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VGA Cables

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September 2, 2005 12:44:51 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

Hi Guys,
I'm going to run a data cable up the wall as a vga lead (put two
db15's on each end). do I need the ferrite thingies????

Regards
Darren

More about : vga cables

Anonymous
September 2, 2005 12:44:52 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

'joe' wrote:
| I'm going to run a data cable up the wall as a vga lead (put
two
| db15's on each end). do I need the ferrite thingies????
_____

What you need is to rethink the project. I assume that by 'data cable' you
mean something like 10Base-T or 100Base-T Ethernet cable. If you look
inside a VGA cable you will find several coax cables that cary the R, G, and
B analog signals (plus several other wires); these coax cables are VERY
different from the unshielded twisted pairs in 10Base-T or 100Base-T
ethernet cables. Very little will come out the other end., certainly
nothing you'd want to look at.

Phil Weldon


"joe" <a@b.com> wrote in message news:D f809i$11jm$1@otis.netspace.net.au...
> Hi Guys,
> I'm going to run a data cable up the wall as a vga lead (put
> two db15's on each end). do I need the ferrite thingies????
>
> Regards
> Darren
>
Anonymous
September 2, 2005 12:44:52 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

"joe" <a@b.com> wrote in message news:D f809i$11jm$1@otis.netspace.net.au...
> Hi Guys,
> I'm going to run a data cable up the wall as a vga lead (put
> two db15's on each end). do I need the ferrite thingies????
>
> Regards
> Darren
>

Not really, because you won't be using a VGA monitor at the other end.
What you can do is buy a very long VGA cable already made up, and powered
signal booster box, like we do where I work. But that results in it being
usable just for VGA text screens. On a steel decking rollforming line,
that's all they're looking at.
Like the OP said, there is a lot of difference between CAT5 (or any twisted
pair) cable and coaxial cable sets for analog signals.
McG .
Related resources
September 3, 2005 12:12:18 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

thanks for the replies,
I have already got a vga cable in the wall and wish to run a second. I will
make it myself as I can't pass a cable down with the db15's on each end. I
have some sheilded 16 strand data cable and it is made for this. The
question I'm chasing is wether I need to have the ferrite thingies on it as
the other one does (as do most normal vga leads).
cheers

darren


"joe" <a@b.com> wrote in message news:D f809i$11jm$1@otis.netspace.net.au...
> Hi Guys,
> I'm going to run a data cable up the wall as a vga lead (put
> two db15's on each end). do I need the ferrite thingies????
>
> Regards
> Darren
>
Anonymous
September 3, 2005 12:12:19 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

Please read the previous replies. Shielded 16 strand data cable WILL NOT
WORK AS A VGA CABLE.

On the other hand, go ahead and try your idea. It will be a good learning
experience. Soldering the DB15 connectors will build character. Or you
could do some research on the Internet and find out what you really need to
do (as well as find out the function of the ferrite rings.)

This URL has the pin outs for common computer related connectors
http://www.networktechinc.com/technote.html .

I don't know if you are going to believe this, but the connector pin out
list indicates that each of the color signals is carried by a SEPARATE
coaxial cable. A coaxial cable has a central conductor surrounded by an
insulator of a specified diameter and composition designed to give the cable
a characteristic impedance. If you don't use the correct cable (even use
coax of the wrong impedance) the results will range from no usable signal to
unviewable images (and that's with a cable just a few feet long.

If you go ahead and continue with your idea, please post your results for
the benefit of others; don't let ALL your work go to waste.

Phil Weldon



"joe" <a@b.com> wrote in message news:D f98i2$1h25$1@otis.netspace.net.au...
> thanks for the replies,
> I have already got a vga cable in the wall and wish to run a second. I
> will make it myself as I can't pass a cable down with the db15's on each
> end. I have some sheilded 16 strand data cable and it is made for this.
> The question I'm chasing is wether I need to have the ferrite thingies on
> it as the other one does (as do most normal vga leads).
> cheers
>
> darren
>
>
> "joe" <a@b.com> wrote in message
> news:D f809i$11jm$1@otis.netspace.net.au...
>> Hi Guys,
>> I'm going to run a data cable up the wall as a vga lead (put
>> two db15's on each end). do I need the ferrite thingies????
>>
>> Regards
>> Darren
>>
>
>
Anonymous
September 3, 2005 2:16:15 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

It will never hurt to put the ferrite rings on at each end. They are there
to help clean up RF noise.
McG.


