should be sleeping.

Assuming that it isn’t obvious, I’m expecting there to be gps tracking on all of the units (like the original post) in addition to the required connection to the server.

Probably an easier way to do this though.

Posted at 2:01 am on Nov 19th, 2007 by Blind

i have a bunch of these. i’d love to be able to harness their power and use them as an R/C control, or at least figure out how to boost the tx power or change the frequency :)

Posted at 2:22 am on Nov 19th, 2007 by steve diraddo

i also noticed that the frs band has a greater frequency than whats required by an analog NTSC video signal. perhaps its possible to transmit video signals with a slight modification or two.

Posted at 2:26 am on Nov 19th, 2007 by steve diraddo

After the obligatory comments about modifying this equipment being against FCC rules, I have a pair of Bellsouth FRS model 1050 radios that have actually have internal 10k pots for more high end radio features like squelch and microphone gain that can be broke out relatively easily. Adding external BNC connectors to the antenna and hooking the radio to some 70cm ham radio antennas will exponentially increase the range on the radios.

Posted at 2:26 am on Nov 19th, 2007 by josh

@#4:

Yes, GMRS is licensed. Barely. You pay a fee, fill out a form and you’re licensed – no test whatsoever. And that’s if you’re hyper-honest. I don’t think most people bother with even that small formality.

Posted at 2:49 am on Nov 19th, 2007 by josh

@4, @7:
Not in canada, Here they are bound only by RSS-210, as is FRS. Refer to Annex 6 of RSS-210 for details.

Posted at 3:00 am on Nov 19th, 2007 by wikityler

Here in NC the police use GMRS somehow. I think it’s on there belt mounted radios. They use EDGE or something on there computers.

Posted at 4:18 am on Nov 19th, 2007 by TJhooker

The freq can be readjusted pretty easily with a handheld freq meter and a pot tool on most model’s.

You can’t go far only .5 mhz but it’s enough to get all the channels to be in between the regular channel’s so that anyone without a adjusted radio only gets garble junk that doesnt even sound like a voice.

Aka poormans scrambler.

Ive done it dozen’s of times

Posted at 4:59 am on Nov 19th, 2007 by TJ

Funny all the licensing crap. I like the idea of having the GPS attached to one of the radios. It is not cost effect to have it on all of them. Nor would young kids like this.

Maybe to use the main radios (FRS with GPS) TX a homing signal to the child FRSs) This way the child Radios can track the parent when the parent is on the move. What and how the protocal would be, I do not how to handle this.

Posted at 6:21 am on Nov 19th, 2007 by Brat

I like the idea of sending video. You have a lot of channels can you make you of that as added bandwith. But how does that make use of the GPS? Maybe to encode the remote users location?

Posted at 6:23 am on Nov 19th, 2007 by Brat

You could connect a radio to your PC and using Voice over IP magic, have conversations with people on the other side of the world!

e.g.: http://www.446user.co.uk/article_12.html

Posted at 6:58 am on Nov 19th, 2007 by lwr

Man, I would love to see some hacks for these things. I’ve got a ton of these radios, a couple of them hacked apart.
Canada used to have the same legislation regarding GMRS. Commercial and private pressure got them to remove the licensing requirements. There is a substantial amount of pressure in the US to follow suit.

I’m not an electronics guru. I’ve tried to send video (NTSC) over a short range FRS link, simply by playing with the plugs. No dice.

However, if someone could come up with a method to do this, we have struck gold. A decent, hackable radio interface that performs well at range, with no need for tuning. Come up with a method to use it as a short haul wireless modem, and you’ve got a dream system.

I’ve seen some of the most innovative people on this board do some amazing things. I can’t believe someone hasn’t come up with something along these lines.

Posted at 7:39 am on Nov 19th, 2007 by Static

Hmm, this is tough. You could modify them for a wall-mounted intercom system. I’m not sure, but you may be able to modify a radio to act as a scanner. I know you can do it with an AM receiver, but I don’t know whether FRS/GMRS radios use AM or what.

Posted at 8:14 am on Nov 19th, 2007 by Skyler Orlando

simple idea: how about a hack to make a 2-way system? that way it could be used hands-free.

if only 2 people are using the link, then a separate channel could be used in each direction. now you have a poor-man’s radio-telephone.

the only way i can think to do this is strap a pair together – making it quite heavy. however since it is hands-free, and if you take the skiing example, the “box” could go in a back-pack or deep-inside pocket or something.

