180

Manuals – Specifications – Links – Pictures

The Tektronix 180 is an all-tube time-mark generator with an oven-controlled crystal oscillator (OCXO). It was designed by Rodgers Jenkins and introduced in 1958.

Time-mark generators put out pulses at user-selectable intervals. They are primarily used for calibrating oscilloscope timebases. Switches on the front panel select which of the divided-down pulse signals will be added together for the output waveform.

In addition to the time-mark generator functionality, the 180A also produces sine waveforms at 5 MHz, 10 MHz, and 50 MHz.

The Tektronix 180 has toggle switches. The 180A has pushbutton switches.

Key Specifications

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Links

• GR Oscillator Calibration with 180A
• Tek Discussion of Hickok Clone of Tek 180A
• Tektronix 180 teardown by Mr Carlson's Lab @ YouTube

Documents referencing 180A

Document	Class	Title	Authors	Year	Links
Service Scope 12 Feb 1962.pdf	Article	A Clarification		1962	180A

Prices

180A

Year	Catalog price	In 2026 dollars
1959	$575	~$6,400

Calibration

The 180A manual suggests an interesting procedure for calibrating the OCXO, by attaching a small antenna to deliberately interfere with the national time standard broadcast, and observing the interference with a communication receiver.

The method is to zero-beat the WWV standard frequency broadcast with the internal crystal oscillator to align the OCXO frequency. First, tune the receiver to a WWV broadcast frequency − say 10 MHz − and watch the audio sub-tone using an oscilloscope connected to the audio out of the receiver, then wait for specific minutes of the hour where there is no audio sub-tone in WWV. Select 1 μs output on the 180A, which will have 10 MHz as a harmonic. Connect a wire from the output of the 180A as an antenna and couple it to the antenna input of the receiver.

This way, the 10 MHz WWV and 10 MHz harmonic from the 180A will beat in the receiver input, and the difference will be visible as a wave in the oscilloscope. To calibrate the 180, adjust C105 to align the crystal frequency so close to the reference WWV 10 MHz that the frequency difference becomes zero or the waveform on the scope becomes flat.

One could also use the S-Meter in the receiver instead of an oscilloscope to perform the same procedure.

Internals

The signal path of the 180A starts with an OCXO producing 1 MHz, which is then divided down using synchronized monostable multivibrators. This scheme does not require precision in the time constant of the monostable multivibrators. The only precision component in the 180A is the OCXO (part number 158-007).

The sine outputs are produced by feeding the 1 MHz OCXO output to a series of three frequency multipliers.

First the 1 MHz is quintupled to get the 5 MHz signal. Then the 5 MHz signal is doubled to the 10 MHz signal. Then the 10 MHz signal is quintupled, yielding the 50 MHz signal. Each of the three frequency multipliers is composed of a 6DK6 pentode driving an LC resonator tuned to 5 MHz, 10 MHz, and 50 MHz.

The 180A, serial number 5599 and up, uses the 120-119 power transformer.

Pictures

180

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180A

External

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  Tel 180A Front Panel #1

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  Tek 180A Front Panel #2

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  Tek 180A Front Panel #3

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  Tek 180A Front

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  Tek 180A Front

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  Tek 180A Rear

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  Tek 180A Top

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  Tek 180A

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  Tek 180A Rear

Internals

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  Tek 180A Top w/o Cover

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  180A Internal - Tubes

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  Tek 180A Internal - Power Supply/Transformer

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  Tek 180A Internal - Main Chassis

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  Tek 180A Internal - Power Supply Tubes

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  Tek 180A Internal - Switches

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  Tek 180A Under Chassis w/o Cover

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  Tek 180A Internal Tubes Live

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  Tek 180A Rear w/o Air Filter

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  180A internal

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  180A internal

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  180A internal

RM180A

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  180A-RM in black

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  180A-RM in black

Schematics

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  180A Block Diagram

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  Oscillator circuit in 180A using 158-007

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  late sn power supply

Components

Some Parts Used in the 180

Some Parts Used in the 180A