"joe" <a@b.com> wrote in message news:D f98i2$1h25$1@otis.netspace.net.au...
> thanks for the replies,
> I have already got a vga cable in the wall and wish to run a second. I
> will make it myself as I can't pass a cable down with the db15's on each
> end. I have some sheilded 16 strand data cable and it is made for this.
> The question I'm chasing is wether I need to have the ferrite thingies on
> it as the other one does (as do most normal vga leads).
> cheers
>
> darren
>
>
> "joe" <a@b.com> wrote in message
> news:D f809i$11jm$1@otis.netspace.net.au...
>> Hi Guys,
>> I'm going to run a data cable up the wall as a vga lead (put
>> two db15's on each end). do I need the ferrite thingies????
>>
>> Regards
>> Darren
>>
>
>
Anonymous
September 3, 2005 2:27:39 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

It seems he might be saying he has one working already. Using a cable that
has at least 3 conductors (analog color lines) individually shielded will
function. I'd be interested to know how his screen looks when he's done :) 
I've done this too, had to cut one end off a 150' vga cable to pull it
through buried conduit in the floor, around a press bed to the motor control
center where the contractors put the PC that runs the line :)  It works in
low res DOS type screens ok. That cable didn't have coax. It has 18
shielded conductors plus a full foil shield around the bundle. The extra
wires? housing grounds. Well, the ferrite rings will help with rf noise.
McG.

"Phil Weldon" <notdiscosed@example.com> wrote in message
news:jD0Se.5718$9i4.4552@newsread2.news.atl.earthlink.net...
> Please read the previous replies. Shielded 16 strand data cable WILL NOT
> WORK AS A VGA CABLE.
>
> On the other hand, go ahead and try your idea. It will be a good learning
> experience. Soldering the DB15 connectors will build character. Or you
> could do some research on the Internet and find out what you really need
> to do (as well as find out the function of the ferrite rings.)
>
> This URL has the pin outs for common computer related connectors
> http://www.networktechinc.com/technote.html .
>
> I don't know if you are going to believe this, but the connector pin out
> list indicates that each of the color signals is carried by a SEPARATE
> coaxial cable. A coaxial cable has a central conductor surrounded by an
> insulator of a specified diameter and composition designed to give the
> cable a characteristic impedance. If you don't use the correct cable
> (even use coax of the wrong impedance) the results will range from no
> usable signal to unviewable images (and that's with a cable just a few
> feet long.
>
> If you go ahead and continue with your idea, please post your results for
> the benefit of others; don't let ALL your work go to waste.
>
> Phil Weldon
>
>
>
> "joe" <a@b.com> wrote in message
> news:D f98i2$1h25$1@otis.netspace.net.au...
>> thanks for the replies,
>> I have already got a vga cable in the wall and wish to run a second. I
>> will make it myself as I can't pass a cable down with the db15's on each
>> end. I have some sheilded 16 strand data cable and it is made for this.
>> The question I'm chasing is wether I need to have the ferrite thingies on
>> it as the other one does (as do most normal vga leads).
>> cheers
>>
>> darren
>>
>>
>> "joe" <a@b.com> wrote in message
>> news:D f809i$11jm$1@otis.netspace.net.au...
>>> Hi Guys,
>>> I'm going to run a data cable up the wall as a vga lead (put
>>> two db15's on each end). do I need the ferrite thingies????
>>>
>>> Regards
>>> Darren
>>>
>>
>>
>
>
Anonymous
September 3, 2005 3:37:15 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

'McGrandpa' wrote, in part:

| It seems he might be saying he has one working already. Using a cable
that
| has at least 3 conductors (analog color lines) individually shielded will
| function.
_____

No, it doesn't sound as if he has one working already; it couldn't. What he
describes seems to be 16 conductors surrounded by ONE shield. Sixteen
coaxial cables would be huge, and hugely expensive. And three coaxial
cables alone won't do the job for VGA, sync (not necessarily shielded) is
also part of the package.

A 'DOS type' screen is likely to be B&W and only 640 X 480 by some low
refresh rate, using a MUCH lower bandwidth. Are you shoure you don't mean
a 75 ohm coax video cable (RG58, for example) rather than a VGA cable that
carries a Red analog video signal, a Green analog video signal, a Blue
analog video signal (three coax cables), a vertical sync signal, a composit
sync signal, and possibly some monitor ID signals.

It IS possible to use twisted pairs to carry analog video signals, but
special drivers and receivers are necessary. Phase shifts and non linear
frequency response in unshielded cables require these additions.