Posted at 8:32 am on Nov 19th, 2007 by aefaradien

another idea (sorry for double post):
2 gps/radio units that always point at the other?

Posted at 8:35 am on Nov 19th, 2007 by aefaradien

FCC rules on FRS and GMRS say “No unmodified radios” (sigh) , and also say only an approved radio can be used… which annoys me, since if I were to freeband my Ham HT and set it for low power (both software changes), I could emulate FRS and GMRS except for the “no mods/approved hardware only” rule. Would be nice to have just one radio to talk to Hams and non-Hams alike just by turning the knob.

You’re also not supposed to push data over them, unless you have an FCC exemption.

That said, what kind of _legal_ fun?

I believe an FRS with Vox plugged into the soundport of a computer would be legal. Load up one of the voice recognition packages, add text-to-speech and build an FRS/eMail gateway. Have a pre-defined “Heinlein/Number of the Beast/Gay Deciever” syntax to control it, and you’d be all set.

Having it tied to an RSS feed accumulator of some sort would rock too – being able to be out on the far side of the farm and say,”Computer, weather report, execute” would rock.

Tie it into one of the cheap USB X-10 controllers, and you’ve got the house lights and outside light. “Computer, Front lights, fifty percent, execute”

The VOIP one has been done with EchoLink, but that’s a Ham-only set up. Should be able to use off-the-shelf software for the rest.

If you can track down one of those old “dialers” you hold to the telephone, or use your PDA headphone jack plugged into the FRS, you could send DTMF from an unmodified radio…. Might be useful to control various things.

One option for an unmodified radio being used more efficently with a vehicle would be a plastic box with a magnet in it. Use long earphone/mic cords through the car window, put the radio up on the roof so the car doesn’t block 90-odd% of the RF. You won’t be able to change channels, but it should substantially improve the range while on the road.

Posted at 8:39 am on Nov 19th, 2007 by Jeff

@10 – You win. That’s the best information on FRS I’ve ever read. I have 5 of these units. Ideally, when we have soccer tournaments that mean my wife and I are trying to keep track of multiple games and kids at different events within a mile or so of each other we can use them. Unfortunately, the band is so crowded with kids being stupid on them that it doesn’t work out. They’re a little better for road trips between cars in a caravan (a convoy if you’re old enough to remember the 70’s film).

Anyway, I’m going to look into that 1/2 step freq change you mentioned. That would rock.

Posted at 8:58 am on Nov 19th, 2007 by Andrew Pollack

the garmin rinos only TX a position report when you key up, so they’re not much good for finding someone who isn’t actively wanting to be found.

data transmission on FRS/GMRS is strictly forbidden; garmiin was granted an exception for the rinos, and that exception has limits (no automatic position beacons – they must be requeted by a human operator).

there are some tools that go with xastir (unix APRS application) to import the rino data into xastir alongside APRS data. pretty cool.

and a minor nit, the opentracker is based on an MC68Hxx controller, not a PIC. I think the original TinyTrack was a PIC, but he’s switched to Atmel micros.

Posted at 9:12 am on Nov 19th, 2007 by jason Winningham

I’m looking for batteries for the watch-style radio in left of picture. Got mine from Marlboro. Can’t find battery XB-10 anywhere.Help.

Posted at 10:22 am on Nov 19th, 2007 by Gary Weber

I use an FRS link for a DTMF controller on board my ROV.

please google “probe II sg” as I don’t have photos up of this project anymore.

Aside from repositioning the antenna to the outside of the ROV and wiring the external speaker output of the first FRS radio to the DTMF controller on the receive side, all I did was parallel the audio from the speaker of an old radio shack portable autodialer device and wire a momentary switch from that into the mic input of the other FRS radio on the transmit side.
(I tried to use VOX, but it’s cumbersome with DTMF.)

It works flawlessly, although I don’t get the additional dtmf a,b,c,or d buttons using the rad shack autodialer for the DTMF tones.

