Off Center Fed (OCF) Dipole Baluns

Elecraft KXPA100 HF Linear Amplifier RFI Kit - 4 Filters for RF In/Out, DC Power, Relay/PTT/Computer Control

RFI-ELECRAFT-KXPA100
$24.95
In stock
1
Product Details
MPN: RFI-ELECRAFT-KXPA100
Type: New
Country/Region of Manufacture: United States
Filter Power Rating (PEP watts): coax cable limit
RFI Suppression Range (MHz): 1-300 MHz
# Ferrite Filters: 4
Typical Use:: DC power, RF In/out, I/O control cables

This is a generic linear amplifier RFI kit for DC powered amplifiers. Works on many popular amplifiers including:

Specially designed for the Elecraft KXPA100 linear amplifier used with the KX3 and the Yaesu 817 radio (and others).

Included are the following chokes and installation guidelines:

RF Input: 1/2" Snap on – 2 turns of RG-8X size coax through center (use additional turns if using smaller cable)

RF Output: 3/4" snap on – 3-4 turns of RG-8X size cable (use additional turns if using smaller cable)1/2

Control or Relay Cable: 1/2" snap on – 2-3 turns thru center - ½” diameter hole

DC Power Line: 3/4" snap on – 2-4 turns of +/- DC cables through center

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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