Phil Weldon

"McGrandpa" <McGrandpaNOT@NOThotmail.com> wrote in message
news:vl4Se.212002$0f.21317@tornado.texas.rr.com...
> It seems he might be saying he has one working already. Using a cable
> that has at least 3 conductors (analog color lines) individually shielded
> will function. I'd be interested to know how his screen looks when he's
> done :)  I've done this too, had to cut one end off a 150' vga cable to
> pull it through buried conduit in the floor, around a press bed to the
> motor control center where the contractors put the PC that runs the line
> :)  It works in low res DOS type screens ok. That cable didn't have coax.
> It has 18 shielded conductors plus a full foil shield around the bundle.
> The extra wires? housing grounds. Well, the ferrite rings will help
> with rf noise.
> McG.
>
> "Phil Weldon" <notdiscosed@example.com> wrote in message
> news:jD0Se.5718$9i4.4552@newsread2.news.atl.earthlink.net...
>> Please read the previous replies. Shielded 16 strand data cable WILL NOT
>> WORK AS A VGA CABLE.
>>
>> On the other hand, go ahead and try your idea. It will be a good
>> learning experience. Soldering the DB15 connectors will build character.
>> Or you could do some research on the Internet and find out what you
>> really need to do (as well as find out the function of the ferrite
>> rings.)
>>
>> This URL has the pin outs for common computer related connectors
>> http://www.networktechinc.com/technote.html .
>>
>> I don't know if you are going to believe this, but the connector pin out
>> list indicates that each of the color signals is carried by a SEPARATE
>> coaxial cable. A coaxial cable has a central conductor surrounded by an
>> insulator of a specified diameter and composition designed to give the
>> cable a characteristic impedance. If you don't use the correct cable
>> (even use coax of the wrong impedance) the results will range from no
>> usable signal to unviewable images (and that's with a cable just a few
>> feet long.
>>
>> If you go ahead and continue with your idea, please post your results for
>> the benefit of others; don't let ALL your work go to waste.
>>
>> Phil Weldon
>>
>>
>>
>> "joe" <a@b.com> wrote in message
>> news:D f98i2$1h25$1@otis.netspace.net.au...
>>> thanks for the replies,
>>> I have already got a vga cable in the wall and wish to run a second. I
>>> will make it myself as I can't pass a cable down with the db15's on each
>>> end. I have some sheilded 16 strand data cable and it is made for this.
>>> The question I'm chasing is wether I need to have the ferrite thingies
>>> on it as the other one does (as do most normal vga leads).
>>> cheers
>>>
>>> darren
>>>
>>>
>>> "joe" <a@b.com> wrote in message
>>> news:D f809i$11jm$1@otis.netspace.net.au...
>>>> Hi Guys,
>>>> I'm going to run a data cable up the wall as a vga lead (put
>>>> two db15's on each end). do I need the ferrite thingies????
>>>>
>>>> Regards
>>>> Darren
>>>>
>>>
>>>
>>
>>
>
>
Anonymous
September 3, 2005 5:17:40 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

"Phil Weldon" <notdiscosed@example.com> wrote in message
news:Lm5Se.5763$_84.3356@newsread1.news.atl.earthlink.net...
> 'McGrandpa' wrote, in part:
>
> | It seems he might be saying he has one working already. Using a cable
> that
> | has at least 3 conductors (analog color lines) individually shielded
> will
> | function.
> _____
>
> No, it doesn't sound as if he has one working already; it couldn't. What
> he describes seems to be 16 conductors surrounded by ONE shield. Sixteen
> coaxial cables would be huge, and hugely expensive. And three coaxial
> cables alone won't do the job for VGA, sync (not necessarily shielded) is
> also part of the package.
>
> A 'DOS type' screen is likely to be B&W and only 640 X 480 by some low
> refresh rate, using a MUCH lower bandwidth. Are you shoure you don't
> mean a 75 ohm coax video cable (RG58, for example) rather than a VGA cable
> that carries a Red analog video signal, a Green analog video signal, a
> Blue analog video signal (three coax cables), a vertical sync signal, a
> composit sync signal, and possibly some monitor ID signals.

No, the cable has 18 shielded STRAIGHT conductors. I cut it myself (was an
off the shelf VGA cable from somewhere) and soldered a new 15 pin dsub on.
The monitors are 15" VGA, they run in 640x480 color. The whole setup came
with a 'booster box' (AC line powered) that drives both keyboard and VGA.
The VGA card is a $20 Chinese no-name type our company sent us. The PC's
are 386DX20 and 25. They've been working for a while now :) 
McG.

