Off Center Fed (OCF) Dipole Baluns

1042221011 - Off Center Fed (OCF) Dipole Baluns
+3

50:450 ohm (9:1) CUBE™ Balun, 1.8-61 MHz, 1.5 KW, SO-239 UHF Input, BBTD, Traveling Wave Antennas

CB-9-1500TS
$119.95
In stock
1
Product Details
MPN: CB-9-1500TS (top studs), CB-9-1500EB (eyebolts)
Country/Region of Manufacture: USA
Input ohms/Output ohms: 50 in / 450 output
Frequency Range < 2:1 SWR (MHz): 1.8-61
PEP Power Rating (watts): 1500
Input Connector: SO-239
Output Connector(s): Top Studs/Side Eyebolts
Hardware Type: Stainless Steel
Enclosure Size: 4" x 4" x 2"
Weight (pounds): 3
Antenna Compatability: Folded Dipole, T2FD, BBTD, ALE

Model CB-9-1500 is a 9:1 multi-core, balanced output balun housed in a water resistant enclosure with top stud/wingnuts (TS) or Eye bolts (halyard top hoist, side eye bolts/outputs) used to translate a 50 ohm input up to 450 ohms at RF power levels up to 1500 watts PEP when used with a matched load. With matched 450 ohm load the SWR over the frequency range 1.8 to 61 MHz is less than 2:1 on the coax feed side. Actual SWR is under 1.25:1 from 1.8-180 MHz so very useful for 30-150 MHz also - see graphs for specific details

Features

* Wide Frequency Range 1.8-161 MHz, usable to 180 MHz < 1.25:1 into resistive load

* High Power, 1500 watts PEP (up to 61 MHz)

* Convenient side tab mounting feet

Many designs for BBTD antennas using 9:1 baluns at HFLINK.COM

We also have the 9:1 with the built-in 1:1 choke/balun in part# CB-9-1-1500EB


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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