The DTMF system on the ROV controls a homebrew video camera switcher to select any one of three onboard video cameras, control the zoom focus and iris of the color camera and to trigger a little speaking thermometer to inform me of the internal temps of the two vehicle sections over the existing video link audio.
(My ROV was designed for outdoor operations and I was concerned about overheating.)

“probe ii sg” is currently mothballed intact, along with all of it’s support gear and spares in my den closet.

Posted at 10:52 am on Nov 19th, 2007 by strider_mt2k

I did a bunch of research into this very idea a year or so ago. I even got to the point of building a 300 baud audio FSK modem (based on an Exar XR2211) to test with my idea.

Part of what I discovered is that prior to the Rhino, there was no provision in the FCC regulations to allow for data transmission in the FRS and GMRS bands. It looks like Garmin lobbied to have the regulations tweaked just enough to make their product work. The rules are not specific to Garmin. It makes a number of stipulations, the most important being:

“Digital data transmissions shall not exceed one second, 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.”

The regulation can be found here:

http://edocket.access.gpo.gov/cfr_2006/octqtr/47cfr95.193.htm

If you live in Canada (as I do), the exact same rules apply. The Canadian section of the GMRS/FRS regulations look like a copy-and-paste of the relevant US section.

Posted at 10:56 am on Nov 19th, 2007 by Keelan

Regarding comments 10 and 19, the rules do not simply specify the bottom and top frequency of the band; the rules specify the exact frequency of individual channels. Modifying a radio to transmit and receive 500kHz off-frequency is a violation of the law. As well 500kHz is way too much; the GMRS/FRS channels are spaced 25KHz apart.

When it comes to something that is globally shared (radio spectrum), play by the same rules that everyone else does; the alternative is chaos.

Posted at 11:05 am on Nov 19th, 2007 by Keelan

The FCC Restrictions are also why there are no trucker-CB-style units available. The entire thing has to be self contained – there are no base stations with an external antenna, microphone, and speakers. Probably to keep them from being tampered with. I would love to see some modem hacks for these too… The range would be awesome!

Posted at 11:18 am on Nov 19th, 2007 by Sean

If you could transmit data easily, pair them up with a 3-axis magnetometer, GPS unit and microcontroller, and play “real-life” scorched earth or something similar

Posted at 11:31 am on Nov 19th, 2007 by chris

Here in Canada, we get to use GMRS without licensing restrictions, which is nice. I doubt it’s legal to send data over the frequencies (packet data in store-forward mode is expressly forbidden). That being said, there are a lot of hacks I’d like to see done with this gear- in rural areas like I live in, nobody ever checks up on illegal transmitters, so it’d be easy to get away with.

1) Video transmission, like others have mentioned.
2) Packet radio modem, for sending still frame-captures and weather data from a weather station.
3) Autopatch system- base station connects to PSTN line and you use a portable DTMF generator to dial out from the gmrs handheld.

Someone mentioned pairing 2 radios into a duplex system- the problem with that is that you’re going to be TX’ing constantly with one radio, which will a) drain the batteries in no time and b) overheat the unit’s tx board. Bad on both counts, but would still be a fun hack.

Posted at 12:57 pm on Nov 19th, 2007 by Rustybadger

This is kind of pie-in-the-sky, but you could use this for home automation or similar. Just set up voice commands on your “hub” PC and pipe the output from your “home base” GMRS into your mic input. You could even establish 2-way communications if the radio unit has a line-in (if it’s PTT, that might be tricky).

Going further down that path, you could leverage all sorts of voice-based PC interfaces, not just home automation. “Computer, Google ‘chinese restaurant 21050′” and it reads you a list of names and phone numbers. “Computer, playlist White Stripes” — I’m sure that would sound terrible in mono over this kind of radio link, but it’s still a neat hack. “Computer, email Jane, subject: ‘Lunch today’, body: ‘I’m going to be in town starting at 11:30…’”. Lots of possibilities here, and you probably don’t even have to write any code or solder anything yourself. Ehh??

Bonus: it’s not a violation of the FCC ban on data transmission if you’re doing everything by voice. Right?

Posted at 1:37 pm on Nov 19th, 2007 by James

Is there any way that the results of Hack-it could be displayed in a blog post so that people who browse the blog, but don’t have time to dig through 100 comments still get to hear the ideas of the winning contestant? If so that would be great.

