Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_terminator_challenge.thumb.jpg.b7f10f594317507d0f40662231b0d9a8.jpg

carastro

Stopping USB extension leads from pulling apart

Recommended Posts

USB leads (the type most of us use) have a 4 core cable. Two cores are for the positive and negative supply lines. The other two cores are the signal lines.

The signal lines are NOT a send and receive. They are differential signalling. Eh what?
To signal, one wire goes towards the positive voltage, the other goes towards the negative voltage.
The receiving circuit looks for the difference between the voltages to determine the signal.
By lightly twisting the signal wires together they form a signal path that is reasonably immune to electrical interference pickup.
The next effect (calculated by clever folks) relates to wire diameter and the insulation on it to form a 'transmission line'. Another funny word.

At the end of it all, you can send data really fast down a 5 metre cable with very little energy used.

If you start joining (extending) cables using connectors then you break up the twisted pair transmission line and compromise signal integrity.
In other words A 5 metre cable is more likely to work correctly than 2 cables each 2.5 metres with a connector.

The next effect is that a lot of cheapie cables give poor performance over long distance. This is impossible to determine without specialised kit.
Unless you count intermittent data loss in the middle of a session as specialised kit.
Spend on the known name products. That is known in the cable world, not a retailer name with a shiny clamshell case.
Screened or shielded cables give better noise immunity, but can be less flexible.

Hope this helps,

David.

  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)
Quote

Carole will be able to use this knot to haul herself up her USB cables if she ever gets a really big mount... 

LOL.  I used to own an NEQ6 but I bought a 2nd mount for astro camps (HEQ5) as I got fed up with having to keep re-polar aligning it.  Left the NEQ6 in the obsy at home.  With the Home LP it was hardly ever getting used.

Then when I decided to buy Polemaster, PA became so much easier, than I decided since I was coping just fine with the HEQ5 I might as well sell the NEQ6 and release some of my equity, so that is what I did.  Really only use the obsy now in the winter months when I can't get to camp.

Anyway, guess what folks?!! 

I tried out the elastic bands today, and they work brilliantly.  Just couldn't think initially how to attach them on both sides with them being joined together.  Combi of the Prisik knot idea and winging it.   

Just have to keep a supply of healthy elastic bands in my cables bag. 

Carole 

Edited by carastro

Share this post


Link to post
Share on other sites

Hrrrr...

I have 3D printed  USB extension lock... Forgot to give it to you last time....

  • Like 1

Share this post


Link to post
Share on other sites
Quote

I have 3D printed  USB extension lock... Forgot to give it to you last time....

I need up to 5 of them depending on whether I am using the dual rig, but normally 3 is sufficient. 

Carole 

Share this post


Link to post
Share on other sites

Your postman will gladly give you a lifetimes supply of elastic bands - it saves dropping them all over the place !!

  • Haha 3

Share this post


Link to post
Share on other sites
On 12/03/2019 at 18:26, Skipper Billy said:

An elastic band tied with a Prusik knot to the cable either side of the plug/socket would give positive pressure when assembled but allow disconnection manually or if a cable snags. 

https://www.animatedknots.com/prusik/

I like the Prusik Knot David :)  I have an application that will suit this perfectly.

Steve

 

Share this post


Link to post
Share on other sites

i pick up 3 or 4 elastic bands every day when the postmans been, he just drops them on the pavement where he leaves his van, he must wonder where they all go !

Share this post


Link to post
Share on other sites
2 hours ago, red dwalf said:

i pick up 3 or 4 elastic bands every day when the postmans been, he just drops them on the pavement where he leaves his van, he must wonder where they all go !

Perhaps he thinks you are collecting them...

  • Like 1

Share this post


Link to post
Share on other sites

Actually dropping those ekastic bands is not funny.  Apart from the littering aspect l know a young dog that died after eating an elastic band from the street.  It somehow twisted up his insides. 

Carole

Share this post


Link to post
Share on other sites

Bloody loads outside my house, I'll have a word with him, I hate littering anyway

Share this post


Link to post
Share on other sites
5 minutes ago, red dwalf said:

Bloody loads outside my house, I'll have a word with him, I hate littering anyway

Ping him with them!

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.