OT: Connecting a DAB aerial to a radio without a socket?
Paul D.Smith
simple way to attach an external antenna to these using some minor
electronics/impedence matching magic?
Paul DS.
Steve Terry
"Paul D.Smith" <paul_d...@hotmail.com> wrote in message
news:h2vmqg$j5s$1...@news.eternal-september.org...
(BNC, Phono, Belling lee TV, etc)
wire the socket with thin coax to the aeral point on the PCB
Steve Terry
charles
I made a 4 turn coil round a pencil and connected the ends of teh wire toa
co-ax plug & connected that to an aerial. I slid the coil over the
collapsed telescopic aerial. Worked well for fm radio - should for DAB too.
--
From KT24
Using a RISC OS computer running v5.11
Brian Gaff
I am sure you do not mean these. Officially no, but it depends if you want
to open the case and drill holes or not!
I once did a bodge with a crock clip and a bit of wire wrapped around the
outside of the metal 3.5mm audio out plug. Need to keep the leads short and
it don't look pretty, and sometimes can cause overload this way.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"Paul D.Smith" <paul_d...@hotmail.com> wrote in message
news:h2vmqg$j5s$1...@news.eternal-september.org...
Paul D.Smith
news:h2vnn5$om3$1...@news.albasani.net...
Thanks - looking to avoid knacking the warrantee for the next 12 months
though ;-).
Paul DS
Paul D.Smith
"charles" <cha...@charleshope.demon.co.uk> wrote in message
news:50772e19...@charleshope.demon.co.uk...
Do you connect BOTH ends of the coil to the co-ax plug? Sounds interesting
and well within my capabilities ;-).
Paul DS
Paul D.Smith
news:lxO4m.52854$OO7....@text.news.virginmedia.com...
> Well some have the telescopic Arial mounted on a tiny socket of course,
> but I am sure you do not mean these. Officially no, but it depends if you
> want to open the case and drill holes or not!
> I once did a bodge with a crock clip and a bit of wire wrapped around the
> outside of the metal 3.5mm audio out plug. Need to keep the leads short
> and it don't look pretty, and sometimes can cause overload this way.
>
> Brian
>
connecting to the battery (-) will have the same affect but it's a good
suggestion since there are a couple of sockets on the back.
Paul DS
charles
<paul_d...@hotmail.com> wrote:
> "charles" <cha...@charleshope.demon.co.uk> wrote in message
> news:50772e19...@charleshope.demon.co.uk...
> > In article <h2vmqg$j5s$1...@news.eternal-september.org>, Paul D.Smith
> > <paul_d...@hotmail.com> wrote:
> >> Many DAB radios have telescopic antenna and no aerial socket. Is
> >> there a simple way to attach an external antenna to these using some
> >> minor electronics/impedence matching magic?
> >
> > I made a 4 turn coil round a pencil and connected the ends of teh wire
> > toa co-ax plug & connected that to an aerial. I slid the coil over the
> > collapsed telescopic aerial. Worked well for fm radio - should for DAB
> > too.
> >
> Do you connect BOTH ends of the coil to the co-ax plug? Sounds
> interesting and well within my capabilities ;-).
yes - one end to the centre and one to the shell of the plug.
Brian Gregory [UK]
news:50772e19...@charleshope.demon.co.uk...
I'm sure that works to some extent, passing some signal into the receiver
but the idea must surely come from someone trying what's appropriate for a
medium wave ferrite rod aerial on an FM/DAB rod aerial and not knowing how
totally inappropriate it is in that case.
--
Brian Gregory. (In the UK)
n...@bgdsv.co.uk
To email me remove the letter vee.
Bill Wright
"Brian Gregory [UK]" <n...@bgdsv.co.uk> wrote in message
news:7uOdnTH4fM3A9cvX...@pipex.net...
Other ways of getting a VHF signal (FM or DAB) into a radio that doesn't
have an aerial socket. These assume that there is a decent aerial at the
other end of the incoming coax feeder.
1. Put a small croc clip on the coaxial inner. Leave the outer disconnected.
Clip to the base of the whip aerial, which should be folded.
2. Extend the whip aerial. Connect the incoming coaxial to a wire half-wave
dipole, hide this behind a curtain or wall unit or something, but make sure
it's very close to the whip aerial.
3. Same as (2) but use an amplifier to drive the dipole. The little UHF/VHF
set back ones are OK, or you can use something with more gain.
4. Connect the inner to a length of insulated wire the same length as the
whip aerial. Leave the outer unconnected. Tape the wire along the length of
the whip aerial.
How to connect an AM radio to an external AM aerial. Make a box or frame big
enough to just contain the radio, with open ends so the radio can be slid in
and out. Put seven turns of insulated wire (1mm dia approx) around the box.
Connect a rotary variable tuning capacitor (the big air spaced ones are
ideal) across the ends of the wire. Connect the aerial to one terminal and
earth to the other. Adjust the cap for max gain. Find the optimium position
inside the box for the radio.
