The SPO-375 datasheet declares industry-grade low PIM performance (typ. ≤ -160 dBc), >100 dB shielding effectiveness and a 50 Ω, low-loss profile — specs that directly affect RF link reliability in dense wireless sites. This deep dive explains those numbers for engineers, installers and procurement teams evaluating the cable for outdoor and small‑cell deployments, translating datasheet claims into measurable field expectations.
This analysis synthesizes the manufacturer datasheet and field‑proven testing practices to show how construction, test method, shielding and installation affect real‑world behavior. It uses industry test conventions and common connector families to give actionable verification steps engineers can use on site or during procurement reviews.
Point: SPO-375 is a 50 Ω low‑loss, low‑PIM coax designed for outdoor jumpers and flexible RF interconnects. Evidence: Manufacturer datasheets and product briefs list key metrics — nominal impedance 50 Ω, typical upper component frequency ratings to component limits (commonly specified to 6 GHz), insertion loss curves, and PIM ≤ -160 dBc. Explanation: Those baseline specs position SPO-375 for tower‑top jumpers and small cell feeders where maintaining link budget and avoiding intermodulation are essential; engineers should treat the datasheet as the starting point for system-level margin calculations.
Point: The construction choices (center conductor, dielectric, corrugated outer conductor, PE jacket) directly determine electrical performance and mechanical durability. Evidence: SPO‑series literature indicates a solid or stranded copper center conductor, PTFE or low‑loss dielectric, corrugated copper outer conductor for flexibility, and a UV‑stabilized polyethylene jacket for outdoor exposure. Explanation: A corrugated outer conductor gives flexibility and bend capability with controlled electrical continuity, while the dielectric selection governs insertion loss and phase velocity; the PE jacket provides UV, moisture and abrasion resistance but requires correct handling to avoid permanent kinks that raise VSWR or PIM. Installation teams should confirm materials shown on the datasheet match the intended exposure and flexibility needs.
Point: Nominal impedance, frequency range and insertion loss are the electrical baseline for link budget calculations. Evidence: SPO‑375 is a 50 Ω cable with manufacturer tables providing loss in dB per meter at discrete frequencies (e.g., 900 MHz, 2.1 GHz, 3.5 GHz, 6 GHz), and VSWR plots. Explanation: To estimate link loss, multiply insertion loss per meter by cable length and add connector loss; the datasheet table typically shows increasing dB/m with frequency. For wideband radios, extract loss values at the highest operating frequency to size amplifier margins. Engineers should read the loss table and VSWR curves together to determine whether the cable meets system budget at the node’s highest channel frequency.
Point: Mechanical specs — outer diameter, minimum bend radius, tensile and crush ratings, UV resistance, and operating temperature — dictate install method and long‑term reliability. Evidence: Datasheets provide numeric values (jacket OD ≈ 0.425" / 10.8 mm as example), recommended dynamic/static bend radii, tensile limits, crush resistance and operating temperature ranges. Explanation: Tight bends or exceeding crush ratings increase risk of permanent deformation that degrades VSWR and PIM; UV and temperature ranges determine suitability for rooftop or direct‑exposure applications. Installers should verify the mechanical table and choose routing and clamp hardware that maintain the manufacturer‑recommended bend radius and do not introduce mechanical stress points.
Point: Understanding how PIM, VSWR, loss and shielding are reported on the datasheet is essential to interpret warranty and acceptance claims. Evidence: Datasheets typically provide two‑tone PIM values, VSWR curves, insertion loss tables and measured shielding effectiveness. Explanation: Interpreting the test conditions (tone power, frequencies, connectorization) alongside the numeric results lets engineers translate a -160 dBc claim to expected on‑site margins, recognizing that test rig, connectors and assembly process can dominate real field PIM performance.
Point: PIM specs are only meaningful with the test method and conditions. Evidence: A typical declaration (≤ -160 dBc) is valid only when accompanied by two‑tone levels (commonly +43 dBm per tone), tone spacing, test frequencies and connector conditions; “100% PIM tested” indicates each cable/assembly is measured during manufacturing. Explanation: -160 dBc at +43 dBm means the third‑order product measured is 160 decibels below the carrier; that is an exceptionally low level, suitable for dense deployments. Engineers should require the exact test frequencies and tone power in procurement language and request batch test reports to validate lot acceptance and traceability.
