1″/25.4mm max Cable Size Chokes
Model BA-200. For use with RG-218 and similar size cables up to 1" OD without connectors installed. Works on all impedance cables, 1.8-300 MHz. Choke outside diameter is 2 inches Requires 9-1/2 inches of cable for 5 bead version, 17" of cable for 10 bead version, and 25" of cable for 15 bead version. Use BA-200-10 or BA-200S-15 for higher choking below 21 MHz. For 10-12 meter frequency use 5 beads up to 15 KW PEP, 10 beads for up to 30 KW PEP and 15 beads for up to 45 KW PEP. We use mix 31 for all chokes. Heat shrink weather proofing kit included. Picture shows 10 bead version.
Rule of thumb suggests you need minimum 5x-10x the coax line impedance for effective choking and the more the better as it will reduce common mode current with higher choking impedance. Select chokes with minimum of 500 ohms at your frequency of interest for best results or upgrade to our CUBE(TM), TUBE(TM), Super Choker(TM) chokes up to 15,000 ohms choking.
Select 10 bead version for 160 meter use, 15 bead version for even higher choking power on lower frequencies. Power rating is same as coax cable used power rating.
Typical choking impedances (BA-58, BA-8, BA-200):
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