HELP: specific 2.4GHz video xmitter interference, what causes it?

I am going nuts.
We are using a 2.4GHz wireless video broadcaster in our home (Germany,
240V, 50Hz, PAL TV 25fps). It is based in the lower level and
transmits a satellite receiver output to the upper level TV room,
about 25ft away (3x 1ft stone walls in between).
The received video signal has a large regular interference, a
horizonal stripe (about 5% high, small vertical bands with colored
specks, almost white appearance) crawls fast through the picture,
accompanied by a chopping noise, about 8-10 chops per second. The
stripe scrolls fast through the picture, about 2-3 times per second,
downwards.
A classical interference. PAL operates at 25cycles per second, German
power at 50Hz, what does this tell about the interference spectrum/
freq?

Yes, we have a variety of other wireless devices in the house,
including a Fritz! WLAN, 2 2.4GHz phone bases (5 mobile phones),
several wireless weather stations, a Razr cell phone.
I pulled ALL plugs of all known wireless devices, unscrewed fuses
wherever needed, NADA! The noise remains, as strong as before.
I even put all wireless phones into a metal box and carried it out of
the building, still no change.
Meaning that all my wireless devices do NOT have any impact at all,
the other noise is the main problem. WHERE THE HELL IS IT COMING FROM?

The received video signal is rather weak, moving the receiver around
yields interesting spots of "almost" no noise (about 1ft apart).
Interesting to note: the noise gets typically more solid if the
overall picture is better and clear/strong. Meaning if I settle for a
grainy video, then the stripe is almost invisible (yet noticable in
the audio part as the mentioned fast 'chop chop chop' noise)

I am at the end of my wits. Cannot analyze freq sprectrum nor do I
have other tools handy to investigate. Am a left handed physicist, not
an electrical freak, hence my plead for support here!
What could cause this strong interference, a neighbor, the power line,
the antenna from the satellite/cable (even switched off the HF
amplifier for TV)?

What else should I try to isolate the problem? Cut the power line of
all my neighbors?

Thanks a bunch!
michael



mw210461@gmail.com

"(E-Mail Removed)" <(E-Mail Removed)> wrote in news:7d76831c-f322-4ff0-
af24-(E-Mail Removed):

> I am going nuts.
> We are using a 2.4GHz wireless video broadcaster in our home (Germany,
> 240V, 50Hz, PAL TV 25fps). It is based in the lower level and
> transmits a satellite receiver output to the upper level TV room,
> about 25ft away (3x 1ft stone walls in between).
> The received video signal has a large regular interference, a
<

<SNIP>

> erence, a neighbor, the power line,
> the antenna from the satellite/cable (even switched off the HF
> amplifier for TV)?
>
> What else should I try to isolate the problem? Cut the power line of
> all my neighbors?
>
> Thanks a bunch!
> michael

Had you ever seen this device work properly anywhere, the one you own ?

Maybe the device is defective.

On 12 Jul., 00:06, DanS <t.h.i.s.n.t.h....@a.d.e.l.p.h.i.a.n.e.t>
wrote:
> "mw210...@gmail.com" <mw210...@gmail.com> wrote in news:7d76831c-f322-4ff0-
> af24-2190158ed...@34g2000hsh.googlegroups.com:
>
> > I am going nuts.
> > We are using a2.4GHzwireless video broadcaster in our home (Germany,
> > 240V, 50Hz, PAL TV 25fps). It is based in the lower level and
> > transmits a satellite receiver output to the upper level TV room,
> > about 25ft away (3x 1ft stone walls in between).
> > The received video signal has a large regular interference, a
>
> <
>
> <SNIP>
>
> > erence, a neighbor, the power line,
> > the antenna from *the satellite/cable (even switched off the HF
> > amplifier for TV)?
>
> > What else should I try to isolate the problem? Cut the power line of
> > all my neighbors?
>
> > Thanks a bunch!
> > michael
>
> Had you ever seen this device work properly anywhere, the one you own ?
>
> Maybe the device is defective.

I am pretty sure I did test it with good results (before we moved),
but cannot say for sure.
Since none of my own devices is causing it I still asume an external
noise source, mainly the neighbor's strong WLAN (I can sensek his
signal with my own PCs while I can hardly get my own ethernet signals
down to the basement).
Would need a Faraday cage to test the entire xmitter system in, but
don't have any setup to do so.
The xmiiter has 4 channels to operate at, all of them show the same
interference.

To restore balance to the world (E-Mail Removed) wrote in
7d76831c-f322-4ff0-af24-2190158ed5a6...oglegroups.com
>> I am going nuts.
>> We are using a 2.4GHz wireless video broadcaster in our home
>> (Germany, 240V, 50Hz, PAL TV 25fps). It is based in the lower level
>> and transmits a satellite receiver output to the upper level TV room,
>> about 25ft away (3x 1ft stone walls in between).
>> The received video signal has a large regular interference, a
>> horizonal stripe (about 5% high, small vertical bands with colored
>> specks, almost white appearance) crawls fast through the picture,
>> accompanied by a chopping noise, about 8-10 chops per second. The
>> stripe scrolls fast through the picture, about 2-3 times per second,
>> downwards.
>> A classical interference. PAL operates at 25cycles per second, German
>> power at 50Hz, what does this tell about the interference spectrum/
>> freq?
>>
>> Yes, we have a variety of other wireless devices in the house,
>> including a Fritz! WLAN, 2 2.4GHz phone bases (5 mobile phones),
>> several wireless weather stations, a Razr cell phone.
>> I pulled ALL plugs of all known wireless devices, unscrewed fuses
>> wherever needed, NADA! The noise remains, as strong as before.
>> I even put all wireless phones into a metal box and carried it out of
>> the building, still no change.
>> Meaning that all my wireless devices do NOT have any impact at all,
>> the other noise is the main problem. WHERE THE HELL IS IT COMING
>> FROM?
>>
>> The received video signal is rather weak, moving the receiver around
>> yields interesting spots of "almost" no noise (about 1ft apart).
>> Interesting to note: the noise gets typically more solid if the
>> overall picture is better and clear/strong. Meaning if I settle for a
>> grainy video, then the stripe is almost invisible (yet noticable in
>> the audio part as the mentioned fast 'chop chop chop' noise)
>>
>> I am at the end of my wits. Cannot analyze freq sprectrum nor do I
>> have other tools handy to investigate. Am a left handed physicist,
>> not an electrical freak, hence my plead for support here!
>> What could cause this strong interference, a neighbor, the power
>> line, the antenna from the satellite/cable (even switched off the HF
>> amplifier for TV)?
>>
>> What else should I try to isolate the problem? Cut the power line of
>> all my neighbors?
>>
>> Thanks a bunch!
>> michael

