Sometimes TV interference.

[Peter Jason]

Last year I had several month's of TV interference
on some channels, mainly pixelation but sometimes
"no signal". Worse on some channels.

Then, up to now, the interference has stopped, all
by itself,

I live in town opposite a large telecommunications
building, and here's a picture of it over my back
fence.....

https://postimg.cc/4mPR4WfM

Note the plethora of weird aerials on its roof
which might be causing the interference on my 2006
Sony wide-screen TV.

If the interference starts up again what do I do?
Are there special filters for this sort of thing,
and if not how should I frame a complaint?



..

 

[Phil Allison]

Peter Jason wrote:

Last year I had several month's of TV interference
on some channels, mainly pixelation but sometimes
"no signal". Worse on some channels.

Then, up to now, the interference has stopped, all
by itself,

I live in town opposite a large telecommunications
building, and here's a picture of it over my back
fence.....

https://postimg.cc/4mPR4WfM

Note the plethora of weird aerials on its roof
which might be causing the interference on my 2006
Sony wide-screen TV.

** Those are mobile phone ( cellular network ) antennas.

If the interference starts up again what do I do?

** FFS speak to your neighbours, see if they are experiencing the same thing.



..... Phil

Are there special filters for this sort of thing,

** No.

and if not how should I frame a complaint?

** With signatures from your neighbours.


..... Phil

 

[Look165]

First : check the shield of your antenna cable and the plugs.
Normally telecom use a separate frequency band and your TV has an AGC.
Me, I should contact a technician of this telecom center to see what can
be done.

Peter Jason a Êcrit le 20/02/2019 à 05:53 :

Last year I had several month's of TV interference
on some channels, mainly pixelation but sometimes
"no signal". Worse on some channels.

Then, up to now, the interference has stopped, all
by itself,

I live in town opposite a large telecommunications
building, and here's a picture of it over my back
fence.....

https://postimg.cc/4mPR4WfM

Note the plethora of weird aerials on its roof
which might be causing the interference on my 2006
Sony wide-screen TV.

If the interference starts up again what do I do?
Are there special filters for this sort of thing,
and if not how should I frame a complaint?



.

 

[John-Del]

On Tuesday, February 19, 2019 at 11:53:21 PM UTC-5, Peter Jason wrote:

Last year I had several month's of TV interference
on some channels, mainly pixelation but sometimes
"no signal". Worse on some channels.

Then, up to now, the interference has stopped, all
by itself,

I live in town opposite a large telecommunications
building, and here's a picture of it over my back
fence.....

https://postimg.cc/4mPR4WfM

Note the plethora of weird aerials on its roof
which might be causing the interference on my 2006
Sony wide-screen TV.

If the interference starts up again what do I do?
Are there special filters for this sort of thing,
and if not how should I frame a complaint?



.

Interference? I don't know how you can tell that with a digital tuner. Pixelation, drop outs, freezes, and no signal indications usually mean borderline signal to noise ratio.

Get a better antenna, add an amplifier, and carefully redirect it. If your TV has a signal level meter (unusual), you can use that. Many ATSC stand alone boxes did have a signal level utility which is helpful in seeing how much signal you have.

 

[Fox's Mercantile]

On 2/20/19 6:27 AM, John-Del wrote:
> Interference? I don't know how you can tell that with a digital tuner.

You can't.

It's like Hatlow's "They'll do it every time."
A bunch of neighbor's pointing at the local amateur radio guy.
Among other comments, "I hear he even interferes with Doc's
diathermy machine.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Phil Allison]

John-Del wrote:

Peter Jason wrote:
Last year I had several month's of TV interference
on some channels, mainly pixelation but sometimes
"no signal". Worse on some channels.

Then, up to now, the interference has stopped, all
by itself,

I live in town opposite a large telecommunications
building, and here's a picture of it over my back
fence.....

https://postimg.cc/4mPR4WfM

Note the plethora of weird aerials on its roof
which might be causing the interference on my 2006
Sony wide-screen TV.

If the interference starts up again what do I do?
Are there special filters for this sort of thing,
and if not how should I frame a complaint?






Interference? I don't know how you can tell that with a digital tuner.

** From the circumstances of course.

Pixelation, drop outs, freezes, and no signal indications usually mean
borderline signal to noise ratio.

** Or, if intermittent, are clear signs of in-band interference.

Get a better antenna, add an amplifier, and carefully redirect it.
If your TV has a signal level meter (unusual), you can use that.

** Mine normally shows over 90% readings for signal level and signal quality - but in the early evening some severe interference and drop outs ( "no signal" message displayed ) are experienced.

