Off Center Fed (OCF) Dipole Baluns

Heil Parametric Receive Audio System RFI Kit - 6 filters

RFI-PRAS
$49.95
In stock
1
Product Details
MPN: RFI-PRAS
Type: NEW
Country/Region of Manufacture: USA
Filter Power Rating (PEP watts): not applicable
RFI Suppression Range (MHz): 1-300 MHz

This RFi kit was created to eliminate RFI issues from the excellent Heil Parametric Receive Audio System which can highly tailor audio signal from your radio to a a powered speaker or multiple headphones. However when installed near a high powered HF antenna it can ave RFi issues. This kit was created out of necessity from a ham using high power antennas near the radio. The use of the ferrite filters completely eliminated the RFI issue allowing the ham to enjoy the use of the PRAS.

The ferrite filters are selected to suppress RFI from 1 to 300 MHz. The filters are easy to install, don’t require modification of the protected equipment and work in almost all cases. See product picture for suggested filter use.

What is included in the kit?

The RFI-PRAS kit contains a a ring filter for the AC power cord used on the DC supply cables to the PRAS and high powered speakerr and 3 additional snap-on filters for the both ends of the speaker cable and for the audio input (from the transceiver/audio source) to the PRAS..

You get 1 ring filter and 5 1/2" ID snap on filters and an installation manual.

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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