The RF beacon transmitter designed to locate downed model RC plane using unmodified license free 2-way radios (LPD,FRS/GMRS/PMR)

32 preset channels quickly called pushing two series of repeated clicks, also user can program specific frequency in range 240.00-930.00MHz, 1kHz step.

User programmed functions:

1.Fading tones transmitter at user set interval or decay function.+ user set startup delay

2.Microphone transmitter

3 Data transmitter: FSK and OOK modes, user set deviation and RF power level

All commands entered serially using single button.Multiple clicks separated by 1-2s pause make numbers, 4seconds inactivity completes command. Single numbers change mode, double digits change settings , there is also 6digits command to enter custom frequency, all other combinations ignored. Valid entry confirmed w/LED reading back the numbers entered .

To reset device to original settings hold button while connecting battery. Default settings: Beacon mode FRS CH5, decay interval, power level 4, crystal trim 4, modulation depth 2, FSK, 4th tone off, low battery cut-off turned on..

While in beacon mode: single click to activate sleep mode, double click to start TX.

Codes:

1.x - set startup delay = x*15minutes, example: 1.2 makes 30minutes startup delay, to cancel delay enter 1.10

2.x - set interval: 2.1 = decay where starting interval is 4seconds growing within 5 hours to 22s then continue fixed., 2.2 and up fixed intervals. example: 2.3 for fixed 6s interval

3.x - preset channel X, example: 3.6 makes CH6 (PMR/FRS) or ch16 LPDi

4.x - set standard, North America set 4.1(FRS/default), Europe set 4.2 (PMR) or 4.3(LPD) and 4.4 for New Zealand FRS

4.7 -low battery. cut-off disable

4.8- low batttery cut-off enable (default)

5.1=Beacon,5.2=FSK,5.3=OOK,5.4=microphone,5.5=wireless alarm.

6.x - deviation (volume) control, default 2(walkie-talkies), set 8~10 for WideFM

7.x - RF power, 8 levels from 1mW (7.1) TO 80mW(7.8), default is 4

8.x - crystal trim, you probably will never need to change this except if your radio distorts audio because of frequency offset of few kHz., default value is 4

9.x - 4th tone frequency offset X kHz, enter 9.10 to turn off 4th tone (default = off)

To find direction. listen how many beeps you're getting and how noisy are the last two tones. When you pointing antenna in transmitter direction or blocking RF path with your body the tones become noisier /weak or completly muted by receiver..
if you hear 3rd tone clearly while radio is laid on the ground you're probably within 100-300ft, if only one tone heard 1-2miles away or behind many buildings/hill. It helps a lot having removable antenna off while searching near target, if your radio has fixed antenna you can reduce sensivity by transmitting few kHc offset standard channel, most radios have quality crystal filter and offset helps. About every Uniden walkie talkie and some Motorola (such as FV300) use cheap ceramic filter that makes receiving channel very wide and offset is not helpful.

While in standby the transmitter draws microamper and while transmitting average current draw is 50mA. With carefuly set duty cycle the beacon can run few weeks using tiny single cell Li-Po .
optional startup delay helps to save battery even more also sleeping beacon doesn't interfere UHF LRS RC

Wireless alarm function: beacon cycles ones whenver pin logic changes, the pin is pulled up internally with 5k resistor. Alarm tiggered if the pin gets connected to ground or released. Example: connect magnetic contacts or prallel to status LED of RC RX, or accelerometer to make bicycle alrm.

Supply voltage over 4.2V can kill the circuit, only use single cell Lithium or 3cell NiCd

If transmitting DATA or PPM with the transmitter make sure incoming pulses lower or equal to supply voltage otherwise connect series resistor about 1k .

to read custom frequency enter 1.1.1 , the LED will blink 6digits: xxx.xxx kHz, (you don't have to switch to 4.5 )

Enter custom freq./CH (option)

$50/ea

pre-programmed channels:
PMR[8]={446.006, 446.019, 446.031, 446.044, 446.056, 446.069, 446.081, 446.094};
FRS[8]={462.563, 462.588 ,462.613, 462.638, 462.663, 462.688, 462.713, 467.563};//
NZ[8] ={476.925, 476.950, 476.975, 477.000, 477.025,477.050,477.075,477.100};//
LPD[8]={433.325, 433.350, 433.375, 433.400, 433.425,433.450,433.475,433.500};//

hear the tones : http://www.youtube.com/watch?v=LiJDhvToRqE

forum: http://www.rcgroups.com/forums/showthread.php?t=1274173&page=15

http://fpv-community.com/forum/showthread.php?tid=81

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