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"skozzy" <no.email@all.com.au> wrote in message
news:40811626$0$4548$afc38c87@news.optusnet.com.au...
I want to make a 10 meter long usb cable, I need to be able to connect
my
telescope digital camera to a desktop pc, all the current cables in the
shops only go upto 3 meters. Is there somewhere selling the connectors ?
I think you will have problems extending the length over 5m which AFAIK is
the USB length spec limit.
There are "repeater/regenerator" cables available to do what you want. I
don't know the cost of these ($50??). Farnell sell some of the connectors.
Can you cut a hole in your roof and bring the telescope inside or move
your
PC?
Rob
limitations (as an astronomer, I expect you'll understand the inevitabilityI want to make a 10 meter long usb cable, I need to be able to connect my
telescope digital camera to a desktop pc, all the current cables in the
shops only go upto 3 meters. Is there somewhere selling the connectors ?
Unlikely to work due to transmission line effects and speed of light
"skozzy" <no.email@all.com.au> wrote in message
news:40811626$0$4548$afc38c87@news.optusnet.com.au...
I want to make a 10 meter long usb cable, I need to be able to connect
my
telescope digital camera to a desktop pc, all the current cables in the
shops only go upto 3 meters. Is there somewhere selling the connectors ?
Unlikely to work due to transmission line effects and speed of light
limitations (as an astronomer, I expect you'll understand the
inevitability
of the latter). The maximum cable length for USB is 5m. To get 10
meters,
buy a hub and two 5 meter cables and use those end to end.
From the USB developer FAQ: "The cable length was limited by a cable delay
spec of 26ns to allow for reflections to settle at the transmitter before
the next bit was sent. Since USB uses source termination and voltage-mode
drivers, this has to be the case, otherwise reflections can pile up and
blow
the driver. This does not mean the line voltage has fully settled by the
end
of the bit; with worst-case undertermination. However, there's been enough
damping by the end of the bit that the reflection amplitude has been
reduced
to manageable levels. The low speed cable length was limited to 18ns to
keep
transmission line effects from impacting low speed signals."
hth,
Alf
alfkatz@remove.the.obvious.ieee.org
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a little bit of both, but I would think the signal is the biggestWell I was going to setup the pc on a small table outside with the scope,
but I do need to move the scope around a bit for different views, if I did
go for a 10 meter cable is the power loss too much or is the signal degraded
to a point where the comptuer won't see any signal ?
skozzy wrote:
Well I was going to setup the pc on a small table outside with the
scope,
but I do need to move the scope around a bit for different views, if I
did
go for a 10 meter cable is the power loss too much or is the signal
degraded
to a point where the comptuer won't see any signal ?
a little bit of both, but I would think the signal is the biggest
problem.
I have done experiments with various devices with a 10 meter cable.
It didn't work on anything.
You can have it for postage costs if you really want to try it.
I have two you can have in fact. One still in the original packaging.
Cheers Don...
--
Don McKenzie
E-Mail Contact Page: http://www.e-dotcom.com/ecp.php?un=Dontronics
USB to RS232 Converter that works http://www.dontronics.com/usb_232.html
Don's Free Guide To Spam Reduction http://www.e-dotcom.com/spam_exp.php
the USB length spec limit.I want to make a 10 meter long usb cable, I need to be able to connect my
telescope digital camera to a desktop pc, all the current cables in the
shops only go upto 3 meters. Is there somewhere selling the connectors ?
I think you will have problems extending the length over 5m which AFAIK is
Thanks for the offer, but the hub and 2 cables seems like a fairly good
option, at least I can use the hub for other things too.
"Don McKenzie" <look@my.sig.com> wrote in message
news:40819DDD.3BDB8F2B@my.sig.com...
skozzy wrote:
Well I was going to setup the pc on a small table outside with the
scope,
but I do need to move the scope around a bit for different views, if I
did
go for a 10 meter cable is the power loss too much or is the signal
degraded
to a point where the comptuer won't see any signal ?
a little bit of both, but I would think the signal is the biggest
problem.
I have done experiments with various devices with a 10 meter cable.
It didn't work on anything.
You can have it for postage costs if you really want to try it.
I have two you can have in fact. One still in the original packaging.
Cheers Don...
--
Don McKenzie
E-Mail Contact Page: http://www.e-dotcom.com/ecp.php?un=Dontronics
USB to RS232 Converter that works http://www.dontronics.com/usb_232.html
Don's Free Guide To Spam Reduction http://www.e-dotcom.com/spam_exp.php
FWIW should you need the plugs and sockets, Jaycar stock them.
yep, that's what I figured, and what I would be doing also.Thanks for the offer, but the hub and 2 cables seems like a fairly good
option, at least I can use the hub for other things too.
though.skozzy wrote:
Thanks for the offer, but the hub and 2 cables seems like a fairly good
option, at least I can use the hub for other things too.
yep, that's what I figured, and what I would be doing also.
I know a google web search will return some answers on USB length
extensions, but most are a little pricey.
Cheers Don...
I get lots of e-mails offering length extensions, they're not USB specific
extended distances.skozzy wrote:
Thanks for the offer, but the hub and 2 cables seems like a fairly good
option, at least I can use the hub for other things too.
yep, that's what I figured, and what I would be doing also.
I know a google web search will return some answers on USB length
extensions, but most are a little pricey.
Cheers Don...
I saw some USB "repeater" cables at Jaycar that are supposed to give
I get lots of e-mails offering length extensions, they're not USB
specific
though.
Alf
Probably more related to signal droop. IIRC, capacity is inversely
proportional to age.
And you have to watch out for signal reflections.
Probably more related to signal droop. IIRC, capacity is inverselyI get lots of e-mails offering length extensions, they're not USB specific
though.
Alf
I get lots of e-mails offering length extensions, they're not USB
specific
though.
Alf
Probably more related to signal droop. IIRC, capacity is inversely
proportional to age.
And you have to watch out for signal reflections.
I think DSE sell some 5 m cables which can be joined together. Up to 5"skozzy" <no.email@all.com.au> wrote in message
news:40811626$0$4548$afc38c87@news.optusnet.com.au...
I want to make a 10 meter long usb cable, I need to be able to connect my
telescope digital camera to a desktop pc, all the current cables in the
shops only go upto 3 meters. Is there somewhere selling the connectors ?
I think you will have problems extending the length over 5m which AFAIK is
the USB length spec limit.
There are "repeater/regenerator" cables available to do what you want. I
don't know the cost of these ($50??). Farnell sell some of the connectors.
Can you cut a hole in your roof and bring the telescope inside or move your
PC?