Aerial co.ax. cable?

[gerryajl]

:confused: Hello. I want to fit an FM aerial on the roof of my house. I can fit it where I used to have a Sky digital dish. (i no longer subscribe to Sky) What I want to know is can I utilse the cable (standard stuff as fitted by Sky installers) that used to take the signal from Sky dish to Sky box to save me running in a new cable. Is it OK for an FM signal. Anybody know? Thanks, Gerry

[John7]

Originally Posted by gerryajl

Hello. I want to fit an FM aerial on the roof of my house. I can fit it where I used to have a Sky digital dish. (i no longer subscribe to Sky) What I want to know is can I utilse the cable (standard stuff as fitted by Sky installers) that used to take the signal from Sky dish to Sky box to save me running in a new cable. Is it OK for an FM signal. Anybody know? Thanks, Gerry

You should be OK. It's the aerial itself which will make the difference, not the cable, so long as it is 75ohm co-axial.

John

[colin.hepburn]

if you are referring to FM radio then you will require 50 ohm cable

[John T]

Originally Posted by colin.hepburn2

if you are referring to FM radio then you will require 50 ohm cable

Since when??

[NickG]

75ohm coax and 300ohm flat twin are the only FM connections I have ever seen.

[colin.hepburn]

http://www.epanorama.net/documents/w...coaxcable.html

[soulminer]

Quoted from that site you provided Colin :

Originally Posted by from Colin's referenced site

50 ohms coaxial cable is very widely used with radio transmitter applications. It is used here because it matches nicely to many common transmitter antenna types, can quite easily handle high transmitter power and is traditionally used in this type of applications (transmitters are generally matched to 50 ohms impedance).

75 ohms: The characteristic impedance 75 ohms is an international standard, based on optimizing the design of long distance coaxial cables. 75 ohms video cable is the coaxial cable type widely used in video, audio and telecommunications applications. Generally all baseband video applications that use coaxial cable (both analogue and digital) are matched for 75 ohm impedance cable. Also RF video signal systems like antenna signal distribution networks in houses and cable TV systems are built from 75 ohms coaxial cable (those applications use very low loss cable types). In audio world digital audio (S/PDIF and coaxial AES/EBU) uses 75 ohms coaxial cable, as well as radio receiver connections at home and in car.

Never used 50 ohm co-ax in my life. All radios I have ever owned have 75 and 300 ohm connections on the rear.

[Roger A]

I agree that it should be 75 ohms - all FM aerials are matched to this impedance so it makes sense that the input to the tuner is designed to match this.

Roger

[John T]

www.epanorama.net/documents/wiring/coaxcable.html[/url]

As it states in the above :-
"Most common coaxial cable impedances in use in various applications are 50 ohms and 75 ohms. 50 ohms cable is used in radio transmitter antenna connections, many measurement devices and in data communications (Ethernet). 75 ohms coaxial cable is used to carry video signals, TV antenna signals and digital audio signals.

In addition, this was extracted from the Quad FM4 Tuner handbook. Quad should know!!

FM4 Spec.jpg

[Roger A]

Originally Posted by John T

As it states in the above :-
"Most common coaxial cable impedances in use in various applications are 50 ohms and 75 ohms. 50 ohms cable is used in radio transmitter antenna connections, many measurement devices and in data communications (Ethernet). 75 ohms coaxial cable is used to carry video signals, TV antenna signals and digital audio signals.

In addition, this was extracted from the Quad FM4 Tuner handbook. Quad should know!!

Attachment 245

Indeed they did - it states the aerial connection is 75 ohm unbalanced.

Roger