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The '''Tektronix 180A''' was [[introduced in 1958]] and is an all tube  
{{Instrument Sidebar
time mark generator with an oven-controlled crystal oscillator (OCXO).
|manufacturer=Tektronix
Time mark generators put out pulses at user-selectable intervals. 
|model=180
They are primarily used for calibrating the time-base of oscilloscopes. 
|class=Pulse generator
|series=
|summary=Time-mark generator
|image=Tek 180A-Front-On.jpeg
|caption=Tektronix 180A Time-mark generator
|introduced=1958
|discontinued=(?)
|designers=
|manuals=
* [[Media:Tek 180 manual.pdf|Tektronix 180 Manual]]
* [[Media:070-358.pdf|Tektronix 180A Manual]]
* [https://w140.com/tek_fcp/tek_type_180_field_recal_proc.pdf Tektronix 180 Field Recalibration Procedure]
* [https://w140.com/tek_fcp/tek_type_180a_factory_cal_proc.pdf Tektronix 180A Factory Calibration Procedure]
* [[Media:Tek 180 180a irb no ocr.pdf|Tektronix 180 and 180A Instrument Reference Book]] (needs OCR)
* [[Media:Tek 180a fcp.pdf|Tektronix 180A Factory Calibration Procedure (1963-06-04)]]
}}
The '''Tektronix 180A''' was [[introduced in 1958]] and is an all-tube time mark generator with an oven-controlled crystal oscillator (OCXO).


The signal path of the 180A starts with the OCXO, which produces 1 MHz.
Time mark generators put out pulses at user-selectable intervals.  They are primarily used for calibrating the time-base of oscilloscopes.
That waveform is divided down using synchronized monostable multivibrators.
Switches on the front panel select which of the divided-down pulse signals will be added together to form the output waveform.
Switches on the front panel select which of the divided-down pulse signals
The Tektronix 180 has toggle switches.  The 180A has pushbutton switches.
will be added together to form the output waveform.
 
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.   
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 only precision component in the 180A is the OCXO (part number [[158-007]]).   


In addition to the time mark generator functionality, the 180A also produces
In addition to the time mark generator functionality, the 180A also produces sine waveforms at 5 MHz, 10 MHz, and 50 MHz.  
sine waveforms at 5 MHz, 10 MHz, and 50 MHz.  
These frequencies are produced by feeding the 1 MHz OCXO output to a series of three frequency multipliers.
These frequencies 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.
First the 1 MHz is quintupled to get the 5 MHz signal.
Then the 5 MHz signal is doubled to the the 10 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.
Then the 10 MHz signal is quintupled, yielding the 50 MHz signal.
Each of the three frequency multipliers is composed of a [[6DK6]] pentode
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.
driving an LC resonator tuned to 5 MHZ, 10 MHZ, and 50 MHz.
 
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 180A manual suggests an interesting procedure for calibrating the OCXO,  
The method is to zero-beat the WWV standard frequency broadcast with the internal crystal oscillator to align the OCXO frequency.
by attaching a small antenna to deliberately interfere with the national time standard broadcast,  
First tune ham receiver to  WWV broadcast - say 10 MHz -  and watch the audio subtone using an oscilloscope connected to the audio out of the receiver.
and observing the interference with a communication receiver.
Then wait for specific minutes of the hour where there is no audio subtone in WWV.
Then select 1 μs output on 180A, which will have 10 MHz as the 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.
Then 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.  


The Tektronix 180 has toggle switches.  The 180A has pushbutton switches.
You could also use the S-Meter in the receiver instead of the oscilloscope to perform the same.  


