Coax Common Mode Noise Filter - 1500 Watts, 1.8-60 MHz, -38 dB Common Mode Noise Suppression
CMNF-1500HF for transmitter/receiver coax lines up to 1500 watts PEP - 1.8-60 MHz, -38 dB Common Mode Suppression
For coax feed lines with receive and transmit signals, you will love the small size, wide frequency range and excellent attenuation of common mode noise interference
- Reduces broadband common mode receiver noise* picked up on the outside of the antenna coax feed line.
- Wide frequency range works on all brands of radios and coax fed antennas from 1.8-60 MHz
- Common mode noise rejection up to 20-38 DB (3-6 "S" units) depending on frequency
- Simple plug & play installation: plug a short jumper from the CMNF-1500HF to your amplifier output and plug the feed line (or a jumper to your antenna tuner) into the other SO-239 CMNF-1500HF input. Either connector can be input or output. Rated at 1500 watts PEP.
- will work with Bias-T antenna switches and will pass DC voltage from input to output with no attenuation
* not effective for noise from AC power lines or noise received directly by antenna
Installation Note: For best results, and to reduce co-interference between choked and unchoked coax feed lines with multiple antennas, ALL antenna feed lines entering the radio room need to have a separate feed line choke particularly if they are at a different frequency then HF, like VHF or UHF.
If you use a antenna switch for multiple antennas in the 1.8-61 MHz range, place the CMNF-1500HF in the "common" line of the antenna coax switch and the antenna tuner/amplifier.
For additional common mode noise reduction, consider the CMNF-500HF (500 watts PEP) placed between the receiver and the amplifier.
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This product was formally named CMNF-2 prior to October 31, 2017
Typical user comment:
The filter was quite effective. Was surprised that it actually reduced the noise level more than the signal so S+N/N improved by 1.9 S units. Bill