Here are a couple of things you can see with a 1502, e.g. SMA connector discontinuities 2-3cm apart.
It also discusses the "architecture" and shorting strap, with a picture "researched" from tekwiki.
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On 21/11/21 06:01, Harvey White wrote:
The 1502 uses a tunnel diode, and the waveform looks like a step.? You look down the road to see what happens.? However, the 1502 has a range that is 1/10 that of the 1503, and thus increased resolution for short cables.
The 1503 has 10 times the range (in cable terms) as the 1502, and some varieties are adjustable for different propagation factors in the cable.? Instead of a tunnel diode, it uses (IIRC) a transistor in avalanche mode to generate a sin-squared pulse (I think).? The display presentation is quite different.? The sine pulse fits more of the classic "send the pulse down the line" concept.
If you compare the two, you will see that the measurement scales are different, and the catalog describes the 1503 as a "long distance" cable measurement instrument.
From what I can see of the use, the 1502 was used for shorter cable runs, say from room to room, and the 1503 was used (by cable companies) for checking neighborhood (and longer) cable runs, say to 50,000 feet, perhaps.
A good look at the catalog pages can give a better idea of what Tek thought of the particular uses.
The Tek WIKI has some limited information on both.? The TD pulser may have been used in only the plain 1502 and not the 1502B or 1502C.
I have both the 1502 and 1503, but the non B and non C versions.
Harvey
On 11/20/2021 11:11 PM, Greg Muir via groups.io wrote:
I wholly agree with Tom Gardner¡¯s comments.? Playing with the BNC connector may be converting the 1502 into a parts unit.? Besides, the 1502 was designed for a specific purpose and Tek engineers designed it to those criteria.? Trying to improve its performance to a higher level that I don¡¯t quite understand why you may be trying to make a dragster out of a utility vehicle.? That¡¯s why Tek came out with the 1503 to improve measurement specifications and protect the pulser from ESD.
I have located faults in several mile runs of telco cables that transitioned between aerial and buried with accuracy to a foot or few to the fault using a Tek 013-0169-00 balanced output isolation transformer connected to the output of a 1503 TDR.
I have both 1502s and 1503¡¯s.? I seldom use the 1502s.? I also have a couple of Cabletron TDR5000 TDRs that are unbelievably quite accurate even though the Cabletron company simply made them out of modified old Philips PMxxxx series oscilloscopes. But all of these are used on simple wiring, not coax.? I use FFT DTF for very accurate coax cable fault location.
Greg