>
> It IS possible to use twisted pairs to carry analog video signals, but
> special drivers and receivers are necessary. Phase shifts and non linear
> frequency response in unshielded cables require these additions.
>
> Phil Weldon
>
> "McGrandpa" <McGrandpaNOT@NOThotmail.com> wrote in message
> news:vl4Se.212002$0f.21317@tornado.texas.rr.com...
>> It seems he might be saying he has one working already. Using a cable
>> that has at least 3 conductors (analog color lines) individually shielded
>> will function. I'd be interested to know how his screen looks when he's
>> done :)  I've done this too, had to cut one end off a 150' vga cable to
>> pull it through buried conduit in the floor, around a press bed to the
>> motor control center where the contractors put the PC that runs the line
>> :)  It works in low res DOS type screens ok. That cable didn't have
>> coax. It has 18 shielded conductors plus a full foil shield around the
>> bundle. The extra wires? housing grounds. Well, the ferrite rings will
>> help with rf noise.
>> McG.
>>
>> "Phil Weldon" <notdiscosed@example.com> wrote in message
>> news:jD0Se.5718$9i4.4552@newsread2.news.atl.earthlink.net...
>>> Please read the previous replies. Shielded 16 strand data cable WILL
>>> NOT WORK AS A VGA CABLE.
>>>
>>> On the other hand, go ahead and try your idea. It will be a good
>>> learning experience. Soldering the DB15 connectors will build
>>> character. Or you could do some research on the Internet and find out
>>> what you really need to do (as well as find out the function of the
>>> ferrite rings.)
>>>
>>> This URL has the pin outs for common computer related connectors
>>> http://www.networktechinc.com/technote.html .
>>>
>>> I don't know if you are going to believe this, but the connector pin out
>>> list indicates that each of the color signals is carried by a SEPARATE
>>> coaxial cable. A coaxial cable has a central conductor surrounded by an
>>> insulator of a specified diameter and composition designed to give the
>>> cable a characteristic impedance. If you don't use the correct cable
>>> (even use coax of the wrong impedance) the results will range from no
>>> usable signal to unviewable images (and that's with a cable just a few
>>> feet long.
>>>
>>> If you go ahead and continue with your idea, please post your results
>>> for the benefit of others; don't let ALL your work go to waste.
>>>
>>> Phil Weldon
>>>
>>>
>>>
>>> "joe" <a@b.com> wrote in message
>>> news:D f98i2$1h25$1@otis.netspace.net.au...
>>>> thanks for the replies,
>>>> I have already got a vga cable in the wall and wish to run a second. I
>>>> will make it myself as I can't pass a cable down with the db15's on
>>>> each end. I have some sheilded 16 strand data cable and it is made for
>>>> this. The question I'm chasing is wether I need to have the ferrite
>>>> thingies on it as the other one does (as do most normal vga leads).
>>>> cheers
>>>>
>>>> darren
>>>>
>>>>
>>>> "joe" <a@b.com> wrote in message
>>>> news:D f809i$11jm$1@otis.netspace.net.au...
>>>>> Hi Guys,
>>>>> I'm going to run a data cable up the wall as a vga lead
>>>>> (put two db15's on each end). do I need the ferrite thingies????
>>>>>
>>>>> Regards
>>>>> Darren
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>
Anonymous
September 3, 2005 5:58:03 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

'McGrandpa' wrote, in part:
| No, the cable has 18 shielded STRAIGHT conductors. I cut it myself (was
an
| off the shelf VGA cable from somewhere) and soldered a new 15 pin dsub on.
_____

I wasn't refering to your cable, but to the original poster's cable. With
the booster amplifier box and the low resolution, I see how YOUR cable could
work. It must have been a real pain to work on soldering the pins in such
small connector as DB15 when working with a thick multiple coax cable. And
wasn't the cable three coax plus 3 to 5 unshielded wires?

At any rate, the original poster refers to data cable, which pretty much
rules out coax. To bad that he'll end up running the cable soldering the
connectors, then wondering why nothing works.

