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[burakkucat]

This is just a few questions for Mr Pag to answer, please . . .

1) If one had the option to own a Tester 301C, would it be worth taking possession?
2) What sort of tests can be performed with such a device?

 

[razpag]

1) It all depends on what the price is bud, and what useage you are likely to get out of it ??

2) It is only a Time Domain Reflectometer (TDR), more affectionately called a 'Mole'. It can only find high resistances (or disconnections), and short circuits. The former is shown as a 'peak' on the viewing screen, and the latter is shown as a 'trough'. You then move the horizontal cursor across the viewing screen until you arrive at the start of the peak/trough, and the display will show you in metres how far from where you are measuring, that that particular fault is.
I've actually used it on a mate of mines, who had rennovated an old house and everything was plastered and decorated. Unfortunately, the lighting downstairs wouldn't work. Long story short, we isolated the problem down to a particular length of cable and after isolating both ends I used the 'Mole' to locate exactly where the problem lay. There was a full-on disconnection at 'x' metres. After 'toning' the cable out and measuring to the fault, it only required a section of ceiling plaster-board to be removed. The culprit was the plumber had drilled through the then dead cable when fitting his pipe work. Took about 45 mins to localise the fault and with only slight disruption. Saved having to fully chase in a new cable with a lot more work.

[burakkucat]

a Time Domain Reflectometer (TDR), more affectionately called a 'Mole'.

Your description and explanation of its usage was much appreciated. Thank you.

[geep]

This discussion has got me wondering about my PC's BIOS "SMART LAN" Function. It's an Award BIOS on a Gigabyte GA-P35-DS3R.
It detects the length of the Ethernet cable when it's plugged in. If there's a short in the cable it's supposed to tell you how far along it is.
I wonder if there is some simple TDR functionality in the BIOS + the ethernet interface chips?

Cheers,
Peter

[burakkucat]

It detects the length of the Ethernet cable when it's plugged in. If there's a short in the cable it's supposed to tell you how far along it is.
I wonder if there is some simple TDR functionality in the BIOS + the ethernet interface chips?

It certainly reads as if that may be the case but I'm not too sure about the practicality of implementing such a functionality.

[Ezzer]

The TDR/mole can be thought of working a bit like the ping on a sonar, A pulse goes out and the result depends on whats reflected back and how long it takes to get back. so i would think a pc diagnostic would work on the same basis.

We also had a 18c tester or the megger/megga (cant remember which) which would give you the cable length and where along the lenght you had an earth or battery fault, or a disconection (although we used the 301 for the dis') Although you need to know the cable resistance per meter. We had 2 circular slide rules, one with copper, one with ali' resistances/meters of cable. for each diameter of wire. there was something always really satisfing by using one of those.

[burakkucat]

I've looked at an Ohmmeter 18B (& an 18C) on eBay and I will agree that they are impressive looking pieces of kit. So much so that I made a bid for an 18B.

As you can guess, I tend to collect quality test equipment . . .

[Edited to correct a spelling mistake.]

[Ezzer]

the big clunky switches along with the look of the thing seemed to get the odd funny comment from passers by. Like "Germany calling, germany calling." And my favorate "ITS ALIVE !"

[razpag]

Great bit of kit was the Ohm18. It also made you look incredibly intelligent as you twisted various dial to get a resistance reading. Can't say I ever put in for a bad 'dig' with that kit.

[burakkucat]

I made a bid . . . but was ultimately outbid and so didn't win the 18B. (Still looking out for an RF444B and a JDSU HST-3000.    )

[Ezzer]

RF444b on ebay. Yeah right, would love to see that. Like rocking horse manure.

Ther're made by a chap near Ipswich, think the rate was 170 quid for a new one

[razpag]

RF444b on ebay. Yeah right, would love to see that. Like rocking horse manure.

Ther're made by a chap near Ipswich, think the rate was 170 quid for a new one

Nearly right Ezzer my old mate. They are made by an individual in Ipswich, but having just received mine last week (4 week turnaround time) I can tell you they are £400 to purchase.

[Ezzer]

400 ! wow now thats inflation, unless there is something new about them or do you get a directional aerial with them now ?