In article ,
Mark Carver wrote:
Don Pearce wrote:

That should do nicely. I know DAB is supposed to use mulitpath signals
actively, but I did some simulations ages ago, and you still get much
better performance by choosing the nearest transmitter and aiming a
directional antenna at it.

As an aside. I've always used my vertical Band II (aka FM band) dipole
for DAB, it works very well, pulling in distant muxes from miles away.
I lashed up a properly cut dipole for DAB (225 MHz), and stuck it
nearby. It was no better (or worse) than the Band II.

I know that theory - but had no success with it. My 4 element band III
works fine for FM when horizontal but is dreadful on DAB - and I'm in a
strong signal area. Swing it vertical and the DAB is fine - but FM noisy.
It's feeding a DA which feeds four tuners. The aerial is easy to get at as
it's accessible from my roof terrace and has clear line of sight to the CP
and Croydon transmitters - both of which are close to the same 'line'.
Removing the DA and plugging in the aerial direct makes no difference.

Of course the Band II dipole is half wave within its band, but full
wave(ish) in the DAB band.

Yes. Yet in my case a simple omni DAB aerial diplexed into the horizontal
FM one works fine - although I'd love to know why the vertical aerial
doesn't for FM.

I split the feed passively between my FM tuner in the living room, and
DAB 'Midi' system in the kitchen.

I have a second FM aerial mounted at the top of the house - horizontal -
which feeds just the one combined FM and DAB tuner. That works well on
both.

--
*A conclusion is the place where you got tired of thinking *

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

"Dave Plowman (News)" wrote in message
...
I know that theory - but had no success with it. My 4 element band III
works fine for FM when horizontal but is dreadful on DAB
The latter being as you'd expect.

I must say that DAB aerials work very badly on FM. But FM aerials work OK on
DAB.

But if the FM aerial has a balun it tends to be crap on DAB. If the FM
aerial is a single folded dipole with a balun it is really crap for DAB.

This is based on casual practical experience. I haven't bothered to do
tests.

Bill

In article ,
Bill Wright wrote:

"Dave Plowman (News)" wrote in message
...
I know that theory - but had no success with it. My 4 element band III
works fine for FM when horizontal but is dreadful on DAB
The latter being as you'd expect.

Yes.

I must say that DAB aerials work very badly on FM. But FM aerials work
OK on DAB.

Yes too.

But if the FM aerial has a balun it tends to be crap on DAB. If the FM
aerial is a single folded dipole with a balun it is really crap for DAB.

Ah. It does indeed have a balun. However, it works ok when vertical for
DAB but not FM. That's what is confusing me. And I don't mean DXing - just
local stations.

This is based on casual practical experience. I haven't bothered to do
tests.

RF is and will remain a closed book to me. ;-)

--
*Age is a very high price to pay for maturity.

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

"Bill Wright" wrote in message
...

"Dave Plowman (News)" wrote in message
...
I know that theory - but had no success with it. My 4 element band
III
works fine for FM when horizontal but is dreadful on DAB
The latter being as you'd expect.

I must say that DAB aerials work very badly on FM. But FM aerials work
OK on DAB.

But if the FM aerial has a balun it tends to be crap on DAB. If the FM
aerial is a single folded dipole with a balun it is really crap for
DAB.

This is based on casual practical experience. I haven't bothered to do
tests.

Bill



What it comes down to Bill is that a non-yagi aerial is essentially a
piece of wire in the air - albeit high up in the air. There may be a
mismatch at the aerial end which could cause a couple of dB loss, but
the offset of the increased signal will far outweigh that loss.

Essentially any vertical aerial at roof height will give a so much
bigger signal that everyone will think it is brilliant, even if
technically it is not!


--
Woody

harrogate three at ntlworld dot com

"Woody" wrote in message
...
What it comes down to Bill is that a non-yagi aerial is essentially a
piece of wire in the air - albeit high up in the air. There may be a
mismatch at the aerial end which could cause a couple of dB loss, but the
offset of the increased signal will far outweigh that loss.

Essentially any vertical aerial at roof height will give a so much bigger
signal that everyone will think it is brilliant, even if technically it is
not!

Yes. In general this is correct. I call it the 'motorbike' principle, after
the man on one of the estates who put his old motorbike on his neighbour's
flat roof and used it as a CB aerial.

Bill

On Wed, 6 Feb 2008 10:59:39 -0000,it is alleged that "Bill Wright"
spake thusly:


"Woody" wrote in message
...
What it comes down to Bill is that a non-yagi aerial is essentially a
piece of wire in the air - albeit high up in the air. There may be a
mismatch at the aerial end which could cause a couple of dB loss, but the
offset of the increased signal will far outweigh that loss.

Essentially any vertical aerial at roof height will give a so much bigger
signal that everyone will think it is brilliant, even if technically it is
not!

Yes. In general this is correct. I call it the 'motorbike' principle, after
the man on one of the estates who put his old motorbike on his neighbour's
flat roof and used it as a CB aerial.

Bill


Now _that_ would have made a lovely photo for your site :-)

--
_
( ) ASCII ribbon campaign against html e-mail
X and usenet posts
/ \

"Chip" wrote in message
...
On Wed, 6 Feb 2008 10:59:39 -0000,it is alleged that "Bill Wright"
spake thusly:


"Woody" wrote in message
...
What it comes down to Bill is that a non-yagi aerial is essentially a
piece of wire in the air - albeit high up in the air. There may be a
mismatch at the aerial end which could cause a couple of dB loss, but
the
offset of the increased signal will far outweigh that loss.

Essentially any vertical aerial at roof height will give a so much
bigger
signal that everyone will think it is brilliant, even if technically it
is
not!

Yes. In general this is correct. I call it the 'motorbike' principle,
after
the man on one of the estates who put his old motorbike on his neighbour's
flat roof and used it as a CB aerial.

Bill


Now _that_ would have made a lovely photo for your site :-)

Yes, and I had a photo of it but it was pre-digital and I can't find it.

Bill

On Wed, 6 Feb 2008 19:43:54 -0000, "Bill Wright"
wrote:


"Chip" wrote in message
et-News.net...
On Wed, 6 Feb 2008 10:59:39 -0000,it is alleged that "Bill Wright"
spake thusly:


"Woody" wrote in message
...
What it comes down to Bill is that a non-yagi aerial is essentially a
piece of wire in the air - albeit high up in the air. There may be a
mismatch at the aerial end which could cause a couple of dB loss, but
the
offset of the increased signal will far outweigh that loss.

Essentially any vertical aerial at roof height will give a so much
bigger
signal that everyone will think it is brilliant, even if technically it
is
not!

Yes. In general this is correct. I call it the 'motorbike' principle,
after
the man on one of the estates who put his old motorbike on his neighbour's
flat roof and used it as a CB aerial.

Bill


Now _that_ would have made a lovely photo for your site :-)

Yes, and I had a photo of it but it was pre-digital and I can't find it.

It wasn't an "Ariel" bike, was it?

:-)
--
Frank Erskine

On Tue, 22 Jan 2008 13:57:31 +0000, Paul Martin wrote:

In article ,
Bill Wright wrote:

I must say that DAB aerials work very badly on FM. But FM aerials
work OK on DAB.

But if the FM aerial has a balun it tends to be crap on DAB. If the FM
aerial is a single folded dipole with a balun it is really crap for DAB.

I'd guess that the folded dipole will be resonant at 3x the frequency
it's cut for, whereas the simple dipole has resonance at 2x, in analogy
with open and closed organ pipes.

No, it is still 3x for an open dipole (and 5x, 7x etc.)

d

--
Pearce Consulting
http://www.pearce.uk.com