RE: Cable Signal amplifier and splitter: a peek inside

shabaz — Thu, 09 Dec 2021 00:58:51 GMT

So glad that in 50-ohm world at least (guessing cable TV is 75 ohm, I don't know much about it), things are simplified these days with (admittedly more expensive) ready-matched MMIC parts, it's a far longer procedure to have to impedance-match and then tweak each inductor since they might not fall onto popular values! (Sure simulation software can do it but perhaps only the larger orgs would use that, and besides these boxes were probably designed a decade or more ago - at one place I worked at, it was all manually done by their RF expert, sitting in front of VNA all day). Still, I guess once it's done then millions of these cable-TV amplifiers can be churned out cheaply.

RE: Cable Signal amplifier and splitter: a peek inside

Jan Cumps — Tue, 07 Dec 2021 20:21:09 GMT

Transistors seem to be:

BFG540 N37 (120 mA, 20 V, 9 MHz)

BFG520 N36 (70 mA, 20 V, 9 MHz)

Both NPN NXP, UHF / Satellite-TV use.