[Justin Aerial]

Has anyone ever played about trying to see if an external aerial (DAB or FM) can be used with a radio which doesn`t have an external aerial socket ?
What happens if you connect it to the kind of "wire aerial" that is often on those kind of radios ? I know that there are loads of reasons why that`s bad practice, but does it actually improve the signal ?

[chrisjr]

It can improve things. Though often not to the same extent as using a proper connector.

If the radio has a telescopic aerial then what you can do is bare a few inches of the inner conductor in the coax lead and wrap it round the aerial. Make sure the screen braid of the coax is trimmed well back so it can't touch the aerial.

If it has a flexible wire aerial and you don't mind attacking it with a pair of cutters you can bare a bit of the wire aerial and joint that onto the bare end of the inner conductor in the coax lead. If you can find a point connected to the 0V power connection of the radio then you might get a slight extra improvement by connecting the screen braid to it.

I have actually seen radios with coax sockets bodged onto them. If there is enough clearance behind the case for the socket it is not that difficult to wire up if you have any technical skill and knowledge.

And of course some DAB radios have the telescopic aerial attached by a F Type screw in fixing. So you can unscrew the built in aerial and connect directly to an external aerial.

[soulboy77]

From experience connecting any external wire however bodged offers some improvement in reception.

At my last house I connected my FM radio to a TV aerial socket with a filter to get rid of the other bands. Worked like a treat and though I had a proper FM aerial waiting in the garage to be installed, I never bothered in the end.

Assuming you can get the casing apart easily then fitting an F-type socket on the back of a FM or DAB receiver is a simple job if you are handy with a soldering iron. I have just had a quick look at my DAB receiver in the dining room and am pleased to find the telescopic aerial can be unplugged to facilitate connection to a proper aerial system if required.

[Dr.OliverTwich]

Another thing to try is placing the radio on a large metal tray - or even lengths of aluminium (cooking) foil.... they can act as a sort of reflector and add something to the signal.

(Tip learned from BBC Radio Tuning Clinics circa 1993).

Another was to close the telescopic aerial down and wrap 6-8 turns of insulted wire around it, with that wire connected between the inner and outer of an coax attached to an FM/VHF aerial (in the hopes it would act as a transformer and induce a signal into the radio's aerial.)

BOTH ideas got reports back from the public of improved reception! {IIRC the first idea came from a member of the public}.

[SteveMcK]

We have poor FM reception at home, and I tried this with a clock-radio. Adding a longer bit of wire (a few metres of standard hook-up wire) helped. Connecting to an external aerial didn't make much difference. There was a stronger signal, but more noise. I didn't try to match the aerial, though. perhaps a decent RF transformer or balun might have worked better. In the end I replaced the dangly wire thing with a telescopic aerial screwed to the alarm clock case. That gave almost acceptable reception.

Next thing is to try an internet radio. Anyone had any experiences with the Pure Siesta Flow ?

[ianradioian]

I have run a length of coaxial down the outside wall , from the upstairs window,of my house on the front, so it acts as an aerial towards the Birmingham multiplex ( about 40 miles away), and the centre wire is wrapped round the telescopic aerial on the set. I now get jazzFM perfectly instead of breaking up and raspberrying me constantly. Try a length of coaxial, it worked for me.

[gomezz]

Originally Posted by soulboy77

From experience connecting any external wire however bodged offers some improvement in reception.

I can second that. My DAB radio is connected to my TV aerial (using a room-end amp/splitter) but I suspect it is the run of downlead which improves the signal rather than the aerial itself (the signal was actually being badly affected by the mains lead for my old laptop). My other DAB radio in the bedroom is a bit burbly on just its whip aerial.

[tr_ramsgate]

I seem to remember, years ago, using a portable radio in the kitchen (where my telephone line comes in to the house)and accidentally touching the telescopic aerial against the telephone.

It was an old fashioned phone with a dial with a finger guide that was metal.

The signal strength shot up.

[soulboy77]

Originally Posted by gomezz

I can second that. My DAB radio is connected to my TV aerial (using a room-end amp/splitter) but I suspect it is the run of downlead which improves the signal rather than the aerial itself (the signal was actually being badly affected by the mains lead for my old laptop). My other DAB radio in the bedroom is a bit burbly on just its whip aerial.

In my first house I proudly installed an FM aerial and downlead for my newly acquired hi-fi separates set-up. I had excellent reception over the in-door aerial that had come with the tuner. Moving out, I took down the aerial but left the down lead in place. Turning on the FM tuner for the last time before packing up, the reception was as strong as ever without the aerial attached!

