36 AWG Coaxial Cable

36 AWG coaxial cable is the crossover point between standard miniature coax (RG-174 at 2.8 mm / RG-178 at 1.8 mm) and ultra-fine micro coaxial grades (42–50 AWG at 0.19–0.48 mm). At 36 AWG, the silver-plated conductor measures 0.127 mm, producing 0.75 mm finished cable OD with ePTFE dielectric and dual-layer shielding.

This gives 36 AWG a unique combination: fine enough for miniature probes and compact cable assemblies, yet large enough for practical mechanical strength, field-serviceable termination without robotic equipment, and significantly lower DC resistance than finer gauges. The result is a cable that NDT technicians can terminate in the field with standard LEMO 00 or BNC crimping tools — something impossible at 42+ AWG.

36 AWG is the preferred construction for NDT contact probe lead cables, TOFD matched transmitter/receiver pairs, miniature medical probe connections, and immersion test cables.

Complete Specifications — 36 AWG Coaxial Cable

36 AWG vs. Standard Miniature Coax — Why Upgrade from RG-178 or RG-174

Key tradeoff: 36 AWG has higher DC resistance (880 vs. 250 Ω/km) and slightly higher attenuation per meter than RG-178. However, at NDT operating frequencies (0.5–15 MHz) and typical cable lengths (1–3 m), the total attenuation difference is less than 0.6 dB — negligible compared to transducer coupling variation. The benefit: 58% smaller OD (0.75 mm vs. 1.8 mm), enabling smaller probe housings and more flexible cable assemblies.

When to stay with RG-178: Cable runs exceeding 5 m at frequencies above 10 MHz, where cumulative attenuation of 36 AWG becomes significant. Or Applications where 1.8 mm OD is not a constraint.

Dielectric Options — ePTFE vs. FEP

Recommendation: Use ePTFE for any phase-matched application (PAUT, TOFD) or where lowest capacitance matters. Use FEP for general single-element contact probes where phase matching is not required and cost optimization is a priority.

Jacket Options by Application Environment

Outer assembly jacket (over multiple 36 AWG cables or combined with strain relief) is selected independently. Typical NDT cable assembly: 36 AWG cable inside PUR outer jacket, total OD 3–5 mm, with LEMO 00 or BNC connector.

Application — Where 36 AWG Is the Right Choice

NDT Contact Probe Lead Cables
The most common application for 36 AWG coaxial cable. Single-element ultrasonic probes for manual thickness gauging (corrosion survey) and flaw detection use 36 AWG as the internal lead cable connecting the piezoelectric element to the connector at the probe housing. The 0.75 mm cable routes easily inside miniature probe housings (8–15 mm diameter), while the 0.127 mm conductor provides sufficient mechanical strength for field replacement. Typical configuration: 36 AWG ePTFE cable, 150–300 mm length inside probe, terminated to LEMO 00 or Microdot connector.

TOFD Matched Pairs
Time-of-Flight Diffraction testing requires transmitter and receiver cables with precisely matched propagation delay. 36 AWG with ePTFE dielectric provides excellent delay consistency thanks to tight Dk control. We supply TOFD pairs length-matched within ±2 mm physical length and ±0.1% electrical length, with LEMO 00 connectors at 50 Ω. Available in 1 m, 1.5 m, 2 m, and 3 m standard lengths; custom lengths on request.

Immersion Test Cables
Automated scanning in water tanks requires cables that maintain 50 Ω impedance while continuously submerged. 36 AWG with PE outer jacket and IP68-sealed LEMO 00 connectors provides stable performance in water immersion environments. The 0.75 mm cable OD allows compact cable routing through immersion fixture arms.

Miniature Medical Probes
Single-element intracavitary ultrasound probes (transrectal, transvaginal, intraoperative) benefit from 36 AWG for the connection between the piezoelectric element and the probe cable junction. The 0.75 mm OD fits within miniature probe tips where RG-178 (1.8 mm) would be too large, while the lower DC resistance compared to 42+ AWG provides better signal-to-noise at the lower frequencies (3–10 MHz) used in these Applications .

Phased Array Wedge Cables
Short (50–200 mm) cables connecting PAUT probe elements to the wedge interface connector. 36 AWG provides durable, field-replaceable connections in the high-wear wedge assembly zone. Thicker than 42 AWG alternatives, but significantly more robust for repeated wedge changes in field conditions.

Eddy Current and EMAT Probes
Electromagnetic NDT probes using eddy current or EMAT technology at frequencies from 100 kHz to 10 MHz. 36 AWG provides adequate bandwidth with excellent shielding (> 45 dB) to reject electromagnetic interference in industrial environments.

Research and Laboratory Instrumentation
Custom sensor cables for university and industrial research labs. 36 AWG offers the best combination of fine gauge (for miniature sensors), standard connector compatibility (LEMO, BNC, SMA), and ease of custom termination for prototype quantities.

Connector Options and Termination

0.75 mm cable OD is compatible with all connectors listed above via appropriate cable clamp inserts. LEMO 00 is the most common choice for NDT applications due to its compact size, positive locking, and availability in sealed (IP67/68) versions for field and immersion use.

