AM88 PLL AM TRANSMITTER

The AM88 is a low power AM broadcast transmitter designed for low power hobby and experimental use in the standard AM broadcast bands used in most areas of the world. This includes 530-1710 kHz (Medium Wave) and 150-285 kHz (Long Wave) used in Europe and Asia. In addition, frequencies between these bands (285-530 kHz) can also be covered. Extended coverage up to 2047 kHz and down to below 50 kHz can be obtained with some simple circuit adjustments, but the primary intent of the design is low power use under FCC part 15 rules. The AM88 can also generate NBFM signals over its entire tuning range up to 75 kHz deviation, for use in low frequency carrier current systems in the 100-300 kHz range. In this case power lines, twisted pairs, or coaxial cables may be used as a transmission medium. It is also possible to use up to 100 mW and a 10 foot maximum antenna at certain frequencies in the AM broadcast band without violating FCC part 15 rules. In addition, QRP CW or AM operation is possible on the 160 meter amateur band (1800-2000 kHz). This requires a suitable amateur license.

For part 15 LOWFER beacon, CW, or BPSK operation or for use in the 136 kHz amateur band, we suggest the LF90 LF transmitter

 

A few applications of the AM88 are:

• Low power AM broadcasting to cover a house, yard, etc
• As a source of AM signals for experimentatiom
• Talking signs using our Voice Messenger for real estate sales, advertising, etc
• As a source of AM programming for antique radio hobbyists
• Antenna experimentation and Part 15 hobby broadcasting

  Some specs and features of the AM88 are as follows:

• Frequency range 150-1710 kHz, useable 50-2047 kHz, 1 kHz steps
• Frequency synthesized, better than 20 Hz frequency accuracy
• Operates from any 11 to 15 V DC Neg Gnd supply
• Size 4.00" X 4.00" X 1.00" H (102mm X 102 mm X 25 mm)
• Power out AM mode: 100 mW max (2000 kHz) to 200 mW (150 kHz) into 50 ohms
• CW or FM power output up to 1 watt at lower frequencies
• Modulation capability > 85% AM high level
• Excellent Audio, Freq response 20 Hz to 10 kHz
• Audio input line level high Z, 0.3 V rms into 5K ohms
• Built in audio limiter
• Built in overmodulation protection
• Spurs -40 dB down typical, depends on frequency.
• Designed for 50 ohm load, built in harmonic filters.
• No noisy microprocessor used, DIP switch frequency setting
• AM, CW, and FM modulation capability
• Easy setup, high quality G-10 Fiberglass board
• Excellent learning and experimental tool
• Fits our NC1550 case
• Excellent for use along with our MPX96 for a complete AM-FM LP broadcast setup
• Low Cost