Phil Weldon

"McGrandpa" <McGrandpaNOT@NOThotmail.com> wrote in message
news:UQ6Se.212088$0f.150519@tornado.texas.rr.com...
>
> "Phil Weldon" <notdiscosed@example.com> wrote in message
> news:Lm5Se.5763$_84.3356@newsread1.news.atl.earthlink.net...
>> 'McGrandpa' wrote, in part:
>>
>> | It seems he might be saying he has one working already. Using a cable
>> that
>> | has at least 3 conductors (analog color lines) individually shielded
>> will
>> | function.
>> _____
>>
>> No, it doesn't sound as if he has one working already; it couldn't. What
>> he describes seems to be 16 conductors surrounded by ONE shield. Sixteen
>> coaxial cables would be huge, and hugely expensive. And three coaxial
>> cables alone won't do the job for VGA, sync (not necessarily shielded) is
>> also part of the package.
>>
>> A 'DOS type' screen is likely to be B&W and only 640 X 480 by some low
>> refresh rate, using a MUCH lower bandwidth. Are you shoure you don't
>> mean a 75 ohm coax video cable (RG58, for example) rather than a VGA
>> cable that carries a Red analog video signal, a Green analog video
>> signal, a Blue analog video signal (three coax cables), a vertical sync
>> signal, a composit sync signal, and possibly some monitor ID signals.
>
> No, the cable has 18 shielded STRAIGHT conductors. I cut it myself (was
> an off the shelf VGA cable from somewhere) and soldered a new 15 pin dsub
> on. The monitors are 15" VGA, they run in 640x480 color. The whole setup
> came with a 'booster box' (AC line powered) that drives both keyboard and
> VGA. The VGA card is a $20 Chinese no-name type our company sent us. The
> PC's are 386DX20 and 25. They've been working for a while now :) 
> McG.
>
>>
>> It IS possible to use twisted pairs to carry analog video signals, but
>> special drivers and receivers are necessary. Phase shifts and non linear
>> frequency response in unshielded cables require these additions.
>>
>> Phil Weldon
>>
>> "McGrandpa" <McGrandpaNOT@NOThotmail.com> wrote in message
>> news:vl4Se.212002$0f.21317@tornado.texas.rr.com...
>>> It seems he might be saying he has one working already. Using a cable
>>> that has at least 3 conductors (analog color lines) individually
>>> shielded will function. I'd be interested to know how his screen looks
>>> when he's done :)  I've done this too, had to cut one end off a 150' vga
>>> cable to pull it through buried conduit in the floor, around a press bed
>>> to the motor control center where the contractors put the PC that runs
>>> the line :)  It works in low res DOS type screens ok. That cable didn't
>>> have coax. It has 18 shielded conductors plus a full foil shield around
>>> the bundle. The extra wires? housing grounds. Well, the ferrite rings
>>> will help with rf noise.
>>> McG.
>>>
>>> "Phil Weldon" <notdiscosed@example.com> wrote in message
>>> news:jD0Se.5718$9i4.4552@newsread2.news.atl.earthlink.net...
>>>> Please read the previous replies. Shielded 16 strand data cable WILL
>>>> NOT WORK AS A VGA CABLE.
>>>>
>>>> On the other hand, go ahead and try your idea. It will be a good
>>>> learning experience. Soldering the DB15 connectors will build
>>>> character. Or you could do some research on the Internet and find out
>>>> what you really need to do (as well as find out the function of the
>>>> ferrite rings.)
>>>>
>>>> This URL has the pin outs for common computer related connectors
>>>> http://www.networktechinc.com/technote.html .
>>>>
>>>> I don't know if you are going to believe this, but the connector pin
>>>> out list indicates that each of the color signals is carried by a
>>>> SEPARATE coaxial cable. A coaxial cable has a central conductor
>>>> surrounded by an insulator of a specified diameter and composition
>>>> designed to give the cable a characteristic impedance. If you don't
>>>> use the correct cable (even use coax of the wrong impedance) the
>>>> results will range from no usable signal to unviewable images (and
>>>> that's with a cable just a few feet long.
>>>>
>>>> If you go ahead and continue with your idea, please post your results
>>>> for the benefit of others; don't let ALL your work go to waste.
>>>>
>>>> Phil Weldon
>>>>
>>>>
>>>>
>>>> "joe" <a@b.com> wrote in message
>>>> news:D f98i2$1h25$1@otis.netspace.net.au...
>>>>> thanks for the replies,
>>>>> I have already got a vga cable in the wall and wish to run a second. I
>>>>> will make it myself as I can't pass a cable down with the db15's on
>>>>> each end. I have some sheilded 16 strand data cable and it is made for
>>>>> this. The question I'm chasing is wether I need to have the ferrite
>>>>> thingies on it as the other one does (as do most normal vga leads).
>>>>> cheers
>>>>>
>>>>> darren
>>>>>
>>>>>
>>>>> "joe" <a@b.com> wrote in message
>>>>> news:D f809i$11jm$1@otis.netspace.net.au...
>>>>>> Hi Guys,
>>>>>> I'm going to run a data cable up the wall as a vga lead
>>>>>> (put two db15's on each end). do I need the ferrite thingies????
>>>>>>
>>>>>> Regards
>>>>>> Darren
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>
Anonymous
September 3, 2005 10:03:34 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

"Phil Weldon" <notdiscosed@example.com> wrote in message
news:Lq7Se.6089$FW1.1025@newsread3.news.atl.earthlink.net...
> 'McGrandpa' wrote, in part:
> | No, the cable has 18 shielded STRAIGHT conductors. I cut it myself (was
> an
> | off the shelf VGA cable from somewhere) and soldered a new 15 pin dsub
> on.
> _____
>
> I wasn't refering to your cable, but to the original poster's cable. With
> the booster amplifier box and the low resolution, I see how YOUR cable
> could work. It must have been a real pain to work on soldering the pins
> in such small connector as DB15 when working with a thick multiple coax
> cable. And wasn't the cable three coax plus 3 to 5 unshielded wires?

