Off Center Fed (OCF) Dipole Baluns

FT140-43, ID=.9", OD=1.4", RFI Range 25-300 MHz

SKU F140-43
$3.89
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FT140-43, ID=.9", OD=1.4", RFI Range 25-300 MHz
Product Details
RFI Range (MHz): 20-250 Mhz
ID-B (in/mm): .9/23
OD-A (in/mm): 1.4/35.6
Height-C (in/mm): .5/12.7
Weight (oz/gm): 33 grams
Initial permeability: 850
A(L): 1060
Frequency (MHz)/Single turn impedance (ohms): 25MHz:38 ohms, 100 MHz:80 ohms

Ferrite Ring Toroid Core, ID = .9"/23mm, Mix 43

Excellent for impedance transformers like 2:1, 4;1, 9:1 or use our convenient Balun/Unun DIY kits with all the parts needed.

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