Portable Operation RFI Kits

MINI-CHOKER Coax Line Isolator, 500 Watts PEP, up to -35Db Common Mode Rejection, 1-61 MHz

SKU MC-1-500-50
In stock
Product Details


- Uses proprietary Multi-Mix, Multi-Core, Multi-Turn ferrite technology for maximum choking (up to -35 dB common mode noise rejection) and maximum bandwidth

- 500 Watts PEP, 50 ohm SO-239 connectors In/Out, 1-61 MHz

- Works for all coax fed antennas from 1.8-61 MHz (160-6 meters) - excellent for multi-band beams, verticals, dipoles, magnetic loops and highly unbalanced off center fed antennas.

- 2-5 times more common mode noise rejection, wider bandwidth and higher power then competing isolators

MINI-CHOKER feed line chokes are used to suppress common mode current carried on the outside of the coax braid which is often responsible for receiver noise and RFI in the receiver/transmitter. These chokes are very useful for suppressing RFI common mode current at the antenna feed point, at 1/2 wavelength intervals along the coax feed line and also at the entrance to the radio station.

This choke is available with a SO-239 input/output and ground/static bleeder stud (optional) for attachment to a ground rod. Use an isolator every 1/2 wavelength for the antenna operating frequency (include velocity factor in calculation). Use the ground lug option for long coax antenna feed lines (over 1/2 wavelength at the operating frequency of any antenna system in the near field of the coax).

For Higher Power needs use our MAXI-CHOKER 3KW version.

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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:


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.

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