¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. TekScopes
  2. Topics

Patch cable for 7S12 015-1017-01 (750 pS)

 

Recent talk of the 7S12 prompted me to exhume my one. It lacks the 015-1017
cable from the pulser to the S6 loop-thru. I am using a SMA patch cable of
six inches, and the 7S12 works OK, but I would prefer the right cable.
Alas, can't see any on That Auction Site, haven't tried Walter or Qservice.
Is it an RG-type ? If so which ? Plenty of SMA cables around from eg.
Telesonic. Must it be rigid / semi-rigid ? IOW can I make one ? Is there a
table of propagation delay for RGxxx ?
Sorry, lots of questions.
Tim

--
"Success is a collection of well-curated failures"
 

I have the original one, and I have two chinese sma semirigid cable, blue, that I have not tested yet.

If you want I can test risetime of the two wires and post the results



SMA Male plug RG402 Cable Semi Rigid Flexible Coax Coaxial Low Loss RF 50ohm Lot




-----Mensaje original-----
De: [email protected] [mailto:[email protected]] En nombre de Tim Phillips
Enviado el: viernes, 24 de diciembre de 2021 11:45
Para: [email protected]
Asunto: [TekScopes] Patch cable for 7S12 015-1017-01 (750 pS)

Recent talk of the 7S12 prompted me to exhume my one. It lacks the 015-1017 cable from the pulser to the S6 loop-thru. I am using a SMA patch cable of six inches, and the 7S12 works OK, but I would prefer the right cable.
Alas, can't see any on That Auction Site, haven't tried Walter or Qservice.
Is it an RG-type ? If so which ? Plenty of SMA cables around from eg.
Telesonic. Must it be rigid / semi-rigid ? IOW can I make one ? Is there a table of propagation delay for RGxxx ?
Sorry, lots of questions.
Tim

--
"Success is a collection of well-curated failures"
 

Tim,
The velocity factor of these semi-rigid patch cables is about 0.67 . For instance the 1 ns cable (015-1023-00) measures about 20 cm (insertion length). There is no indication like RGxxx on these cables.
Wikipedia has a large table of RG characteristics.
Albert
 

In the same boat, I made my own.

I did a little research on the physics of coax and electromagnetic propagation (speed of light) in it, and found that for RG-174 8 inches of cable takes approximately 1ns to propagate. I bought several feet of RG-174 from a local shop, and had a couple of packages of male SMA crimp connectors left over from another project. I painstakingly created the patch cable to as near 8 inches as I could.

While finding a place to store the resulting cable in my component drawers I came across my TinySA antenna and patch cables (2). Low and behold they are about 8 inches long - I had two in hand and didn't know it. I can tell mine from those because mine is something like 1/16" longer. So maybe its worth acquiring a TinySA (tinysa.org)?

My creation is not equal to the precision engineering and construction of the specified Tek equipment, but it's in hand and works well within the limits of my needs. Don't let the loss of fidelity keep you from making progress. In the process you'll learn and will develop a deeper understanding of the requirements of the equipment. Just always keep a healthy understanding of the limits of what you know, and what you're taking on faith.

Dave

On Friday, December 24, 2021, 06:15:15 AM PST, Albert Otten <aodiversen@...> wrote:

Tim,
The velocity factor of these semi-rigid patch cables is about 0.67 . For instance the 1 ns cable (015-1023-00) measures about 20 cm (insertion length). There is no indication like RGxxx on these cables.
Wikipedia has a large table of RG characteristics.
Albert
 

Reminds me of one of my college programming classes that was centered around designing small logic circuits. In one lecture, the professor held up a piece of wire that was approximately that same length and asked what it was. I raised my hand and replied that electricity would travel from one end to the other in about 1 nanosecond. I think that surprised him a bit - until I admitted that I'd overheard him ask that same question in another class. :) I have enough of an electrical background to understand the principle but I doubt I'd have known the answer he was looking for at that time.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dave Peterson via groups.io" <davidpinsf@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 24, 2021 10:10:32 AM
Subject: Re: [TekScopes] Patch cable for 7S12 015-1017-01 (750 pS)
In the same boat, I made my own.

I did a little research on the physics of coax and electromagnetic propagation
(speed of light) in it, and found that for RG-174 8 inches of cable takes
approximately 1ns to propagate. I bought several feet of RG-174 from a local
shop, and had a couple of packages of male SMA crimp connectors left over from
another project. I painstakingly created the patch cable to as near 8 inches as
I could.