Posted at 2:10 pm on Nov 19th, 2007 by Crypto77

Re: linking with voice recognition software… voice quality and interference is terrible on these puppies, so I don’t think that will work. However, DTMF (or your own equivalent) would seem pretty basic, and probably falls within the law. Furthermore, since you’re leaving the radio portion intact, it would not really be considered “modified”. What would be suitably hackish is to embed a custom tone generator with keypad physically into one unit (rather than taping an old DTMF generator to the mic) and a recognition circuit built into the other one, which could then send the “codes” sent over the link to a USB/serial connection for consumption by a computer or other device.

Posted at 3:32 pm on Nov 19th, 2007 by RK

@ #14 (Skyler Orlando) & #15 (aefaradien): Some radios have channel and privacy code scanning built in, such as my Cobra 950s. I believe regular radio scanners should be able to pick up FRS/GMRS frequencies without trouble, it’s just an FM signal. For the intercom thing, hands-free is easy, if not always reliable, if your radio has VOX features.

And just to reiterate what others have said, there’s a reason there haven’t been hacks for these radios – almost all modifications and data transmission are illegal. For FRS, that means no internal modifications (or antenna mods), and keelan (#30) summed up the data issue nicely. FCC Part 95.191-194, for reference. GMRS is expressly forbidden from transmitting data. (Part 95.631(f))

There’s also a reason the rules exist – these bands are basically designated for family communications on trips. If you want to do data, Ham or MURS (http://wireless.fcc.gov/services/index.htm?job=operations&id=multi_use) are the legal options.

Posted at 6:47 pm on Nov 19th, 2007 by TheOneTrueStickman

>I’ve been surprised by the lack of
>hacks for these little guys.

I hacked one, see http://www.GeoCities.com/Almost_There_Weather_Balloon/

Good Luck!
Ken_S.

Posted at 8:54 pm on Nov 19th, 2007 by Almost There

MURS, Multi-Use Radio Service, allows voice and data with much fewer restrictions than FRS.

151.820 MHz
151.880 MHz
151.940 MHz
154.570 MHz
154.600 MHz

http://en.wikipedia.org/wiki/Multi-Use_Radio_Service

Posted at 10:34 pm on Nov 19th, 2007 by tony

Modifiying this type of radio to send video is not practical and would put out energy on frequency’s used by other services.

The FRS channels are 25KHz apart. An NTSC video transmission using AM or FM is at least 8.4MHz wide. (You can’t practically turn an FM walkie talkie into a vestigal sideband video transmission to get the bandwidth down to 6MHz)

There are lots of other radio services using the 3MHz either side of the FRS channels.

Even if you wanted to anyway, changing the receiver filters and building add on video modulator and demodulator circuits is not practical.

Posted at 11:18 pm on Nov 19th, 2007 by Bob

My wish is mating a GPS receiver module of about $50 to a gmrs and a timer to burst transmit its position every minute.

Would install it permanently hidden in my car to be able to find it if stolen.
No. I do not want Lo-Jack monthly payments.

Posted at 12:31 am on Nov 20th, 2007 by Miguel

Got this idea at lunch today, when a motorcycle set off someones sound based car alarm. Your own lojack system, would require I guess a Rino. Just hack the buttons (or you could build devise a mechanical actuator to keep the Rino unmodified.) You would want some sort of sensor in the car, that would activate the ptt button. It would leave it on for say 30 seconds so you can listen in, after which it activates 15 seconds every minute. If the gps doesn’t show movement, you could use a DTMF tone to shutdown the broadcast and rearm the system. Even if the car manages to go out of range, a grid search could be done to try to locate it. Probably less than $40 dollars for parts if you already have the Rinos.

Posted at 12:42 am on Nov 20th, 2007 by PT

Some of them can probably be hacked to work on the 70cm ham band.

Really, if you want to experiment with radios, get your ham license and do it on the ham bands. It’s not only the legal way, it’s also where most of the people who know what they’re doing are.

Posted at 8:51 am on Nov 20th, 2007 by Brent

How about instead of that little ‘Roger’ beep thing that it does when you finish talking, that could actually be serial(UART?) GPS data from one of the smaller modules, so they would be transmitting their location whether or not they know it…? It would probably require some rather larger or more expensive equipment to receive and plot the position (a-la a laptop with some custom hardware) but I could see it being useful in a military setting(paintball anyone?).

