Portable Operation RFI Kits

Coax Inline Common Mode Choke Unun - 500 Watts 25-300 MHz- 10, 11, 6, 4, 2 Meters

SKU FC-8X-3-31
$27.95
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Coax Inline Common Mode Choke Unun - 500 Watts 25-300 MHz- 10, 11, 6, 4, 2 Meters
Product Details
Brand: Palomar Engineers
MPN: FC-8X-3-31
Effective Frequency Range (MHz): 25-300 MHz (3 bead)
PEP Power Rating (watts): same as coax cable rating
Estimated Insertion Loss (db): .025
Input Connector Type: none
Output Connector Connector Type: none
Ground Connector (Y/N): none
Enclosure Size (LxWxH inches): none

ASSEMBLED COAX FEED LINE CHOKES

Many customers have requested an assembled sleeve unun or balun 1/4" size cable and we have one all completed with shrink tubing and PL-259 end connectors or open ended on one end for a balanced connection such as a beam, dipole, etc.

All you need to add are 2 barrel connectors (Part # DFBC-1) to insert into your coax cable. For best results add one feed line choke at the antenna to keep the RF on the antenna and another feed line choke at the station entrance to reduce the common mode noise picked up by the antenna braid and fed into the station. Rated 500 watts from 25-300 MHz into 1:1 SWR load.

Common Mode Rejection Ratio up to 20 dB (over 3 "S" units) - see graph for specifics..

Available with PL-259 output or solder lug output (for attachment to a balanced output such as a yagi antenna for dipole fed antenna


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 300x292 - Portable Operation RFI Kits