Broadcast Engineering and Small Scale AM and FM Transmitter Manufacturer
Wiring, Equipment repairs, Freelance cable work.
Products
AM Broadcast Transmitters
AM BROADCAST TRANSMITTERS'
This is a series of Low Power AM Medium-Wave Broadcast Transmitters'
Ready-built and turned to your required frequency or re-tuneable using DIP switches.
AM Transmitter operates between 1024KHz and 1600KHz in the Medium Waveband (AM Band) and is designed to be a reliable and stable unit. The Transmitter circuit design employs a Colpitts FET oscillator in a Phase-locked loop circuit for accuracy and ease of frequency selection. It is also very stable and therefore does not drift off frequency. The Phase Lock circuit provides selection in 1KHz steps, so that the unit can be used in either Europe, which has 9KHz spacing between channels, or in the USA and other parts of the World where 10kHz is used between channels. A rugged Power MOSFET is also used on the RF output stage, which drives the output toroid and variable tuning capacitor.
There are 3 in the range, 1 Watt, 4 Watt and 8 Watt.
CAUTION
You need to check if you require a Broadcasting Licence to operate this equipment in your Country. The UK requires you to hold a Broadcasting Licence to Operate this transmitter on the Medium Waveband.
1 Watt, 4 Watt and 8 Watt variants
1 Watt Transmitters
Technical Specifications:
1 Watt Unit
Size - 150mm wide, 150mm depth, 75mm high
Weight. - 0.7Kg
Power requirement - DC 12 -15 V @ 1A max
Audio input and output
RCA Phono sockets, left and right audio between 75mV and 775mV RMS
Audio Bandwidth ( - 3dB) - 70Hz to 6KHz
Modulation level – up to 100%
RF Output level – 1 to 1.5 Watt (dependant on Aerial Match)
RF Output Capacitor – 370pF variable
RF connection – screw terminal for signal and earth connection
Display
Signal level - 10 segment Bar-Graph multi-colour LED
Frequency – 4 7-segment LED display
Ventilation – passive convection
4 and 8 Watt Transmitters (2 models available)
Technical Specifications:
8 Watt Unit
Size - 150mm wide, 150mm depth, 75mm high
Weight. - 1Kg
Power requirement - DC 24 V @ 1.2A max
Audio input and output
RCA Phono sockets, left and right audio between 75mV and 775mV RMS
Audio Bandwidth (- 3dB) - 70Hz to 6KHz
Modulation level – up to 100%
RF Output level – 4 - 10 Watts (dependant on model and Aerial Match)
RF Output Capacitor – 300pF variable (300v rated 4W, 750v 8W)
RF connection – screw terminal for signal and earth connection
Display
Signal level – 10 segment Bar-Graph multi-colour LED
Frequency – 4 7-segment LED display
Ventilation - Cooling fan forced airflow
8 Watt unit on air
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20 Watt Transmitters - 3 models
3 Models - 20 Watt Output
3 models. 20 Watt RF output AM transmitters, one version has 50 ohm output. (ATU at extra cost)
Two other models are designed for use with long-wire connected directly. A low-band model (600-1023KHz) and a high-band model (1024-1630KHz)
AM 20 details
This transmitter has been designed to cover the AM Medium Wave band. It is tuneable across the band and to maximise the output power, pre-set tuning components are selectable in circuit.
Features of the AM20:
• Digital IC design
• 24 Volt 3Amp DC powered (UK adapter included)
• 9KHz channel spacing for EU operation
• Inherently stable
• Audio input with automatic Modulation circuit (volume) via 2 RCA phono sockets (stereo input)
• Low Distortion Analogue modulator Amplifier.
• SO259 Aerial Socket on rear of unit
• up to 20W RF output (80W peak) into 50 Ohm load
• 531 to 1638KHz selectable from front panel
• Tuning Meter LED
1-2 Watt AM Pole Transmitter £170 This AM Transmitter has been designed for use where there is limited space for a conventional long-wire aerial. It instead uses a telescopic 15 metre vertical pole and so can be retracted when not in use. This makes the transmitter portable in a way.. It operates between 1024KHz and 1620KHz in the Medium Waveband (AM Band) and is designed to be a reliable and stable unit.
100 mW AM Transmitter
Smallest Transmitter we make!
· Digital IC design
· 12 Volt DC powered (UK adapter included)
· 9KHz channel spacing for EU or 10KHz for USA (state when ordering)
· Inherently stable
· Audio input with Modulation depth (volume) via ¼” Jack socket
· Low Distortion
· TV Coaxial Aerial Socket on rear of unit
· up to 100mW RF output
· 531 to 1629KHz selectable internally
· Ready-made, ready to go!
This AM Transmitter is a self-contained unit housed in an ABS box of dimensions 150mm by 130mm by 40mm. Covers frequencies 531Khz to 1629 KHz. Powered by an external power adapter providing 12V DC, it is plugged into the rear socket. Audio input via a ¼ inch jack socket is on the front which mono’s up a stereo feed between 100mV and 1V.
FM Transmitter - 7 Watts RF Output.
Features:
Digital technology with DSP and PLL circuitry.
Inherently stable.
Adjustable Frequency, Audio Level and Power output.
100mW to 7 Watts RF output.
Harmonic RF output Filter.
50 Ohm RF Load.
Unit remembers settings when power is lost and re-powered.
12 Volts DC max 3 Amps.
Audio distortion less than 0.1%, stereo separation better than 60dB.
78 to 108MHz coverage.
This is a state-of-the-art FM Broadcast transmitter, encased in an attractive Steel enclosure, size 150 by 150 by 75mm high. Weight 700 grams.
The transmitter has adequate enough power to cover a small town!
*NEW* FM Transmitter 100Watt RF Amplifier
£260
100 Watt Amplifier
This RF amplifier is designed to operate on the FM Broadcast Band, 88 to 108MHz.
The amplifier is wideband, and requires up to 5 Watts drive to give full 100 Watts output into your Aerial. This compliments our 7 Watt FM transmitter as the driver.
Less input reduces the output, so therefore with 2.5 Watts drive the output level is 50W.
It can safely be operated at any output level. The amplifier utilises a Switch Mode Power supply of 24V DC at up to 10 Amps capability.
Product
Operation.
The RF driver unit is used to tune the aerial for minimum SWR at the operating frequency.
This means that when the power amplifier is inserted, it can be rest assured that the match to the aerial is good. If the match to the aerial. Is poor it could damage the output transistors of this amplifier.
For setup, insert SWR meter between RF Driver unit and aerial. Adjust aerial (length) for minimum loss (SWR reflected power). Now insert the amplifier in-place of the SWR meter, or better still, fit amplifier after the driver and before the SWR meter. That way you can monitor the reflected power from the aerial.