Posted at 10:54 am on Nov 20th, 2007 by M4CGYV3R

hmmmm
a Bomb – just fill the case with some mouldable explosive and set the talk switch to send enough current into the explosive to detonate it… just need some batts and A capacitor…

or a metal detector,
using the antenna as the reciever, and program it to send out a pulse every second when you hold the talk button and if it hits something and recieves it have it send another immidately and so the closer you get the faster it beeps
Granted you would have to attach it to a stick or something and possibly replace the talk button with an On/OFF switch but whatever

Posted at 3:32 pm on Nov 20th, 2007 by A_Blind_man

You can boost the reception on these things with just a little soldering and a scrap of wire. Pop the case open and find where the antenna solders to the board. Make a rough measurement of the antenna and find a scrap of small wire that is approx. the same length. Solder it onto the same spot the stock antenna attaches and route it in the case so it points roughly 180 degrees away from the factory antenna. Instant boost in reception for most of these. The basis of this hack is that most of these radios contain 1/8 wave antennas, not very efficient. by doubling the antenna length you make it into a 1/4 wave antenna which is infinitely more efficient in propagating the radio signal.

Enjoy

Posted at 4:01 pm on Nov 20th, 2007 by javaworm

What about taking the insides out of the radio and fashioning a case for a cell phone that also contains the frs/grms radio guts in it. along with that add a plug to use the speaker of the radio as a speaker phone for the cell phone.

this would give you short range communication with your frs radio along with cell usage without taking it out of the case.

Posted at 5:46 pm on Nov 20th, 2007 by doug

I would love to see a software program that could take a live feed of the screen (or at least the tracks of other identified rinos) and put it on the web, into GMaps, etc.

Would hacking the screen data feed be the same thing as hacking the radio (wrt fcc regs)?

One excellent thing that differentiates Rino from Opentracker is that the Rino is already tracking peers.

With the right setup, I imagine OpenTracker could be set up to track larger events with multiple GPSs.

Posted at 12:09 am on Nov 21st, 2007 by M

anyone ever heard of PSK31? (http://en.wikipedia.org/wiki/PSK31)

its great, text chat over half-duplex radio link. That would be nice, maybe using just a PIC, a couple of DAC and a couple of ADC and two FRS.
I’ve read that in open spaces some guys got 10 Km (6.21 miles) of working range for a talkabout.

Posted at 5:00 pm on Nov 22nd, 2007 by beakpy

The GPS and FRS technologies married together are much more capable and less expensive than the Project Lifesaver http://www.projectlifesaver.org/site/ system being touted by many law enforcement agencies. My county just spent $15k for two receivers and some training – for 50 year old Ham radio fox hunt technology!
Hey Garmin, do you smell business possibility?

Posted at 9:10 am on Nov 23rd, 2007 by n0qbh

UH.. The Garmin Rhino out of the box transmits and receives GPS position data. As I read the rhino manual, you can send a position beacon every 30 seconds by cycling the PTT. Shouldn’t be a problem to hack in circuitry to automate that. No license is needed if you stick with using the FRS channels. The only drawback with the rhino is, that it the packaging of the data for RF transmission is proprietary to Garmin . That may hamper gatewaying Rhino position beacons.

Jeff; RS used to sell and FRS radio where the antenna and basic xceiver mag mounted to the roof connected to a speakermic with a long cord, as you subscribed.

Steve D.; Are you proposing to use the entire FRS allocation to send ONE video signal? That may be a good way to attract attention ;)

aefaradien; Yes radio-telephone is a simple idea but implementing it in single radio service band generally isn’t.

To close; obtaining a technician class amatuer radio license isn’t that difficult or costly. Even with the limitations Amateur Radio has to be the best way to play with RF.

Posted at 4:57 pm on Nov 26th, 2007 by static

What a really fantasic idea! I’m pretty sure that you’d better patten and market befor I DO! “COUNTDOWN!”

Posted at 5:20 pm on Nov 28th, 2007 by J.R VanHoek

GMRS licensing is a “must do” requirement. Licensing is not a formality, but the law. A license is not a request, but a requirement. Breaking the law because it is an inconvenience, or you don’t think it should apply to you, leads to anarchy. It is everyone’s responsibility to see that laws are first JUST, and second ENFORCED. Failing to do so is Anti-American. What kind of a citizen do you choose to be?