No, it isn't 'standard' VGA cable. There are no coaxials in this one.
>
> At any rate, the original poster refers to data cable, which pretty much
> rules out coax. To bad that he'll end up running the cable soldering the
> connectors, then wondering why nothing works.
>
> Phil Weldon
>
> "McGrandpa" <McGrandpaNOT@NOThotmail.com> wrote in message
> news:UQ6Se.212088$0f.150519@tornado.texas.rr.com...
>>
>> "Phil Weldon" <notdiscosed@example.com> wrote in message
>> news:Lm5Se.5763$_84.3356@newsread1.news.atl.earthlink.net...
>>> 'McGrandpa' wrote, in part:
>>>
>>> | It seems he might be saying he has one working already. Using a
>>> cable that
>>> | has at least 3 conductors (analog color lines) individually shielded
>>> will
>>> | function.
>>> _____
>>>
>>> No, it doesn't sound as if he has one working already; it couldn't.
>>> What he describes seems to be 16 conductors surrounded by ONE shield.
>>> Sixteen coaxial cables would be huge, and hugely expensive. And three
>>> coaxial cables alone won't do the job for VGA, sync (not necessarily
>>> shielded) is also part of the package.
>>>
>>> A 'DOS type' screen is likely to be B&W and only 640 X 480 by some low
>>> refresh rate, using a MUCH lower bandwidth. Are you shoure you don't
>>> mean a 75 ohm coax video cable (RG58, for example) rather than a VGA
>>> cable that carries a Red analog video signal, a Green analog video
>>> signal, a Blue analog video signal (three coax cables), a vertical sync
>>> signal, a composit sync signal, and possibly some monitor ID signals.
>>
>> No, the cable has 18 shielded STRAIGHT conductors. I cut it myself (was
>> an off the shelf VGA cable from somewhere) and soldered a new 15 pin dsub
>> on. The monitors are 15" VGA, they run in 640x480 color. The whole setup
>> came with a 'booster box' (AC line powered) that drives both keyboard and
>> VGA. The VGA card is a $20 Chinese no-name type our company sent us. The
>> PC's are 386DX20 and 25. They've been working for a while now :) 
>> McG.
>>
>>>
>>> It IS possible to use twisted pairs to carry analog video signals, but
>>> special drivers and receivers are necessary. Phase shifts and non
>>> linear frequency response in unshielded cables require these additions.
>>>
>>> Phil Weldon
>>>
>>> "McGrandpa" <McGrandpaNOT@NOThotmail.com> wrote in message
>>> news:vl4Se.212002$0f.21317@tornado.texas.rr.com...
>>>> It seems he might be saying he has one working already. Using a cable
>>>> that has at least 3 conductors (analog color lines) individually
>>>> shielded will function. I'd be interested to know how his screen
>>>> looks when he's done :)  I've done this too, had to cut one end off a
>>>> 150' vga cable to pull it through buried conduit in the floor, around a
>>>> press bed to the motor control center where the contractors put the PC
>>>> that runs the line :)  It works in low res DOS type screens ok. That
>>>> cable didn't have coax. It has 18 shielded conductors plus a full foil
>>>> shield around the bundle. The extra wires? housing grounds. Well,
>>>> the ferrite rings will help with rf noise.
>>>> McG.
>>>>
>>>> "Phil Weldon" <notdiscosed@example.com> wrote in message
>>>> news:jD0Se.5718$9i4.4552@newsread2.news.atl.earthlink.net...
>>>>> Please read the previous replies. Shielded 16 strand data cable WILL
>>>>> NOT WORK AS A VGA CABLE.
>>>>>
>>>>> On the other hand, go ahead and try your idea. It will be a good
>>>>> learning experience. Soldering the DB15 connectors will build
>>>>> character. Or you could do some research on the Internet and find out
>>>>> what you really need to do (as well as find out the function of the
>>>>> ferrite rings.)
>>>>>
>>>>> This URL has the pin outs for common computer related connectors
>>>>> http://www.networktechinc.com/technote.html .
>>>>>
>>>>> I don't know if you are going to believe this, but the connector pin
>>>>> out list indicates that each of the color signals is carried by a
>>>>> SEPARATE coaxial cable. A coaxial cable has a central conductor
>>>>> surrounded by an insulator of a specified diameter and composition
>>>>> designed to give the cable a characteristic impedance. If you don't
>>>>> use the correct cable (even use coax of the wrong impedance) the
>>>>> results will range from no usable signal to unviewable images (and
>>>>> that's with a cable just a few feet long.
>>>>>
>>>>> If you go ahead and continue with your idea, please post your results
>>>>> for the benefit of others; don't let ALL your work go to waste.
>>>>>
>>>>> Phil Weldon
>>>>>
>>>>>
>>>>>
>>>>> "joe" <a@b.com> wrote in message
>>>>> news:D f98i2$1h25$1@otis.netspace.net.au...
>>>>>> thanks for the replies,
>>>>>> I have already got a vga cable in the wall and wish to run a second.
>>>>>> I will make it myself as I can't pass a cable down with the db15's on
>>>>>> each end. I have some sheilded 16 strand data cable and it is made
>>>>>> for this. The question I'm chasing is wether I need to have the
>>>>>> ferrite thingies on it as the other one does (as do most normal vga
>>>>>> leads).
>>>>>> cheers
>>>>>>
>>>>>> darren
>>>>>>
>>>>>>
>>>>>> "joe" <a@b.com> wrote in message
>>>>>> news:D f809i$11jm$1@otis.netspace.net.au...
>>>>>>> Hi Guys,
>>>>>>> I'm going to run a data cable up the wall as a vga lead
>>>>>>> (put two db15's on each end). do I need the ferrite thingies????
>>>>>>>
>>>>>>> Regards
>>>>>>> Darren
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>
September 3, 2005 5:49:22 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

Thanks for the responses fellas.
I've taken this all onboard and have ordered 2x15metre vga cables (one for
spare) and will just have to work out how to get them up the wall. My
thinking was just to zip up some db15's to the end of some cable, there is
obviously more to this than I understand. This has saved me a great deal of
heart ache. Once again thanks for the helpful replies.

