Coax confusion

[wozz]

Im no TV expert just pull in the cables as and when needed.

Ive always thought there to be a few different types, can some explain or link me to some information regarding their uses and construction.

The reason for this is i have always thought:

low loss- air spaced, no foil, no good for anything but terrestrial

rg6- good for all signals, has foil, air spaced

ct100- best, with foil, foam filled.

Today i had a drum with 'low loss RG6' on the drum and it was foam filled??

 

[Lurch]

The standard co-ax from the wholesalers, no good for anything really, no need to even bother looking at it.

RG6 can have a foam or air spaced dielectric. It isn;t too good for most modern digital services.

CT100 or equivalents, again can have foam or air spaced dielectrics. Should be the minimum you fit for anything nowadays (Virgin, Sky, DTT, any DVB service etc...).

http://www.wrightsaerials.tv/articles/coax-cable-quality.shtml

Bill knows his stuff. Plenty of reading on the site to keep you busy for a while.

 

[wozz]

cheers lurch exactly what i was after.

ive always bought ct100 equiv (foam). as i thought it covered all bases but the other day the wholesalers gave me HYC100 with air spaced wasnt too sure if it was the same thing and neither were they.

 

[wozz]

another question for you. (i have been reading a book on CCTV)

why is RG59 the most suitable for CCTV when all of the above are 75ohm?

 

[Lurch]

why is RG59 the most suitable for CCTV when all of the above are 75ohm?

It's not just about the impedance, it's about the losses at particular frequencies due to characteristics of the cables. Put simply, CT100 is less lossy at TV frequencies(around 5-900Mhz, and above that for satellite) and RG59 is less lossy at CVBS frequencies, which is what a standard CCTV camera will output (around 5Mhz).

 

[buddha]

interesting,whats the best cable to run to extend a virgin media point??????

 

[wozz]

i used CT100 with F plugs had the levels checked the other day and they were fine for TIVO

 

[buddha]

nice one wozz thanks.screw fix sell PF 100,is that the same?was also looking at the sky+ shotgun cable,wondered if that would be good for viirgin,gonna bung some cat5 in for good measure

 

[wozz]

see the link above, as far as im aware if its copper on copper its fine, all the shotgun I have seen is RG6, no idea if it will work. Im 50metres from the cabinet and a few hundred from the main exchange for the area, and my levels change alot, they usually re crimp all the plugs and 'adjust' things in the cabinet or ask networks to 'boost things' so it seems its a funny old animal.

Im having a second box installed soon and have already installed the cable he was fine with this.

 

[Robojin]

And just for good measure look at CT125 and CT167 for really long runs from the dish particularly (Large houses, Flats etc)

Coaxial Cables CT100 CT125 CT167 CT233

It never ceases to amaze me that most Sky contractors use such carp shotgun cable when they should not, and should know better, but about profits not quality

 

[batty]

And just for good measure look at CT125 and CT167 for really long runs from the dish particularly (Large houses, Flats etc) Coaxial Cables CT100 CT125 CT167 CT233

It never ceases to amaze me that most Sky contractors use such carp shotgun cable when they should not, and should know better, but about profits not quality

Thats down to sky though i think they only get a set amount per job they do.

 

[RB2004]

best cable available at the moment is Webro HD100

and should be used now, because of the Freeview HD channels launching.

its tripple copper shielded cable with foam spaced core... which exceeds VMs alluminium tripple shielded RG6.. if extending VM cables.. nobody should really be using any dual shielded cable (which almost all coax is.. other than the cheap wholesale stuff) As only HD100 exceeds the VM spec.

If using F connectors.. I find the VM type the best.. those are PPC EX6 NT+ now.. with a kind of serrated nut.

 

[batty]

So technically i shouldn't be getting a picture down my aerial cable thats been in 20 years.

 

[Apache]

I have a perfect picture on my tv using cheap (from ebay) shotgun cable after an incident with the original cable. You can come and wire it up with gold plated rabbit's feet the picture won't improve. it's a bit like the site selling speaker cables at half a million pounds a meter, you can pay a lot more money for something a fraction of a percent better!

 

[steptoe]

now,

I just need to start a bidding frenzy for this wet string I have for sale.........

 

[Doc Hudson]

now,I just need to start a bidding frenzy for this wet string I have for sale.........

If you include some ready made terminating knots to go with the string it will make it easier for the DIY user, so you could probably ask for more. ie. Wet string + 2 x Terminating knots.

Doc H.

 

[streetlighter]

RG6 was used for satellite installs for many years before Raydex brought out the CT100 coax cable with the copper foil and braiding. The Cheap low loss coax is next to useless for digital TV applications as the poor quality braiding will not stop interferance getting into the signal.

I use foam filled RG6 for Freeview and Freesat installs and it works fine for me, been told by the lads on the satellites forum that Webro FT100 cable is the best and they do a shotgun version of that too.

 

[SteveT]

now,I just need to start a bidding frenzy for this wet string I have for sale.........

Trouble is with wet string, it drys out and its impedance changes!