I reckon it is due to folk turning on their fluoro kitchen lights.


..... Phil

 

[whit3rd]

On Wednesday, February 20, 2019 at 4:27:40 AM UTC-8, John-Del wrote:

On Tuesday, February 19, 2019 at 11:53:21 PM UTC-5, Peter Jason wrote:
Last year I had several month's of TV interference...

I live in town opposite a large telecommunications
building

Interference? I don't know how you can tell that with a digital tuner. Pixelation, drop outs, freezes, and no signal indications usually mean borderline signal to noise ratio.

Get a better antenna, add an amplifier, and...

If 'better antenna' means aim-able, or selective of TV frequencies, that's good.

Instead of an amplifier, get an ATTENUATOR. It's possible that an out-of-band signal is
overloading the first stages of amplification, before filtering.
When that happens, any pre-amplification just makes the effect worse.

<https://www.ebay.com/itm/RadioShack-15-678-75-Ohm-Bidirectional-Attenuator-Improves-TV-UHF-VHF-Reception/401494806442>

If attenuation leaves the signal good
but removes the interference, it means (1) the neighbor isn't accidentally clobbering
a TV frequency, and (2) either a selective antenna or a trap or lowpass filter can solve
the problem. Usually cellphone frequencies are too high for TV interference,
and won't go through antenna wires effectively anyhow, but the cell bands
are certainly known and separable from UHF television signals.

 

[Ralph Mowery]

In article <mnmp6e9ldvk18vels8m5oq4korfpsgp9tr@4ax.com>, pj@jostle.com
says...

Last year I had several month's of TV interference
on some channels, mainly pixelation but sometimes
"no signal". Worse on some channels.

Then, up to now, the interference has stopped, all
by itself,

Is this off the air with an antenna, Direct TV, or cable ?

If off the air it may be the leaves on the trees. When they come out,
they tend to absorbe some of the signal.

If cable, they should resolve the issue for you. Same for the sat
dishes.

 

[Jeff Liebermann]

On Wed, 20 Feb 2019 15:53:14 +1100, Peter Jason <pj@jostle.com> wrote:

>Last year

That would be 2018.

>I had several month's

Several would be 2 or more months.

of TV interference
on some channels,

Is that OTA TV, cable TV, satellite TV? How many channels do you
normally see on your TV? How many of those channels show
interference? VHF, UHF, or both? Interference is rarely on more than
one channel at a time unless you have a broadband source (6MHz per
channel) that's causing the alleged interference.

mainly pixelation but sometimes
"no signal".

Pixelation can mean many things. Usually, it means a weak signal or
bit loss. Lots of possible culprits.

>Worse on some channels.

Which channels?

Then, up to now, the interference has stopped, all
by itself,

Are you sure you didn't do anything to make it go away? Antenna
connection? Loose shield on the RG-6/u coax cable? Nearby noise
source got turned off? I once disarmed a "negative ion generator"
that was wiping out OTA TV reception in part of an apartment building.

I live in town opposite a large telecommunications
building, and here's a picture of it over my back
fence.....

The cellular antennas have a very narrow vertical beamwidth. My
guess(tm) is 11 degrees vertical beamwidth on 850MHz and 6 degrees on
1900MHz. In other words, all the RF is going over your head and not
into your house. However, if you have a rooftop antenna, or live in a
multistory house that puts you into the beam, then maybe the cellular
stuff is causing a problem.

https://postimg.cc/4mPR4WfM

Note the plethora of weird aerials on its roof
which might be causing the interference on my 2006
Sony wide-screen TV.

Ah, you decided to disclose the maker and age of the TV without
bothering to supply a model number. Very good. It's a start. I
don't suppose there might be something wrong with a 13 year TV? The
transition from analog to digital TV started in 1996 and was done in
2009. So, your TV probably has an ATSC tuner. 2006 puts your TV in
the middle of the transition, which makes it difficult for me to guess
the quality of the tuner.

Cellular interference to OTA TV is quite real, especially LTE in the
700MHz band. This might offer a few clues:
"Out-of-Band Interference: Myth or Reality?"
<https://www.tvtechnology.com/opinions/outofband-interference-myth-or-reality>

>If the interference starts up again what do I do?

You walk over to the neighbors and see if they are getting the same
interference on the same channels. If yes, then find the owner of the
nearby antenna farm and unload your frustrations on their public
relations department. If no, and you have an outside antenna, try to
borrow a different TV and compare what you see on the screen. If only
your 2006 Sony has the problem, it might be time to get a better TV.

