Extending USB 3.0 in the observatory

[keithc]

Hi,

My observatory project is well under way with the observatory scheduled to be erected on July 15th. It is my wish to place a USB 3.0 hub on or close to the pier but that requires a USB 3.0 cable length of around 6m. I have a 10 port self powered USB 3.0 Hub and 3m USB 3.0 cable and I'm able to connect my camera and NEQ6 Pro mount and wireless gamepad transmitter/receiver to the hub and everything works just fine. I can automatically slew the scope to the desired object with Cartes du Ciel, control the camera with Backyard Nikon and download images and make fine adjustments to the scope position with the gamepad.

So far so good. The observatory will have a warm room where the PC will reside but the 3m USB cable is not long enough to be able to position the hub by the pier. I was advised to buy a 5m USB 3.0 Active Extension Cable, which I did, but this does not work. I get an error every time I connect the hub to the extension cable and any devices I plug into the hub are not recognised. I've now been advised that this method will not work so have abandoned my efforts and retuned the extension cable.

I specifically want to use USB as my camera, a Nikon D810, is USB 3.0 compatible and the image files it produces are very large so need fast transfer rates.

Has anyone else attempted to do this? There are conflicting recommendations for USB 3.0 cable lengths, some say 3m max others 5m max. My latest idea is to buy a second 3m USB 3.0 cable and a 2 port USB 3.0 hub (self powered) and use that to extend the USB 3.0 cable to the 10 port hub (i.e PC --> 3.0m USB Cable --> 2 port hub --> 3.0m USB cable --> 10 port hub --> devices). . Has anyone any experience of doing this? Does anyone know if this would work?

It's my intension to get a guide scope package and, eventually, a remote focuser, so getting this to work now will make things much easier as I add additional equipment.

Thanks,

Keith

[damnut]

hi Keith,

rather than daisy chain hubs, try running an active cable to the first hub. Then you can run what you desire from the hub onwards.

http://www.amazon.co.uk/dp/B005LJKEXS/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=569136327&pf_rd_s=lpo-top-stripe&pf_rd_t=201&pf_rd_i=B007B61I2K&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_r=1H0N5EPMM3T8THBY257T

[kalasinman]

I appreciate the perceived need for speed from the camera to storage. With image sessions one often uses a cool down pause between frames or a settling period after each dither. This usually gives plenty of time for raw subs to download, even over USB2

[Tinker1947]

USB2 should work on the active extension, forget the speed of USB3, for downloading images with the DSLR cool down time (i use 20 seconds)  all should flow nicely.....so  PC - Active Extension - Power Hub, all your bits here......

[JamesF]

I think I'd agree on USB2.  For large images from long exposures a few seconds more on the transfer time isn't so bad.

If you really must go USB3 all the way then you'll probably need a USB3 active repeater or second hub in middle as it's not recommended to use cables longer than three metres (though you can string several together if you have some sort of active connection joining a chain of three metre cables).

James

[Dr_Ju_ju]

Have you considered running USB over network cables, which will not limit your distance e.g. http://www.ebay.co.uk/itm/USB-3-0-to-Ethernet-Adapter-RJ45-1000Mbps-LAN-Gigabit-Network-Portable-Card-/271616039812?pt=LH_DefaultDomain_3&hash=item3f3d93db84

[JamesF]

I'm not at all sure the device you've linked to there does what you think it does.

James

[michael8554]

3M does seem to be the limit for max speed working, you can go longer but the speed goes down.

So perhaps a quality 3M repeater cable ->  an ordinary 3M cable -> 10 port hub ->  your camera etc

The hub should act as the booster on the end of the ordinary 3M cable.

Michael

[DMouse]

Hi, I have used a USB over network device from ICRON to control my telescope in my shed from over 150 ft away. This is USB 2, but ICRON do an active USB 3 device that can do 15m, they also do a box that connects over fibre optics for USB 3 over longer distances, not cheap but they work. I would drop ICRON a line before ordering. They were very helpful when I had a few initial issues but my Ranger 2304-lan works very well.

Here is the link to the USB active cable

http://www.icron.com/products/oem/usb-extenders/cat5/usb-3-0-sp3001-15/

Clear Skies

Paul

[keithc]

Following the advice and comments, I today bought a 4 port USB Gigabit Server from Maplins for £29.99. It's USB 2.0 but so far every USB device I have attached has worked lawlessly. Tested the download speed of my Nikon D810 with Backyard Nikon and 40Mb file takes around 10 seconds, so with a minimum cool down period of 30 seconds between frames, this should do the job nicely.

Thanks for the advice and comments.

Keith.