Regards
Darren Mackay

"joe" <a@b.com> wrote in message news:D f809i$11jm$1@otis.netspace.net.au...
> Hi Guys,
> I'm going to run a data cable up the wall as a vga lead (put
> two db15's on each end). do I need the ferrite thingies????
>
> Regards
> Darren
>
Anonymous
September 3, 2005 7:25:19 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

'McGrandpa' wrote, in part:
| No, it isn't 'standard' VGA cable. There are no coaxials in this one.
_____

Then you didn't have a VGA cable at all; a VGA cable has three coax and 5 or
6 ordinary conductors. And the signal you get out the other end could only
be marginally useful even for low resolution text.

Phil Weldon
Anonymous
September 3, 2005 7:34:18 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

'joe' wrote:
| Thanks for the responses fellas.
| I've taken this all onboard and have ordered 2x15metre vga cables (one for
| spare) and will just have to work out how to get them up the wall. My
| thinking was just to zip up some db15's to the end of some cable, there is
| obviously more to this than I understand. This has saved me a great deal
of
| heart ache. Once again thanks for the helpful replies.
_____

Soldering DB15 connectors to a VGA cable is going to be tedious. If there
is any way you can attach the connectors prior to running the cable up the
wall, do it so you can check for proper connections before doing the extra
work, and while having everything in one place.

As far a ferrite rings go; the ferrite rings reduce RFI (radio frequency
interference) - signals generated inside your computer - from using the
cable as an antenna and possibly disrupting radio and television reception
in your home. You can buy 'clamshell' ferrite cylinders that can be snapped
over a cable near the connection end nearest the computer (and that don't
have to be slipped over the cable before the connectors are installed. Any
electronics supply shop ought to have the 'clamshell' ferrite cylinders - in
the USA RadioShack has them for less than $3 US.

Good luck.

Phil Weldon

"joe" <a@b.com> wrote in message news:D fb6g5$2adp$1@otis.netspace.net.au...
> Thanks for the responses fellas.
> I've taken this all onboard and have ordered 2x15metre vga cables (one for
> spare) and will just have to work out how to get them up the wall. My
> thinking was just to zip up some db15's to the end of some cable, there is
> obviously more to this than I understand. This has saved me a great deal
> of heart ache. Once again thanks for the helpful replies.
>
> Regards
> Darren Mackay
>
> "joe" <a@b.com> wrote in message
> news:D f809i$11jm$1@otis.netspace.net.au...
>> Hi Guys,
>> I'm going to run a data cable up the wall as a vga lead (put
>> two db15's on each end). do I need the ferrite thingies????
>>
>> Regards
>> Darren
>>
>
>
Anonymous
September 3, 2005 9:13:22 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

Does the monitor have BNC connectors on the back? If it does, use a BNC
monitor cable. The BNC cable has five (six?) individual connectors, which
can be snipped off and re-soldered without too much trouble.

--
"War is the continuation of politics by other means.
It can therefore be said that politics is war without
bloodshed while war is politics with bloodshed."


"joe" <a@b.com> wrote in message news:D fb6g5$2adp$1@otis.netspace.net.au...
> Thanks for the responses fellas.
> I've taken this all onboard and have ordered 2x15metre vga cables (one for
> spare) and will just have to work out how to get them up the wall. My
> thinking was just to zip up some db15's to the end of some cable, there is
> obviously more to this than I understand. This has saved me a great deal
> of heart ache. Once again thanks for the helpful replies.
>
> Regards
> Darren Mackay
>
> "joe" <a@b.com> wrote in message
> news:D f809i$11jm$1@otis.netspace.net.au...
>> Hi Guys,
>> I'm going to run a data cable up the wall as a vga lead (put
>> two db15's on each end). do I need the ferrite thingies????
>>
>> Regards
>> Darren
>>
>
>
Anonymous
September 3, 2005 11:05:45 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

"Phil Weldon" <notdiscosed@example.com> wrote in message
news:zfjSe.6140$9i4.2090@newsread2.news.atl.earthlink.net...
> 'McGrandpa' wrote, in part:
> | No, it isn't 'standard' VGA cable. There are no coaxials in this one.
> _____
>
> Then you didn't have a VGA cable at all; a VGA cable has three coax and 5
> or 6 ordinary conductors. And the signal you get out the other end could
> only be marginally useful even for low resolution text.
>
> Phil Weldon
>
>

The screens used by the program that runs the rollformer look like any BIOS
screen, 640x480 16 colors. The cable i cut came with molded 15 pin VGA
connectors and ferrite rings. I'm not the engineer, I'm just the guy that
puts to work what the engineers send us. Whatever 'marginally useful' is
Phil, the screens the line operator works from are sharp and clear.
McG.
Anonymous
September 4, 2005 1:43:13 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

'First of One' wrote:
| Does the monitor have BNC connectors on the back? If it does, use a BNC
| monitor cable. The BNC cable has five (six?) individual connectors, which
| can be snipped off and re-soldered without too much trouble.
_____

A monitor with RGB input would have three BNC connectors, one for each color
(Red, Green, and Blue). A fourth connector would be for composite sync
(horizontal sync plus vertical sync). If there were a fifth BNC connector
(which I haven't seen) the fourth and fifth connectors would probably be one
for horizontal (or composite) sync and one for vertical sync.