While finding a place to store the resulting cable in my component drawers I
came across my TinySA antenna and patch cables (2). Low and behold they are
about 8 inches long - I had two in hand and didn't know it. I can tell mine
from those because mine is something like 1/16" longer. So maybe its worth
acquiring a TinySA (tinysa.org)?

My creation is not equal to the precision engineering and construction of the
specified Tek equipment, but it's in hand and works well within the limits of
my needs. Don't let the loss of fidelity keep you from making progress. In the
process you'll learn and will develop a deeper understanding of the
requirements of the equipment. Just always keep a healthy understanding of the
limits of what you know, and what you're taking on faith.

Dave


On Friday, December 24, 2021, 06:15:15 AM PST, Albert Otten
<aodiversen@...> wrote:

Tim,
The velocity factor of these semi-rigid patch cables is about 0.67 . For
instance the 1 ns cable (015-1023-00) measures about 20 cm (insertion length).
There is no indication like RGxxx on these cables.
Wikipedia has a large table of RG characteristics.
Albert
 

UT-141 50 ohm Hardline, which is used to make the TEK jumper on the 7S12, has a MIL number RG-405.
If there where enough people (say 5) who wanted one, I have the professional tools to make them. They would cost $15.00 plus shipping (9.00 for priority mail) for material and labor. I have a 7S12 so would use that to make the mechanical model fit properly.??Regards,Jeff Kruth
In a message dated 12/24/2021 11:10:36 AM Eastern Standard Time, davidpinsf@... writes:?In the same boat, I made my own.

I did a little research on the physics of coax and electromagnetic propagation (speed of light) in it, and found that for RG-174 8 inches of cable takes approximately 1ns to propagate. I bought several feet of RG-174 from a local shop, and had a couple of packages of male SMA crimp connectors left over from another project. I painstakingly created the patch cable to as near 8 inches as I could.

While finding a place to store the resulting cable in my component drawers I came across my TinySA antenna and patch cables (2). Low and behold they are about 8 inches long - I had two in hand and didn't know it. I can tell mine from those because mine is something like 1/16" longer. So maybe its worth acquiring a TinySA (tinysa.org)?

My creation is not equal to the precision engineering and construction of the specified Tek equipment, but it's in hand and works well within the limits of my needs. Don't let the loss of fidelity keep you from making progress. In the process you'll learn and will develop a deeper understanding of the requirements of the equipment. Just always keep a healthy understanding of the limits of what you know, and what you're taking on faith.

Dave

On Friday, December 24, 2021, 06:15:15 AM PST, Albert Otten <aodiversen@...> wrote:?

Tim,
The velocity factor of these semi-rigid patch cables is about 0.67 . For instance the 1 ns cable (015-1023-00) measures about 20 cm (insertion length). There is no indication like RGxxx on these cables.
Wikipedia has a large table of RG characteristics.
Albert
 

I have a 7s12 and I think that the problem isn?t the propagation delay, the 7s12 has a fine zero time adjust, I think rather is a problem with the cable losses. If you loose the risetime in the cable you can?t meassure high frequency components.
 

On Fri, Dec 24, 2021 at 09:17 PM, Miguel Work wrote:


I have a 7s12 and I think that the problem isn?t the propagation delay, the
7s12 has a fine zero time adjust, I think rather is a problem with the cable
losses. If you loose the risetime in the cable you can?t meassure high
frequency components.
You are right in that the risetime is important but you normally can't control the risetime of the cable/transmission line you're measuring. Risetime of pulser and cables determine the steepness of the edge and therefore have a great influence on obtainable resolution.

Raymond
 

On Fri, Dec 24, 2021 at 09:17 PM, Miguel Work wrote:


I have a 7s12 and I think that the problem isn?t the propagation delay,
Correct. Precision of delay time in cable between pulser and sampler isn't important.

Raymond
 

One of the firsts things that you can check is the big difference beetween cheap and expensive 50 ohms load resistors, then you can measure if they are inductive or capacitive at high frequencies. Many of the cheap chinese load resistors only have a SMD resistor. One step beyond might be connect it to a computer and make frequency analysis with a 7854, or any other scope connected to recorders outputs, or XY scope outputs. Modern VNA has TDR time analysis with inverse FFT from frequency response.
 

Hi have tried the cable that comes with the nanovna p4 and I only see a little difference of few picoseconds, 4ps

In the photos you can see de difference between a cheap and a microcircuits 50R SMA load.

/g/TekScopes/album?id=271036

1 - 11 of 11