FAT5 - Series Modulator

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 Modulator documentation click here

Kits for the FAT5 Modulator (both types) are available now . See the kits page.

Kit of parts for TDA2050 modulator Kit of parts for LM3886 modulator

The high power modulator uses an LM2876/3876/3886 IC which can cope with supply voltages up to 84V on-load. A downside is that the chip needs at least 24V to overcome the internal low-voltage cut-out, making it unsuitable for lower power transmitters.

The medium power modulator is adequate for supply voltages up to the TDA2050 limits of 50V (less is recommended for reliability). The TDA2050 has no low-voltage cut-out and will work with low voltages such that a 10W carrier transmitter can be built working off a modulator supply of 13.8V. Using the FAT5 PA module PCB, with all four FETs fitted, 50W carrier can be achieved with around 13.5 Volts on the FET drains. After circuit losses this equates to a main supply rail of about 33 Volts making the TDA2050 modulator the best choice for most situations.

Low / medium power modulator

FAT5 Medium Power TDA2050  Modulator (click to enlarge in new window)

Fully assembled TDA2050 modulator


Medium / high power modulator

FAT5 High Power Modulator (click to enlarge in new window)

Fully assembled LM3886 modulator

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