RF line sweep that measures return loss, cable loss, and distance-to-fault on a wireless site. The first acceptance test on every line.
A sweep test measures how cleanly a wireless site's transmission line carries RF energy across its operating band. The three core results — return loss, cable loss, and distance-to-fault — go straight onto the closeout document and gate carrier acceptance. It's the first test crew runs on every line.
HexTel crews calibrate the sweep tester per-site, sweep each line across the full operating band(s), and capture return loss + DTF plots that get attached to the line in the closeout packet. Failed sweeps trigger DTF-driven troubleshooting before re-test. Sweep data is paired with PIM and AIM results for the carrier acceptance review.
A sweep test (RF line sweep) measures how well a wireless site's transmission line carries RF energy. The technician injects a known signal at one end and measures the reflected energy across the relevant frequency band, producing three core results: return loss (how much energy is reflected back), cable loss (insertion loss along the line), and distance-to-fault (DTF — where any reflections are physically located along the line).
Return loss and VSWR (Voltage Standing Wave Ratio) measure the same physical phenomenon — energy reflected back due to impedance mismatch — but expressed differently. Return loss is in dB (higher absolute number = better; -20 dB is much better than -10 dB). VSWR is a ratio (1.0 is perfect; 1.5 is good; 2.0 is marginal). Most carriers spec return loss; legacy sites still see VSWR thresholds.
Carrier acceptance thresholds vary by band and program. Common new-build targets are -20 dB across the full operating band, with marginal acceptance to -18 dB on legacy or retrofit work. Anchor site programs and high-band 5G NR work often spec tighter — -22 dB and below. The exact threshold lives in the RFDS or scope document.
DTF (distance-to-fault) is the sweep test mode that locates where along the line a reflection is happening. If a connector at 47 feet up the tower is loose, the DTF plot will show a reflection peak at exactly 47 feet. This is what crews use to find and fix line problems without re-sweeping the entire site.
A sweep test measures linear RF performance — return loss, cable loss, DTF. A PIM test measures non-linear behavior — interference generated when high-power signals mix at non-linear passive components. A line can pass a sweep test (good return loss, clean DTF) and still fail PIM if it has a contaminated connector. Both tests run at acceptance.
Common testers: Anritsu Site Master (S331, S412, MS27101A), Rohde & Schwarz Cable Rider, Keysight FieldFox. The tester is calibrated immediately before the sweep using a known open/short/load standard. Crews keep cal kits on the truck and re-cal between sites.
A 30-minute scoping call covers your portfolio, carrier acceptance thresholds, and the cleanest path to repeatable test packets.
