On 12/02/2018 16:52, Andrew wrote:
On 11/02/2018 20:59, Don Pearce wrote:
On Sun, 11 Feb 2018 20:18:56 +0000, Andrew
wrote:

How do these work if only a 6 inch stub sticks out of the roof ?

To get a decent FM signal indoors I need a dipole of some sort
that is about 59 inches long, plus reflector and director.

I ask this because I am getting interference on 88.50 Mhz
from Rowridge, but not all the time. Earlier today it
was bad, but the other BBC FM stations were not affected.

When I drove into town, FM R2 on my car radio was fine,
but I don't know what transmitter it is picking up. No
interference at all. Strange.

I am midway between IOW and Wrotham.

Poorly is how they perform. Much better to have a telescopic antenna
that rises to about a quarter wave (75 cm). If you live in a poor
signal area with interfering transmitters coming in, a directional
antenna is the only answer, and you can't have that on a car.

How about DAB? That works 100% better than FM in a car.

d

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DAB is rubbish where I live, and I only want to find out why
88.50 (R2) from the IOW is regularly plagued with much more
hissing than usual, plus a buzzing and faint crackling too.
(But R1,3 and 4 were not afflicted the same way). It's
indoors FM reception that am interested in. I have a 3-element
fm aerial in the loft pointing at the IOW.

Awful yesterday, but today it is fine. It was only when I
went out at 2PM to check out Currys instant sale that I
noticed that my car radio picked up R2 FM without any
interference at all.



Somebody local with a badly suppressed piece of equipment?

--
Graeme Wall
This account not read.

In article ,
Andrew wrote:
DAB is rubbish where I live, and I only want to find out why
88.50 (R2) from the IOW is regularly plagued with much more
hissing than usual, plus a buzzing and faint crackling too.
(But R1,3 and 4 were not afflicted the same way). It's
indoors FM reception that am interested in. I have a 3-element
fm aerial in the loft pointing at the IOW.

Thing is that being a different frequency, different things can effect
only that one.

Think you've already been given the best advice. The biggest aerial you
can manage outside, with a decent quality downlead.

--
*Reality is a crutch for people who can't handle drugs.

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

On 12/02/2018 17:56, Graeme Wall wrote:
On 12/02/2018 16:52, Andrew wrote:
On 11/02/2018 20:59, Don Pearce wrote:
On Sun, 11 Feb 2018 20:18:56 +0000, Andrew
wrote:

How do these work if only a 6 inch stub sticks out of the roof ?

To get a decent FM signal indoors I need a dipole of some sort
that is about 59 inches long, plus reflector and director.

I ask this because I am getting interference on 88.50 Mhz
from Rowridge, but not all the time. Earlier today it
was bad, but the other BBC FM stations were not affected.

When I drove into town, FM R2 on my car radio was fine,
but I don't know what transmitter it is picking up. No
interference at all. Strange.

I am midway between IOW and Wrotham.

Poorly is how they perform. Much better to have a telescopic antenna
that rises to about a quarter wave (75 cm). If you live in a poor
signal area with interfering transmitters coming in, a directional
antenna is the only answer, and you can't have that on a car.

How about DAB? That works 100% better than FM in a car.

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


DAB is rubbish where I live, and I only want to find out why
88.50 (R2) from the IOW is regularly plagued with much more
hissing than usual, plus a buzzing and faint crackling too.
(But R1,3 and 4 were not afflicted the same way). It's
indoors FM reception that am interested in. I have a 3-element
fm aerial in the loft pointing at the IOW.

Awful yesterday, but today it is fine. It was only when I
went out at 2PM to check out Currys instant sale that I
noticed that my car radio picked up R2 FM without any
interference at all.



Somebody local with a badly suppressed piece of equipment?


except that it clobbers 88.50 Mhz, but not the other three
BBC FM channels from the same xmitter.

Aha :-

http://www.bbc.co.uk/reception/engineeringnews/item5

http://www.bbc.co.uk/receptionsearch

However, by entering "reception problems" into the search
box on the BBC homepage, you don't get any link to this
at all !!. had to use Mr Google to find it.

On 12/02/2018 19:12, Andrew wrote:
On 12/02/2018 17:56, Graeme Wall wrote:
On 12/02/2018 16:52, Andrew wrote:
On 11/02/2018 20:59, Don Pearce wrote:
On Sun, 11 Feb 2018 20:18:56 +0000, Andrew
wrote:

How do these work if only a 6 inch stub sticks out of the roof ?

To get a decent FM signal indoors I need a dipole of some sort
that is about 59 inches long, plus reflector and director.

I ask this because I am getting interference on 88.50 Mhz
from Rowridge, but not all the time. Earlier today it
was bad, but the other BBC FM stations were not affected.

When I drove into town, FM R2 on my car radio was fine,
but I don't know what transmitter it is picking up. No
interference at all. Strange.

I am midway between IOW and Wrotham.

Poorly is how they perform. Much better to have a telescopic antenna
that rises to about a quarter wave (75 cm). If you live in a poor
signal area with interfering transmitters coming in, a directional
antenna is the only answer, and you can't have that on a car.

How about DAB? That works 100% better than FM in a car.

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


DAB is rubbish where I live, and I only want to find out why
88.50 (R2) from the IOW is regularly plagued with much more
hissing than usual, plus a buzzing and faint crackling too.
(But R1,3 and 4 were not afflicted the same way). It's
indoors FM reception that am interested in. I have a 3-element
fm aerial in the loft pointing at the IOW.

Awful yesterday, but today it is fine. It was only when I
went out at 2PM to check out Currys instant sale that I
noticed that my car radio picked up R2 FM without any
interference at all.



