Yeah if you need the short distance performance the 1502 is the only way to
go. The newer models which have LCD redoubt if the LCD has not gone bad now
it will. And the unfortunate part is the LCD was custom.
keep your eyes open a lot of sellers don't know what they have but like
another member said make sure the tunnel diode is good.
A few people have looked at the ex Soviet tunnel diodes but as far as I
know no one has found a substitute.
To me sounds like a perfect project to use a modern pulsar there are an
awful lot of 1502s out there.
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On Thu, Jun 28, 2018, 1:00 PM Harvey White <madyn@...> wrote:
On Thu, 28 Jun 2018 11:02:57 -0700, you wrote:
As Stefan said, how fast a step pulse you need and how much scope
bandwidth you need both depend on how much resolution you need. Do you
happen to have sampling plug-in set for your 7000 series mainframes? If
not, how much scope bandwidth do you have available? Also, how fast a
risetime can you generate in a pulse?
Also as Stefan mentioned, if you can get down to a nS, you should be able
to get pretty close!
I'd recommend (for the long term) that you keep an eye on ebay for a good
deal on a Tektronix 1502 TDR. One of the handiest units I have. A person
can't have too many TDRs though! Check out a 7S12 when you have time.
Absolutely delightful! :-)
The 1502 (not a/b/c) certainly has a tunnel diode in it for the main
generator. It is difficult to impossible to get ahold of when damaged
(and it damages easily since it's right across the input). If you do
get a 1502, make sure that the TD is working.
I don't know anything about the 1502 A/B/C, so I cannot speak of the
tunnel diode (if any) in it.
A 1503 does not have a TD to generate the pulse, has 10 times the
distance at effectively 1/10 the resolution, that is, if the 1502
would be good to 1 cm, the 1503 is good to 10 cm.
Harder to damage, though.
Harvey
Best of luck with the cable!
Tom