>Are there special filters for this sort of thing,

Yes, there are TV bandpass filters. However, few of these will work
with unspecified multiple channels. It might be helpful if you would
insert some numbers in your description. If you are numerically
challenged, just look for an "LTE TV Filter" such as:
<https://www.techhive.com/article/3235649/tv-antenna/lte-filters-for-tv-antennas.html>
<https://www.channelmaster.com/TV_Antenna_LTE_Filter_p/cm-3201.htm>
More:
<https://www.google.com/search?q=lte+tv+filter>

>and if not how should I frame a complaint?

Try an LTE filter first and see if it helps. Then find whomever owns
the antenna farm and ask them whom to contact. Most large
teleconfusion establishments have a mechanism for handling such
complaints.

Good luck.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Peter Jason]

On Thu, 21 Feb 2019 18:03:25 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Wed, 20 Feb 2019 15:53:14 +1100, Peter Jason <pj@jostle.com> wrote:

Last year

That would be 2018.

Yes.

I had several month's

Several would be 2 or more months.

About 4 months

of TV interference
on some channels,

Is that OTA TV, cable TV, satellite TV? How many channels do you
normally see on your TV? How many of those channels show
interference? VHF, UHF, or both? Interference is rarely on more than
one channel at a time unless you have a broadband source (6MHz per
channel) that's causing the alleged interference.

OTA? The TV has an aerial with no amplifier, with
a coax cable. The assy is shown here.....
https://postimg.cc/XGG83TfM
The top set have been disconnected because they're
too high to reach, so the TV runs on the bottom
one.

mainly pixelation but sometimes
"no signal".

Pixelation can mean many things. Usually, it means a weak signal or
bit loss. Lots of possible culprits.

Worse on some channels.

Which channels?

All channels, though the lower-freq ones are
worse.

Then, up to now, the interference has stopped, all
by itself,

Are you sure you didn't do anything to make it go away? Antenna
connection? Loose shield on the RG-6/u coax cable? Nearby noise
source got turned off? I once disarmed a "negative ion generator"
that was wiping out OTA TV reception in part of an apartment building.

No. It all just stopped.

I live in town opposite a large telecommunications
building, and here's a picture of it over my back
fence.....

The cellular antennas have a very narrow vertical beamwidth. My
guess(tm) is 11 degrees vertical beamwidth on 850MHz and 6 degrees on
1900MHz. In other words, all the RF is going over your head and not
into your house. However, if you have a rooftop antenna, or live in a
multistory house that puts you into the beam, then maybe the cellular
stuff is causing a problem.

https://postimg.cc/4mPR4WfM

Note the plethora of weird aerials on its roof
which might be causing the interference on my 2006
Sony wide-screen TV.

Ah, you decided to disclose the maker and age of the TV without
bothering to supply a model number. Very good. It's a start. I
don't suppose there might be something wrong with a 13 year TV? The
transition from analog to digital TV started in 1996 and was done in
2009. So, your TV probably has an ATSC tuner. 2006 puts your TV in
the middle of the transition, which makes it difficult for me to guess
the quality of the tuner.

A good point, so next time it happens I'll put it
up into the maid's room, and buy a
newone..especially since these have greater
functionallity for movie formats.

Cellular interference to OTA TV is quite real, especially LTE in the
700MHz band. This might offer a few clues:
"Out-of-Band Interference: Myth or Reality?"
https://www.tvtechnology.com/opinions/outofband-interference-myth-or-reality

If the interference starts up again what do I do?

You walk over to the neighbors and see if they are getting the same
interference on the same channels. If yes, then find the owner of the
nearby antenna farm and unload your frustrations on their public
relations department. If no, and you have an outside antenna, try to
borrow a different TV and compare what you see on the screen. If only
your 2006 Sony has the problem, it might be time to get a better TV.

I have an el-cheapo signal-strength meter, and
this shows up to the second-top indication.
https://www.jaycar.com.au/digital-tv-signal-strength-meter/p/LT3332

Are there special filters for this sort of thing,

Yes, there are TV bandpass filters. However, few of these will work
with unspecified multiple channels. It might be helpful if you would
insert some numbers in your description. If you are numerically
challenged, just look for an "LTE TV Filter" such as:
https://www.techhive.com/article/3235649/tv-antenna/lte-filters-for-tv-antennas.html
https://www.channelmaster.com/TV_Antenna_LTE_Filter_p/cm-3201.htm
More:
https://www.google.com/search?q=lte+tv+filter

and if not how should I frame a complaint?

