75 ohm terminals.

Well, any metal bit of the unit near the terminals is a good plan usually I
found, but as I say, almost anything is better than a bit of ribbon cable
below ground level!
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"David Paste" wrote in message
...
On 9 Aug, 22:55, "Woody" wrote:

Core to either screw and screen to earth.

Forgive my ignorance, but earth as in the earth wire in the mains plug
type earth?

Brian Gaff wrote:

it needs a balun/ transformer there.

In practice though, you can do all sorts of things and get away with it.

I couldn't bring myself to recommend the O/P just sucks it and sees
after Bill's "that's what's wrong with this country" comment ;-)

On 10/08/2010 08:12, Alan White wrote:
On Tue, 10 Aug 2010 02:43:28 +0100, UnsteadyKen
wrote:

Here we stick with the a reversed coax Belling Lee type, requiring a
female connector on the FM downlead. Presumably this is to stop us
connecting the the radio aerial to the telly and vice versa.

I don't think I've ever come across that. The downlead on both FM and TV
aerials has required a male Belling and the FM and TV receivers have had
female Bellings.

It's quite common for Japanese FM tuners to have female Bellings, I
think my Sony does, I can't remember for certain though.

Easier to just use a sex changer on a male connector, than fiddle about
trying to solder on a female BL IME.


--
Mark
Please replace invalid and invalid with gmx and net to reply.

http://www.paras.org.uk/

On Tue, 10 Aug 2010 08:28:59 +0100, Mark Carver
wrote:

It's quite common for Japanese FM tuners to have female Bellings, I
think my Sony does, I can't remember for certain though.

My various incarnations of Quad tuners were fitted with female Belling's
as was my AVI tuner.

--
Alan White
Mozilla Firefox and Forte Agent.
Twenty-eight miles NW of Glasgow, overlooking Lochs Long and Goil in Argyll, Scotland.
Webcam and weather:- http://windycroft.co.uk/weather

In article ,
Mark Carver wrote:
On 10/08/2010 08:12, Alan White wrote:
On Tue, 10 Aug 2010 02:43:28 +0100, UnsteadyKen
wrote:

Here we stick with the a reversed coax Belling Lee type, requiring a
female connector on the FM downlead. Presumably this is to stop us
connecting the the radio aerial to the telly and vice versa.

I don't think I've ever come across that. The downlead on both FM and TV
aerials has required a male Belling and the FM and TV receivers have had
female Bellings.

It's quite common for Japanese FM tuners to have female Bellings, I
think my Sony does, I can't remember for certain though.


It's a German idea, to the best of my knowledge

--
From KT24

Using a RISC OS computer running v5.16

On 10 Aug, 02:43, UnsteadyKen wrote:

Screw type terminals and F sockets for 75ohm FM aerial connections are
common nearly everywhere but the UK.http://goo.gl/mmpz

Why do we have a different system? Just convention, or is either
system technically superior?


A quite efficient and very cheap dipole FM or DAB aerial can be made
from a length of coax cable. Remove 29" (or adjust to suit the
frequency of your favourite stationhttp://goo.gl/mhp8) of the outer
covering, carefully wriggle the inner insulated conductor out of the
braid. Arrange in a T shape and fasten to a handy bit of wood or
plastic. It works well as the only joint is where it connects to the
input.

Here's a picture of my efforts.http://unsteadyken.posterous.com/

Yes, it was actually seeing that picture on Sunday that prompted me to
make my own yesterday! It now nestles behind the wardrobe, out of
sight, doing sterling service. Mine differs from your description in
that I added a chocolate block connector at the middle of the T to
join the coax to two lengths of mains flex I liberated from a salvaged
lead.

One question though: How dramatically does altering the length of the
Ts affect the tuning of the aerial? I tend to listen to R3 and Classic
FM which are at differing ends of the spectrum, so to tune to one
frequency would presumably affect the other? Not that I need to - my
reception is now actually /very/ good. In good reception areas, would
it be OK to tune the aerial to 98MHz i.e. in the middle of the 88 -
108 FM band?

Of course, now that I have a good reception, it has become even more
apparent just how bloody appalling the sound quality of a lot of tin-
pot radio stations are!

Thanks Ken.

On 10 Aug, 08:12, Alan wrote:

I don't think I've ever come across that. The downlead on both FM and TV
aerials has required a male Belling and the FM and TV receivers have had
female Bellings.


My bedroom stereo has a male socket on it, requiring a female on the
lead. It's a Panasonic, FWIW.

On 10 Aug, 08:12, "Brian Gaff" wrote:
Well, any metal bit of the unit near the terminals is a good plan usually I
found, but as I say, almost anything is better than a bit of ribbon cable
below ground level!

