06-12-2018, 12:13 PM
I'm impressed. The part I needed were found from a small business run (I suspect) from the owner's home in the UK. The replacement 4 kHz filter arrived already!
The original filter has shifted center frequency by about 1 kHz, it is used in combination with the narrow SSB filter (to enhance selectivity). The shift means it is interfering with the passband of the narrow filter. Not really really serious, but quite noticable when switching from upper to lower sideband, rather like switching a heavy treble boost for one mode and bass boost for the other.
I'll probably take a quick diversion from the RCA to fix this at the weekend. Fortunately, the '225 is nice and easy to work on.
Ed
The original filter has shifted center frequency by about 1 kHz, it is used in combination with the narrow SSB filter (to enhance selectivity). The shift means it is interfering with the passband of the narrow filter. Not really really serious, but quite noticable when switching from upper to lower sideband, rather like switching a heavy treble boost for one mode and bass boost for the other.
I'll probably take a quick diversion from the RCA to fix this at the weekend. Fortunately, the '225 is nice and easy to work on.
Ed
I don't hold with furniture that talks.
