Mini teardown/overview of XTD's XDT-PA100X HF amplifier скачать в хорошем качестве

Mini teardown/overview of XTD's XDT-PA100X HF amplifier

This XDT-PA100X by XTD (that's what the silkscreen on the PCB says) is sold as a 100W HF (1.8-30MHz) amplifier. I opted for an IC705 interface, but, that was ignored and I got the generic (maybe Xiegu) interface cable. I had planned to take it out portable tomorrow to use with the IC705, and decided to have a look inside first to check. The amplifier transistors are IRF530N HEXFET PowerMOSFET parts. Not RF parts at all! The little part near the input transformer that I couldn't read in the video turned out to be an 78L05, a 5V voltage regulator, which sets the biasing for the IRF530N transistors with a small variable resistor feeding the gates through a ferrite bead and the input transformer winding. The power input to the 78L05 bias regulator is cut when in receive, as expected. An LM317 sets the fan speed with a thermistor floating near the IRF530N tabs. The thermistor doesn't feed into the biasing as I would have expected, as is common to prevent thermal runaway. TX/RX switching is done with two transistors near the LM317. Hope this helps someone! 73, George M1GEO!