

A cheap noise reducing speaker

- Many a good qso has been wrecked by that high pitched crackling noise that is common on weak signals
post 05 Feb 2025
RF Filter Links →
70Mc/s Low Pass Filter
The filter published there is working without problem and needs no or very little tuning
Audio Filter & Speakers
Passive audio filters have been around for many years,If your receiver didn't have a CW filter, this little jewel worked fairly well
A cheap noise reducing speaker
Many a good qso has been wrecked by that high pitched crackling noise that is common on weak signals
Band Filters
Real world signals include multiple frequencies over a wide range
70
The filter published there is working without problem and needs no or very little tuning
Passive audio filters have been around for many years,If your receiver didn't have a CW filter, this little jewel worked fairly well
Many a good qso has been wrecked by that high pitched crackling noise that is common on weak signals
Real world signals include multiple frequencies over a wide range