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


* [http://w140.com/tek-180a.pdf Tektronix 180A Manual (PDF)]
{{MissingSpecs}}
* [http://w140.com/tek_fcp/tek_type_180_field_recal_proc.pdf Tektronix 180 Field Recalibration Procedure (PDF)]
* [http://w140.com/tek_fcp/tek_type_180a_factory_cal_proc.pdf Tektronix 180A Factory Calibration Procedure (PDF)]


==See Also==
* [[Media:Gr oscillator calibration with 180a.pdf|GR Oscillator Calibration with 180A (PDF, needs OCR)]]
* [[Media:Tek discussion of hickok clone of 180a.pdf]]
==Pictures==
===180===
<gallery>
<gallery>
Tek 180A front.jpg
Tek 180-s1 1.jpg
Tek 180a block diag.png|180A Block Diagram
Tek 180-s1 2.jpg
Tek-180a-ocxo schem.png|Oscillator circuit in 180A using [[158-007]]
Tek 180-s1 3.jpg
Tek 180-s1 4.jpg
Tek 180-s1 5.jpg
Tek 180-s1 6.jpg
Tek 180-s1 7.jpg
Tek 180-s1 8.jpg
</gallery>
 
===180A===
'''External'''
<gallery>
Tek 180A front.jpg | Tel 180A Front Panel #1
Tek_180_Front.jpg | Tek 180A Front Panel #2
Tek_180A_On.jpg | Tek 180A Front Panel #3
Tek_180A-1.jpg | Tek 180A Front
Tek_180A-2.jpg | Tek 180A Front
Tek_180A-3.jpg | Tek 180A Rear
Tek_180A-4.jpg | Tek 180A Top
Tek_180A-5.jpg | Tek 180A
TeK_180_Rear.jpg | Tek 180A Rear
</gallery>
'''Internals'''
<gallery>
Tek_180A-Top.jpg | Tek 180A Top w/o Cover
Tek_180A-Internal-1.jpg|180A Internal - Tubes
Tek_180A-Intertnal-2.jpg | Tek 180A Internal - Power Supply/Transformer
Tek_180A-Intertnal-3.jpg | Tek 180A Internal - Main Chassis
Tek_180A-Internal-3.jpg | Tek 180A Internal - Power Supply Tubes
Tek_180A-Switches.jpg | Tek 180A Internal - Switches
Tek_180A_Underside.jpg | Tek 180A Under Chassis w/o Cover
Tek_180A_Inside_Tubes.jpg | Tek 180A Internal Tubes Live
Tek_180A-rear-No-Filt.jpg | Tek 180A Rear w/o Air Filter
Tek 180a internal 1.jpg|180A internal
Tek 180a internal 1.jpg|180A internal
Tek 180a internal 2.jpg|180A internal
Tek 180a internal 2.jpg|180A internal
Tek 180a internal 3.jpg|180A internal
Tek 180a internal 3.jpg|180A internal
Tek_180A-Internal-1.jpg|180A Internal - Tubes
</gallery>
'''RM180A'''
<gallery>
Tek 180a-rm 1.jpg|180A-RM in black
Tek 180a-rm 1.jpg|180A-RM in black
Tek 180a-rm 2.jpg|180A-RM in black
Tek 180a-rm 2.jpg|180A-RM in black
</gallery>
'''Schematics'''
<gallery>
Tek 180a block diag.png|180A Block Diagram
Tek-180a-ocxo schem.png|Oscillator circuit in 180A using [[158-007]]
Tek 180a late sn power supply.png|late sn power supply
Tek 180a late sn power supply.png|late sn power supply
</gallery>
</gallery>
[[Category:Pulse generators]]
[[Category:Introduced in 1958]]

Revision as of 17:17, 20 January 2023

Tektronix 180
Time-mark generator
Tektronix 180A Time-mark generator

Produced from 1958 to (?)

Manuals
Manuals – Specifications – Links – Pictures

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

Time mark generators put out pulses at user-selectable intervals. They are primarily used for calibrating the time-base of oscilloscopes. Switches on the front panel select which of the divided-down pulse signals will be added together to form the output waveform. The Tektronix 180 has toggle switches. The 180A has pushbutton switches.

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).

In addition to the time mark generator functionality, the 180A also produces sine waveforms at 5 MHz, 10 MHz, and 50 MHz. These frequencies 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 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 ham receiver to WWV broadcast - say 10 MHz - and watch the audio subtone using an oscilloscope connected to the audio out of the receiver. Then wait for specific minutes of the hour where there is no audio subtone in WWV. Then select 1 μs output on 180A, which will have 10 MHz as the 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. Then 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.

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

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

Key Specifications

  • please add

See Also

Pictures

180

180A

External

Internals

RM180A

Schematics