Off Center Fed (OCF) Dipole Baluns

HF Linear Amplifier RFI Kit - Kenwood 922/A - 4 Filters for RF In/Out, AC Power, Relay/PTT

RFI-LA-K
$54.95
In stock
1
Product Details
MPN: RFI-LA-K
Filter Power Rating (PEP watts): coax cable limit
RFI Suppression Range (MHz): 1-100 MHz

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

ALPHA models – all AC models including 76, 77, 78, 86, 87A, 89, 91B, 99, 274, 374, 8100, 8406, 8410, 9500

AMERITRON models – all AC models including AL80A, AL80B, AL82B, AL572, AL800, AL800H, AL811, AL811H, AL1200

HEATHKIT models – all AC models including SB200, SB201, SB220, SB221, SB230, HA10, HL2200, SB1000

HENRY RADIO models – all AC models including 1K, 2K, 3K, 4K, 5K, 8K

KENWOOD models – all AC models including TL922, TL922A

All AC powered rigs like B&W, Collins, Command, Dentron, Drake, Gonset, Hallicrafters, Hammarlund, Hunter, Icom, Palomar, Palstar, QRO, SBE, Swan, Tokyo Hy-Power, Yaesu

Included are the following chokes and installation guidelines:

RF Input: F240 toroid – 5-9 turns of RG-58 size through center

RF Output: FSB-1 (Big Clamp on) – 3 turns of RG-8 size cable

Relay Cable: FSB-1/2 – multiple turns through choke – ½” diameter hole

AC Power Line: FSB-1 (Big Clamp on) – 3 turns 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