Try an LTE filter first and see if it helps. Then find whomever owns
the antenna farm and ask them whom to contact. Most large
teleconfusion establishments have a mechanism for handling such
complaints.

Good luck.

Thank you.
I can always use a bit of luck.

 

Peter Jason wrote: "Last year I had several month's of TV interference
on some channels, mainly pixelation but sometimes
"no signal". Worse on some channels.

Then, up to now, the interference has stopped, all
by itself, "


Welcome to the world of digital OTA TV broadcast - the
biggest scam ever perpetuated on American consumers
since the 'Federal' Reserve"

 

[Jeff Liebermann]

On Fri, 22 Feb 2019 14:45:08 +1100, Peter Jason <pj@jostle.com> wrote:

On Thu, 21 Feb 2019 18:03:25 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Wed, 20 Feb 2019 15:53:14 +1100, Peter Jason <pj@jostle.com> wrote:

Hmmm... The time zone shows that you're in +1100 which I would
guess(tm) is south-eastern Australia on DST. Is that correct?
If so, much of what I said may not apply as the TV and cellular
standards might be different. I know zero about those for Australia
and therefore suggest you find a local source of technical help.

>OTA?

OTA = Over The Air as in broadcast TV.

The TV has an aerial with no amplifier, with
a coax cable. The assy is shown here.....
https://postimg.cc/XGG83TfM
The top set have been disconnected because they're
too high to reach, so the TV runs on the bottom
one.

I see a few problems.
1. You are well below the main lobes of the cellular antennas on the
nearby roof but close enough that you are going to see problems
created by all the transmitters.
2. Running the 3 guy wires through the elements of the lower antenna
will have a detrimental effect on the antenna pattern and gain. I
suggest you remove the galvanized guy wires and replace them with a
non-conductive equivalent such as a UV resistant polyester or kevlar
guy wires.
3, The mast clamp, where the 3 guy wires meet, is heavily rusted.
This is normally not a problem. However, in a high RF field
environment, rusted metal can produce a diode junction, which will mix
two or more signals or their harmonics to produce what is called
intermodulation. This intermodulation is a possible source of your
alleged interference. You can temporarily fix a problem cause by a
rusty connection by simply beating on the mast with a hammer to break
through the rust. However, given time and weather, it will be back. I
suggest you replace the clamp with something that is hot dip
galvanized or plastic insulated.
4. The unused upper antenna appears to include a small UHF antenna
below the main VHF antenna. I only see a single coaxial cable, but no
VHF/UHF band splitter. If you eventually resurrect the upper antenna,
you might check if it's wired properly.
5. Thank you for the nice photo of the upper antenna, which is not
being used, but only part of the lower antenna, which is being used. I
wanted to see the feed point of the lower antenna, which was cut off.
Also, I can barely see half of what might be a UHF element on the
front of the lower antenna.

Worse on some channels.

Which channels?

All channels, though the lower-freq ones are
worse.

Improbable. There are no jammers or signal sources that can wipe out
the entire TV spectrum. For Australia DTV, that would be 694-820 MHz.
<https://www.communications.gov.au/what-we-do/spectrum/digital-dividend-spectrum>
Certainly not interference caused by a cellular transmitter, which
would be far more noticeable on the higher channels than the lower.

It's possible that there is so much RF that the front end of your
unspecified model Sony TV receiver is being overload. This is called
"blocking" where the high RF level is rectified by the amplifying
devices in the front end of the receiver, causing the biasing of the
devices to change, and generally reducing its gain. This would reduce
the receiver sensitivity on all channels, as you describe. However,
unless something in the antenna farm is running really high power, or
your unspecified model Sony TV receiver is poorly designed, such
blocking is improbable. (Possible, but not likely).

Are you sure you didn't do anything to make it go away? Antenna
connection? Loose shield on the RG-6/u coax cable? Nearby noise
source got turned off? I once disarmed a "negative ion generator"
that was wiping out OTA TV reception in part of an apartment building.

No. It all just stopped.

Well, I see three possibilities:
1. Your antenna and/or coaxial cable system is intermittent due to
either a short across the coax, or a bad connection on the center pin
or shield. It could be anywhere but most likely at the connector
ends. Also, look for "U" staples punching through the coax cable.
2. Your TV has a problem. Test with by borrowing another TV and
comparing. If only your TV has the problem, the culprit is obvious.
3. A fairly high power cellular transmitter nearby was turned off.

A good point, so next time it happens I'll put it
up into the maid's room, and buy a
newone..especially since these have greater
functionallity for movie formats.

Is there some reason why you have failed twice to provide the model
number of your 2006 Sony TV?

