The Tektronix 1502 is a series of Time Domain Reflectometers which replaced the 1501 in 1975. The 1502 is for high resolution, sister model 1503 for long range.

Tektronix 1502
Time Domain Reflectometer
Tektronix 1502 Time Domain Reflectometer (CRT version)

Produced from 1975 to (?)


They are commonly used to test coaxial cables, although they have many other uses. The US military was a major purchaser, therefore most of the first series (the 1502, no letter) will be found surplus with some sort of US military property ID tag and an NSN sticker.

Hans Geerling did most of the circuit design on the 1502.

Key Specifications

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Internals and version differences

The first version used a CRT and is an almost completely analog design except for some discrete digital logic used to pre-fire and fire the tunnel diode pulser. The later models (1502B/C) used a liquid-crystal display and a Z80 microprocessor.

The other major difference between versions is the line charging method. The 1502 uses a fast (36 ps) tunnel diode pulser, the later models used a half sine wave to charge the line. The TD pulser, with its Dirac delta edge, gives much better short range sensitivity, although it is much easier to destroy.

Repair issues

→ see 1502/Repairs


MOHR Test and Measurement manufactures a direct replacement to the 1502B and 1502C using an updated version of the same pulser/sampler. Any procedures or recorded waveforms are repeatable using the MOHR TDR.CT100B TDR Cable Analyzer.


Documents Referencing 1502

Document Class Title Authors Year Links
Tekscope 1975 V7 N2.pdf Article Two Weatherproof TDR Cable Testers for Field Use Ivan Ivanov 1975
Tekscope 1975 V7 N3.pdf Article New Products 1975
TekWeek (partial) October 10, 1975.pdf Article Spectrum analyzers require high technology Thor Hallen Dave Friedley 1975


1979: $3,750 (~$14,700 in 2022 Dollars)

According to an internal memo, in 1979 annual sales were estimated at 543 units.