Technical Overview for the RX 75 Ω Line Isolator
Updated: 2025-08-27 — Technical Overview for the RX 75 Ω Line Isolator validated against the production schematic.
Intro
This RX 75 Ω line isolator is purpose-built for active antennas, delivering +30 dB common-mode rejection across 500 kHz–200 MHz while keeping insertion loss below 2 dB. It mounts on a stainless (RVS) spike that provides both a mechanical anchor and a defined low-impedance path for unwanted common-mode noise currents to ground.
Ready to deploy: Includes the short RVS ground peg and is IP66 sealed when taped. Designed for long-term outdoor installation. Buy it here →
Specs at a Glance
| Parameter | Value |
|---|---|
| Impedance | 75 Ω (F-connector) |
| Frequency range | 500 kHz – 200 MHz |
| CM rejection | ≥ +30 dB (HF measured) |
| Insertion loss | < 2 dB |
| Grounding | Stainless RVS spike with galvanic isolation of enclosure |
| Connector sealing | IP66 after taping |
RX 75Ω Line Isolator with RVS Ground Peg closeup view
How It Works
The schematic confirms the design simplicity:
- Two F-connectors provide the 75 Ω interface in/out.
- Two gas discharge tubes (one at each port) clamp surges and ESD to the RVS spike ground.
- RVS spike ground provides a defined CM drain path while the enclosure itself is galvanically insulated on one side via ASA insert — preventing loops.
Installation direction (important):
The side with the RVS ground clamp/peg must always face the antenna side of the connection so a local ground reference is established before the choking action.
The side with the RVS ground clamp/peg must always face the antenna side of the connection so a local ground reference is established before the choking action.
- Antenna side: Mount the unit near the feedpoint with the RVS clamp pointing toward the antenna. First the peg provides the reference ground, then the choke follows toward the coax run.
- Shack side: Mount the second unit at the shack entry with the RVS clamp pointing toward the incoming long coax from the antenna (not toward the radios). Again: ground reference first, then the choke into the shack.
Install with Confidence
Connect inline at both ends: one unit near the antenna, one at the shack wall. Always orient the RVS clamp side toward the antenna/long-coax side so the antenna system gets a reference ground before the choke. The included RVS peg ensures stable grounding even in temporary or portable deployments.
Buy it here →
Mini-FAQ
- Is this choke only for RX? — Yes, it is optimized for receive systems and not rated for TX power.
- Why the RVS spike? — Provides a controlled low-impedance drain for common-mode noise while avoiding galvanic loops with the enclosure.
- Do I need one or two? — Best practice is to install one at the antenna and another at the shack entrance for full suppression coverage.
- Which way around? — Always point the RVS clamp side toward the coax run that brings noise in, so shunting happens before the signal path continues.
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