Point: VSWR and insertion loss define matched performance; shielding defines immunity to external fields. Evidence: Datasheet VSWR plots show ratio vs. frequency, insertion loss tables quantify dB/m, and shielding effectiveness is provided in dB across frequency. Explanation: A low VSWR (close to 1.1:1) reduces reflected power and standing waves; insertion loss reduces available SNR at the radio. Shielding >100 dB ensures minimal coupling from nearby feeders or transmitters, lowering susceptibility to induced common‑mode currents and unintentional PIM sources. For link design, translate insertion loss into dB of system margin and compare shielding figures to site interference risk.
Point: Frequency dependence — phase velocity, dispersion and group delay — affects timing and wideband signal integrity. Evidence: Datasheets often list phase velocity (percent of c) and include loss vs. frequency curves and group delay variations. Explanation: For timing‑sensitive carriers or MIMO arrays, stable phase velocity and low dispersion are required to avoid beamforming degradation or channel skew. Engineers should extract phase velocity and group delay flatness from the charts and verify that cumulative group delay over run length stays within system tolerances for wideband carriers.
Point: Proper connector selection, mating, routing and test workflows preserve the low PIM promise in the field. Evidence: Connector vendors provide low‑PIM connector families compatible with SPO‑series cables and datasheets give recommended assembly practices. Explanation: Following recommended torque, soldering and cleanliness practices keeps interface PIM low; routing and grounding avoid exogenous PIM sources; on‑site PIM testing verifies acceptance. Below are prescriptive details to convert datasheet claims into reliable installations.
Point: Connectors and assembly practice set the PIM floor for the assembly. Evidence: Low‑PIM connector families marketed for SPO/SPF/SPP‑375 series (examples include TC‑SPP375 and TC‑SPO375 options) along with vendor torque and solder specs are industry standard. Explanation: Use specified low‑PIM connectors, follow manufacturer torque values using a calibrated wrench, and ensure solder joints (where required) are correctly applied. Cleanliness is critical: any oxide, machining burr or foreign particle at the mating surface can generate intermodulation. For assemblies using factory‑term connectors like TC-SPO375-NF-LP, require vendor assembly certificates or perform independent PIM verification.
Point: Mechanical routing and RF grounding prevent movement‑induced PIM and reduce common‑mode currents. Evidence: Field reports and installation guidelines emphasize gentle bends, secure clamping, and dedicated bonding points to system ground. Explanation: Route the cable with the manufacturer‑recommended bend radius, avoid pinch points and secure the cable to minimize vibration and movement relative to connectors. Bond shields at defined grounding locations using low‑impedance bonds to avoid floating shield sections that can pick up currents; consistent bonding reduces the chance of PIM generated by shield‑to‑structure contact or corroded interfaces.
Point: A repeatable test workflow validates that assemblies meet datasheet PIM. Evidence: Standard two‑tone PIM test rigs use +43 dBm per tone (or per spec), calibrated loads, and a defined frequency pair representative of site carriers. Explanation: Select tone frequencies that straddle live carrier bands and use recommended power levels; for critical installs target a margin better than the datasheet (e.g., test target ≤ -162 dBc where -160 dBc is specified). Document test instrument calibration, test configuration, and raw results in a traceable acceptance report. Store reports keyed to cable serial or batch numbers for procurement traceability.
Point: Real deployments reveal how SPO‑375 performs relative to datasheet claims and alternatives. Evidence: Field measurements commonly compare insertion loss, measured PIM, and mechanical handling against expected datasheet tables. Explanation: Below are representative deployment contexts and a concise spec‑led comparison to help teams trade off loss, flexibility and cost versus alternatives.
Point: Tower‑top jumpers face mechanical stress and RF density that can expose deviations from datasheet performance. Evidence: Typical field tests show insertion loss matching datasheet within measurement uncertainty; PIM can degrade if connectors or routing are mishandled. Explanation: In a properly assembled and routed jumper, expect measured loss and VSWR to track datasheet curves; measured PIM should meet factory test limits if connectors and handling are compliant. Deviations usually trace to improper torque, contaminated connectors, or crush/dents in the corrugated conductor that increase local VSWR and PIM.
Point: Small cells and DAS nodes require compact, flexible cable runs with predictable PIM floor. Evidence: The SPO‑375 family’s flexible corrugated outer conductor and thin jacket are designed for tight routing while maintaining electrical continuity. Explanation: For small cell installations, size and bend radius matter; use grommets and strain relief to avoid jacket abrasion. Seal outdoor entry points with manufacturer‑approved adhesive boots or heat shrink to prevent moisture ingress. Correct connectorization and sealing preserve the low PIM characteristic in confined architectures.
