Lightning Arrestors — One-Shot Protection
Many hams rely on lightning arrestors. What’s less obvious is that most of these are single-use devices. They use gas discharge tubes (GDTs) that short surges to ground during a strike. Once fired, the internal gas capsule is either degraded or destroyed, leaving the protector compromised. (Think of it like an airbag in your car — once deployed, it’s done.)
Why GDT Arrestors Fail After One Event
- Permanent breakdown: After one high-energy event, the gas tube often becomes a short or a leaky resistor.
- Shifted clamping voltage: Even if it still works, the trigger voltage may drift, leaving your gear exposed.
- False sense of safety: They look fine externally but silently offer no protection.
Modern Alternatives — Multi-Strike Designs
Several manufacturers now offer protectors that can withstand repeated surges:
- Raycap (PolyPhaser/Transtector): Uses multi-gap spark arrays for RF arrestors. Unlike single GDT capsules, these arc paths self-heal and can survive multiple discharges. Raycap reserves MOV technology (Strikesorb) for AC/DC mains, not coaxial RF.
- NexTek: Builds multi-strike coaxial protectors for military and commercial RF, including both broadband DC-pass and DC-blocking λ/4 short designs. They are rated for repeated surges and designed for low PIM (intermod).
- Bourns: Known for component-level GDTs and MOVs, but also integrates hybrid surge protectors for telecom and RF lines. These combine MOVs, GDTs, and fast clamps to absorb multiple hits without failure.
- Quarter-wave stubs: Band-specific, but extremely robust. They act as a high RF impedance and a short to fast lightning impulses — essentially infinite lifetime, but single-band only.
Comparison at a Glance
| Brand / Type | Technology | Multi-Strike? | Frequency Range | Notes & Ham Suitability |
|---|---|---|---|---|
| Suhner / Classic PolyPhaser | GDT cartridge | No — replace after 1 hit | Broadband HF–UHF | Affordable and widely available, but deceptive: looks fine after a hit while offering no protection. Good for budget installs but must be replaced. |
| Raycap (PolyPhaser/Transtector) | Multi-gap spark array | Yes — self-healing | Broadband HF–UHF | Reliable multi-strike design. Excellent for ham stations, though more expensive than GDT cartridges. A smart upgrade if you want lasting protection. |
| NexTek | Hybrid (GDT, λ/4 short, DC-block) | Yes — designed for multiple surges | HF–Microwave | Top-tier military/commercial gear with low PIM. Pricing is high but unmatched durability. Overkill for many hams unless you want pro-grade security. |
| Bourns | Hybrid (GDT + MOV + clamps) | Yes — depends on module | HF–Telecom bands | Mostly telecom-targeted. Components can be repurposed in ham builds. Affordable if DIY, but not as plug-and-play as Raycap or NexTek. |
| Quarter-wave Stub | λ/4 short | Yes — unlimited | Single band only | Perfect for repeaters or mono-band HF/VHF setups. Dirt cheap and 100% reliable if cut correctly. Not practical for multiband ham stations. |
Practical Takeaways
- If you’re using Suhner or classic PolyPhaser GDT cartridges — replace after a strike.
- For multiband HF/VHF stations, consider Raycap multi-gap units or NexTek hybrids.
- For fixed-band systems (repeaters, military, commercial), λ/4 stubs remain the most robust solution.
- Always remember: a lightning protector is only as good as your grounding and bonding.
You can explore our coax surge protection collection here to find certified arrestors for your station.
Mini-FAQ
- Do PolyPhaser arrestors survive multiple strikes? — Not the GDT types. Only Raycap’s multi-gap arrays are reusable.
- Is Raycap using MOVs in RF protectors? — No. MOVs are used in their Strikesorb mains line. Their RF products use GDTs or multi-gap arrays.
- What about NexTek and Bourns? — NexTek builds full coaxial protectors for multiple surges. Bourns provides hybrid protector modules and components.
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