[Justin Aerial]

Originally Posted by soulboy77

From experience connecting any external wire however bodged offers some improvement in reception.

At my last house I connected my FM radio to a TV aerial socket with a filter to get rid of the other bands. Worked like a treat and though I had a proper FM aerial waiting in the garage to be installed, I never bothered in the end.

Assuming you can get the casing apart easily then fitting an F-type socket on the back of a FM or DAB receiver is a simple job if you are handy with a soldering iron. I have just had a quick look at my DAB receiver in the dining room and am pleased to find the telescopic aerial can be unplugged to facilitate connection to a proper aerial system if required.

You can get decent FM and even DAB out of some TV aerials, we tested a load of FM and DAB aerials and also, TV aerials for FM/DAB reception and were surprised at how well some of the TV aerials picked up FM and DAB. BUT, it`s either because you`re in a strong signal area anyway, or just lucky. There`s a big difference in signal between FM/DAB signals off TV aerials and the correct aerial.

[Justin Aerial]

Originally Posted by chrisjr

It can improve things. Though often not to the same extent as using a proper connector.

If the radio has a telescopic aerial then what you can do is bare a few inches of the inner conductor in the coax lead and wrap it round the aerial. Make sure the screen braid of the coax is trimmed well back so it can't touch the aerial.

If it has a flexible wire aerial and you don't mind attacking it with a pair of cutters you can bare a bit of the wire aerial and joint that onto the bare end of the inner conductor in the coax lead. If you can find a point connected to the 0V power connection of the radio then you might get a slight extra improvement by connecting the screen braid to it.

How short should the wire set back aerial be left ? Does it make any differnce how long it is ? How much extra signal would you get from the external aerial if connected in this way ? More accurately, how much less signal would you get compared with plugging an aerial into an external aerial socket ?

[spiney2]

Take a short length of any old wire.

bare one end, connect it to your tv aerial cable outer. Either dismantle the plug, or if moulded on, bare a length of wire, then wrap it round the outer metal part of the RCA (push in) aeiral plug.

Other end of wire, wrap that around the telescopic aerial, say 5 or 6 times.

Whether that works "depends". If it's in the right place/direction, the aerial downlead outer might pick up DAB more reliably than the telescopic aeiral alone (it's very unlikely to be worse).

If that seems to work, just use a longer bit of wire .......

The other thing to try, is, just connect a longer piece of wire to the telescopic aerial!

[chrisjr]

Originally Posted by Justin Aerial

How short should the wire set back aerial be left ? Does it make any differnce how long it is ? How much extra signal would you get from the external aerial if connected in this way ? More accurately, how much less signal would you get compared with plugging an aerial into an external aerial socket ?

In this sort of bodge job there are no rules. It's basically a case of whatever works.

You are not going to get the full signal possible from a "proper" aerial connection. Especially if you leave the screen braid unconnected.

I've no doubt it is possible to crunch the maths and work out to thirty decimal places exactly how much extra signal you get but I've never bothered to measure or calculate it. But it can make the difference between having to listen in mono to kill the hiss and having relatively clear stereo.

And lets face it for the majority of people that is all that matters.

[Justin Aerial]

Originally Posted by chrisjr

In this sort of bodge job there are no rules. It's basically a case of whatever works.

You are not going to get the full signal possible from a "proper" aerial connection. Especially if you leave the screen braid unconnected.

I've no doubt it is possible to crunch the maths and work out to thirty decimal places exactly how much extra signal you get but I've never bothered to measure or calculate it. But it can make the difference between having to listen in mono to kill the hiss and having relatively clear stereo.

And lets face it for the majority of people that is all that matters.

So, just to clarify (and I`m going to link to this thread from my FM/DAB web page ! ) you`re saying that you do, generally speaking, get a worthwhile improvement from attaching an external aerial to your radio via the set back aerial ?
Mind you, at the end of the day, a decent aerial for both FM and DAB is the FM Half Wave dipole, and they only cost about £13, so it`s not really the end of the world if it doesn`t work that well, is it ? ! ?

[Justin Aerial]

Originally Posted by spiney2

Take a short length of any old wire.

bare one end, connect it to your tv aerial cable outer. Either dismantle the plug, or if moulded on, bare a length of wire, then wrap it round the outer metal part of the RCA (push in) aeiral plug.

