Friday, 26 January 2018

High power UHF DVB-T amplifier, filters and testing

High power UHF DVB-T amplifier, filters and testing- very draft


I have a used 150 W pallet amplifier from a scrapped DVB-T transmitter via eBay. It is bolted to a heat sink from a satellite transmitter.



I am basically following the 1 kW CW UHF amplifier from W6PQL. I have the low pass filter for the amplifier. I temporarily soldered some SMA connectors to test its frequency response. Down about 1 db at 500 MHz, but -40 db at the third harmonic; very good.




It has been suggested to use a pass band cavity filter duplexer. I had one on hand that I had just tuned for a repeater, trying to get a narrow pass-band.

Just using three cavities, I varied two of the three cavities to try to get a wider response. No joy, little wider, but more importantly 10 db loss.




To be continued...

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