Interference bursts
 

Hello

I recently moved house and am having a problem with some interference
which cuts in in bursts across most of the airband. There is no
regularity to it nor can I really work out what is causing it, and I
was hoping someone on here may recognise it or would be able to help
me through try to get rid of it. I've posted two mp3s, in case they
might help, however I can't post an example of this with a
transmission on when it it more noticable:

http://www.reevery.net/interference/2.mp3
http://www.reevery.net/interference/3.mp3

My equipment is a GRE PSR-282 and the interference occurs with my
short telescopic aerial and my loft-mounted discone. In case it helps,
I live about 500m from a TV repeater, which is 12kW and pointing
almost in the opposite direction. The nearest mobile telephone mast is
about 1km away. There is a TV aerial and a satellite dish on the side
of my building but I would have thought any interference from anything
TV would be continuous.

Would any of these be a factor, and if so do you think an airband
filter might get rid of this? It's definitely something local as I had
no problems at my previous address, and it sounds like it could be a
data pulse. Any help would be greatly appreciated!

Thanks

Matthew

Interference bursts
 

link dont appear to work?

not central heating ignitor is it?
thats the usual culprit of wideband rasping noises at very random intervals?

mike

wrote in message
oups.com...
Hello

I recently moved house and am having a problem with some interference
which cuts in in bursts across most of the airband. There is no
regularity to it nor can I really work out what is causing it, and I
was hoping someone on here may recognise it or would be able to help
me through try to get rid of it. I've posted two mp3s, in case they
might help, however I can't post an example of this with a
transmission on when it it more noticable:

http://www.reevery.net/interference/2.mp3
http://www.reevery.net/interference/3.mp3

My equipment is a GRE PSR-282 and the interference occurs with my
short telescopic aerial and my loft-mounted discone. In case it helps,
I live about 500m from a TV repeater, which is 12kW and pointing
almost in the opposite direction. The nearest mobile telephone mast is
about 1km away. There is a TV aerial and a satellite dish on the side
of my building but I would have thought any interference from anything
TV would be continuous.

Would any of these be a factor, and if so do you think an airband
filter might get rid of this? It's definitely something local as I had
no problems at my previous address, and it sounds like it could be a
data pulse. Any help would be greatly appreciated!

Thanks

Matthew

Interference bursts
 

wrote in message
oups.com...
Hello

I recently moved house and am having a problem with some interference
which cuts in in bursts across most of the airband.

Airband being about 150 MHz?

There is no
regularity to it nor can I really work out what is causing it, and I
was hoping someone on here may recognise it or would be able to help
me through try to get rid of it. I've posted two mp3s, in case they
might help, however I can't post an example of this with a
transmission on when it it more noticable:

http://www.reevery.net/interference/2.mp3
http://www.reevery.net/interference/3.mp3

Interesting. Sounds like a QAM, QPSK, or PSK data
signal.


My equipment is a GRE PSR-282 and the interference occurs with my
short telescopic aerial and my loft-mounted discone. In case it helps,
I live about 500m from a TV repeater, which is 12kW and pointing
almost in the opposite direction. The nearest mobile telephone mast is
about 1km away. There is a TV aerial and a satellite dish on the side
of my building but I would have thought any interference from anything
TV would be continuous.

Right. All of those should be continuous.
Maybe the TV repeater also has a control data link?


Would any of these be a factor, and if so do you think an airband
filter might get rid of this? It's definitely something local as I had
no problems at my previous address, and it sounds like it could be a
data pulse. Any help would be greatly appreciated!

Thanks

Matthew


Hmm. I see your receiver is portable. Maybe walk or drive
around the area and see if the signal strength varies.
Maybe try a directional antenna in order to locate the source.

--
rb

Interference bursts
 

On 21 Mar, 03:35, "Ron Baker, Pluralitas!"
wrote:
Airband being about 150 MHz?

Approximately. I'm mainly interested in the 118 to 138 section and it
seems to be stronger in the 130s.

