TV to radio

[Liz65]

Since moving, can't receive radio on my Technics system. There is a jack at the back which looks as if it takes a co-axial aerial. If I hooked up to the TV aerial, would I get the normal radio stations, or, more importantly, could I damage the system?

[Buenchico]

(2 part post):

It's fairly unusual, but not unknown, for hi-fi units to use a jack socket or a co-ax socket (which are different things) for an aerial input. Check to see if it's labelled 'aerial', 'antenna', 'ae', 'ant', 'rf' or if it's got a symbol like a capital'Y' (with an extra vertical 'arm' in the centre). If any of those are present, you're correct in assuming that it's an aerial socket.

Irrespective of whether it's actually an aerial socket, or not, you won't be able to do any damage by connecting a coaxial aerial to it. That's because the outer sheaf of a coaxial cable is electrically isolated from the central core, so there's no way that you could 'short' any circuit.

[Buenchico]

However, I've got serious doubts as to whether you'd be able to receive any radio signals by using a TV aerial. The size and shape of aerial isn't an arbitrary matter. The elements have to be certain lengths so that they will 'resonate' with the incoming signals. FM radio signals use VHF (very high frequencies), whereas TV signals use UHF (ultra high frequencies). The size of the required elements, for optimal reception, is completely different. Further, TV signals are usually either vertically or horizontally 'polarized', whereas VHF radio uses diagonal polarization. Most importantly, VHF radio transmissions are broadcast from different transmitters to UHF TV transmissions, so your TV aerial will be pointing in the wrong direction.

Give it a try, by all means, but don't expect great results. If it doesn't work, head to your nearest branch of Maplin Electronics. If you're in a fairly strong signal area, you might be able to use an indoor aerial like this one:
http://www.maplin.co.uk/module.aspx?ModuleNo=2 2497&doy=18m12
Otherwise you might need one of these on your roof:
http://www.maplin.co.uk/module.aspx?ModuleNo=3 6358&doy=18m12

Chris

[ACtheTROLL]

I think bu is right

coax is just a connector used for this type of thing
I seem to remember "stereo systems" came with a flat "T" shaped aerial that no one used because it was the size of a small aircraft hanger.

couple of questions (both no brainers - sorry if you're insulted ;-)
depending where you have moved to .... have you re-tuned the presets?

also .... I seem to think that one of the late 20th century design classics - seen on many a prestige limosine
was the humble metal coat hanger

of course reception is a tricky thing .... but I'd have thought that a TV connection would be at least as good as a half decent hanger.

there is no electrical reason for not having a go that I can think of - other than possibly the signal could be too strong

[Seafarer1966]

I use a portable tv aerial to get better FM reception on my hifi. It cost about four quid from Woolies and the reception is great. It's the same type of aerial socket as on a tv.

[Liz65]

Thanks for help everyone - ended up buying a splitter connection for �1.50 and hooked up to incoming TV aerial. Can get FM stations so far, but as yet, not AM

[Buenchico]

Thanks for taking the time to reply.

Take another look at the connections on your Technics unit. Most decent hi-fi systems have two separate aerial inputs. One is for FM and allows two leads to be connected to the receiver. (In your case, the inner and outer layers of the coaxial cable form the two leads). The other is for AM and allows a single cable to be connected. You can usually get a reasonable signal by connecting a short length of wire and (for example) hiding it behind a curtain. People like me (i.e. 'radio nutters'!) have much longer wires going up into the loft.

Chris