background image

FM30

• 

 1  

 DIGITAL FM 

STEREO  

TRANSMITTER KIT

 

Ramsey Electronics Model No.  FM30 

• 

Synthesized 87.9MHz to 108.1MHz for no frequency drift! Direct 
digital input of frequency, no jumpers or DIP switches! 

• 

Designed for extruded, rugged metal case, all lines have RF 
chokes, and fully regulated for the cleanest sounding low noise 
performance yet! 

• 

BNC style RF output for easy, reliable connections. 

• 

Fully digitally controlled transmit power for custom coverage 
capabilities! 

• 

Digital volume and balance controls for easy audio level 
adjustments. 

• 

Runs from 13.8-16VDC, includes 15V DC adapter. 

• 

Quality of signal indicator lets you know when you have a good 
signal or over-modulated signal. Lets you know when to turn it up, 
or down! 

• 

Great for schools, health clubs, yard casting, drive-in movie 
theaters, haunted rides, amusement parks, churches, etc! 

A new and improved version of our popular stereo transmitter 
kits, the FM30 is an ideal upgrade for improved performance 
and ease of use! With a low-noise design and a metal case, the 
FM30 suffers from much less interference for a better S/N ratio. 
The FM30 also has full digital front panel control of output 
power, volume, balance, stereo/mono, and frequency! 

Summary of Contents for FM30

Page 1: ...rols for easy audio level adjustments Runs from 13 8 16VDC includes 15V DC adapter Quality of signal indicator lets you know when you have a good signal or over modulated signal Lets you know when to...

Page 2: ...ce Capacitance Meter RAMSEY AMATEUR RADIO KITS HR Series HF All Mode Receivers DDF1 Doppler Direction Finder Kit QRP Series HF CW Transmitters CW7 CW Keyer QRP Power Amplifiers RAMSEY MINI KITS Many o...

Page 3: ...PC Board Parts Layout 11 FM30 Parts List 12 FM30 PC Board Assembly Steps 14 FM30 Schematic Centerfold 20 FM30 Setup 26 Antenna Ideas 29 Appendix A FCC Rules and Info 31 Appendix B 33 Summary 35 Warra...

Page 4: ...range low noise audio quality frequency stability and stereo channel separation of this build it yourself synthesized FM stereo transmitter If you follow our assembly directions carefully and use your...

Page 5: ...to regulate to 12V VR1 only needs about 0 8V across it this means it can regulate 12 8V and up C9 is used in conjunction with VR1 for good regulation of the 12V The 12V is then fed to VR2 a standard...

Page 6: ...erence the state of the output pin 1 of U5 A goes high 5V If the voltage on pin 3 goes below that on pin 2 the output goes low 0V The comparator is set up with these specific diodes and voltage refere...

Page 7: ...The PLL portion also contains an oscillator circuit which works in conjunction with the external parts of D5 and the STUB that weird trace on the back of the board D5 is called a varactor diode and i...

Page 8: ...ty of signal detector useless that we have on the audio inputs Q4 corrects the tuning sensitivity by acting like a variable pot based on the tuning voltage As the tuning voltage goes down Q4 is turned...

Page 9: ...e in one simple project digital power RF and analog If you want more information on these subjects there are a lot of great electronics books and websites out there and here are some keywords to searc...

Page 10: ...s minimal chance of inserting wires into wrong holes Second whenever possible we in stall in an order that fits our Learn As You Build Kit building philosophy This entails describing the circuit that...

Page 11: ...FM30 11 FM30 PARTS LAYOUT DIAGRAM...

Page 12: ...own red brown R34 1 180 ohm resistor brown grey brown R20 2 270 ohm resistor red violet brown R6 9 4 1k ohm resistors brown black red R10 16 27 36 37 2 2 2k ohm resistors red red red R22 24 2 3 3k ohm...

Page 13: ...1 DPDT Power switch S1 6 2 2uH inductors green body red red gold silver L1 2 3 4 5 6 2 4 turn air core inductors L8 9 1 2 1mm center post positive power jack J3 2 RCA audio jacks J8 J10 2 8 pin dual r...

Page 14: ...part on the large pad so that the legs line up with their individual smaller pads Once you re sure everything is aligned properly solder the three leads of the part With those soldered you re going t...

Page 15: ...laced correctly to function properly Line the part up with the mark on the board and sol der it in place 12 Install L1 2 2uH inductor green body red red gold silver 13 Install C7 10nF or 0 01uF cerami...

