FM Aerial installation Q's

[Colin Blackburn]

It's a possibility. There is a 12V DC supply to the house which I could utilise. Any particular name or brand I should look for?

Colin

[Dave Plowman]

I think many normal DAs also work from a 12 volt DC supply. You'd need to take the cover off, though. ;-)

[Dave Plowman]

Yes - it could also be intermoduation problems from the large amount of RF in this part of sauf lunnon.

But a much more clever than me engineer pal in Harrow had simlair findings. But some time ago - I'd guess things have moved on since then.

[tony sayer]

In article , Dave Plowman writes

Its far from Rocket science Dave. However I have heard that due to your location you do have problems with FM but not everyone is so afflicted!..

[tony sayer]

In article , Colin Blackburn writes

Well if you have strong signals then perhaps you can getaway with just passive splitting. Only real answer is to try it and see.

[Andy Hall]

I was thinking that you could use something like a Labgear CM7274 or an Antiference UX4. These are masthead amplifiers with 4 outputs which can go directly to your sockets and can be powered over the co-ax with 12v DC. Normally they are powered from a distribution amplifier run from the mains or a separate 12v power supply like the Labgear PSM112 - these need

[Colin Blackburn]

Thanks for the names and ideas (everyone else too.) I think I will initially wire in a splitter---I get a strong signal, hell I can see Pontock Pike from the bedroom window with a pair of binoculars---then look at masthead amplifiers and possibly DAs with fancy wiring!

Cheers,

Colin

[The Natural Philosopher]

Makes no difference.

The problem is to achieve reflectionless splitting. In real terms this can only be done with matched resistive pads on each end of every cable,. This is totally impractical - who is goindg to put 75ohm terminators in every socket in the hose that is not in use? AND that results in losses, degrading the signal anyway.

Distrubution amplifiers isolate each cable from all the others, That's what they are there for. Use them.

[tony sayer]

In article , Colin Blackburn writes

If you can see the Pike from your window then don't bother with an amp a splitter will do with those sort of levels around. Don't bother with a masthead type amp as it will overload and cause more grief than what its worth!..

[Colin Blackburn]

Er, that bit is easy. I only use one socket at a time and all the sockets are accessible. All I need to do is terminate every socket and then switch the cable to the TV for the terminator for the room I am using.

I have said elsewhere why I am not minded to use this route if at all possible. It is more impracticable for me than having a terminator in the unused sockets.

Colin

[Owain]

"Colin Blackburn" wrote | On the general theme of aerial installations is there a reasonable | way to wire in several aerial points off one aerial without a | distribution amplifier, ie just using a splitter or splitters. | Say I want four sockets, should I split near the aerial or run | a single co-ax as far as possible before splitting? There would | only ever be one socket in use at once but I can appreciate that | long 'stubs' may cause various problems on the line as a whole.

You could just wire your aerial to one central point with a socket, have the cables to the room sockets terminating there on plugs, and plug in whichever room is required. If you have a strong signal and use good quality connectors there should be negligible effect on the signal. If, subsequently, you want to try passive splitters or a distr. amp., the cabling is already in place.

Owain

[PJ]

On Fri, 19 Sep 2003 9:43:48 +0100, The Natural Philosopher wrote (in message ):

My clock radio is surprisingly good actually :)

If you go here:

and then click on the "Model 3" button on the left.

I've had it for a couple of days now and I'm becoming rather evangelical about it:)

I think it suits classical much better than rock/pop, but I listen to Radio 3 all the time so it suits me fine. There are still some classical shows on Radio 3.

Having really rather good sound quality at night is lovely. It can interfere with sex life however...

[PJ]

On Thu, 18 Sep 2003 21:50:12 +0100, harrogate wrote (in message ):

You'd like my clock radio :)

[stefek.zaba]

Probably a cheaper near-equivalent, but maybe the honest stuff. It sells at 25-30 quid the 100yd reel at not-taking-the-Micheal-on-price places.

