Off Center Fed (OCF) Dipole Baluns

2981648738 - Off Center Fed (OCF) Dipole Baluns
+3

CB Radio Generic Mobile Transceiver RFI/Noise Reduction Kit, RFI Range: 20-60 MHz, Works on all brands

RFI-CB-MOBILE
$19.95
In stock
1
Product Details
MPN: RFI-CB-MOBILE
Country/Region of Manufacture: United States
Filter Power Rating (PEP watts): 500
Common Mode Attenuation (db): <=25 dB
RFI Suppression Range (MHz): 20-60 MHz
# Ferrite Filters: 2

Palomar Engineers RFI Filter Kit for CB Radio Radio Transceivers from 20-30 MHz uses ferrite rings for the DC power supply and the coax to the antenna.

BUY THIS KIT NOW TO SOLVE YOUR RFI/EMI NEEDS! WORKS WITH ALL BRANDS (Cobra, DAS, Midland, Uniden etc.) OF CB/HAM/COMMERCIAL RADIO RIGS in 20-60 MHz range.


Purpose

The RFI kit is designed to be installed on your radio transceiver to reduce Radio Frequency Interference (RFI) caused by common mode current on the outside of the coax braid at the output of your radio and on the DC power supply cable.

This kit will help reduce or eliminate:

1. “Hot mic” RFI caused by poor grounding of antennas or common mode currents from linear amps feeding unbalanced (coax fed) antennas without baluns/line isolators.

2. RFI to neighbor’s electronic devices including audio/video systems, computers, telephones, garage door openers, etc.

3. RFI to your other radios, audio/video systems, computers, telephones, etc.

A side benefit is a reduction in noise floor in your receiver depending on the amount of noise being introduced by common mode currents (which are blocked/reduced by the chokes in this kit).

These chokes use a special mix of ferrite core material that is effective in suppressing radio frequency interference from Ham Radio amplifiers.


Included are the following chokes and installation guidelines:

DC Input: F240 Ring – 3-7 turns of DC power cable - sized for smaller plugs

RF Input/Output: F240-31 ring - wrap 6 turns of RG8X size cable near the back of the radio

Also make sure you connect a good RF ground to the transceiver ground post.

For additional RFI suppression, use a MC-1-500-50 mini feed line choke at the antenna feed point to suppress common current on the coax feed line during transmit and a CMNF-500-50 Coax Noise Filter to reduce common mode noise during receive operations.

If you use a switching power supply for base operation, consider the RFI-SMPS switching power supply RFI kit.

If you use a linear amplifier we have RFI kits for linear amplifiers that help suppress RFI in your shack or in your neighbor’s house.

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Testimonial

Hi Bob,

Radio: Flex-6700 running barefoot -10 to 100 Watts max.
Antenna: MFJ-1216 – 160/80 meter OCFD wire antenna with matching network.
Elevation: Over 60 feet AGL – fully extended.
Installed: Mid November 2013

I operate mainly on the digital modes running less than 50 Watts.  All of the sudden after a few days operating with this antenna, I start to have RFI and my radio was acting up; such as changing bands, SWR changing values, radio failures and turning off. However, when I used my Hy-Gain 18 HT vertical on the same band none of the abnormality occurred.
I contacted MFJ and confirm that what I was noticing was a failure of their “matching network” AKA balun.  They offered no solutions. Then I contacted Palomar Engineers and bought the 1:1 new toroid RF beads.  I called Palomar Engineers and I happened to talked to you directly; regarding the on going issue with the MFJ antenna. I found out that the 1:1 balun was not what I needed (I was miss-informed by MFJ that it was 1:1 matching network.)
You offered to make the required balun 4:1 and the rest is history.

Here are my findings:

  1. No more RFI displayed on the monitors.
  2. Radio not acting up or turning off.
  3. The SWR at 160/80 meter is 1.2:1
  4. No antenna tuner required.  (radio goes to Bypass automatically.)
  5. Worst SWR is on 10 meter with a 2:1 but still usable, with antenna tuner 1.5.
  6. One happy OCFD user!

Thanks to Palomar Engineers design and engineering for solving this issue.

73, Ernest – W4EG