I have an el-cheapo signal-strength meter, and
this shows up to the second-top indication.
https://www.jaycar.com.au/digital-tv-signal-strength-meter/p/LT3332

I'm not familiar with that product. It will tell you if you have a
signal in the TV band, but will not tell you on what channel, or
whether it's a TV transmitter or cellular transmitter.

Thank you.
I can always use a bit of luck.

You're welcome. However, there's a problem. You're doing a splendid
job of obscuring your information and ignoring my questions. This is
YOUR problem, not mine. I'm trying to help, but making me do extra
work by having to guess your location, your TV model, and your
relative position to the likely source of interference, is not being
very cooperative or helpful. When you see a sentence end in a
question mark, please try to answer the question.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Phil Allison]

Jeff Liebermann wrote:

Improbable. There are no jammers or signal sources that can wipe out
the entire TV spectrum. For Australia DTV, that would be 694-820 MHz.

** Australian DTV is broadcast on the VHF band in all capitol cities using channels 6 to 12. Rural areas use UHF.


https://en.wikipedia.org/wiki/Australian_and_New_Zealand_television_frequencies#Frequency_allocation_table

The OP's antenna pic shows he is still using VHF signals.

https://www.communications.gov.au/what-we-do/spectrum/digital-dividend-spectrum

** That link is irrelevant cos it speaks only of the frequencies that were "freed up" by the switch to DTV - they were all UHF ones.

The VHF band acquired new DTV signals on all the previously unused gaps between analogue TV signals as well as the existing ones.


..... Phil

 

[Peter Jason]

On Fri, 22 Feb 2019 14:48:51 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Fri, 22 Feb 2019 14:45:08 +1100, Peter Jason <pj@jostle.com> wrote:

On Thu, 21 Feb 2019 18:03:25 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Wed, 20 Feb 2019 15:53:14 +1100, Peter Jason <pj@jostle.com> wrote:

Hmmm... The time zone shows that you're in +1100 which I would
guess(tm) is south-eastern Australia on DST. Is that correct?
If so, much of what I said may not apply as the TV and cellular
standards might be different. I know zero about those for Australia
and therefore suggest you find a local source of technical help.

OTA?

OTA = Over The Air as in broadcast TV.

The TV has an aerial with no amplifier, with
a coax cable. The assy is shown here.....
https://postimg.cc/XGG83TfM
The top set have been disconnected because they're
too high to reach, so the TV runs on the bottom
one.

I see a few problems.
1. You are well below the main lobes of the cellular antennas on the
nearby roof but close enough that you are going to see problems
created by all the transmitters.
2. Running the 3 guy wires through the elements of the lower antenna
will have a detrimental effect on the antenna pattern and gain. I
suggest you remove the galvanized guy wires and replace them with a
non-conductive equivalent such as a UV resistant polyester or kevlar
guy wires.
3, The mast clamp, where the 3 guy wires meet, is heavily rusted.
This is normally not a problem. However, in a high RF field
environment, rusted metal can produce a diode junction, which will mix
two or more signals or their harmonics to produce what is called
intermodulation. This intermodulation is a possible source of your
alleged interference. You can temporarily fix a problem cause by a
rusty connection by simply beating on the mast with a hammer to break
through the rust. However, given time and weather, it will be back. I
suggest you replace the clamp with something that is hot dip
galvanized or plastic insulated.
4. The unused upper antenna appears to include a small UHF antenna
below the main VHF antenna. I only see a single coaxial cable, but no
VHF/UHF band splitter. If you eventually resurrect the upper antenna,
you might check if it's wired properly.
5. Thank you for the nice photo of the upper antenna, which is not
being used, but only part of the lower antenna, which is being used. I
wanted to see the feed point of the lower antenna, which was cut off.
Also, I can barely see half of what might be a UHF element on the
front of the lower antenna.

Worse on some channels.

Which channels?

All channels, though the lower-freq ones are
worse.

Improbable. There are no jammers or signal sources that can wipe out
the entire TV spectrum. For Australia DTV, that would be 694-820 MHz.
https://www.communications.gov.au/what-we-do/spectrum/digital-dividend-spectrum
Certainly not interference caused by a cellular transmitter, which
would be far more noticeable on the higher channels than the lower.

It's possible that there is so much RF that the front end of your
unspecified model Sony TV receiver is being overload. This is called
"blocking" where the high RF level is rectified by the amplifying
devices in the front end of the receiver, causing the biasing of the
devices to change, and generally reducing its gain. This would reduce
the receiver sensitivity on all channels, as you describe. However,
unless something in the antenna farm is running really high power, or
your unspecified model Sony TV receiver is poorly designed, such
blocking is improbable. (Possible, but not likely).

