FM Transmitter Help

Transmitter Selection Guide

1. Do you want to broadcast in Stereo or Mono?
2. Do you want a completely accurate broadcast frequency that will not drift (i.e. PLL tuning)?
3. What range do you wish to cover (radius in miles or km)?

If money is no object then obviously the more sophisticated you make your set-up the better the results will be. To give you a guide on selecting the  products to meet your requirements here are some examples followed by information of power output and transmitting distances you can expect.

If you go down the Modular route in Examples 1 to 4 you can start with the basic configuration in Example 4 and then add extra modules as shown the Examples 1 to 3.

Example 1 - Modular Stereo PLL Transmitter

To build this you will need these three kits:

• 1187 - 3 Watt FM VCO Amplifier (88-108MHz) plus
• 1079 - FM Stereo Encoder plus
• 1144 - PLL FM Synthesizer (88-108MHz)
  

This set-up can be used to drive one of our high powered Linear FM Amplifier for greater range.

The complete set-up can be used in conjunction with the stereo audio line out from a hi-fi, mixer, soundcard, MP3 player, etc or our kit 1050 - 3 Input Stereo Hi-Fi Preamplifier.

Example 2 - Modular Stereo Transmitter

As example 1 above but omitting the PLL FM Synthesizer (88-108MHz).

To build this you will need these two kits:

• 1187 - 3 Watt FM VCO Amplifier (88-108MHz) plus
• 1079 - FM Stereo Encoder
  

This set-up can be used to drive one of our high powered Linear FM Amplifier for greater range.

The complete set-up can be used in conjunction with the stereo audio line out from a hi-fi, mixer, soundcard, MP3 player, etc or our kit 1050 - 3 Input Stereo Hi-Fi Preamplifier.

Example 3 - Modular Mono PLL Transmitter

As example 1 above but omitting the 1079 - FM Stereo Encoder.

To build this you will need these two kits:

• 1187 - 3 Watt FM VCO Amplifier (88-108MHz)
• 1144 - PLL FM Synthesizer (88-108MHz)
  

This set-up can be used to drive one of our high powered Linear FM Amplifier for greater range.

The complete set-up can be used in conjunction with the audio line out from a hi-fi, mixer, soundcard, MP3 player, etc or our kit 1052 - 3 Input Mono Mixer.

Example 4 - Modular Mono Transmitter

This basic mono setup will give you the ability to upgrade to PLL or Stereo setup at a later date.

• 1187 - 3 Watt FM VCO Amplifier (88-108MHz)

This transmitter can be used to drive one of our high powered Linear FM Amplifier for greater range.

The complete set-up can be used in conjunction with the audio line out from a hi-fi, mixer, soundcard, MP3 player, etc or our kit 1052 - 3 Input Mono Mixer.

Example 5 - Standalone Mono Transmitter

Any of the transmitters detailed below ccan be used in conjunction with the audio line out from a hi-fi, mixer, soundcard, MP3 player, etc or our kit 1052 - 3 Input Mono Mixer:

• 1009 - 1 Watt FM Transmitter   or
• 1028 - 3 Watt FM Transmitter   or
• 1021 - 15 Watt FM Transmitter or
• 1031 - 25 Watt FM Transmitter

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Transmitter Ranges

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Transmitter Connections

• AUDIO INPUT - The audio frequency input is connected at points  ground and signal. Some kits are supplied with an electret microphone that can be used in place of a line-in audio source if you prefer. Adjust the variable resistor for best audio performance

• ANTENNA - The antenna can be a 50 Ohm Open Dipole, Ground Plane, 5/8 or YAGI connected using 50 Ohm coax cable (Order Code RG58)

• POWER SUPPLY - connect a power supply with correct voltage that is rated to supply at least the current drawn by the transmitter (see transmitter Technical Specifications). If you already have a power supply of the correct voltage but with a higher current rating then it is also suitable. See our Accessories and Power Supplies pages

The most important thing to remember is that an aerial must ALWAYS be connected to the output before power is applied to the circuit.

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Transmitter Tuning

This is really a very simple task that involves turning the screw head in a few variable capacitors. You will need a small flat bladed screwdriver to do this. You will also need an SWR meter (not supplied).

Kits 3028, 3032 and 1028 are supplied with a small peaking circuit that can be used with a simple multimeter (Order Code 4009) in place of an SWR meter.

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Transmitters and the Law

Quasar Electronics Limited and it's employees accept no responsibility whatsoever for any consequences arising from the use or misuse of unlicensed or unapproved equipment. If you live outside the UK we suggest that you check local laws before operating or purchasing transmitting equipment. Again, it is your responsibility not to break the law.

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