Off Center Fed (OCF) Antenna Feed Line Choke for 1/4" coax (1.8-61 MHz)
Got an off center fed antenna fed with RG-8X size coax and having feed line radiation (RFI) problems?
This feed line choke will help solve the problem of feed line radiation (which causes RFI to nearby object close to you coax) as well as Improving antenna pattern by preventing your dipole from becoming a tripole
Simple to install as an extension to your existing coax feed line using a female to female barrel connector (available separately).
Install quickly, reduce your coax radiation issues and start working more DX with a better transmission (and reception) antenna pattern.
Also works with single or multi-band loop antennas using a 2:1, 4:1 or 6:1 transformer without a choke.
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:
- No more RFI displayed on the monitors.
- Radio not acting up or turning off.
- The SWR at 160/80 meter is 1.2:1
- No antenna tuner required. (radio goes to Bypass automatically.)
- Worst SWR is on 10 meter with a 2:1 but still usable, with antenna tuner 1.5.
- One happy OCFD user!
Thanks to Palomar Engineers design and engineering for solving this issue.
73, Ernest – W4EG