Hello againThanks to Dave Plowman, Dave Stanton, Andy Hall, Lurch and others for illuminating me about the way my FM aerial works. I was actually "Thought Police" for that post, now I am "patrick j" which I'm hoping to settle on. I used to be "PJ" but there's another PJ so I can't be that.Anyway now to my next question which for those knowledgeable about FM (VHF) aerials will no doubt be screaminingly obvious :)I know that I am to point the aerial at the transmitter, but I want to be sure I have it the right way around.I've "borrowed" a 296x173 pixel jpeg from the Antiference web-site which shows the aerial along with an omnidirectional: is a three element aerial and the widest element is at one end, the narrowest at the other. The middle element is a bit more towards the narrowest element than it is the widest one. The dipole is immediately below the middle element.My feeling is that I should point the end with the narrowest element towards the transmitter. Is that right?The next issue is getting it actually pointing accurately at the transmitter. Swivelling it around until I get the best signal makes sense, but the tuner it will be plugged into is in my living room and the aerial is on the roof so it isn't the easiest of things to do.What I plan to do is to work out the where the transmitter is on the compass from my house using an ordinance survey map and then use compass to angle the aerial. Has anyone got a better way? I can't align it with other FM (VHF) aerials because there aren't any :)Today I have been up on the roof putting the big cables around the chimney to grasp the brackets to which the pole is attached. Great fun :)

I think that's better.....THe middle, unconnected element is part and parcel of the dipole sinceit is in line with it.Generally there is a larger space from dipole to reflector than dipoleto first director as you describe.Yes it is.For a three element antenna, pointing is not going to be at allcritical, so the compass will be good enough. Even if you are 30degrees off beam it won't make a huge difference and you ought to beable to do better than that. Another way is to work from a landmarkon the map...Is the VHF transmiiter that you want to use cosited with TV for yourarea? If so then just aim in the same general directionWith FM transmission, unless the signal is weak the tuner will notgive any or much hiss as you turn the antenna away from thetransmitter, so unless you have a signal meter in the tuner, itwouldn't be much use anyway.A professional installer would use a signal strength meter, althoughthese are mainly for UHF TV where antennas are much more directionalnormally and...

Which Direction for FM Aerial?

Apr 11, 2004 25 Replies

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patrick j 22 years ago

On Mon, 12 Apr 2004 10:41:19 +0100, Andy Luckman wrote (in message ):

That is most interesting. The aerial is up now, but I have some more tasks to perform on the roof in the coming months so I might redo the lashings in this manner. Fortunately I have used two brackets and two lashings so as long as I pick a day with little wind I can replace each lashing in turn.

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patrick j 22 years ago

On Mon, 12 Apr 2004 11:28:55 +0100, Set Square wrote (in message ):

It's amazing how much it does move. Your mention of it piqued my interest and I found this web-site:

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Andy Luckman 22 years ago

Try consulting the CAI list. Better than average chance of finding someone skilled.

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tony sayer 22 years ago

In article , Lurch writes

I don't think that cable has much say in what its used for;-()

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Dave Stanton 22 years ago

Known as a 'GPO SLICE' as invented by the GPO for telephone pole lashings.

Dave

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Dave Stanton 22 years ago

That should read 'GPO SPLICE', jeeez my spelling !

Dave And you were born knowing all about ms windows....??

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