====== CW Filter Model FR4 ======
{{fr-4.jpg?150|}}

===== Description =====
The FR4 filter is for use between receivers or transceivers, and high impedance headphones.  It is a passive audio filter centered around 850 Hz.  A switch is included to completely remove the filter from the headphone line for phone reception.

===== Specifications =====
  ***Center Frequency:** 850 Hz
  ***Bandwidth at 6 dB Down:** 400 Hz
  ***Bandwidth at 60 dB Down:** 2.4 KHz
  ***Input Impedance:** 2000 ohms
  ***Output Impedance:** 2000 ohms
  ***Insertion Loss:** Less than 3 dB
  ***Size:** HWD 2-1/2" x 4-3/4" x 6"
  ***Shipping Weight:** 1 lb 12 oz
  ***Finish:** Baked enamel case, molded plastic side panels with wood grain inserts