Page 16: ...nstall C47 10uF electrolytic Do I have to remind you about the polar ity again No I didn t think so 32 Install C17 0 1uF ceramic disc capacitor marked 104 33 Install C49 10nF or 0 01uF ceramic disc ca...

Page 17: ...560pF disc capacitor marked 561 51 Install R15 the last 56k ohm resistor green blue orange 52 Install R14 27k ohm resistor red violet orange 53 No part is installed in the R33 position this part was...

Page 18: ...Install C55 10nF or 0 01uF ceramic disc capacitor marked 103 74 Let s move toward the back of the board near J9 and install L6 2 2uH inductor green body with red red gold silver bands 75 Install C67 4...

Page 19: ...iagram 99 Install SP1 the mini speaker You ll see a sign on one side of the part and the same sign on the board Line these two up and solder the part 100 Install R31 3 3k ohms orange orange red 101 In...

Page 20: ...FM30 20 FM30 SCHEMATIC CENTERFOLD...

Page 21: ...FM30 21...

Page 22: ...stor orange orange red 114 Install C33 1nF or 0 001uF ceramic disc capacitor marked 102 115 Install Q3 2N3904 NPN transistor Follow the flat side on the part and the Layout Diagram for correct placeme...

Page 23: ...unconventional but much more user friendly this way F3 Install C6 0 1uF ceramic disc capacitor marked 104 F4 Install R7 10k ohms brown black orange F5 Install R4 also a 10k resistor brown black orang...

Page 24: ...est of the pins of the connector Be careful handling the board when you re done those pins stay hot for a little while F16 Look over your connected boards and make sure all the solder joints look good...

Page 25: ...does the silkscreen for the part but it s a little hard to see so you can also check placement by the longer lead This longer lead is the positive side and should be placed in the hole opposite the fl...

Page 26: ...u should hear a beep and see FM 30 Rev 1 2 on the dis play then in a few seconds the screen will change to a default display The default display shows the current set power frequency clipping detector...

Page 27: ...ntil it sounds right to you The order of characters is approximately on average 60kHz g 60kHz and 75kHz c 75kHz and 90kHz C 90kHz Remember from the circuit description that the indicator doesn t speci...

Page 28: ...coverage area if de sired Use the RF adjustment control to fine tune the RF output level to just reach the area you intend to cover The audio connection consists of using shielded audio cables to conn...

Page 29: ...na length from 88 to 107 MHz Some antenna designers have the view that an approximate di pole such as 2 5 ft on a side will do fine while others believe it is worth the effort to calculate the length...

Page 30: ...walls and other VHF path obstacles you might set up the FM30 s output in a carrier current configuration If you know how then do so safely If not you can show your FM30 and this book to a licensed rad...

Page 31: ...nd Visa are accepted In the United States this is how the FCC regards your transmitter kit Licensed FM broadcast stations and their listeners have ALL the rights Your use of a device such as the FM30...

Page 32: ...ef fect prior to June 23 1989 2 It is the sole responsibility of the builder user of any FM broadcast band device to research and fully avoid any and all interference to licensed FM broadcast transmis...

Page 33: ...of 88 108 MHz FM Broadcast band unlicensed operation is that the field strength of the signal must not ex ceed 250 microvolts meter at a distance of 3 meters from the transmitter FCC rule 15 239 If y...

Page 34: ...ion under good conditions By restricting the maximum field strength at a specific distance from your antenna the FCC clearly plans for your signal to die out at a specific distance from your antenna n...

Page 35: ...district describing your intended operation Mention the operating frequency and planned hours of operation This could be a good step to take if your pro ject is in behalf of a school Scout or communit...

Page 36: ...the posting of printed notices on devices in tended for non licensed operation under Part 15 Rules You will find such no tices written up for the front or back of the instruction manual for nearly an...

Page 37: ...today s FCC en forcement actions get bigger fines and real prison terms for scofflaws From CB now 3 bands of it for varying applications to easy entry level Amateur Radio with long term licensing to...

Page 38: ...FM30 38 This page intentionally left blank for notes and scribbles...

Page 39: ...and received five extra 1K resistors you can pretty much be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronic...

Page 40: ...hrs Intermediate 6 hrs Advanced 4 hrs RAMSEY ELECTRONICS INC 590 Fishers Station Drive Victor New York 14564 Phone 585 924 4560 Fax 585 924 4555 Manual Price Only 5 00 Ramsey Publication No FM30 Assem...

Reviews: