Seeing the other thread on FM and aerials has reminded me about
something I've been meaning to find out about.

I would like to have a proper FM aerial installed on the roof. The
thing is that there are two receivers that I would like to connect it
to. One is in the lounge at the front of the house and the other is in
the dining room at the back. One option would be to have the coax
coming down from the aerial, eirther at the front or the back of the
house, bring it into the house and then split it somehow. I'd rather
avoid this option to minimise internal disruption. I was wondering
instead how feasible it would be to have two separate wires coming from
the aerial - one going down to the front of the house and the other to
the back. Would this need some fancy splitter or something or could
the two coax leads simply be wired into the same aerial. (I guess
there's also the option of having two separate aerials but that seems a
bit over the top.)

In case it's relevant, I get pretty decent stereo reception already
with one of the receivers (its a hi-fi tuner component) even with the
T-shaped bit of wire that came with it, so I reckon I'm in a reasonably
strong signal areas. The other receiver gets weaker reception usually,
but I think that is partly to do with there being fewer options in
arranging its 'bit of wire' optimally because of how the room is
organised. The latter would I think particularly benefit from a proper
aerial but it would be a shame not to make use of it for the other
receiver too.

Thanks.

Ian

wrote:
Seeing the other thread on FM and aerials has reminded me about
something I've been meaning to find out about.

I would like to have a proper FM aerial installed on the roof. The
thing is that there are two receivers that I would like to connect it
to. One is in the lounge at the front of the house and the other is in
the dining room at the back. One option would be to have the coax
coming down from the aerial, eirther at the front or the back of the
house, bring it into the house and then split it somehow. I'd rather
avoid this option to minimise internal disruption. I was wondering
instead how feasible it would be to have two separate wires coming from
the aerial - one going down to the front of the house and the other to
the back. Would this need some fancy splitter or something

Yes, a good quality low loss spitter. www.maplin.co.uk code: QQ69A


or could
the two coax leads simply be wired into the same aerial.


NO ! Certainly not, you cannot parallel up RF in the same way as 50Hz lekky
:-) You have to use a proper RF splitter to avoid mismatches and reflections
within the cables.

If the signal is weak (not a problem by the sound of your description) you
should use an active splitter, or an amplifier in line *before* a passive
splitter. Have a sift in the Maplins site. Anything that covers the frequency
range of FM (88-108 MHz) will be suitable.

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

On 10 May 2005 15:29:41 -0700, wrote:

Seeing the other thread on FM and aerials has reminded me about
something I've been meaning to find out about.

I would like to have a proper FM aerial installed on the roof. The
thing is that there are two receivers that I would like to connect it
to. One is in the lounge at the front of the house and the other is in
the dining room at the back. One option would be to have the coax
coming down from the aerial, eirther at the front or the back of the
house, bring it into the house and then split it somehow. I'd rather
avoid this option to minimise internal disruption. I was wondering
instead how feasible it would be to have two separate wires coming from
the aerial - one going down to the front of the house and the other to
the back. Would this need some fancy splitter or something or could
the two coax leads simply be wired into the same aerial. (I guess
there's also the option of having two separate aerials but that seems a
bit over the top.)

If you simply wire two cables in to the aerial you'll lose a lot of
signal. Depending on the lengths of the cable, if you unplug one
receiver you might lose reception on the other (an open-circuit cable
of a certain length wired across another might act as a
short-circuit).

You can buy a splitter to fit near the aerial, to feed two cables, but
you obviously have to make sure it's quite waterproof (unless you live
somewhere with no rain).

You will lose a bit of signal with a splitter, but probably a lot less
than you would by simply wiring the two cables together (and it would
be tricky physically to get two cables into the connection block in
the aerial!).

--
Frank Erskine
Sunderland

Mark Carver wrote:


Yes, a good quality low loss spitter. www.maplin.co.uk code: QQ69A

That will do nicely, but make sure you put it in a nice waterproof mast
mounting box. CPC do those (and while you are at it you may as well
order the splitter fromthem since they will probably be cheaper for that
as well)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Mark Carver wrote:


Yes, a good quality low loss spitter. www.maplin.co.uk code: QQ69A


That will do nicely, but make sure you put it in a nice waterproof mast
mounting box. CPC do those (and while you are at it you may as well
order the splitter fromthem since they will probably be cheaper for that
as well)

Indeed. In fact they do a mast mounting outdoor splitter for 8.20 inc VAT (+£5
handling if the order's less than £30)

http://cpc.farnell.com/jsp/endecaSea...AFCS1000&N=411


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

Thanks to all who replied. It was all very helpful information.

Ian

In case it's relevant, I get pretty decent stereo reception already
with one of the receivers (its a hi-fi tuner component) even with the
T-shaped bit of wire that came with it, so I reckon I'm in a reasonably
strong signal areas. The other receiver gets weaker reception usually,
but I think that is partly to do with there being fewer options in
arranging its 'bit of wire' optimally because of how the room is
organised. The latter would I think particularly benefit from a proper
aerial but it would be a shame not to make use of it for the other
receiver too.