Other end of wire, wrap that around the telescopic aerial, say 5 or 6 times.

Whether that works "depends". If it's in the right place/direction, the aerial downlead outer might pick up DAB more reliably than the telescopic aeiral alone (it's very unlikely to be worse).

If that seems to work, just use a longer bit of wire .......

The other thing to try, is, just connect a longer piece of wire to the telescopic aerial!

I have tried that and it didn`t work, which is not surprising because that`s altering the tuning of the existing aerial. The thing is that attaching an external aerial to the existing aerial is also doing that, although if you can mount the existing aerial up in the loft then it`d probably be further away from sources of interference than the set back one ?

[chrisjr]

Originally Posted by Justin Aerial

So, just to clarify (and I`m going to link to this thread from my FM/DAB web page ! ) you`re saying that you do, generally speaking, get a worthwhile improvement from attaching an external aerial to your radio via the set back aerial ?
Mind you, at the end of the day, a decent aerial for both FM and DAB is the FM Half Wave dipole, and they only cost about £13, so it`s not really the end of the world if it doesn`t work that well, is it ? ! ?

I've seen all sorts of things done.

I've wrapped the wire aerial round the TV downlead and got a useful boost in signal.

I've also laid a wire aerial close to a mains cable running down a wall and got a better signal.

Rather more bizarre I suppose is an arrangement my dad cobbled together years ago. He took a telescopic aerial off an old dead portable radio. Then he bared the end of a bit of wire and wrapped that round the end of the aerial. He secured this aerial to the outside of the window to the living room. Fed the bit of wire through the hole in the window frame where the TV aerial entered then simply knotted the wire to the wire aerial of the radio! And it worked

Just goes to prove what I have always thought. RF is a black art and more often than not the rule book can be chucked out the window

[r_mitchell85]

Originally Posted by chrisjr

I've also laid a wire aerial close to a mains cable running down a wall and got a better signal.

this always seems to improve my FM radio reception. I assume it is something to do with the earth connection.

another thing Ive found sometimes helps, if possible, is wrapping the wire around a central heating pipe... or putting it close to a radiator.

[spiney2]

Originally Posted by chrisjr

I've seen all sorts of things done.

I've wrapped the wire aerial round the TV downlead and got a useful boost in signal.

I've also laid a wire aerial close to a mains cable running down a wall and got a better signal.

Rather more bizarre I suppose is an arrangement my dad cobbled together years ago. He took a telescopic aerial off an old dead portable radio. Then he bared the end of a bit of wire and wrapped that round the end of the aerial. He secured this aerial to the outside of the window to the living room. Fed the bit of wire through the hole in the window frame where the TV aerial entered then simply knotted the wire to the wire aerial of the radio! And it worked

Just goes to prove what I have always thought. RF is a black art and more often than not the rule book can be chucked out the window

Well ...... yeah, all those things might well work. But, rf is most certainly NOT a black art! It's science.

[SteveMcK]

Originally Posted by spiney2

Well ...... yeah, all those things might well work. But, rf is most certainly NOT a black art! It's science.

I'd say it's engineering, which always includes a bit of black art in with the science

[spiney2]

Originally Posted by SteveMcK

I'd say it's engineering, which always includes a bit of black art in with the science

No. Electromagnetic theory isn't witchcraft, just DIFFICULT !

[Justin Aerial]

Originally Posted by spiney2

Well ...... yeah, all those things might well work. But, rf is most certainly NOT a black art! It's science.

Err no, RF (TV / radio reception) is a Black Art.......

As defined by the fact it`s not (practically speaking) predictable.

[SteveMcK]

Originally Posted by spiney2

No. Electromagnetic theory isn't witchcraft, just DIFFICULT !

Oh the theory isn't difficult, at least it wasn't when I studied it. That's the science part. It's the practical issues when theory meets the real world that is difficult, and that's definitely art!

[chrisjr]

Can I just ask?

Am I the only one that can see the smiley at the end of my comment that sparked this debate about whether RF is a black art or not?

[Justin Aerial]

Originally Posted by chrisjr

Can I just ask?

Am I the only one that can see the smiley at the end of my comment that sparked this debate about whether RF is a black art or not?

I`m old school, all these Forum icons are a foreign language to me old son.......

[SteveMcK]

Originally Posted by chrisjr

Can I just ask?

Am I the only one that can see the smiley at the end of my comment that sparked this debate about whether RF is a black art or not?

Oh, we can see it, but we won't let that get in the way of a good argument