Off Center Fed (OCF) Dipole Baluns

FSB31-1.5, ID=1.465", RFI Range 1-300 MHz

SKU FSB31-1.5-1
$49.95
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FSB31-1.5, ID=1.465", RFI Range 1-300 MHz
Product Details
Initial Permeability (@ 10KHz): 1500
Material: MnZn
Max cable size - in/mm: 1.394/35.4
OD (A) - in/mm: 2.445/62.1
ID (B) - in/mm: 1.465/37.2
Length (C) - in/mm: 2.5/63.5
Z (ohms per bead - single turn 1 MHz): 60
Z (ohms per bead - single turn 5 MHz): 90
Z (ohms per bead - single turn 10 MHz): 150
Z (ohms per bead - single turn 25 MHz): 190
Z (ohms per bead - single turn 100 MHz): 490
Z ohms (per bead - single turn 250 MHz): 530

Note this "split bead" comes in two halves which are tie wrapped or taped together. Due to the longer length of the split bead halves, the impedance is higher than other similar mix split beads. Useful for large bundles of wire or cables or coaxial feed lines.

Price shown is for the 2 parts of the ferrite


This item is not stock, please allow up to 2 weeks for delivery depending on quantity and availability.

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