FM through coax cable

[john_1983]

Help a luddite out...

I recently added an FM tuner to my hifi, and innocently thought I could connect the TV aerial that's in the loft to it via coax and it would all work great - not so, no FM signal. I need to keep the aerial for BT TV. I don't want to listen to the radio that much to buy something digital, this FM tuner was lying around so trying to find a cheap//council (delete as applicable) solution.

I've looked into it, and it looks like a diplexer is what I need. For my own clarity - can I install a dedicated FM aerial in the loft, and run that signal to my tuner through the coax as well as the TV signal? And would I need a diplexer at each end (2 aerials into one cable, and then splitting the cable in the living room to feed each box)?

I've read about possible interference between the two signals on the one cable, so checking here first!

[mgv8]

I used the cheep cable T that came with the unit and it worked well.

[TonyRPH]

john_1983 said:

<snip>
For my own clarity - can I install a dedicated FM aerial in the loft, and run that signal to my tuner through the coax as well as the TV signal? And would I need a diplexer at each end (2 aerials into one cable, and then splitting the cable in the living room to feed each box)?
<snip>

Yes, you can buy a dedicated amplifier / combiner which will amplify both the TV and FM signals from the respective aerials.

You'll then need to split the signal again at the receiving end (a standard splitter will work fine here - does not need to be FM or TV specific, just 75 ohms).

[john_1983]

What I've forgotten to mention so far is that the signal around here isn't great, and the coax goes through an old amplifier that's connected to the main fuseboard (old house, old electrics). Still works fine, and splits the aerial signal into 5 for different rooms. Hence a T aerial connected to the tuner isn't of much use.

Tony - thanks, much appreciated. So on my shopping list - FM aerial, diplexer, standard splitter for the living room end.

[megaphone]

I'm surprised you're getting nothing through the TV aerial, it's not ideal but usually gets you some radio channels, BBC stuff etc.

Yes try an FM aerial and combiner up in the loft and split it at the bottom.

[hornmeister]

A standalone TV Ariel even in the attic should be passable. If you've got amplifiers and splitters etc then it'll cause problems.

Cheapest option is to disconnect this wire from the rest of the stuff and if that works just get a separate ariel connected to this line.

If in quite a strong signal area and just have the tuner connected to a 14 element Ariel in the attic it if picks up FM & DAB fine.

[TonyRPH]

megaphone said:

I'm surprised you're getting nothing through the TV aerial, it's not ideal but usually gets you some radio channels, BBC stuff etc.

Yes try an FM aerial and combiner up in the loft and split it at the bottom.

He has boosters in the system, they are possibly tuned to reject Band III (FM) signals, which would explain why he's not getting much in the way of FM reception.

A proper TV / FM combiner / amplifier will solve this issue.

[megaphone]

TonyRPH said:

megaphone said:

I'm surprised you're getting nothing through the TV aerial, it's not ideal but usually gets you some radio channels, BBC stuff etc.

Yes try an FM aerial and combiner up in the loft and split it at the bottom.

He has boosters in the system, they are possibly tuned to reject Band III (FM) signals, which would explain why he's not getting much in the way of FM reception.

A proper TV / FM combiner / amplifier will solve this issue.

Yes, good point. Many distro amps have separate FM input for this. I can see the OP having an issue as he says the amp is connected to the fuse board so possibly remote, so probably only one coax running to it, even if he combines an FM up top he still may have an issue. My need to bypass the amp as suggest by others.

Edited by megaphone on Wednesday 22 January 18:53

[john_1983]

Thanks for all the replies. Will have a detailed look at the amp etc over the weekend

[bristolracer]

You could use one of these.

https://www.ebay.co.uk/itm/Televes-Diginova-F-LTE-...

They are used quite widely in commercial systems these days saves on having multiple aerials.

[Gary C]

megaphone said:

I'm surprised you're getting nothing through the TV aerial, it's not ideal but usually gets you some radio channels, BBC stuff etc.

Yes try an FM aerial and combiner up in the loft and split it at the bottom.

Why would you need to split it ?

[TonyRPH]

Gary C said:

Why would you need to split it ?

One feed to the FM tuner, the other feed to the TV.

That's why a split is required.

[Gary C]

TonyRPH said:

Gary C said:

Why would you need to split it ?

One feed to the FM tuner, the other feed to the TV.

That's why a split is required.

Do you mean just split the cable, or filter out the signals ?

[TonyRPH]

Gary C said:

Do you mean just split the cable, or filter out the signals ?

In this case just to split the cable - there's no need to split or filter the signals at this point.

In fact splitting the signals would require some specialist filters and more amplification, but it's not required at all.

[Gary C]

TonyRPH said:

Gary C said:

Do you mean just split the cable, or filter out the signals ?

In this case just to split the cable - there's no need to split or filter the signals at this point.

In fact splitting the signals would require some specialist filters and more amplification, but it's not required at all.

I read it wrong then, as you were !

[TheInternet]

megaphone said:

I'm surprised you're getting nothing through the TV aerial, it's not ideal but usually gets you some radio channels, BBC stuff etc.

Not sure if it's what you meant, but the OP should be able to get several radio stations via their TV, which could potentially be fed to the hifi.

[TonyRPH]

TheInternet said:

megaphone said:

I'm surprised you're getting nothing through the TV aerial, it's not ideal but usually gets you some radio channels, BBC stuff etc.

Not sure if it's what you meant, but the OP should be able to get several radio stations via their TV, which could potentially be fed to the hifi.

@The Internet - I believe he meant that you can usually pick up FM stations (but with reduced signal strength) via a TV aerial.

However in this case the OP has a booster (amplifier) in his TV aerial feed, which will quite likely be filtering band III (FM) transmissions, and hence his FM reception is poor.

But yes, you are correct of course saying that it's possible to receive loads of radio stations via the Freeview / Freesat transmissions.

[996owner]

You'd get a very poor signal using a tv antenna to feed an fm tuner.

FM frequency is 88-108Mhz

https://www.smartaerials.co.uk/blog/broadcasting-f...
TV Aerial Frequency Bands
The part of the UHF that is used for digital TV is split into 47 UHF channels each 8Mhz wide. Separate groupings of frequencies have been created within this that form ‘Groups’ or ‘Bands’. Below are the aerial groups past and present that you should be familiar with. Grouped aerials exist that are designed to maximise the signal strength and out of band interference but are less common these days. Below are the TV aerial groups, the frequencies and UHF channels they cover, and the corresponding colour associated with that aerial band.

Group A – Red – UHF Channels 21-37 – 470-606Mhz

Group B – Yellow – UHF Channels 35-53 – 582- 734Mhz

Group C/D – Green –UHF Channels 48-68 – 686Mhz – 854Mhz

[TonyRPH]

996owner said:

You'd get a very poor signal using a tv antenna to feed an fm tuner.

FM frequency is 88-108Mhz

<snip>

Yep, but in good signal areas it'll often work fine for the mainstream stations like BBC.

I used to do aerial installations in a past life (amongst other things like TV / HiFi repairs etc. etc.) so quite well versed with it all.

[megaphone]

Hopefully the OP will let us know how he got on.