From: Mark Gaffney <markgaffney@mac.com>
Date: April 21, 2009 8:45:07 PM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Re: firewire cables...
Hi Milton, Here`s 2 links to references to 10 metre cables I found, the first from TIS ; http://www.astronomycamerasblog.com/2007/09/26/maximum-firewire-cable-length/ &
http://www.electronicsnews.com.au/Article/Long-distance-firewire-1394a-cables/428449.aspx
The second link relates to my set-up more particularly where it says.." However, for some time 10 metre cables have been available used with quite reliable results.." I realise I`m already extending beyond that parameter & am talking about a further extension! My Unibrain is a 3 port FW hub but has provision for an independent power source (not ethernet though..). I could perhaps look into the power adapter if I can find a place where they`re sold, I think I got the Unibrain on Amazon. I thought you must have had a back-up in the Intel department to do your work with that platform. I`ve seen you talking about porting your images to DVD before. Do you use an external HD as well? I find with DVDs, they go in the storage box & are seldom looked at again- with the exception of movies which I burn with Fast Copy DVD or Toast 9, when my burners have been working! I should have my Lacie DL DVD burner back from repairs today! A small blip in the power & I lost all my work in Windows XP on Virtual PC recently. I`ve been waiting for the DVD drive to re-load!
Mark.
On 22/04/2009, at 11:56 AM, Milton Aupperle wrote:
Hi Mark;
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
Hi Milton, The Unibrain repeaters are rated at up to 110 metres I
noticed.
Not if it's connected purely by FireWire. The only way a repeater can do that is if it uses optical cable or Ethernet and you have 2 boxes. Basically it's:
Mac <-> Firewire1 <-> Repeater <-> Optical / Ethernet Cable <-> Repeater2 <-> Firewire <-> Camera.
I don`t know in what configuration though (I mean do I need a
2nd {before the extender cable} or third repeater[ as you say in
series within the first 4.5 metres] to do it safely?).
A FireWire 400 cable should not exceed 4.5 meters in length without a repeater. The device may not work properly otherwise.
For focusing
now I have a 2nd monitor on a long VGA cable ready to be taken outside
on a portable picnic table & take my keyboard & mouse out on M-F usb
extension cables. Today I`m getting a new Apple keyboard & mouse so I
don`t have to alter my permanent inside set-up at all. If, as you say
I have problems with data rates or something else I`ll have to think
about taking the Mini outside (it is fairly portable after all). It`s
just that I have to frig around moving it`s cables, power source & all
the other paraphenalia etc. every time I`m imaging in that case! At
present with just the Flea 2 everything is hunky-dory. I also now have
an Orion dew zapper powered by my Celestron battery tank! By the way
do you do all your developing on the same G4 laptop!!
I do the bulk of my development on a G5 Dual core or the G4 Laptop using CodeWarrior. Using XCode on the Dual core x86 box is too slow and cumbersome.
HTH..
Milton Aupperle
Mark.
On 22/04/2009, at 7:25 AM, Milton Aupperle wrote:
Hi Mark;
Frankly, the only way to know is if you try it out. It may manifest
in different situations too. For example, if your running the cameras
at high frame rates, it may run into issues where as at lower rates
it might not.
And you are way out of spec with your cable distances, as you should
never be over 4.5 meters without a repeater between them for FireWire
400 speeds.
http://en.wikipedia.org/wiki/FireWire
I'm still curious why you wouldn't move the Mini and Screen closer to
the Telescope rather than long data cables. It also makes it easier
to achieve focus too when it's all beside you.
When your using it, you could get a card board box, put the mini and
LCD inside it and then wrap the box in a plastic bag as a light
rain / dew shield. It won't survive a monsoon or heavy rain but, it
would give you some relief for a brief shower or dew.
That's what I plan on doing next year in the winter for my Laptop so
I can image at -30° C or colder. The plastic bag should trap enough
heat from the heating pad to keep the laptop from freezing up, which
happened last winter several times when it dipped down to -38°C or
-50°C with wind chill (the digital thermometer doesn't go any colder
than -50°C).
HTH..
Milton
On 21-Apr-09, at 1:55 PM, Mark Gaffney wrote:
Hi Milton & others, I`m at present running a 10 metre 6p to 6p cable
from the firewire 400 port on my Mac Mini to a Unibrain repeater/hub
similar to this; http://www.unibrain.com/Products/p1394/FR400.htm
from that I have the ACC-01-2007 4.5 metre 6 pin to 9 pin locking
IEEE-1394a to 1394b cable from the PGR development kit going to my
Flea 2. I hope to also run a 3 metre 6p to 6p cable from the
repeater/
hub to my TIS DBK 21 A F04.AS. My question is this; Can I extend the
cables running from the repeater/hub an extra 4.5 metres by adding a
male to female firewire extension cable to each of the cameras? The
extra length may be necessary when I move to my projected new
telescope pad in the front garden. I already have one of the 4.5
metre
extension cables but stopped using it a while ago when I had problems
with the long connection-this was before obtaining the Unibrain
repeater/hub. Mark.
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