CT125 is the next size up from CT100 - slightly bigger outer diameter, slightly lower attenuation losses over distance, more often used for distribution feeds in bigger installations (e.g. for piping sat TV signals or cable-TV feeds round a block of flats); there's CT167 and CT233 sizes which continue the trend upwards in diameter and lower losses. All of these more exotic sizes share the same design impedance as CT100 - 75 ohm; but because they're sold in much lower quantity than CT100, you pay a b-i-g price hike for them over the CT100 (a bit like the hike in 4mmsq mains cable compared to 2.5mmsq!). For a domestic installation with "normal" lengths of cabling, you don't need anything beyond CT100, and it gets harder - indeed impossible! - to get coax plugs and sockets to mount neatly to the larger sizes.

HTH, Stefek

[Andy Hall]

It might or might not be. CT100 has a defined construction and RF specification. Various other cables purport to be the same and may or may not be. Some of the cheap ones sold as satellite cable may have inferior screening or mechanical construction or may have worse than spec. losses at high frequencies.

Whether this particular cable is OK is hard to know. To be able to tell that,you would need to know the losses at various frequencies and compare them to the real thing and Maplin don't seem to publish that data. As a comparison, RS have a Raydex CT100 for £44 for 100m and CPC have one for £19.60 for 50m - i.e. almost twice the Maplin price. Both of these appear to follow the official specs.

This sounds like a copy of CT125, basically a lower loss cable. Again you would pay just under twice Maplin prices for the official stuff. The cable diameter is about 8mm rather than 6mm.

.andy

To email, substitute .nospam with .gl

[Andy Hall]

Even Ravel's Bolero??

.andy

To email, substitute .nospam with .gl

[Andy Hall]

-()

So do you think this is a fairly good product? I'm looking for a good quality bedside radio and also really only listen to classical content.

I am slightly concerned that there are no technical specs given, although a lot that are published are, admittedly, somewhat meaningless.

.andy

To email, substitute .nospam with .gl

[ignored]

In message , Andy Hall writes

tooooo much information!!!

you too huh?

:)

[tony sayer]

In article , PJ writes

That seems from the description on the Maplin site to be much the same thing and the price is about what I'd expect, though it can be got cheaper then that if you can find an aerial wholesaler. Could also try

[PJ]

On Sat, 20 Sep 2003 0:43:24 +0100, Andy Hall wrote (in message ):

Yes, I am very pleased with the Tivoli clock radio. In fact I bought it at the end of a surprisingly long search when which started a few months ago when I came to the realisation that I really like good quality sound at night before going to sleep.

I had been using a Roberts R9939 for ages, which is fine for the money but really limited in terms of reproducing music with any real detail.

The Tivoli clock radio has a stereo tuner and on the back is quite a range of outputs all from 1/8 stereo jacks. There is a mono output for a subwoofer, so you could run a comprehensive sound system from it!

I do use the stereo headphones socket occasionally on it, if there is something really good on the radio, but I find the single speaker on top of the unit to be quite excellent. Having the speaker on top gives an omnidirectional output which suits bedside listening very well.

The Tivoli does not sound particularly good when absolutely brand new, it takes a few days to "run in" but over that period the sound quality continues to improve in leaps and bounds. I find sometimes at night the quality can be so good it sort of takes me by surprise. For chamber music it can be really amazing capturing nuances etc. extremely vividly.

For some time I had been considering getting a second-hand mini system on ebay, before the Tivoli clock radio was introduced just in the last couple of weeks. The problem though with the mini system idea for me is that even a mini-system is a complicated thing to have in the bedroom IMHO, and I don't know where I'd put the speakers. Also the mini systems I've heard tend to be fine for rock/pop, but for classical the Tivoli is hugely superior I think.

Other things I looked at were the Pure radios and the Bose Acoustiwave. The Bose is lovely to look at but far too expensive, and I can't see the point in stereo by the bedside. I prefer the upward facing omnidirectional Tivoli. The Bose might be very good in a small office situation or something. The Pure radios didn't offer me very much because I don't feel any desire for the DAB stations.