Posted at 1:16 pm on Dec 11th, 2007 by KW7DSP

GMRS requires a license. All these hacks mentioned are either in violation of FRS regs, GMRS regs, or both.

Posted at 4:40 pm on Dec 11th, 2007 by GMRS Licensee

REMOTE POWER
————
How about an external 6v battery pack that can maintain power longer than the AAA’s that go in the FRS units? Maybe a 4-AA or D pack. Maybe even a 12v to 6v convertor with car adapter too. Hi power units suck the AAA’s in few minutes even super-aklalines.

OTHER DATA UNITS
—————-
Data is allowed on FRS other than Rhinos. Look up ChatNow units. ~2 mile range text messaging.

AUTO SEND FOR RHINOS
——————–
Set up transmit GPS on PTT and either use a VOX setting to trip everytime it hears sounds from the kid or make your own tone decoder and 555 delay drop out ckt. It listens for touch-tone or single tone, fires the 555, it latches for 1-2 minutes, holding down PTT sending GPS. Will require project battery connection and an outboard project box. All parts from Radio Shack.

BABY/CAR/ROOM MONITOR (BUG)
—————————
Use VOX setting set to 1 or (Not recommended–>) a rubber band around PTT. With a external power source you have a powerful 2~10 mile listening device. But transmitting too long tends to piss others off. So think twice about this one. Tends to induce FCC/Ham foxhunts…

LONG DISTANCE INTERCOM
———————-
Using the VOX feature, remote power source (solar powered?), and wall mounting fixtures you can also set up a remote 2-way intercom. Like to a vacationing friends door, a remote gate entry, an outddor event entrance (party in the woods?), etc. Ppl wouldn’t need to know how to use it just talk into it. Put it in a project box so the only thing they can do is press the CALL button to CALL you. Have a sign that says PUSH CALL THEN JUST TALK.

AUTOPATCH (WIRELESS TELEPHONE)
——————————
Get the CES Radio (in Florida USA) Simplex Autopatch unit and build an mic/earphone/PTT/AGC (Squelch) interface unit and connect to your FRS (Not recommended. May be totally illegal!). You can make phone calls on your FRS unit. But everyone listening will know your business and record your dialed phone numbers if you don’t use the preset CES phone dialer feature. It allows passcodes and toll blocking to stop other FRS’ers from phreaking your patch. When connected it transmits continually briefly (millisecond click) opening the reciever to listen for any carrier (You pushing your PTT) every second. When it hears the carrier it drops the transmitter and you can talk until you release PTT. And it starts all over again. Its touch-tone controlled and will drop after so minutes inactivity. It also has reverse patch (incoming call too). Its designed for HAM radio and Business band NOT FRS (per se).

SIMPLEX REPEATER
—————-
Radio Shack used to sell this and you can still get them at HAM radio online stores. You can make your own with a PC, sound card, and the VOX setting. All it does is listen for any sound breaking squelch. Records it into a sound file for about 30 seconds. hen Transmits it back out to the FRS via a PTT or Vox. Imagine putting one of these on top of a building and you can talk to your friends all over the metro or county. A lot farther than with the FRS unit by itself. It takes a bit getting used to it as it is nothing but a very limited echo machine or parrot box. Ppl need to pace themselves so as not to “step” on one anothers recording phase transmissions. A guy on the other side of a mountain can’t hear your FRS recording a repeat. But he will hear the repeat. Google it for more information…

Cheers
Spooky

Posted at 1:50 pm on Feb 8th, 2008 by spooky

FRS/GMRS AUTOMATED DISPATCHER
———————————-
using a pc with voice synthesizer or wave file player you can program, like in vbasic, an automated dispatcher. you would use the frs’s built-in vox (voice operated switch) feature set to mid-point. you program your pc application to check your email, your home environment, caller id, phone messages, room temp, room audio, your keyboard, or whatever.

the application simply uses canned (pre-recorded) or text-to-voice messages to send one way messages to you from 2~10 miles away via your frs radio. To overcome the vox’s behavior of cutting off first syllable just add an audio preamble like ‘uhh’, a ‘beep’, or a noise to get the vox ptt to key before your pre-canned message starts. Remember to start audio within a 1/2 second or less later depending on your vox setting.

