Off Center Fed (OCF) Dipole Baluns

442283848 - Off Center Fed (OCF) Dipole Baluns
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FB68-31 - 3/8" ID, RFI Range 1-300 MHz

Store/Ferrite Core Products/Mix 31/Slip On - Mix 31 - RFI Range 1-300 MHz
SKU FB68-31
$1.75
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FB68-31 - 3/8" ID, RFI Range 1-300 MHz
Store/Ferrite Core Products/Mix 31/Slip On - Mix 31 - RFI Range 1-300 MHz
Product Details
Initial Permeability (@ 10KHz): 1500
Material: MnZn
Max cable size - in/mm: .25/6.3
OD (A) - in/mm: .687/17.45
ID (B) - in/mm: .375/9.5
Length (C) - in/mm: 1.125/28.6
Z (ohms per bead - single turn 1 MHz): 27
Z (ohms per bead - single turn 5 MHz): 69
Z (ohms per bead - single turn 10 MHz): 89
Z (ohms per bead - single turn 25 MHz): 138
Z (ohms per bead - single turn 100 MHz): 225
Z ohms (per bead - single turn 250 MHz): 265

Ferrite Slip On Bead, ID = .375in/9.5mm, Mix 31

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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