Off Center Fed (OCF) Dipole Baluns

1128089414 - Off Center Fed (OCF) Dipole Baluns
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Coax Common Mode Noise Filter - 1500/5000 Watts, 100 KHz to 30 MHz, up to -38 dB Common Mode Noise Suppression!

CMNF-1500LF
$89.95
In stock
1
Product Details
MPN: CMNF-1500HF
Type: NEW
Country/Region of Manufacture: United States
Filter Power Rating (PEP watts): 1500
Choking Impedance (ohms): 1000-6500
Common Mode Attenuation (db): 21-36 db
RFI Suppression Range (MHz): 1.8-60
Insertion Loss (db): .05
# Ferrite Filters: 5
Enclosure Size (inches): 4" x 4" x 2"
Typical Use:: Noise filter at radio end of coax between amplifier and antenna tuner

CMNF-1500LF for transmitter/receiver coax lines up to 1500 watts PEP - 100 KHz - 12 MHz, Up to -38 dB Common Mode Noise Suppression!

For coax feed lines with receive and transmit signals, you will love the small size, wide frequency range and excellent attenuation of common mode noise interference

- Reduces broadband common mode receiver noise* picked up on the outside of the antenna coax feed line.

- Wide frequency range works on all brands of radios and coax fed antennas from 200 KHz to 7 MHz

- Common mode noise rejection up to 20-36 DB (3-6 "S" units) depending on frequency

- Simple plug & play installation: plug a short jumper from the CMNF-1500LF to your amplifier output and plug the feed line (or a jumper to your antenna tuner) into the other SO-239 CMNF-1500LF input. Either connector can be input or output. Rated at 1500 watts PEP.

- will work with Bias-T antenna switches and will pass DC voltage from input to output with no attenuation

* not effective for noise from AC power lines or noise received directly by antenna

Installation Note: For best results, and to reduce co-interference between choked and unchoked coax feed lines with multiple antennas, ALL antenna feed lines entering the radio room need to have a separate feed line choke particularly if they are at a different frequency then HF, like VHF or UHF.

If you use a antenna switch for multiple antennas in the .2-7 MHz range, place the CMNF-1500LF in the "common" line of the antenna coax switch and the antenna tuner/amplifier.

Got Common Mode Noise? Not Sure - Find out now by clicking link below:

Palomar Engineers Common Mode Noise on Coax User Diagnosis Test




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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