All you need is an audio patch cable between your pc’s sound card’s line out or speaker jack to your frs mic jack (available at radio shack). an audio splitter would be good so you can run an external pc speaker to hear whats going on too. experiment with different audio output levels.

one neat feature is a user interface that allows a dispatcher to make his/her responses on the frs/gmrs routine by simply pressing a number from a displayed menu, mouse clicking a button, or pressing one key on keyboard. things like ‘calling unit number’ (fill in the blank), ‘over’, ‘roger that’, ‘10-4′, ‘what is your location?’, ‘repeat that’, ‘return to base’, ‘call hq by land-line’, etc. the human dispatcher would hardly ever have to actually talk. they could just push a button or click a mouse to send and reply to your frs message. this is a more efficient and standardized way of communicating when the human has problems speaking or conveying information correctly. it also makes one voice for many ppl using the system. a female voice is more attention getting.

to send commands back to the base station some sort of dtmf touch-tone decoder might work. except mfgs don’t make tone pads any more due to drug pushers (et al) using them on pay-phones to send secret msgs to beepers. you’d have to make your own or get one on ebay. there are many dtmf decoder downloads for your sound card on the internet.

there’s also the possibility to use voice-to-text but prolly won’t work well as most systems are speaker dependent and don’t work well in high noise environment that frs might introduce to the audio input stage. but if you said the same command 3 or more times perfectly the application could filter out false triggering from static, squelch tails, channel chatter from kids, and deliberate voice hackers trying to take control…

ultimate pc to pc remote control via an frs unit in a high noise low-audio-bandwidth environment? psk31… google it… its the latest low-tech method to get pc data across a low-bandwidth audio channel even in poor conditions… imagine what remote control scenarios you can come up with… its even been heard in operation on noisy cb radio!!! here’s what it sounds like in the wild (scroll to bottom) http://en.wikipedia.org/wiki/PSK31 (or click on my site’s url).

Cheers
spooks

Posted at 2:23 pm on Feb 11th, 2008 by spooky

I am about to test using one of these radios for a remote
paintball gun. I had made a laser tripwire paintball gun,
but I would like to in addition be able to fire it on command.
I already use the radios for comms during play. This
would allow me to sucker people toward the remote guns
position, and then paint them from afar. On my radios, when
one is receiving, an led flashes at about 1hz. I am going to
use the flashing led to trigger the gun using the same
components that the laser tripwire does. All I have to do is
add one transistor.

I could also use the radio as a suppression signal. If non
players enter the field (we are out of town, but we share
with dirtbikes and mountain bikes) I can use the radio to
kill the tripwire function.

Posted at 12:21 pm on Sep 14th, 2008 by Mike

I think you should use some kind of voice modulation to send a specific command to the paintballgun, then you can include some very simple encryption/code because otherwise you would be vulnerable to other players using your gun. See http://en.wikipedia.org/wiki/PSK31
You can put all this on a PIC controller, really easy

Posted at 12:17 pm on Sep 24th, 2008 by beak42

Thats true, but…

With the radios I use, I have 22 channels with 121 ‘privacy codes’. The first privacy code is just the standard frequency for the channel. I’m not sure what they are doing to get the other 120 ‘privacy codes’. It could be a shift in frequency or even something else. It doesn’t really explain it, and I don’t have a scanner.

If you’re not on the right ‘privacy code’, you don’t get to access the gun.

This means there are over 2000 possible ways to run it.

These radios have a scan function but only pick up traffic on privacy code 1, so I am safe from people with the same radios. Other radios may have a better scan function, but if it’s not strictly a frequency shift, it may not matter.

I finished the project and it runs great. It has some quirks that make it work, and may therefore not work with other configurations (radios) without modification.

I’ve got schematics, photos and maybe one day I’ll attach a video.

At my website

I am interested in something faster than psk31, as I have great plans for the mix of radios and paintball.

I would be quite interested to see psk31 coded into a pic if you’ve got any resources?

