coxail \ VGA

086lavey

Is there such a device for coxail to VGA ?

KoolKid

Is this what your looking for?

086lavey

thats the one , are they handy got , my elec wholesaler had not a idea :rolleyes:

KoolKid

Try a few of the ones listed in the stickey.
Where are you located?

Stoner

HDMI over Cat5e is better, I'll look up a unit for you now


for HDMI
http://cpc.farnell.com/jsp/search/results.jsp?N=411+2005+206488&Ntk=gensearch&Ntt=VGA&Ntx=mode+matchallpartial&isGoback=false

Sorry had a quick look but cant find the coax to VGA on CPC, but they do have them, maybe give them a call, I usually get this type of device from them, if you have the cable in already then I guess you are stuck with coax, but one or even better two number cat5e or Cat6 cables would be a better job, you could get audio that way too.

086lavey

thanks for getting back to me , im in the west , deal with CEF a fair bit , but as i said they cant help , its for a cctv job in my own house , might change the dvr for a hd one yet and use cat 5 , thanks

Stoner

Em I might move this to home security, I didn't realise that this was for CCTV, i though it was for a monitor for some reason, the lads there will help you better, I would not go with cat5 cable on CCTV unless it was an IP camera system

Jnealon

Stoner wrote: »

Em I might move this to home security, I didn't realise that this was for CCTV, i though it was for a monitor for some reason, the lads there will help you better, I would not go with cat5 cable on CCTV unless it was an IP camera system

Cat 5 is more reliable that coax imo, less prone to interferance and can be used on longer runs

086lavey

thanks , have the cameras wired with coaxil and 8 core alarm cable for power supply , wired them when i was first fixing the house , so im stuck with this now , only wanted the coxail to vga, for signal down to two tvs for viewing the dvr has two outputs for this ,

C.TECH

Jnealon wrote: »

Cat 5 is more reliable that coax imo, less prone to interferance and can be used on longer runs

This is a pet peeve of mine. CATV is NOT more reliable, is NOT less prone to interference, it is MORE prone to EMI interference. IMHO 'longer runs' is debatable(A debate I'll jump right into anytime).

The fact is that CATV is cheaper, even when you add the cost of passive baluns, there is a saving to be made. Couple this with some Installers running multiple video signals down a single four pair CATV and the savings on cost are considerable.
This is why there are a lot of guys justifying CATV use, by making up facts and figures that just aren't true, even an active balun with CATV to only one camera will NEVER be superior to a good old RG59+Power.

It might save you a few bob here and there, and that's fine, but please don't perpetuate the myth that it is preferable to use CATV over RG59 in any situation other than a 'no choice' scenario.

CATV is inferior to RG59 for CCTV and will affect the signal and quality of the image, this is a fact.

Jnealon

C.TECH wrote: »

This is a pet peeve of mine. CATV is NOT more reliable, is NOT less prone to interference, it is MORE prone to EMI interference.

Being a balanced system Cat5 is less prone to interference than coax.
The twists in the cable cancel out the noise, just google it or pick up any book on the subject

C.TECH

Jnealon wrote: »

Being a balanced system Cat5 is less prone to interference than coax.
The twists in the cable cancel out the noise, just google it or pick up any book on the subject

Thanks for pointing me to Google, that repository of all factual knowledge. So the 'twists' cancel out the interference? well that's cool, Kinda makes you wonder why every signal cable isn't twisted and why they make things from different materials with different screening and thickness etc..

I don't mean to get at you J, but you are perpetuating the myth, through ignorance and a sincere hope that cheaper cable is better..it isn't.

I took your advice and googled my pants off...


From Wiki:

RG-59 is often used at baseband video frequencies, such as composite video. It may also be used for broadcast frequencies, but its high-frequency losses are too high to allow its use over long distances; in these applications, RG-6 or RG-11 is used instead. In cases where the transmission distance is too long for these media, such options as UTP (unshielded twisted pair) or fiber optic can be used. However, UTP such as CAT6 has too many twists in the twisted pairs which results in a poorly performing media for analog signals over long distances; the preferred medium is fiber optic cable.