Are you sure you didn't do anything to make it go away? Antenna
connection? Loose shield on the RG-6/u coax cable? Nearby noise
source got turned off? I once disarmed a "negative ion generator"
that was wiping out OTA TV reception in part of an apartment building.

No. It all just stopped.

Well, I see three possibilities:
1. Your antenna and/or coaxial cable system is intermittent due to
either a short across the coax, or a bad connection on the center pin
or shield. It could be anywhere but most likely at the connector
ends. Also, look for "U" staples punching through the coax cable.
2. Your TV has a problem. Test with by borrowing another TV and
comparing. If only your TV has the problem, the culprit is obvious.
3. A fairly high power cellular transmitter nearby was turned off.

A good point, so next time it happens I'll put it
up into the maid's room, and buy a
newone..especially since these have greater
functionallity for movie formats.

Is there some reason why you have failed twice to provide the model
number of your 2006 Sony TV?

I have an el-cheapo signal-strength meter, and
this shows up to the second-top indication.
https://www.jaycar.com.au/digital-tv-signal-strength-meter/p/LT3332

I'm not familiar with that product. It will tell you if you have a
signal in the TV band, but will not tell you on what channel, or
whether it's a TV transmitter or cellular transmitter.

Thank you.
I can always use a bit of luck.

You're welcome. However, there's a problem. You're doing a splendid
job of obscuring your information and ignoring my questions. This is
YOUR problem, not mine. I'm trying to help, but making me do extra
work by having to guess your location, your TV model, and your
relative position to the likely source of interference, is not being
very cooperative or helpful. When you see a sentence end in a
question mark, please try to answer the question.

Thanks

I'll be back. And have some more details next
week.

 

[Peter Jason]

On Fri, 22 Feb 2019 14:48:51 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Fri, 22 Feb 2019 14:45:08 +1100, Peter Jason <pj@jostle.com> wrote:

On Thu, 21 Feb 2019 18:03:25 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Wed, 20 Feb 2019 15:53:14 +1100, Peter Jason <pj@jostle.com> wrote:

Hmmm... The time zone shows that you're in +1100 which I would
guess(tm) is south-eastern Australia on DST. Is that correct?
If so, much of what I said may not apply as the TV and cellular
standards might be different. I know zero about those for Australia
and therefore suggest you find a local source of technical help.

OTA?

OTA = Over The Air as in broadcast TV.

The TV has an aerial with no amplifier, with
a coax cable. The assy is shown here.....
https://postimg.cc/XGG83TfM
The top set have been disconnected because they're
too high to reach, so the TV runs on the bottom
one.

I see a few problems.
1. You are well below the main lobes of the cellular antennas on the
nearby roof but close enough that you are going to see problems
created by all the transmitters.
2. Running the 3 guy wires through the elements of the lower antenna
will have a detrimental effect on the antenna pattern and gain. I
suggest you remove the galvanized guy wires and replace them with a
non-conductive equivalent such as a UV resistant polyester or kevlar
guy wires.
3, The mast clamp, where the 3 guy wires meet, is heavily rusted.
This is normally not a problem. However, in a high RF field
environment, rusted metal can produce a diode junction, which will mix
two or more signals or their harmonics to produce what is called
intermodulation. This intermodulation is a possible source of your
alleged interference. You can temporarily fix a problem cause by a
rusty connection by simply beating on the mast with a hammer to break
through the rust. However, given time and weather, it will be back. I
suggest you replace the clamp with something that is hot dip
galvanized or plastic insulated.
4. The unused upper antenna appears to include a small UHF antenna
below the main VHF antenna. I only see a single coaxial cable, but no
VHF/UHF band splitter. If you eventually resurrect the upper antenna,
you might check if it's wired properly.
5. Thank you for the nice photo of the upper antenna, which is not
being used, but only part of the lower antenna, which is being used. I
wanted to see the feed point of the lower antenna, which was cut off.
Also, I can barely see half of what might be a UHF element on the
front of the lower antenna.

Worse on some channels.

Which channels?

All channels, though the lower-freq ones are
worse.

Improbable. There are no jammers or signal sources that can wipe out
the entire TV spectrum. For Australia DTV, that would be 694-820 MHz.
https://www.communications.gov.au/what-we-do/spectrum/digital-dividend-spectrum
Certainly not interference caused by a cellular transmitter, which
would be far more noticeable on the higher channels than the lower.