Hmm. I see your receiver is portable. Maybe walk or drive
around the area and see if the signal strength varies.
Maybe try a directional antenna in order to locate the source.

Sounds like a plan. I don't have a directional antenna but I'll have a
prowl round the area over the next few days and see where it's
strongest. If it sounds like PSK etc then I guess it could be a
neighbour's WiFi, I doubt it will be the repeater having a data feed
but I'll wonder over that way and have a listen. I was slightly
inaccurate above - the repeater is 12W and not 12kW.

Interference bursts
 

wrote in message
ups.com...
On 21 Mar, 03:35, "Ron Baker, Pluralitas!"
wrote:
Airband being about 150 MHz?

Approximately. I'm mainly interested in the 118 to 138 section and it
seems to be stronger in the 130s.

Hmm. I see your receiver is portable. Maybe walk or drive
around the area and see if the signal strength varies.
Maybe try a directional antenna in order to locate the source.

Sounds like a plan. I don't have a directional antenna but I'll have a
prowl round the area over the next few days and see where it's

Cool. I'd be curious to hear what you find.

strongest. If it sounds like PSK etc then I guess it could be a
neighbour's WiFi, I doubt it will be the repeater having a data feed
but I'll wonder over that way and have a listen. I was slightly
inaccurate above - the repeater is 12W and not 12kW.

You were only 30 dB off. :)

--
rb

Interference bursts
 

Ron Baker, Pluralitas! wrote:
Hmm. I see your receiver is portable. Maybe walk or drive
around the area and see if the signal strength varies.
Maybe try a directional antenna in order to locate the source.

Well, I've done a bit of driving around the area, ableit with the whip
on the antenna. I think I've traced the source to a number of antennae
on top of a nearby tower block. Parked underneath it there is very
little signal, however within direct sight of these antennae there is
a continuous high-pitched tone. As I move further away from this in
any direction this gets weaker and eventually peters out. The broken
sound I recorded still exists over most of the region when the
continuous tone is unnoticeable.

I'm going to put the problems down to something on top of this block.
There are mobile phone transmitters on there, that I know, and another
long whip which could be UHF or VHF. I haven't looked into what effect
this is having on FM or AM radio so I will have another trip up there
soon. However it doesn't affect me from the flat. I also made a point
of driving near a number of mobile transmitters and they don't have an
effect on the scanner.

I've got an airband filter on order, hopefully this might clear up
some of the noise but whatever it is I guess won't be completely
legitimate...

Interference bursts
 

wrote in message
oups.com...
Ron Baker, Pluralitas! wrote:
Hmm. I see your receiver is portable. Maybe walk or drive
around the area and see if the signal strength varies.
Maybe try a directional antenna in order to locate the source.

Well, I've done a bit of driving around the area, ableit with the whip
on the antenna. I think I've traced the source to a number of antennae
on top of a nearby tower block. Parked underneath it there is very
little signal, however within direct sight of these antennae there is
a continuous high-pitched tone. As I move further away from this in
any direction this gets weaker and eventually peters out. The broken
sound I recorded still exists over most of the region when the
continuous tone is unnoticeable.

I wonder if they have the same source then.


I'm going to put the problems down to something on top of this block.
There are mobile phone transmitters on there, that I know, and another
long whip which could be UHF or VHF. I haven't looked into what effect
this is having on FM or AM radio so I will have another trip up there
soon. However it doesn't affect me from the flat. I also made a point
of driving near a number of mobile transmitters and they don't have an
effect on the scanner.

It's good to eliminate possibilities too.


I've got an airband filter on order, hopefully this might clear up
some of the noise but whatever it is I guess won't be completely
legitimate...


If it it an image response by your receiver that should
work.

A dipole is a directional antenna. Not as directional as some
but a dipole is easy to make. At 130 MHz a half wave dipole
would be a little more than a meter long.
But I hope the filter works for you.

--
rb