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BillTin

USB cable lenght?

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I would like to be able to bring the laptop inside the house while the capture plan is being run. I 've been looking at a USB active cable of 10 meters or 32.8 feet for this purpose. Anybody has any experience doing this.  Any suggestion would be greatly appreciated.

 

Bill

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The maximum without an active repeater is 15 feet for USB2 and 9 feet for USB3.  

Your 33 feet active repeater cable should compensate reasonably well...but they're not all created equal.  Buy a reputable brand name and get one with the active repeater in the middle of the cable (at the 16'ish feet mark), not at the end if possible.

Regards.

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Also look to add a Quality Powered USB Hub at the Telescope End of this Active Extension Cable.  Most Laptop USB Ports provide only the Minimum Spec Power, and most Extension USB Cords transfer only enough Power to run their own Repeater Circuitry and (maybe) still meet the USB Minimum Power Output Specs.

The Canon DSLR does not require Power from the USB Cable, but any Guide Camera or other Attachment is usually USB-Powered.  If possible, find one which is 12V Powered, so that you can use a 12V Battery when you take your Rig to a Dark Site.

I have had success with ANKER and NEEWER Brands from Amazon.

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On 1/6/2020 at 7:02 AM, s3igell said:

Also look to add a Quality Powered USB Hub at the Telescope End of this Active Extension Cable.  Most Laptop USB Ports provide only the Minimum Spec Power, and most Extension USB Cords transfer only enough Power to run their own Repeater Circuitry and (maybe) still meet the USB Minimum Power Output Specs.

The Canon DSLR does not require Power from the USB Cable, but any Guide Camera or other Attachment is usually USB-Powered.  If possible, find one which is 12V Powered, so that you can use a 12V Battery when you take your Rig to a Dark Site.

I have had success with ANKER and NEEWER Brands from Amazon.

Startech also has 12V powered hubs; I have the industrial 7-port version, with extended temperature range operation, and it works great.

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Just checking in on this thread. 

I use a StarTech.com 15m USB 2.0 Active Extension Cable - M/F - 15 meter USB 2.0 Repeater Cable Cord - USB A Male to USB A Female - 15 m, Black (USB2AAEXT15M)

It seems to connect fine via an unpowered USB hub without the included power adapter and am well beyond the so-called length limits of unpowered cables.  My question is whether these so-called length limits apply neither connected device (in my case a D5300 and a NexStar mount) requires USB power?  I am experiencing intermittent connection issues with with BYN however these occur whether or not I am using the power adapter.  

Advice above from s3igell  is to use both a powered cable and a powered hub, but is that not "overkill" on the power?  (I know if it works, don't knock it 🙂  

I would appreciate your comments, with thanks!

 

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This particular cable has the active repeater device at the end of the cable, at the 15M mark (45+ feet).  StarTech is a top brand...but even a top brands are subjected to the limit of the actual USB2 protocol.

The maximum for a USB2 cable without a repeater is 15 feet.  Anything beyond 15 feet the signal weakens considerably, so having a repeater at the 45 feet mark is not really useful, the signal is already too weak to be amplified... resulting in data lost beyond recovery - this is most likely why you are getting camera disconnects.

To put it simple, you must have a repeater every 15 feet; that is the best approach.

A powered hub is to provide power to the connected USB devices if they don't have an external power supply. It does not amplify the data signal; only an active repeater can do this and as stated above, you should amplify the signal every 15 feet. Your camera has its own power source so it does not draw power from the hub itself so in this case it does not matter if the hub is powered or not; albeit the repeater electronics may benefit from it... but the fact that it is at the 45 feet mark makes it irrelevant IMO as power is not the root issue, data weakness is.  

Regards,

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I used the 15M active usb cable from StarTech (part# USB2AAEXT15M) last night with success. I have a Celestron Nexstar SE 6" with a Celestron focuser motor and an old Canon Revel XS. All of them have a separate power supply. I also powered the usb hub and the cable repeater. I did not have any disconnects for 2 hour period. I am very new to the hobby and I can appreciate the advice from the administrator. I think it would be better to go with 2 7M cables so the signal gets amplified half way if you require the extended distance. I hope it helps.

 

Bill 

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