Off Center Fed (OCF) Dipole Baluns

3152949211 - Off Center Fed (OCF) Dipole Baluns
+3

50:75 ohm (1.5:1) CUBE™ Balun/Unun, 1.8-61 MHz, 1.5KW PEP, Dipole

CB-1.5-1500EB
$119.95
In stock
1
Product Details
Type: BALUN/Unun
Input ohms/Output ohms: 50 in/75 out
Frequency Range < 2:1 SWR (MHz): 1.8-61 MHz
PEP Power Rating (watts): 1500
Insertion Loss (dB): <.2
Input Connector: SO-239 UHF
Output Connector(s): Top Studs/Side Eyebolts/So-239
Transformer Topology: broadband binocular core
Hardware Type: Stainless Steel
Enclosure Size: 4" x 4" x 2"
Weight (pounds): 2

Available as a Unun for 50 ohm coax to 75 ohm coax or 75 unbalanced load or as a Balun for 50 ohm coax to balanced load such as a low (less than a wavelength high) dipole with either side eye bolts and halyard hoist or as post mountable top studs output.

This is an impedance transformer for 50 to 75 ohms and may require a additional feed line choke to keep common mode current off the coax braid.

CB-1.5-1500EB is useful for a dipole center feedpoint for low dipoles with 75 ohm antenna impedance.

Top stud version also useful for 75 ohm ladder line to coax interface


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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