DIGITAL RADIO CONNECTION

[Luisa]

Hello

I have recently had fitted the new digital socket which has connections for TV and Radio.

Question is where can i get the proper connections for my Kenwood HD-600 hi-fi unit?

Or will any do? And what is it called please?

I've looked on the Kenwood site a and they dont have it listed, it was bought at least twenty years ago but it is a first class audion system.

 

[ChrisFrost]

Your Kenwood has an FM radio tuner. Do you have an FM radio aerial installed on the roof or in the loft?

 

[Luisa]

Yes it has TV and Radio and as it is new I imagine it must be FM.

 

[ChrisFrost]

The socket has TV and FM, but are you sure there's an FM aerial on the roof. If not, then you won't get any reception.

 

[ericmark]

The modern socket will allow you to combine up to four frequencies together in the loft and use a single coax cable to deliver to your room then split the signals again.

You must of course have the aerials to combine from in the first place. A dipole for 100Mhz normal radio will be around 2 meters long where one for TV 500Mhz is more like 60 cm long. Although one could build an aerial with traps to work with both radio and TV this as far as I am aware is normally only done with Aperture radio gear and not for TV and Radio.

However any metal in the air is likely to receive better than no aerial at all. So it will work of sorts. However the filters tend to be for Sky, Terrestrial TV, DAB, and VHF. And the older radios are set for VHF, MW, LW, and SW so most of the signal will be filtered out. So often a bit of wire stuck on the wall with blue tack will work better than the aerial on the roof.

The term VHF refers to frequency used where as FM refers to the mode for domestic radio they mean the same (F8E). All other frequencies are now digital (F2D I think?).

With the Ham band most bands are double each other in frequency so a 1/4 wave aerial for one band becomes a 1/2 wave aerial for next. However 477.75-861.75 MHz (TV) 174–240 MHz (DAB) and 87.5-108 MHz (VHF) are not multiples of each other likely as all transmitted from same mast and do not want harmonics so to make an aerial to receive all three would not be easy. Also the local FM transmitter may not be in same place as TV so you may wish to point aerial in a different direction.

Can't really see point in DAB my free to air satellite box is cheaper than a DAB radio and receives more channels. Just seems a complete waist of spectrum.

 

[ChrisFrost]

I think the above might be a touch OTT for Luisa's requirements


Luisa, as long as everything aerial wise is set up right then chances are you'll have one of the following sockets on the back of your Kenwood for the FM aerial

These are male and female TV coax sockets. You can buy a length of cable with the correct sex plugs on each end. It's the same kind of cable that you would use for a TV aerial connection. The cables aren't directional.


Occasionally I come across FM tuners with a screw type connector. This is called an F socket.

. Once again you can buy cables with F plug on one end and an RF plug on the other.

Hope this helps

 

[ericmark]

I have re-read and I wonder what is digital?

DAB is digital but so is RDS, years ago I played with packet radio again digital or was it I needed a Modem or TNC which as far as I am aware is a device to change analogue to digital hence why the device to connect a computer to broad band is not a modem. All it does is change the voltage.

We hear the phrase digital aerial but really no such beast it was the need for a broad band aerial to receive all the multiplex signals which coined the phrase but nothing digital about them.

A lan or telephone outlet could be regarded as digital. Assuming broad band on telephone. And of course older systems did use BNC connectors so it could be coax connectors.

I will guess it's a standard UHF aerial and there is nothing digital about it! But I find it a problem in answering when it could be something very different to what I had assumed.

I still think the question is all to do with band pass filters. Now what I am uncertain of is how a band pass filter will work when there is no VHF aerial? What I wonder is if using the outer one would still get a connection to the aerial or if the capacitors and inductances will isolate the system.

The dti did many years ago a publication called "How to Improve Television and Radio Reception" which had detailed instructions on how to build a band pass filter and was the main stay of many a radio ham trying to stop his high powered signal from getting into a TV. This was before we could buy filters with ease and I still have some printed circuit boards and the coils and capacitor kits to build them.

However I have not a clue what is in the modern ready built units one would hope at least a de-coupling capacitor so any static would not give the house holder a nasty belt.

However as to if this capacitor would allow the VHF signal to pass is another question and the main question is should one connect to outer or inner of the coax?

Personally I have used a length of coax outer as the aerial for my domestic radio. In order to use the digi-eye all capacitors in the face plate had to be shorted out. So as a result the outer works well for me as a long wire aerial.

So the real interesting thing is what happens with the modern face plate? Has anyone tried to use the outer and if so what was the result?

 

[GRC]

Is the OP actually saying that they've got a new Cable TV installation, from the likes of Virgin Media....

as opposed to merely fitting a double coaxial socket to an existing cable and aerial?

 

[ChrisFrost]

Who knows. We haven't heard back from her since Jan 3rd

 

[Luisa]

So sorry for not getting back after such a long time. i forgot that i have stopped responses coming through to my gmail because of being woken up at strange hours by my stupid smart phone!!!

Anyway I sort of gave up on it. But the reply with the pictures was most helpful.

And thank you ALL for taking the time to help me. I appreciate it a lot.

i will go to the shop tomorrow to get the proper plugs male/female