Ha! I certainly hope so!

Cheers Brian.

In article
,
David
Paste wrote:
On 10 Aug, 02:43, UnsteadyKen wrote:

Screw type terminals and F sockets for 75ohm FM aerial connections are
common nearly everywhere but the UK.http://goo.gl/mmpz

Why do we have a different system? Just convention, or is either system
technically superior?

These things have simply 'evolved' from different starting points in
different countries. You can argue that it makes sense to have 'coaxial'
types of plug-socket when using coaxial (unbalanced) cables and pairs of
screw terminals for balanced twin-feed. But as you have found, almost
anything may crop up! :-)


One question though: How dramatically does altering the length of the Ts
affect the tuning of the aerial? I tend to listen to R3 and Classic FM
which are at differing ends of the spectrum, so to tune to one frequency
would presumably affect the other?

To complicate matters, the answer will depend on the cable and the 'load'
(i.e. input to the tuner) since the optimum depends both on the inherent
radiation coupling of the antenna and the 'match' into whatever it is
conected to. Also objects nearby can alter the behaviour. The good news is
that - if fairly well matched by the cable and tuner - a single dipole is
not ultra frequency-sensitive. So it probably matters more where the
antenna is placed and the relative field levels, etc, in the location.


Not that I need to - my reception is now actually /very/ good. In good
reception areas, would it be OK to tune the aerial to 98MHz i.e. in the
middle of the 88 - 108 FM band?

Probably fine. In principle the 'tuning' also depends on the diameter of
the elements and some other factors. But in practice you probably won't
notice. :-)

If in doubt adopt the Barber's Technique. Start 'too long' and snip shorter
until it seems 'Oops! just too short, now' and stop. :-)

FWIW The last time I made an indoor dipole I just made it from a stick
bought as a 'plant support pole' and taped two lengths of wire to it to
make the halves of the dipole. Cut so the total length was about half a
wavelength. Not ideal in theory, but actually works fine. The reality is
probably that if something like that doesn't work, then you will need
something much better. i.e. more elements and up higher. For that, more
precision in the sizes, etc, becomes more important.

Of course, now that I have a good reception, it has become even more
apparent just how bloody appalling the sound quality of a lot of tin-
pot radio stations are!

The wider you open the window, the more muck blows in. :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

David Paste said...

Why do we have a different system? Just convention, or is either
system technically superior?

Just custom I believe, they've been around since the dawn of radio.
1922; according to wiki http://en.wikipedia.org/wiki/RF_connector
and I suppose they just carried them over to telly use when that
arrived. The Yanks have always tended to use twin feeder cables for
radio and TV aerials. Probably because once a standard emerges then
manufacturers don't want to try anything different in case it puts the
buyers off.

Mine differs from your description in
that I added a chocolate block connector at the middle of the T to
join the coax to two lengths of mains flex I liberated from a salvaged
lead.

As long as it works, I just used what I had lying around.

One question though: How dramatically does altering the length of the
Ts affect the tuning of the aerial? I tend to listen to R3 and Classic
FM which are at differing ends of the spectrum, so to tune to one
frequency would presumably affect the other?

I wouldn't describe it as having a dramatic effect, it can help if you
are trying to pull in a very weak or distant station, but then, as you
say it affects all the others. Moving the aerial a few inches can make
a much bigger difference. You can also try changing the alignment from
vertical to horizontal or sloping to see what happens.


Not that I need to - my
reception is now actually /very/ good. In good reception areas, would
it be OK to tune the aerial to 98MHz i.e. in the middle of the 88 -
108 FM band?

Yes, that's what I did. I wanted to get stations ranging from Radio 2
on 90.10 to a local station Connect FM which is at 107.4 so went for
98MHz.
We get very good FM reception here in Corby with the main Peterborough
transmitter 15 miles away over open country giving excellent signals
for BBC and Classic FM on FM and DAB, with a transmitter in Geddington
which provides a relay of BBC Northampton and Connect FM only 4km away
and has just started providing a DAB relay as well..
Our local community station Corby radio opened last year with a mast in
the centre of town http://www.corbyradio.com/ so we're well served for
radio round here;.

Of course, now that I have a good reception, it has become even more
apparent just how bloody appalling the sound quality of a lot of tin-
pot radio stations are!

Too bloody true, it's not so much the sound quality I object to it is
the dismal bland programming, especially now that the Heart group seems
to be snapping up all the local independents in the East
Anglia/Midlands area and turning them into identikit clones.



--
Ken O'Meara
http://www.btinternet.com/~unsteadyken/