Siemens Mechanical Filter (150Hz and 75Hz) on ebay

[Zazzle]

Hey,

For those who are listening to CW and looking for extrem narrow filters. There are some old, big mechanical filters available on ebay.de (Germany) since several weeks. So, in case you have a receiver that comes with 10/100Hz tuning steps, this may be a filter of interest.

I got myself a 100Hz Filter and it's pretty awesome. Bad side: a IF of about 30kHz, which means you've to come up with your own IF Downmixer-Circuit. Used it for testing with my Yaesu VR5000.  Used the 10,7M IF output jack and mixed the signal it down to 30Khz (variable, So I also have an adjustable  BFO).

Look for "Mechanisches Filter Siemens E401"

150Hz Filter
75Hz Filter

Greetings!
~Zazzle