It's possible that there is so much RF that the front end of your
unspecified model Sony TV receiver is being overload. This is called
"blocking" where the high RF level is rectified by the amplifying
devices in the front end of the receiver, causing the biasing of the
devices to change, and generally reducing its gain. This would reduce
the receiver sensitivity on all channels, as you describe. However,
unless something in the antenna farm is running really high power, or
your unspecified model Sony TV receiver is poorly designed, such
blocking is improbable. (Possible, but not likely).

Are you sure you didn't do anything to make it go away? Antenna
connection? Loose shield on the RG-6/u coax cable? Nearby noise
source got turned off? I once disarmed a "negative ion generator"
that was wiping out OTA TV reception in part of an apartment building.

No. It all just stopped.

Well, I see three possibilities:
1. Your antenna and/or coaxial cable system is intermittent due to
either a short across the coax, or a bad connection on the center pin
or shield. It could be anywhere but most likely at the connector
ends. Also, look for "U" staples punching through the coax cable.
2. Your TV has a problem. Test with by borrowing another TV and
comparing. If only your TV has the problem, the culprit is obvious.
3. A fairly high power cellular transmitter nearby was turned off.

A good point, so next time it happens I'll put it
up into the maid's room, and buy a
newone..especially since these have greater
functionallity for movie formats.

Is there some reason why you have failed twice to provide the model
number of your 2006 Sony TV?

I have an el-cheapo signal-strength meter, and
this shows up to the second-top indication.
https://www.jaycar.com.au/digital-tv-signal-strength-meter/p/LT3332

I'm not familiar with that product. It will tell you if you have a
signal in the TV band, but will not tell you on what channel, or
whether it's a TV transmitter or cellular transmitter.

Thank you.
I can always use a bit of luck.

You're welcome. However, there's a problem. You're doing a splendid
job of obscuring your information and ignoring my questions. This is
YOUR problem, not mine. I'm trying to help, but making me do extra
work by having to guess your location, your TV model, and your
relative position to the likely source of interference, is not being
very cooperative or helpful. When you see a sentence end in a
question mark, please try to answer the question.

The TV is a Sony ''Bravia'' XBR KDL-40XBR
https://www.sony.com.au/electronics/support/res/manuals/3217/32172841M.pdf

But normally I use the tuners in the ...
Panasonic DMR-PWT540

https://www.appliancesonline.com.au/manuals/DMR-PWT540GL/14082014134757DMR-PWT540GL%20Manual.pdf
because this allows faster surfing between
channels. Also, I record everything for later
select viewing.
The current antenna is
http://docshare.tips/hills-2007-antenna-catalogue_5875af0db6d87fe0468b45a0.html


The interference happens thru the Bravia tuner &
thru the Panasonic ones.

The roof antenna system has been the same for
about 7 years.

 

On Sunday, February 24, 2019 at 7:39:00 PM UTC-5, Peter Jason wrote:

On Fri, 22 Feb 2019 14:48:51 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Fri, 22 Feb 2019 14:45:08 +1100, Peter Jason <pj@jostle.com> wrote:

On Thu, 21 Feb 2019 18:03:25 -0800, Jeff
Liebermann <jeffl@cruzio.com> wrote:

On Wed, 20 Feb 2019 15:53:14 +1100, Peter Jason <pj@jostle.com> wrote:

Hmmm... The time zone shows that you're in +1100 which I would
guess(tm) is south-eastern Australia on DST. Is that correct?
If so, much of what I said may not apply as the TV and cellular
standards might be different. I know zero about those for Australia
and therefore suggest you find a local source of technical help.

OTA?

OTA = Over The Air as in broadcast TV.

The TV has an aerial with no amplifier, with
a coax cable. The assy is shown here.....
https://postimg.cc/XGG83TfM
The top set have been disconnected because they're
too high to reach, so the TV runs on the bottom
one.