It really would not be convenient to run RGB up the wall or within a wall in
a home; four or five coax cables are quite bulky.

Coax cables have a controlled impedance that must match the requirements of
the output and input circuits. The connectors used must also match the
impedance of the cable.

If impedances are mismatched, the abrupt change between a connector and the
cable can reflect signals, resulting in 'ghosting' as the reflected signal
is delayed by length added to its path. Even worse, for high power signals
(as in transmitters), power is reflected back into the output amplifier.

Coax cables also have a frequency roll-off; higher frequencies lose more
amptitude than lower frequencies (for video this results in loss of
resolution.

NTSC video sent over a lossy cable (try an ordinary unbalance shielded audio
cable [usually found with RCA (phono) connectors) will not only lose detail,
but also color since the color information is in the upper frequencies of
the signal.

BNC is one type of connector for coax cables; UHF is another, older type
connector.
Also used on coax cables are TNC connectors (that is the type connector seen
on small, high frequency communication devices - Cell phones,
'walkie-talkies'.)
N type connectors are used on coax cables carrying microwave signals up to
10 or 11 GHz. Above that coax becomes to lossy, and more exotic paths must
be used, heliax and wave guides.

For any type of coax pinches and sharp bends will cause an abrupt impedance
change, resulting in reflections and possible high frequency amptitude loss.
Improper installation of connectors can cause similar problems.

Phil Weldon



"First of One" <daxinfx@yahoo.com> wrote in message
news:rdmdnYyFiYSAj4feRVn-gA@rogers.com...
> Does the monitor have BNC connectors on the back? If it does, use a BNC
> monitor cable. The BNC cable has five (six?) individual connectors, which
> can be snipped off and re-soldered without too much trouble.
>
> --
> "War is the continuation of politics by other means.
> It can therefore be said that politics is war without
> bloodshed while war is politics with bloodshed."
>
>
> "joe" <a@b.com> wrote in message
> news:D fb6g5$2adp$1@otis.netspace.net.au...
>> Thanks for the responses fellas.
>> I've taken this all onboard and have ordered 2x15metre vga cables (one
>> for spare) and will just have to work out how to get them up the wall. My
>> thinking was just to zip up some db15's to the end of some cable, there
>> is obviously more to this than I understand. This has saved me a great
>> deal of heart ache. Once again thanks for the helpful replies.
>>
>> Regards
>> Darren Mackay
>>
>> "joe" <a@b.com> wrote in message
>> news:D f809i$11jm$1@otis.netspace.net.au...
>>> Hi Guys,
>>> I'm going to run a data cable up the wall as a vga lead (put
>>> two db15's on each end). do I need the ferrite thingies????
>>>
>>> Regards
>>> Darren
>>>
>>
>>
>
>
Anonymous
September 4, 2005 1:43:14 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

"Phil Weldon" <notdiscosed@example.com> wrote in message
news:RNoSe.6820$FW1.6599@newsread3.news.atl.earthlink.net...
> A monitor with RGB input would have three BNC connectors, one for each
> color (Red, Green, and Blue). A fourth connector would be for composite
> sync (horizontal sync plus vertical sync). If there were a fifth BNC
> connector (which I haven't seen) the fourth and fifth connectors would
> probably be one for horizontal (or composite) sync and one for vertical
> sync.

http://www.computerplug.com/show_product.php?product_id...

PC CRT displays like the Sony F500 come with BNC connectors in addition to
the standard HD15 port. AFAIK it's a fairly common standard layout for
high-end PC displays, at least a couple of years ago.

Back in the early 3dfx days, some people connected their primary video card
using BNC cables, and the Voodoo using HD15. Upon launching into a game,
they'd just flip a slider to switch inputs on the monitor, avoiding the use
of a pass-through cable.

> It really would not be convenient to run RGB up the wall or within a wall
> in a home; four or five coax cables are quite bulky.

See above. It's quite possible to snip off the BNC connector heads, run the
single cable through the wall, then solder/crimp on the heads without
disturbing the thick insulating material. Anyway, this discussion is just
academic. If "joe"'s monitor does not have BNC connectors, then it won't
work.

--
"War is the continuation of politics by other means.
It can therefore be said that politics is war without
bloodshed while war is politics with bloodshed."
!