You'll lose around 3.5 odd dB with a splitter, that is approximately
half power. If your signals are good at the moment then I expect that
you should be fine afterwards. Suppose if your going to do it then try
and see. If your getting a rigger in then ask him to bring a splitter
and an aerial so if the split results in unacceptable loss, then he can
add on another aerial.
--
Tony Sayer

Mark Carver wrote:

Indeed. In fact they do a mast mounting outdoor splitter for 8.20 inc
VAT (+£5 handling if the order's less than £30)

http://cpc.farnell.com/jsp/endecaSea...AFCS1000&N=411

Not looked inside one of those for years, so they may have changed, but
the last anti-ference one I saw was basically an inductive splitter PCB
in a waterproof box, but there was no screening. This would not be so
good for digital TV signals where impulse inteference can be a problem.

http://cpc.farnell.com/jsp/endecaSea...=AP00648&N=411

May be a better bet...

They used to do a plain mast mounting box that would take one of the
metal bodied splitters you linked to before - but I can't seem to find
it in the (useless) online search!

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Mark Carver wrote:

Indeed. In fact they do a mast mounting outdoor splitter for 8.20 inc
VAT (+£5 handling if the order's less than £30)

http://cpc.farnell.com/jsp/endecaSea...AFCS1000&N=411


Not looked inside one of those for years, so they may have changed, but
the last anti-ference one I saw was basically an inductive splitter PCB
in a waterproof box, but there was no screening. This would not be so
good for digital TV signals where impulse inteference can be a problem.

http://cpc.farnell.com/jsp/endecaSea...=AP00648&N=411

May be a better bet...

They used to do a plain mast mounting box that would take one of the
metal bodied splitters you linked to before - but I can't seem to find
it in the (useless) online search!

I've got Triax ones that are screened. The modern versions have F-Type
connections.

http://www.triax.dk/ifs/files/triax/...d/Wideband.jsp

Not sure who stocks them in the UK, Taylor Bros of Oldham probably.
(another useless website, but a very helpful firm)


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

Mark Carver wrote:

Not looked inside one of those for years, so they may have changed,
but the last anti-ference one I saw was basically an inductive
splitter PCB in a waterproof box, but there was no screening. This
would not be so good for digital TV signals where impulse inteference
can be a problem.

http://cpc.farnell.com/jsp/endecaSea...=AP00648&N=411

May be a better bet...

They used to do a plain mast mounting box that would take one of the
metal bodied splitters you linked to before - but I can't seem to find
it in the (useless) online search!


I've got Triax ones that are screened. The modern versions have F-Type
connections.

http://www.triax.dk/ifs/files/triax/...d/Wideband.jsp


Not sure who stocks them in the UK, Taylor Bros of Oldham probably.
(another useless website, but a very helpful firm)

CPC have them (the link I posted above was for a Triax one - although I
just noticed I actually posted the link for a switch and not a splitter
- but they have them as well)

(it was the anti-ference one that *may* not be screened)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:

Mark Carver wrote:


Yes, a good quality low loss spitter. www.maplin.co.uk code: QQ69A


That will do nicely, but make sure you put it in a nice waterproof mast
mounting box. CPC do those (and while you are at it you may as well
order the splitter fromthem since they will probably be cheaper for that
as well)


I have never regretted bringing both aerials into a lab gear amplifier
that gives about 10dB gain and takes 10 cables all over the house
carrying TV and FM signals eto wall sockets..

In article , The Natural
Philosopher writes
John Rumm wrote:

Mark Carver wrote:


Yes, a good quality low loss spitter. www.maplin.co.uk code: QQ69A


That will do nicely, but make sure you put it in a nice waterproof mast
mounting box. CPC do those (and while you are at it you may as well
order the splitter fromthem since they will probably be cheaper for that
as well)


I have never regretted bringing both aerials into a lab gear amplifier
that gives about 10dB gain and takes 10 cables all over the house
carrying TV and FM signals eto wall sockets..

Yes and that is a very sensible option. But putting an amp on a TV
aerial to split it for FM isn't such a good idea. In fact avoid
amplifiers unless they are distribution ones.

Front end overload by out of band signals is the reason, TETRA for one
for example!....
--
Tony Sayer

tony sayer wrote:

In article , The Natural
Philosopher writes

John Rumm wrote:


Mark Carver wrote:



Yes, a good quality low loss spitter. www.maplin.co.uk code: QQ69A


That will do nicely, but make sure you put it in a nice waterproof mast
mounting box. CPC do those (and while you are at it you may as well
order the splitter fromthem since they will probably be cheaper for that
as well)



I have never regretted bringing both aerials into a lab gear amplifier
that gives about 10dB gain and takes 10 cables all over the house
carrying TV and FM signals eto wall sockets..


