The simplest, most cost effective feed line choke is a ferrite ring installed as shown in the picture (at the antenna feed point) to stop feed line radiation or at the radio end of the coax to suppress common mode coax noise current on the coax braid.

Great choke for log periodics, HF beams, Transceiver/Amp isolation

Improves antenna pattern by preventing your dipole from becoming a tripole

Suppresses pesky coax braid radiation and RFI

Reduces coax braid common mode current up to -32 dB ( 5+ “S” units) on receive

Use one choke for each antenna feed line

Add a double female barrel connector to act as an “extension” of the existing coax.

Jumper Chokes

Store/Jumper Chokes

Jumper Chokes — Plug-In Feed-Line Choke & Noise Filters

Stop common-mode current riding the outside of your coax. Our **Jumper Chokes** drop in at the **feed point** or **radio end** to cut braid-borne noise, tame “RF in the shack,” and restore a cleaner pattern. Choose the size and power that match your station.

Fast install, big effect

Typical improvement **~30 dB** class, model-dependent. One at the antenna and/or one at the radio for best results. :contentReference[oaicite:1]{index=1}

Right model for the job

From **RG-8X 1.5 kW** jumpers to **5 kW** LMR-400/RG-213 units; specialty ranges for loops/OCF/end-fed too. :contentReference[oaicite:2]{index=2}

Place where it matters

Install **right below the feed point** or use as a **line isolator** anywhere along the run to block induced RF. :contentReference[oaicite:3]{index=3}

Quick setup (60-sec check)

Radio end test: Touch center pin vs. shell. If shell raises noise, you’ve got braid-borne common-mode → add a choke. :contentReference[oaicite:4]{index=4}
Placement: At antenna feed point (best), and/or at station entry/radio input. Use short jumpers; weatherproof outdoors. :contentReference[oaicite:5]{index=5}
Power: Pick 1.5 kW or 5 kW PEP to match duty cycle; use RG-8X or RG-213/LMR-400 as appropriate. :contentReference[oaicite:6]{index=6}

Tip: For multi-antenna switches, choke **each input before the switch** to keep paralleled braids from sharing noise. Add a **CMNF** at the radio for extra isolation.

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