Somebody local with a badly suppressed piece of equipment?


except that it clobbers 88.50 Mhz, but not the other three
BBC FM channels from the same xmitter.

Aha :-

http://www.bbc.co.uk/reception/engineeringnews/item5

http://www.bbc.co.uk/receptionsearch

However, by entering "reception problems" into the search
box on the BBC homepage, you don't get any link to this
at all !!.Â* had to use Mr Google to find it.

That doesn't surprise me.

--
Graeme Wall
This account not read.

Graeme Wall

-----------


DAB is rubbish where I live, and I only want to find out why
88.50 (R2) from the IOW is regularly plagued with much more
hissing than usual, plus a buzzing and faint crackling too.
(But R1,3 and 4 were not afflicted the same way). It's
indoors FM reception that am interested in. I have a 3-element
fm aerial in the loft pointing at the IOW.

Awful yesterday, but today it is fine. It was only when I
went out at 2PM to check out Currys instant sale that I
noticed that my car radio picked up R2 FM without any
interference at all.



Somebody local with a badly suppressed piece of equipment?


** Very handy to have a portable AM/FM radio to use track down such local sources.

Assuming the portable picks up the same noises inside the OP's house, walking away from the house in different directions should indicate the direction of the interference.

The description fits noise typically made by High Voltage power insulators that are suffering corona when the air is humid or misting.

If the portable or car radio does NOT pick up the same noises when tuned to 88.5 MHz, then things get interesting.


..... Phil

Is that not what I just said?
I've often wondered why they don't add low power transmitters to telephone
cell masts.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Phil Allison" wrote in message
...
Brian Gaff wrote:

----------------


I think many of these are helically wound, and some have amps in them.
I've
often wondered how they can be good over such a wide bandwidth myself as
theoretically any wound component should have a narrow bandwidth or be
very
bad at picking much up at all.


** Helical winding makes a short whip antenna resonant and so resistive
across most of the FM band. The bandwidth is somewhat narrower than a
regular 1/4 wave and the output signal lower pretty much in proportion to
the length ratio.

Long range performance on stereo FM would be impossible were it not for
the use of high powered transmitters equipped high gain antennas.




.... Phil

Brian Gaff wrote:

------------------------

Is that not what I just said?


** No, it answers what you posted.

1. A helically wound ( flexible) antenna is made resonant on the band, not inductive.

2. The Q is slightly damped so covers +/- 10% from centre frequency OK.

3. Signal pickup is down by about the length ratio to a 1/4 wave whip.

4. Tiny Rx antennas work if you push enough watts into a big, high gain one at the Tx end - this is how we communicate with spacecraft near Pluto.


...... Phil




I think many of these are helically wound, and some have amps in them.
I've
often wondered how they can be good over such a wide bandwidth myself as
theoretically any wound component should have a narrow bandwidth or be
very
bad at picking much up at all.


** Helical winding makes a short whip antenna resonant and so resistive
across most of the FM band. The bandwidth is somewhat narrower than a
regular 1/4 wave and the output signal lower pretty much in proportion to
the length ratio.

Long range performance on stereo FM would be impossible were it not for
the use of high powered transmitters equipped high gain antennas.




.... Phil

In article , Andrew Andrew97d-
scribeth thus
How do these work if only a 6 inch stub sticks out of the roof ?

To get a decent FM signal indoors I need a dipole of some sort
that is about 59 inches long, plus reflector and director.

I ask this because I am getting interference on 88.50 Mhz
from Rowridge, but not all the time. Earlier today it
was bad, but the other BBC FM stations were not affected.

When I drove into town, FM R2 on my car radio was fine,
but I don't know what transmitter it is picking up. No
interference at all. Strange.

I am midway between IOW and Wrotham.

Ye canna screw the laws of Physics yer know whatever car stylists might
what;!.

I've got an Audi estate car thats got the radio aerial in the rear
windscreen its nowhere as good as a Quarter wave mag base aerial in the
middle of the roof. OK its sufficient for most users but its not ideal
but then again how many want an aerial in the middle of the roof;?.

As per the Bee sting aerial yes better but can be a bit directional
depending on how much of the car roof is available as a ground plane in
any direction;!..
--
Tony Sayer

In article , Don Pearce
scribeth thus
On Sun, 11 Feb 2018 20:18:56 +0000, Andrew
wrote:

How do these work if only a 6 inch stub sticks out of the roof ?

To get a decent FM signal indoors I need a dipole of some sort
that is about 59 inches long, plus reflector and director.

I ask this because I am getting interference on 88.50 Mhz
from Rowridge, but not all the time. Earlier today it
was bad, but the other BBC FM stations were not affected.

When I drove into town, FM R2 on my car radio was fine,
but I don't know what transmitter it is picking up. No
interference at all. Strange.

I am midway between IOW and Wrotham.

Poorly is how they perform. Much better to have a telescopic antenna
that rises to about a quarter wave (75 cm). If you live in a poor
signal area with interfering transmitters coming in, a directional
antenna is the only answer, and you can't have that on a car.

How about DAB? That works 100% better than FM in a car.

Depends where you and the serving transmitter are among other
things;!...

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


--
Tony Sayer

In article , Brian Gaff
scribeth thus
Is that not what I just said?
I've often wondered why they don't add low power transmitters to telephone
cell masts.
Brian

It would cost a lot of money to do and not work that well on FM, at least on DAB yes
you can do that , single frequency networks, but transmitting on DAB is very
expensive anyway

Due in part to the monopolistic way the system is set up and the bigger number of
transmitters needed at those frequencies..


https://radiotoday.co.uk/2018/02/ofc...to-connect-fm/

and


https://radiotoday.co.uk/2018/01/con...rice-increase/
--
Tony Sayer