Yes and that is a very sensible option. But putting an amp on a TV
aerial to split it for FM isn't such a good idea. In fact avoid
amplifiers unless they are distribution ones.

Front end overload by out of band signals is the reason, TETRA for one
for example!....

That Labgear you recommended me Tony, has been flawless throughout.

Best piece of advice ever.

You can get splitting devices to run two receivers from one aerial in most
dealers. I believe Argos may have them as well. They're not fancy. They're
just small boxes with a few coils and capacitors inside that make sure the
signal is divided between the two or more receivers efficiently without any
reflected signals getting in the way.

Two separate cables from the one aerial is incorrect and would not give as
good results as a proper splitter. It'd also be a waste of cable.

If you're in London, make sure the aerial is mounted horizontally and
pointed at Wrotham where the transmitter is. Phone the BBC Engineering
Department for the bearing and for general advice.

If this is too much, you could always go the whole hog and get D.A.B.

Nemo

wrote in message
oups.com...
Seeing the other thread on FM and aerials has reminded me about
something I've been meaning to find out about.

I would like to have a proper FM aerial installed on the roof. The
thing is that there are two receivers that I would like to connect it
to. One is in the lounge at the front of the house and the other is in
the dining room at the back. One option would be to have the coax
coming down from the aerial, eirther at the front or the back of the
house, bring it into the house and then split it somehow. I'd rather
avoid this option to minimise internal disruption. I was wondering
instead how feasible it would be to have two separate wires coming from
the aerial - one going down to the front of the house and the other to
the back. Would this need some fancy splitter or something or could
the two coax leads simply be wired into the same aerial. (I guess
there's also the option of having two separate aerials but that seems a
bit over the top.)

In case it's relevant, I get pretty decent stereo reception already
with one of the receivers (its a hi-fi tuner component) even with the
T-shaped bit of wire that came with it, so I reckon I'm in a reasonably
strong signal areas. The other receiver gets weaker reception usually,
but I think that is partly to do with there being fewer options in
arranging its 'bit of wire' optimally because of how the room is
organised. The latter would I think particularly benefit from a proper
aerial but it would be a shame not to make use of it for the other
receiver too.

Thanks.

Ian

nemo wrote:


If you're in London, make sure the aerial is mounted horizontally and
pointed at Wrotham where the transmitter is. Phone the BBC Engineering
Department for the bearing and for general advice.

Be aware that that only transmits BBC stations and Classic FM, most of
London's local stations, in addition to 'filler' services of R1-4 and Classic
are transmitted from either Croydon or Crystal Palace. The latter national
services from CP are vertical polarization only, the locals (and Wrotham) are
mixed polz.


If this is too much, you could always go the whole hog and get D.A.B.

No good for serious quality listening I afraid, but it will get you extra
stations not available on FM.

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

In article , nemo
writes
You can get splitting devices to run two receivers from one aerial in most
dealers. I believe Argos may have them as well. They're not fancy. They're
just small boxes with a few coils and capacitors inside that make sure the
signal is divided between the two or more receivers efficiently without any
reflected signals getting in the way.

Two separate cables from the one aerial is incorrect and would not give as
good results as a proper splitter. It'd also be a waste of cable.

If you're in London, make sure the aerial is mounted horizontally and
pointed at Wrotham where the transmitter is.


Not quite. Wrotham transmits Mixed polarisation but you might find it
simpler to mount your aerial horizontally. If your in parts of South
London, Crystal palace may give you better results.

Phone the BBC Engineering
Department for the bearing and for general advice.

If this is too much, you could always go the whole hog and get D.A.B.

Not if your talking about hi-fi reception;(....

--
Tony Sayer

In article ,
tony sayer wrote:
If you're in London, make sure the aerial is mounted horizontally and
pointed at Wrotham where the transmitter is.

Not quite. Wrotham transmits Mixed polarisation but you might find it
simpler to mount your aerial horizontally. If your in parts of South
London, Crystal palace may give you better results.

Absolutely. The BBC national stations from Wrotham are terrible in this
part of S London due to the hills in the way. Driving down Trinity Road
where it crosses Wandsworth Common in a traffic jam where it inches
forward results in near total cancellation of an R4 signal at times due to
extreme multipath. My current car uses diversity reception - it has two
aerials and selects the best one - but is still not perfect. The 'fill in'
transmitter at CP cures this problem totally.

John Birt when DG of the BBC used to live just off this road in the
'Toastrack'. There was no external FM aerial on his house, but a standard
UHF TV one. After a Feedback discussion on general FM reception problems I
wrote to them saying that either he never listened to BBC FM radio, had
cloth ears, or had a line feed. I have an 8 element yagi for FM on my
house and still had problems with Wrotham. A short time later we got a
fill in transmitter. ;-)

--
*The older you get, the better you realize you were.

Dave Plowman London SW
To e-mail, change noise into sound.