From CommScope;

works both well and inexpensively at distances of up
to 1500 feet. Because it does not require conversion electronics, it has fewer connection points that
could lead to signal loss or breakdown. It is also
well shielded against EMI. Coax also tends to introduce fewer digital artifacts than UTP.
UTP is emerging as a viable CCTV media. An active
UTP system offers reasonable performance over distances of up to 1500 feet and is comparable to
coax at distances between 1500-3000 feet. UTP’s
big advantage is that it works well in the world of
structured wiring; a UTP CCTV network can integrate into a campus data network using protocols
like Ethernet. While the present cost of baluns and
hubs is a factor, those costs should come down over
the next few years. Its disadvantages are that conversion electronics are required and UTP offers only
minimal protection against EMI. Higher category
UTP (i.e. Cat 6) offer somewhat better EMI protection
than medium to lower category UTP (i.e. Cat
5)

[url]www.fmsystems-inc.com:[/url]

It is clear that while the picture brightness does degrade on longer UTP cables, the loss of picture definition
suffers far more. The loss of definition on longer UTP cables can be catastrophic even when the brightness of the
monitor is increased to make up for low frequency loss on the cable.
The BALUNS often used to convert from 75 Ohm cable to UTP facilities add even more to the losses
identified above and can only degrade performance further. Baluns can be used on very short UTP facilities, but on
cables more than 500 feet, Amplifier/Equalizers should provided to overcome the losses.

http://www.security-camera-warehouse.com:


For one the transmission of video with the copper gauge wire is much better than CAT5 wire. Two RG59 has better shielding and can protect the signal from interference.

Jnealon

Try again

Google here

Sources:
Wikipedia
Transmission of a signal over a balanced line reduces the influence of noise or interference due to external stray electric fields. Any external signal sources tend to induce only a common mode signal on the line and the balanced impedances to ground minimizes differential pickup due to stray electric fields. The conductors are sometimes twisted together to ensure that each conductor is equally exposed to any external magnetic fields that could induce unwanted noise.

Audioholice
Myth V Reality
Category 5 cable includes four twisted pairs in a single cable jacket and typically features three twists-per-inch of 24-gauge copper wire. The wires are twisted to decrease interference and noise during balanced operation, where-in the wires carry equal-but-opposite signals (differential mode). In an A/V installation, a balanced line is a transmission line consisting of two conductors (wires) of the same type with equal impedance to ground and other circuits. In theory the common-mode noise from the two wires cancels each other when the two signals are added together at the destination because they both carry similar amounts of electro-magnetic interference (EMI) that are 180-degrees out of phase. Differential mode also reduces electromagnetic radiation from the cable, minimizing interference to adjacent wiring and circuitry. It is this ability to operate in a fully differential mode that makes balanced transmission desirable.

C.TECH

I think you need to try again..

our argument was rg59 vs catv, I cited references indicating rg59 was superior to catv in a common cctv installation. You just posted a description of catv itself.

I hope you see the difference and we can leave this as settled.

Jnealon

Don't think so, I stated that a balanced system is less prone to interference then an unbalanced one
They both have their pros and cons but to dispell it as a myth is wrong

C.TECH

Jnealon wrote: »

Don't think so, I stated that a balanced system is less prone to interference then an unbalanced one
They both have their pros and cons but to dispell it as a myth is wrong

Jnealon wrote: »

Being a balanced system Cat5 is less prone to interference than coax

Jnealon wrote: »

Cat 5 is more reliable that coax imo, less prone to interferance

It is a myth, that CATV is preferential (or even equivalent) to RG59 in a standard CCTV installation. I haven't dispelled it, I've proved it.

I will concede that...

Jnealon wrote: »

can be used on longer runs

..but only where RG11 or fibre aren't an option. I have no problem with CATV over very long distance, it's this new fad of using CATV as a first choice in any Installation, and then claiming it's better than COAX, that gets on my nerves. It really is inferior.

Jnealon

Where have you proved it

C.TECH

Jnealon wrote: »

Where have you proved it

Here

http://www.boards.ie/vbulletin/showthread.php?t=2056394632

Jnealon

Sorry you have proved nothing.
Unbalanced systems are more prone to interference than balanced, this is basic first year electronic, I would even say leaving cert physics.
The fact that there are more products on the market to mask the interference induced in coax systems sums it all up

CCTV Surveillance - starting at page 141
CCTV - starting at page 242


From the books above rg59, rg6 and rg11U have a higher db loss per meter than cat5