Bill
charles
why should a coupling coil only work at MF? I must admit that I didn't do
any theoretical calculations, I just had something that worked. As qwell
as using it at home, I used a similar device in a certain large office, in
west London, building fed off its wired distribution system.
Brian Gregory [UK]
news:cM-dnSHeY8mc8MvX...@pipex.net...
I'd be worried that the receiving aerial might pick up what's radiated from
the driven dipole and the system would start oscillating.
Brian Gregory [UK]
A coil will couple to another coil such as on a ferrite rod aerial but the
couple of inches of FM rod aerial your coil is around won't work much like
another coil.
Bill Wright
>> UHF/VHF set back ones are OK, or you can use something with more gain.
>
> I'd be worried that the receiving aerial might pick up what's radiated
> from the driven dipole and the system would start oscillating.
Yes, you'd think so wouldn't you? Surprisingly, this isn't all that much of
a problem. We do this sort of thing for showrooms where radios are demoed
(sounds like a rare request but we have a customer who needs this at
different locations now and then). If the receive aerial is well up and
away, feedback isn't much of a problem. The thing is to get a good off-air
signal then the gain can be less. However I've used 50dB and got away with
it. That was in a metal building though!
Bill
charles
<n...@bgdsv.co.uk> wrote:
> A coil will couple to another coil such as on a ferrite rod aerial but
> the couple of inches of FM rod aerial your coil is around won't work
> much like another coil.
Be that as it may, it obviously provides sufficient coupling to give a good
signal into the portable. Aerodynamic experts say that, theoretically, a
bumble bee can't fly - but it does.
Brian Gregory [UK]
> In article <_aCdna-IMfHZy8rX...@pipex.net>, Brian Gregory
> [UK]
> <n...@bgdsv.co.uk> wrote:
>
>> A coil will couple to another coil such as on a ferrite rod aerial but
>> the couple of inches of FM rod aerial your coil is around won't work
>> much like another coil.
>
> Be that as it may, it obviously provides sufficient coupling to give a
> good
> signal into the portable. Aerodynamic experts say that, theoretically, a
> bumble bee can't fly - but it does.
Yes I carefully said it would work to some extent. I've seen it suggested
before so it obviously can and does work usefully in many cases. However You
I bet you could do anything you liked with the bit of wire you coiled round
the rod and as long as it was all still just as close to the rod it would
still work pretty much as it does when it's a coil.
If you want to experiment change your coil so half the turns go round the
rod in one direction then change direction and wind the rest of the turns in
the opposite direction, making a useless coil. I bet it still more or less
the same.
Brian Gregory [UK]
> In article <_aCdna-IMfHZy8rX...@pipex.net>, Brian Gregory
> [UK]
> <n...@bgdsv.co.uk> wrote:
>
>> A coil will couple to another coil such as on a ferrite rod aerial but
>> the couple of inches of FM rod aerial your coil is around won't work
>> much like another coil.
>
> Be that as it may, it obviously provides sufficient coupling to give a
> good
> signal into the portable. Aerodynamic experts say that, theoretically, a
> bumble bee can't fly - but it does.
Yes I carefully said it would work to some extent. I should think it works
by capacitive coupling. I've seen it suggested before so it obviously can
and does work usefully in many cases. However I bet you could do almost
anything you liked with the bit of wire you coiled round the rod and as long
as it was all still just as close to the rod it would still work pretty much
as it did when it was coiled.
If you want to experiment change your coil so half the turns go round the
rod in one direction then change direction and wind the rest of the turns in
the opposite direction, making a useless coil. I think it'll probably still
work more or less the same.
Brian Gregory [UK]
I sent it again with corrections.
Paul D.Smith
"DAB to AM/FM transmitter" ready for radio DSO. Apparently this is how
we're supposed to avoid having to junk all our old radios.
Paul DS.
Bill Wright
> Seeing option #3, I imagine you've already started experimenting with your
> "DAB to AM/FM transmitter" ready for radio DSO. Apparently this is how
> we're supposed to avoid having to junk all our old radios.
Where did you read that? (seriously)
Bill
alan....@live.com
Graham.
--
Graham.
%Profound_observation%
Brian Gaff
stability from the outside aerial.
I'd forgotten this old thread.
If anyone finds such an aerial do let us know as the one on my old Pure
Sonus 1 has had many accidents and lookes decidedly dented and wobbly.
It has one of those connections.
Brian
--
From the Sofa of Brian Gaff Reply address is active
<alan....@live.com> wrote in message
news:7b57f8da-3773-42e9...@googlegroups.com...
Brian Gaff
I'd need an sma telescopic aerial. I don't know why thy used such a dinky
connector rather then an f on a mains radio.
--
From the Sofa of Brian Gaff Reply address is active
news:8gt09al6rugev52q8...@4ax.com...