Posted at 10:02 am on Oct 2nd, 2008 by Mike

Privacy codes are actually a squelch system.

details here:
http://www.rei.com/expertadvice/articles/twoway+radios.html

The code can be analog or digital (I have digital), and are used such that a radio set with a privacy code will only transmit audio when it receives the
proper privacy code. This lets you skip anyone elses chatter on the same frequency.

It doesn’t eliminate their chatter, so there can still be interference, but less likely.

Posted at 10:18 am on Oct 2nd, 2008 by Mike

I think all you guys who even mention fcc are fags, and that person who said Gaydar, you should kill yourself before aids gets you and you spread it to someone else. What you need is Raid, not gaydar, RAID, breathe deep and then just die FAG. This government is Rogue and looting every penny left to leave you high and dry, and if you decide to finally wake up and protest or dissent they have plans to kill you with either a neutron bomb or nuke your ass, just depends on where you are and what’s around that they might still want, town full of niggers, they’ll nuke your asses, so who gives a shit about what this rotten bunch of lying devils says in their rules? They just stole 5 trillion and you can’t even ask them where the money went and you people are worried about fcc? Get a life, hack the crap out of anything and everything, anything that might help us after the nuclear wars are over is great to me, but stop acting like a bunch of pansy faggots who need permission from the king!

Posted at 11:22 am on Nov 24th, 2008 by sizzlean

Note:

I just tested trying to send video via FRS. IT DOES NOT WORK :[… just a black screen with lines. The modulation is not correct. I think it is because the frequency bandwith is too small.

What do you guys think?

Posted at 8:54 am on Nov 26th, 2008 by joe

Video is possible on this radio. But in order to do it, it would have to be digital. Not sure on the fps this would give you. Also, you can hack this to get an easy 10-20 mile converage and 20 – 40 mile from base to base. useing some high grade heliax coax and a good collinear antenna high gain base antenna(Specially digned for 460mhz) up on a good tall tower. you can buy a SWR meter for 144/440Mhz and will work for your needs. my tests with this setup and a simplex repeater as stated above, i could talk to friends around the county easy. also note that turning the squelch pod a lil to get extra range. also dont forget to use tone codes to keep people out of your way. now if i unplug the repeater from the base and use the scan feature… I hear more people talking then what i do on a CB radio. beat that. this is old news. i should have posted this 4 years ago when i was testing it. ok now within the last year. i put 2 VOX boards together. built a dipole CB antenna and mounted it in the mid section of my tower. I connected the mic of the FRS/GMRS to the CB useing VOX and the MIC of the CB to the Speaker of the FRS/GMRS and now i can goto the other side of town and show a CB buddy I can talk to him on my wrist radio. So now back to my double duplex data repeater research. peace out.

Posted at 12:27 pm on Jan 31st, 2009 by scott201201

one note. most new GMRS/FRS radios dont have removable antennas. you have to cut a small jumper strip the end, seperate the inside wire from the outside ground. solder the inside connector to where the antenna used to be. and the outside sheild to a close ground. that should be close or next to the antenna solder somewhere. if your not sure then ohm it out. selecting a radio that can run while being charged and a good range radio. the more watts the better.

Posted at 12:33 pm on Jan 31st, 2009 by scott201201

The guy a couple of comments up who was so rude (fags, gay, slurs etc.) doesn’t have very nice manners. This is a great forum with incredibly creative minds, very few here could be seen as running in the middle of a mindless herd.

Normally, everyone knows to ignore “trolls” so as not to encourage them. Unfortunately, he was not a troll. He just was frustrated and had very bad manners. Essentially, I have to admit, he is right.

We should be focusing our creative technical minds on extra-legal effeciencies in communicating, and perpetuating that knowledge to as many people as possible, before “the grid” goes down. No longer is this the advice of “conspiracy theorists” that I used to lampoon. It is the advice of former Reagan cabinet officials (read “Paul Craig Roberts) and Wall Street analysts who told the truth.

Strip out what the young ruffian above said about aids, sexual preference, etc., but take the point well that the government is careful to fence the people into small legalities which forms our prison, while they offer to any company or organization that can pay, all the exceptions and access and freedom they want. This renders our lawfulness inconsequential, like a frugal wife pinching pennies while her husband is out buying the Brooklyn Bridge.

Respectfully,
a Patriot

Posted at 4:10 pm on Feb 21st, 2009 by PhilipKindred