I see a few problems.
1. You are well below the main lobes of the cellular antennas on the
nearby roof but close enough that you are going to see problems
created by all the transmitters.
2. Running the 3 guy wires through the elements of the lower antenna
will have a detrimental effect on the antenna pattern and gain. I
suggest you remove the galvanized guy wires and replace them with a
non-conductive equivalent such as a UV resistant polyester or kevlar
guy wires.
3, The mast clamp, where the 3 guy wires meet, is heavily rusted.
This is normally not a problem. However, in a high RF field
environment, rusted metal can produce a diode junction, which will mix
two or more signals or their harmonics to produce what is called
intermodulation. This intermodulation is a possible source of your
alleged interference. You can temporarily fix a problem cause by a
rusty connection by simply beating on the mast with a hammer to break
through the rust. However, given time and weather, it will be back. I
suggest you replace the clamp with something that is hot dip
galvanized or plastic insulated.
4. The unused upper antenna appears to include a small UHF antenna
below the main VHF antenna. I only see a single coaxial cable, but no
VHF/UHF band splitter. If you eventually resurrect the upper antenna,
you might check if it's wired properly.
5. Thank you for the nice photo of the upper antenna, which is not
being used, but only part of the lower antenna, which is being used. I
wanted to see the feed point of the lower antenna, which was cut off.
Also, I can barely see half of what might be a UHF element on the
front of the lower antenna.

Worse on some channels.

Which channels?

All channels, though the lower-freq ones are
worse.

Improbable. There are no jammers or signal sources that can wipe out
the entire TV spectrum. For Australia DTV, that would be 694-820 MHz.
https://www.communications.gov.au/what-we-do/spectrum/digital-dividend-spectrum
Certainly not interference caused by a cellular transmitter, which
would be far more noticeable on the higher channels than the lower.

It's possible that there is so much RF that the front end of your
unspecified model Sony TV receiver is being overload. This is called
"blocking" where the high RF level is rectified by the amplifying
devices in the front end of the receiver, causing the biasing of the
devices to change, and generally reducing its gain. This would reduce
the receiver sensitivity on all channels, as you describe. However,
unless something in the antenna farm is running really high power, or
your unspecified model Sony TV receiver is poorly designed, such
blocking is improbable. (Possible, but not likely).

Are you sure you didn't do anything to make it go away? Antenna
connection? Loose shield on the RG-6/u coax cable? Nearby noise
source got turned off? I once disarmed a "negative ion generator"
that was wiping out OTA TV reception in part of an apartment building.

No. It all just stopped.

Well, I see three possibilities:
1. Your antenna and/or coaxial cable system is intermittent due to
either a short across the coax, or a bad connection on the center pin
or shield. It could be anywhere but most likely at the connector
ends. Also, look for "U" staples punching through the coax cable.
2. Your TV has a problem. Test with by borrowing another TV and
comparing. If only your TV has the problem, the culprit is obvious.
3. A fairly high power cellular transmitter nearby was turned off.

A good point, so next time it happens I'll put it
up into the maid's room, and buy a
newone..especially since these have greater
functionallity for movie formats.

Is there some reason why you have failed twice to provide the model
number of your 2006 Sony TV?

I have an el-cheapo signal-strength meter, and
this shows up to the second-top indication.
https://www.jaycar.com.au/digital-tv-signal-strength-meter/p/LT3332

I'm not familiar with that product. It will tell you if you have a
signal in the TV band, but will not tell you on what channel, or
whether it's a TV transmitter or cellular transmitter.

Thank you.
I can always use a bit of luck.

You're welcome. However, there's a problem. You're doing a splendid
job of obscuring your information and ignoring my questions. This is
YOUR problem, not mine. I'm trying to help, but making me do extra
work by having to guess your location, your TV model, and your
relative position to the likely source of interference, is not being
very cooperative or helpful. When you see a sentence end in a
question mark, please try to answer the question.

The TV is a Sony ''Bravia'' XBR KDL-40XBR
https://www.sony.com.au/electronics/support/res/manuals/3217/32172841M.pdf

But normally I use the tuners in the ...
Panasonic DMR-PWT540

https://www.appliancesonline.com.au/manuals/DMR-PWT540GL/14082014134757DMR-PWT540GL%20Manual.pdf
because this allows faster surfing between
channels. Also, I record everything for later
select viewing.
The current antenna is
http://docshare.tips/hills-2007-antenna-catalogue_5875af0db6d87fe0468b45a0.html


The interference happens thru the Bravia tuner &
thru the Panasonic ones.

The roof antenna system has been the same for
about 7 years.

the OP needs a spectrum analyzer
m

 

[micky]

In sci.electronics.repair, on Wed, 20 Feb 2019 07:14:36 -0600, Fox's
Mercantile <jdangus@att.net> wrote:

On 2/20/19 6:27 AM, John-Del wrote:
Interference? I don't know how you can tell that with a digital tuner.

You can't.

It's like Hatlow's "They'll do it every time."

It's a long time since I saw that cartoon. I'd forgotten all about it,
but I sure liked it at the time.

A bunch of neighbor's pointing at the local amateur radio guy.
Among other comments, "I hear he even interferes with Doc's
diathermy machine.

He shouldn't do that.