MAXI-CHOKER Coax Line Isolator/Choke, 1-61 MHz, 1.5/3KW/5KW, up to -60 Db Common Mode Rejection, Static Bleeder Option
Product Details
Brand: Palomar Engineers
MPN: MC-1-1500/MC-1-3000/MC-1-5000MC
Country/Region of Manufacture: United States
Effective Frequency Range (MHz): 1-61 (1.5KW, 3KW, 5KW)
PEP Power Rating (watts): 1500/3000/5000 to 61 MHz
Common Mode Attenuation (db): 15-42 (1.5KW), 20-48 dB (3KW), up to 60 dB (5KW)
Estimated Insertion Loss (db): .0123 dB (1 MHz) - .1218 dB (50 MHz)
Input Connector Type: SO-239 female/N (option)
Output Connector Connector Type: SO-239 female/ N (option)
Ground Connector (Y/N): optional with static bleeder
Enclosure Size (LxWxH inches): 12" long, 2" diameter (3KW)/11" x 2-3/4" (5KW)
MAXI-CHOKER™ — Coax Line Isolator / Feed-Point Choke
1–61 MHz HF 50 Ω • SO-239 1.5 / 3 / 5 kW PEP Up to ~30–57 dB CMR Static-bleeder option
What it fixes (why a feed-point choke matters)
Without a proper feed-point choke, your **coax braid becomes part of the antenna**. On transmit, that means unwanted current on the outside of the shield (RF in the shack, pattern distortion). On receive, it **drags noise** back to the radio. MAXI-CHOKER™ presents a **very high choking impedance** on the braid where it matters—**right at the antenna**—and doubles as a **line isolator** anywhere along the run.
- Stops braid currents at the antenna feed point → cleaner TX pattern, less RF in shack
- Cuts received hash coupled onto the feed line
- Stabilizes multi-antenna stations and reduces interaction
Where to place it
- Primary: **Right below the antenna feed point** (unbalanced coax feed). That’s the best place to choke common-mode on TX/RX. :contentReference[oaicite:1]{index=1}
- Also useful: as a **line isolator** anywhere along the feed to block induced currents from nearby RF fields. :contentReference[oaicite:2]{index=2}
- Ground/static-bleeder versions: at the **antenna base**, orient the **ground-lug end toward the antenna** so static/RFI is bled off immediately; at the **radio end**, orient the ground-lug toward the **radio**. Bond with low-impedance conductor. :contentReference[oaicite:3]{index=3}
Which model should I choose?
- MC-1-1500: up to 1.5 kW PEP (HF 1–61 MHz)
- MC-1-3000: up to 3 kW PEP (HF 1–61 MHz)
- MC-1-5000: up to 5 kW PEP (HF 1–61 MHz)
- Options: “GB/BG” models add **ground/static bleeder**; same RF performance. :contentReference[oaicite:4]{index=4}
- Need VHF: see **MC-1-2000VHF** (excellent ~15–144 MHz). :contentReference[oaicite:5]{index=5}
- Ladder-line/balanced feed: see **MC-1-1500LL** (balanced stud outputs). :contentReference[oaicite:6]{index=6}
60-second “Do I need a feed-point choke?” check
- RF “tingles” at mic or tuner, touchy USB/audio lines
- SWR changes when you touch the coax or move it
- Pattern weirdness (e.g., unexpected noise pickup direction)
If any ring true, put MAXI-CHOKER™ at the feed point and add a **CMNF** at the radio end for a one-two punch.
| Operating range | HF 1–61 MHz (typical CMR 30–57 dB across ~1–65 MHz) |
|---|---|
| Impedance | 50 Ω |
| Power (ICAS) | MC-1-1500: 1.5 kW PEP • MC-1-3000: 3 kW PEP • MC-1-5000: 5 kW PEP |
| Connectors | SO-239 in/out (GB/BG versions add ground/static-bleeder lug) |
| Placement | Below feed point; also effective as line isolator along the coax |
Duty cycle: Ratings are SSB PEP. For high-duty digital/CW or long key-down, reduce average power or choose a higher-rated model.
Pro tip: Use **MAXI-CHOKER™ at the antenna** + **CMNF at the radio** for maximum isolation on both ends of the line.
