[time-nuts] Cable length calibration

[Charles Steinmetz]

The 1503 was Tek's long-line (10km) TDR analyzer.  IIRC, it put 
haversine pulses of about 5v onto the line under test (~10v open 
circuit).  The 1502 (~600m line length) put pulses of about 200mV onto 
the line under test (~400mV open circuit).

Best regards,

Charles


Scott wrote:

> This is highly dependent on the TDR especially ones designed for long twisted pair runs where a high voltage pulse is used to overcome resistive losses
>
>> David had written:
>>
>> The Tektronix 1502 uses a tunnel diode pulser to produce a 50
>> picosecond output step of about 200 millivolts.  There is a misprint
>> in the theory section of the service manual which says "400 V" instead
>> of "400mV".
>>
>>> Scott had written:
>>>
>>> Time Domain Reflectrometry is the usual technique for finding cable length but even there the cables NVP is an essential parameter if you want to compute length but not essential in time nuts application because we are interested in delay which a TDR reads directly When using a TDR its best if cable is unterminated as the discontinuity at the end is helpful as a marker.   Also most TDRs like the Tek 1502 can put 100v or more on the cable which will blow most GPS antennas