USB

[martin_h]

Does anyone here use an active USB lead to get over the 5M length limit, because sods law dictates that I need 7M to get in the house. Do these leads do the job?

[Psychobilly]

There are two diferent "problem" to overcoem with long runs of USB and it really depends what devices you are going to hang on the end...

Firstly if the the remote devices are "power hungry" like cams etc then the voltage drop onthe power supply lines is an issue...

The sercond problem is degradation of the data signal which needs an active repeater to sort it out...

I use remote powerd hubs.. although watch the PSU's that coem with them if you have a lot of stuff plugged inthe remote end the USB spec calls for 500mA per port to be available for "high power" devices and Active repeater cables..

I have a collection of "USB" bits and pieces which I used to use to sort out problems...

Peter...

[martin_h]

I'll only be using 2 cams at the moment, so if I use a couple of active 5M cables and a powerd hub with a beefy power (5V 5A) supply I'm sorted?

[kevenh]

the powered hub with 'normal' 5m leads would be OK.

Or you could use an active USB cable to get 7m in one cable.

That's my understanding of the USB spec :-)

[astromerlin]

I use 4 5m active USB leads (2 x 10m) + a hub on each end to get from my computer indoors to the telescope outside.

I have found all sorts of problems I am trying to solve to get a stable system.

To date I have found that webcams are not as stable at this length, the SPC900nc crashes so often that I have abandoned it in favour of a toucam which seems fine.

The important thing is having a stable 5v to 5.25v supply at the hubs. Anything under 5v and you'll have so many crashes of webcams you'll tear your hair out.

As I wait patiently growing it back I just need another Toucam to use as a guidecam.

In the end it would probably have been better getting a laptop at the scope end and linking it to the indoor computer.

John