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carastro

Stopping USB extension leads from pulling apart

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I have been imaging for 9 years, and this weekend I had to first occasion ever of USB extension cables pulling out.  Not once but twice it happened to two different leads and extension cables on the same evening !!!!  they did not come out completely but enough to cause the camera/filterwheel not to operate.  These are replacement leads for the ones I had previously and been using them for a year or so now without problem.  

Apart from taping them together with gaffer tape which will cause a sticky mess build up, I was just wondering whether anyone had any other unsticky ideas.  

I know people use hubs but I haven't had a lot of success with hubs which work inconsistently.  

Quiet often I don't use the extension cables and can get away with it,  but as I was using my longest scope I didn't want to find the cables stretched out to the point of causing damage.

Thanks

Carole 

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If we're talking the extension connector, rather than the connection into equipment...

Five cable ties - one on each cable around the bottom of the cable strain relief, and then two looped through those, plus one over the mating point. This lets you create lateral tension without really hefty clamping or adhesives.

Alternatively, form a loop so you can cable tie one cable to the other - you end up with one cable running back along the side of the connectors. This isn't quite as robust but will work pretty well in my experience.

If you've got something to attach them to, then just putting a cable tie on each side through a rigid support behind the cable strain reliefs will work fine.

Reusable cable ties will work if you need to disconnect anything; with some of these you can use velcro ties, but try it and see what inspires most confidence.

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Ah .... beat me to it! Just found that. It's worth buying one just for the name! 😀

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I use elastic bands looped around  the connectors. I don't like spending too much money on astronomy...……. (Ok I lied)

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Thanks Guys, some ideas there, but I think I might give the expensive one a miss lol.

Seems like I am not the only one needing to do this.  Perhaps I have just been lucky up to now. 

Carole 

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I was going to suggest elastic bands too.  Or maybe small elastic hair bands (those smooth ones for pony-tails you can get dozens on a bit of card in pound land). I guess you would pass one over the lead and down to the join, then give it a twist round so it doesn't slip off and pass the other end of the connected lead through the loop and run it down to the join.

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I'd always always always recommend avoiding extension leads wherever you can. Connectors introduce loss, and on longer cable runs you need to avoid loss to have cables perform as they should in terms of throughput and stability. Particularly if you're aiming for USB3 performance you can't go very far without running into trouble.

USB hubs are actually great on longer runs, because they regenerate the signal, which means your loss tolerance effectively resets on that run. You can also get "active" USB cables that have mid-span regeneration but these tend to be quite expensive. I've had to use USB hubs to get even quite short USB3 runs into spec where the cabling was short but adjacent to power, Ethernet etc, even with ferrites!

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If the join is to be permanent then a bit of heat shrink plastic might also find a use.   

How about a matchbox? - cut a notch in each end of the tray part, put the connection in the middle and put it together as a box again by sliding the box part over.  For larger connections a similar idea with margarine tubs works.

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Posted (edited)

My problem with USBs has always been USB plugs jiggling in the hub's sockets and losing connection with the computer.  Sometimes I've only had to brush by a cable to cause a drop out, usually requiring the computer to be rebooted. Absolute pain. I solve the problem by cable tying the cables to the mount which stops cable movement transferring back to the hub. 

Edited by Ouroboros

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Yes not a permanent join.  I like the match box idea.  

Carole

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I don't really want to do a permanent join, as there would be too much cable to put away in my camera bags for both the EFW and the camera, plus I don't always need to use an extension cable. 

After giving it some thought and listening to your suggestions, i decided to buy some velcro cables ties and see if that will work, they will come in useful for tying back cables and other uses in any case.   I had not heard of these before, they might just do the trick.  

Carole 

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Flat lollipop sticks or garden plant labels as splints on both surfaces of the mated plug and socket, with elastic bands or reusable ties to secure.

For plugs wiggling in hubs I made deeper recesses like they had to make for QHY 8 cameras 

Michael 

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For plugs wiggling in hubs I made deeper recesses like they had to make for QHY 8 cameras 

QHY8 camera USBs, oh goodness me, I remember that, right PITA.   How do you make the recesses deeper?

Carole 

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A 3D printer would do it easily, but I drilled and filed rectangular holes in ally plate and epoxied that to the hub.

Took forever to get a snug fit but solved the problem. 

Michael 

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Slightly longer cables? I don't like hubs or joints.

Olly

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On 09/03/2019 at 16:38, carastro said:

I have been imaging for 9 years, and this weekend I had to first occasion ever of USB extension cables pulling out.  Not once but twice it happened to two different leads and extension cables on the same evening !!!!  they did not come out completely but enough to cause the camera/filterwheel not to operate.  These are replacement leads for the ones I had previously and been using them for a year or so now without problem.

Carol,

What caused them to come apart? If it was mild strain on the connection that should have been taken up by the total cable run, then maybe you just need to slightly pinch the connectors to make them grip more (but so you are still able to release them easily). 

I completely get the signal loss arguments posted here, but for my low-end setup I use a short USB extension between the power/PC box at the bottom of my mount, and the camera/focuser on my OTA. It a) allows me to easily put away my power box and cover the OTA without taking all the wires off, and b) if the lead does catch on something when in use (for example, whilst slewing) it offers a quick release that hopefully prevents damage to more expensive kit. 

Ady

 

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Slightly longer cables? I don't like hubs or joints.

They are Atik cables and QHY5 cables, I don;t like joins either, but that's what they supply.  Been using them with extension cables for years, and no trouble before.

Quote

What caused them to come apart? 

No strain, they just seemed to have become loose.  Maybe as some-one say, just give them a squeeze, but why would it happen to two different extension cables on the same evening.  Used in all sorts of different temperatures before.  Only common denominator is they were bought at the same time from the same place. 

I am going to try velcro cable ties in the first instance, might try squeezing them too.   I think I can get away without using extension cables when using my shorter scopes, but had my long one on this last weekend.

Carole 

 

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51 minutes ago, carastro said:

but why would it happen to two different extension cables on the same evening

IMHO, it's either external force, or bad luck. In that order of likelihood...

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Just now, adyj1 said:

IMHO, it's either external force, or bad luck. In that order of likelihood...

I've just thought, when you say 'on the same evening', do you mean at different times during the evening, or did they both go at the same time? If it wasn't both at the same time, then I'd have to add in the previous suggestion of 'connections getting looser over time' . 

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IT wasn't exactly the same time, but close.  I was moving the cables to lift them into my plastic box around that time, to save the "joins" resting on the floor and risk of damp/wet, but all I did was lift the cables as I normally do.  there was no strain on them.  Thinking about it, I think they have just got loose over time.

Carole 

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Some great ideas here.   Will try a few out, am waiting for some vecro cable ties to arrive and for the rain to stop so I can actually get at my cables which are still in the van from the weekend astro camp.  

Carole 

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21 hours ago, 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/

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

https://climbtheearth.com/what-is-a-prusik-knot-how-to-tie-a-prusik-knot-images/

:icon_mrgreen:lly

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