Portable Operation RFI Kits

Coax Common Mode Noise Filter - 500 Watts PEP, .1-10 MHz Low Frequency 160-40 Meters

SKU CMNF-500-50LF
$59.95
In stock
1
Product Details

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 emphasizing low frequency range of 100 KHz to 10 MHz

- Reduces broadband common mode receiver noise* picked up on the outside of the antenna coax feed line.

- Low frequency range works on all brands of radios and coax fed antennas from .1-10 MHz

- Common mode noise rejection up to -40 DB (3-6 "S" units) depending on frequency

- Simple plug & play installation: plug a short jumper from the CMNF-500HF to your radio and plug the feed line into the other SO-239 CMNF-500HF input. Either connector can be input or output. Rated at 500 watts PEP, 50 ohm input/output

- 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 1-61 MHz range, place the CMNF-500HF in the "common" line of the antenna coax switch and the receiver.

Got Common Mode Noise? Not Sure - Find out now by clicking link below:

Palomar Engineers Common Mode Noise on Coax User Diagnosis Test

If you use a higher powered transceiver over 500 watts PEP or use an amplifier, consider the CMNF-1500HF (1.5KW PEP) or CMNF-5000HF (5KW PEP) placed at the output of the amplifier.



Save this product for later
Portable operation is fun but also brings challenges to the radio operator concerning receiver “noise” levels, RF interference from adjacent sources including close by transmitting stations, and RFI from portable generators.  A typical scenario and some suggested Palomar product solutions are shown in the picture below:

Generator RFI testimonial:

Bob 

Received your order in a timely fashion. Tried the generator kit on Sunday & it drops the noise from S9 to S5 and 
took out all the electrical noise.  I may want some more toroids from you at some point for other interference problems
I have  here.
Ken VE3KCY

Using an amplifier?  Don’t forget our Linear Amplifier RFI Kits

Want to make up your own RFI kits for a particular operation? Here are links to some of  typical RFI solutions used in portable operations:

AC/DC common mode filters

Feed Line chokes

Coax Noise Filters

If you use a computer for logging in your portable operations, RFI getting into computers will often lock up your computer and/or radio and a computer RFI suppression kits may be helpful

Computer RFI Kits

Make your expedition or portable operation a pleasant and fun outing and remember to take along your RFI kits so you have more time to operate rather then to troubleshoot intermittent or noisy receiver conditions.

Portable Antenna Kits

If you need an effective portable antenna which folds up for transport yet is easy to deploy at your operating site, consider the BULLET series of end fed wire antennas.

BULLET Antennas (click on link or picture for more info)

Bullet Antenna Product