Field termination: Unlike 42+ AWG cables that require robotic micro-welding, 36 AWG can be terminated in the field using standard LEMO crimp tools and a 10× magnification loupe. This is a significant operational advantage for NDT service companies that need to repair or replace cables on-site.

36 AWG vs. Finer Gauges for NDT — When to Use Which

*42 AWG has lower loss per meter than 36 AWG due to optimized shield-to-conductor geometry, but the advantage is small at NDT frequencies.

Decision framework:
- Single-element contact probes, TOFD → 36 AWG (best durability, lowest cost, field-serviceable)
- Small PAUT (16–32 elements) in compact wedge → 40 AWG (balance of bundle OD and durability)
- Large PAUT (64–256 elements) → 42 AWG (smallest bundle OD, mandatory for high element count)

Ordering Information — 36 AWG

Standard configurations (2–4 week lead time — faster than 42+ AWG):

Bulk reel:
- 36 AWG solid, ePTFE, 50 Ω, FEP jacket, 0.75 mm OD — 500 m / 1,000 m reels
- 36 AWG 7-strand, ePTFE, 50 Ω, PUR jacket, 0.75 mm OD — 500 m reels
- 36 AWG solid, FEP dielectric, 50 Ω, PVC jacket, 0.75 mm OD — 500 m reels (economy)

Terminated assemblies:
- Contact probe replacement cable: 36 AWG + LEMO 00 (one end) + bare (probe end), 200 mm
- TOFD matched pair: 36 AWG + LEMO 00, 1.0 / 1.5 / 2.0 / 3.0 m, matched ±2 mm
- Immersion cable: 36 AWG + IP68 LEMO 00, PE jacket, 1.5 / 2.0 / 3.0 m
- BNC assembly: 36 AWG in PUR outer jacket (3.5 mm OD), BNC connectors, custom length

Custom options:
- 75 Ω impedance (for specific instrument protocols)
- Dual cable (two 36 AWG in common jacket for dual-element probes)
- Armored outer jacket (stainless steel braid over PUR, for harsh field environments)
- Custom color coding
- IP68 sealed connectors for immersion applications

MOQ: 10 assemblies (terminated) / 500 m (bulk reel). Prototype: 5 assemblies minimum.

Frequently Asked Questions

How does 36 AWG compare to 42 AWG for NDT?

36 AWG has 2.5× lower DC resistance (880 vs. 2,195 Ω/km) — providing better signal-to-noise ratio at longer cable runs and significantly more mechanical durability. At NDT frequencies below 15 MHz, attenuation difference over a 2 m cable run is less than 0.6 dB — negligible compared to transducer coupling variation. Choose 36 AWG for single-element contact probes where durability and field serviceability matter. Choose 42 AWG for multi-element PAUT bundles where bundle OD is the constraining factor.

Can 36 AWG be terminated with LEMO 00?

Yes. 0.75 mm cable OD falls within the LEMO 00 cable clamp range (0.7–2.5 mm). Available in 50 Ω and 75 Ω configurations, with standard IP40 shells or sealed IP67/IP68 shells for field and immersion applications. We stock LEMO 00 in both straight and right-angle versions.

Is 36 AWG suitable for phased array (PAUT)?

For small arrays (4–16 elements), yes — the 0.75 mm cable OD produces manageable bundle sizes (up to 5.8 mm for 32 elements). For larger arrays (32+ elements), 40 or 42 AWG is preferred because bundle OD with 36 AWG becomes impractically large. For 64-element PAUT at 36 AWG, bundle OD would be approximately 8.2 mm — possible but unnecessarily large when 42 AWG achieves 5.4 mm.

What is the maximum recommended cable length at 10 MHz?

At 10 MHz with 36 AWG ePTFE, attenuation is approximately 0.6 dB/m. For a 3 dB loss budget (typical for NDT), maximum cable length is approximately 5 m. For most contact probe applications using 1–3 m cables, attenuation is well within acceptable limits. At 5 MHz (common for thick-section steel inspection), maximum practical length extends to approximately 10 m.

Can you supply TOFD pairs matched to ±1 mm?

Standard TOFD pair matching is ±2 mm physical length (which corresponds to approximately ±0.1% electrical length with ePTFE dielectric). Tighter matching to ±1 mm is available as a premium option — requires individual cable measurement and trimming. Add 3–5 business days and approximately 20% price premium.

Is 36 AWG available with 75 Ω impedance?

Yes. 75 Ω is achieved by adjusting the dielectric OD to increase the conductor-to-shield ratio. Cable OD remains 0.75 mm. Available in ePTFE and FEP dielectric. Lead time: same as 50 Ω (2–4 weeks). Common application: specific flaw detector instruments calibrated for 75 Ω input.

How does your 36 AWG compare to Olympus / Evident NDT cables?

Olympus/Evident supplies finished cable assemblies (probe cables, PAUT cables) but does not publish individual cable specifications for the micro coaxial element inside their assemblies. Our 36 AWG cable is the same category of fine-gauge coaxial used inside premium NDT probe assemblies. We supply to probe manufacturers who build their own assemblies, and to end users who need replacement or custom cable configurations not available through OEM catalogs.

Need 36 AWG for NDT contact probes, TOFD pairs, or miniature medical applications? Share connector type, length, frequency range, and environment — engineering quote within 48 hours.

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