17 April 2007
Homebrew narrow CW filter
I finally have it! I built and installed my copy of Yaesu YF-122C filter (455 kHz, BW 500Hz)! The receiver now sounds different from what I'm used to, but its effect is obvious.
16 April 2007
Optional filter plug
If you need to pick the 455 kHz IF signal from an FT817 (FT857 and FT897), you face a little problem: what kind of pin header is that?
The spacing is 2mm, which is very uncommon. Through the service manual you can find the manufacturer part number (9210B-1-03Z172-t or 9210B-1-04Z172-t) which with the help of Google brings you to this page. (ext. link). The harder part now is to locate a suitable female/socket.
On the FT817 signal pins are those towards the inner part of the radio, while all others are grounded (according to the schematic diagram). Or FT857 and FT897 middle pins serve as a pin coding to let the microprocessor automagically identify the added filter.
By the way, these headers are the same of the optional TCXO oscillator.
The spacing is 2mm, which is very uncommon. Through the service manual you can find the manufacturer part number (9210B-1-03Z172-t or 9210B-1-04Z172-t) which with the help of Google brings you to this page. (ext. link). The harder part now is to locate a suitable female/socket.
On the FT817 signal pins are those towards the inner part of the radio, while all others are grounded (according to the schematic diagram). Or FT857 and FT897 middle pins serve as a pin coding to let the microprocessor automagically identify the added filter.
By the way, these headers are the same of the optional TCXO oscillator.
05 April 2007
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