Ice Radio Products

Modern Coaxial Lightning Arrestors: Alpha Delta vs. I.C.E.

This report compares coaxial lightning arrestors from Alpha Delta Corp. and Industrial Communication Engineers, Ltd. (I.C.E.)—two prominent manufacturers in the field. The I.C.E. design described is patented by the U.S. Bureau of Patents and Trademarks.

Alpha Delta Design Overview:

Alpha Delta’s lightning arrestors use a single-component system:

  • Gas Discharge Unit (GDU) – Rated for 400-1000 volts, it connects the coaxial center conductor to an external ground terminal. When voltage surpasses the breakdown threshold, the GDU ignites, shunting excess current to ground.

Limitations of Alpha Delta Design:

  1. Shield Current Bypass

    • The arrestor lacks direct chassis grounding, causing up to 80% of the lightning surge to bypass the GDU and flow through the coax shield into station equipment. This exposes sensitive electronics to damage.

  2. Delayed Activation

    • The GDU activates only after hundreds of volts pass through to the equipment. By the time it engages, modern solid-state radios can already be damaged or destroyed.

  3. Limited Dissipation Capacity

    • Gas discharge units dissipate only 1 watt, handling brief surges lasting microseconds. However, lightning currents, slowed by coaxial inductance, endure longer, causing GDUs to fail frequently.
    • GDUs degrade silently – they may not short out but can fracture, making failure difficult to detect.

  4. No Static Drain

    • Alpha Delta units lack a constant static drain. Coaxial lines accumulate charge like capacitors, leaking voltage through the antenna or dielectric. This causes receiver noise during electrical activity.

I.C.E. Design Overview:

I.C.E. arrestors address these flaws with a multi-component, four-part system:

  1. High-Voltage Blocking Capacitor

    • Allows RF signals to pass freely while blocking DC and low-frequency AC voltages.

  2. Heavy Discharge Inductor/RF Choke

    • Acts as the primary surge neutralizer, providing a constant DC short to ground. This immediately dissipates voltage before it reaches the equipment.

  3. Gas Discharge Unit (GDU)

    • Activates only during extreme back-EMF events to collapse the magnetic field of the inductor. This minimal workload extends the GDU’s lifespan indefinitely.
    • To date, no replacement GDUs have been required for I.C.E. units.

  4. User-Side Resistance

    • A resistor on the equipment side drains residual static from the coax, preventing dielectric leakage and reducing receiver noise.

Key Advantages of I.C.E. Design:

  • Continuous Protection – The inductor is always active, eliminating reliance on voltage thresholds.
  • Minimal GDU Stress – The GDU rarely activates, resulting in long-term reliability.
  • Static-Free Operation – Constant drain mechanisms prevent charge buildup, enhancing receiver performance.

In conclusion, I.C.E. arrestors provide superior, long-lasting protection compared to Alpha Delta units, safeguarding telecommunication equipment with more effective surge dissipation and static control.