Point: Alternatives vary primarily by insertion loss, mechanical flexibility and cost. Evidence: Comparative spec tables from cable families show slight differences in loss per meter, OD, and bend radius. Explanation: Choose SPO‑375 when you need a balance of low loss and low PIM with good flexibility; SPF‑375 and other derivatives may trade slightly lower loss for increased stiffness or vice versa. The table below summarizes typical tradeoffs to guide selection.
| Parameter | SPO‑375 (typical) | SPF‑375 (typical) | Generic 50 Ω low‑PIM |
|---|---|---|---|
| Insertion loss @ 3.5 GHz (dB/m) | ~0.10–0.15 | ~0.09–0.13 | 0.12–0.20 |
| Bend radius (min) | ~4–6× OD | ~6–8× OD | Varies |
| Typical PIM (third-order) | ≤ -160 dBc (per datasheet) | ≤ -160 dBc (variant) | -150 to -160 dBc |
| Shielding (dB) | >100 dB | ~95–100 dB | 80–100 dB |
Point: A concise checklist helps convert datasheet claims into procurement and acceptance criteria. Evidence: Best practices from procurement and field engineering emphasize demanding defined test conditions, batch reports and clear acceptance criteria. Explanation: Use the checklist below during RF procurement and acceptance to ensure that what arrives in the field meets system needs and datasheet claims.
Point: Don’t accept raw numbers without conditions. Evidence: Datasheet PIM numbers are only meaningful when accompanied by tone power, frequency pair and fixture details. Explanation: Require the datasheet to list test power (e.g., +43 dBm), tone frequencies and whether the assembly was 100% tested; request batch test reports and manufacturer traceability, and insist on sample assemblies for independent verification if procurement risk is high.
Point: A clear acceptance protocol reduces returns and site failures. Evidence: Typical acceptance workflows include visual inspection, swept VNA check for VSWR/loss, and two‑tone PIM tests at representative frequencies and powers. Explanation: Define numeric pass/fail thresholds (e.g., VSWR ≤ 1.3:1, insertion loss within ±10% of datasheet, PIM ≤ -160 dBc at specified tone power) and require signed inspection reports with instrument calibration records for each delivery lot.
Point: Correct ordering and storage extend useful life and ensure compatibility. Evidence: Vendor part numbers and connector attachment options (e.g., TC‑SPO375‑NF‑LP style identifiers) plus vendor storage recommendations are standard. Explanation: Use explicit part numbers that include connector type and length, confirm MOQ and lead times, and store reels indoors or under UV‑blocking covers. For assemblies stored long term or exposed to installation stress, schedule periodic re‑test (VSWR/PIM) as part of preventive maintenance. Note the specific connector style TC-SPO375-NF-LP when requesting N‑female solder attachments to obtain factory‑recommended assembly options.
SPO‑375’s datasheet‑level guarantees — notably the low PIM (≤ -160 dBc), high shielding and clear RF loss curves — make it a strong candidate for outdoor jumpers and low‑PIM critical installs when proper connectors and installation practices are followed. Use the checklist above to convert datasheet claims into verified field performance and require batch traceability and acceptance testing to ensure delivered assemblies meet site‑specific margins.
Request the manufacturer’s datasheet showing test conditions, a factory traceable batch PIM report showing the two‑tone power and frequencies used, and calibration certificates for test instruments. If assemblies are vendor‑terminated, ask for assembly certificates or independent third‑party PIM test results. Retain the documentation keyed to each shipment or serial number for warranty and troubleshooting.
Factory‑terminated TC‑SPO375‑NF‑LP assemblies often provide a lower and more predictable PIM floor because factory processes control torque, cleanliness and soldering. Field‑terminated assemblies can match performance if technicians use certified low‑PIM connectors, calibrated torque tools and validated procedures, but procurement should require on‑site verification (two‑tone PIM test) to confirm equivalence before commissioning.
Set acceptance thresholds at or better than the datasheet claim with a margin for measurement uncertainty; for a datasheet value of ≤ -160 dBc, target acceptance at ≤ -158 to -162 dBc depending on test repeatability. For highly critical nodes, demand a 2–3 dB margin below the datasheet to ensure headroom under varying temperature and mechanical conditions. Document instrument settings and calibration with each test report.