Poor weak signal - do a test move the receiver to the same room as the
transmitter (3ft of stone)...
Chris

--
Superb hosting & domain name deals http://dn-22.co.uk
The Handyman http://www.looker.me.uk
The FlatPack Man http://www.flat-pack.info

On Fri, 11 Jul 2008 12:19:37 -0700 (PDT), "(E-Mail Removed)"
<(E-Mail Removed)> wrote:

>I am going nuts.

You have come to the right place.

>The received video signal has a large regular interference, a
>horizonal stripe (about 5% high, small vertical bands with colored
>specks, almost white appearance) crawls fast through the picture,
>accompanied by a chopping noise, about 8-10 chops per second. The
>stripe scrolls fast through the picture, about 2-3 times per second,
>downwards.
>A classical interference. PAL operates at 25cycles per second, German
>power at 50Hz, what does this tell about the interference spectrum/
>freq?

Good analysis. The AC power line frequency is 50.0Hz. Twice the
vertical sync is not exactly 50Hz, resulting in the "crawling"
horizontal bar. What you're seeing is AC power line "interference".
My guess(tm) is that you have an AC power supply problem for whatever
is running either the receiver or the transmitter. The 8-10 chops per
second would be "motorboating" also known as power supply
oscillations. That fits. Methinks you have a power supply problem.

>Meaning that all my wireless devices do NOT have any impact at all,
>the other noise is the main problem. WHERE THE HELL IS IT COMING FROM?

It's internally generated in either the transmitter or receiver. The
easiest way to test this is by replacing or isolating components.
You've already replaced everything electronic in the house. Perhaps
it would be best if you isolated the system. Take the transmitter,
receiver, and their corresponding power supplies to a completely
different location. An RF proof basement is ideal. Try it there. If
the "intereference" is still present, you have an internal problem
with the devices.

>The received video signal is rather weak, moving the receiver around
>yields interesting spots of "almost" no noise (about 1ft apart).

Hmmm... Maybe more than one thing wrong. Weak analog video signals
can do odd things. You might have just a little hum, which usually
won't be noticeable, but is aggrivated by the weak signal. It could
also be something oscillating in the receiver, where AGC is required
to keep it stable. Kinda hard to tell.

>Interesting to note: the noise gets typically more solid if the
>overall picture is better and clear/strong. Meaning if I settle for a
>grainy video, then the stripe is almost invisible (yet noticable in
>the audio part as the mentioned fast 'chop chop chop' noise)

Ummm... any chance you have positioned either the receiver or the
transmitter near some device that has a large 50Hz field? A desk
lamp, other wall warts, TV flyback xformer, motors, etc will qualify.
If so, move it away from these.

>I am at the end of my wits.

You only have one wit, which hopefully has no ending. I use my wit to
produce humor. I suggest you do the same. It sometimes helps with
difficult troubleshooting.

>Cannot analyze freq sprectrum nor do I
>have other tools handy to investigate. Am a left handed physicist, not
>an electrical freak, hence my plead for support here!

Troubleshoot by substitution. Do you have access to another
transmitter and receiver pair? If so replace either the transmitter
or receiver (and power supplies). Replace one item at a time.
Eventually, the culprit will identify itself.

>What could cause this strong interference, a neighbor, the power line,
>the antenna from the satellite/cable (even switched off the HF
>amplifier for TV)?

I don't think it's intererence. My guess(tm) is internal power supply
issues.

>What else should I try to isolate the problem? Cut the power line of
>all my neighbors?

Cutting your neighbors power might result in unexpected consequences,
such as a small riot at your front door. It would be a good test, but
is politicially unacceptable, unless you can make it look like an
accident. Driving your car into a power pole would work, but does
tend to be expensive.

>Thanks a bunch!
>michael

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 12 Jul., 12:00, "Joker7" <sat_r...@hotmail.com> wrote:
> To restore balance to the world mw210...@gmail.com *wrote in
> 7d76831c-f322-4ff0-af24-2190158ed...@34g2000hsh.googlegroups.com
>
>
>
>
>
> >> I am going nuts.
> >> We are using a2.4GHzwireless video broadcaster in our home
> >> (Germany, 240V, 50Hz, PAL TV 25fps). It is based in the lower level
> >> and transmits a satellite receiver output to the upper level TV room,
> >> about 25ft away (3x 1ft stone walls in between).
> >> The received video signal has a large regular interference, a
> >> horizonal stripe (about 5% high, small vertical bands with colored
> >> specks, almost white appearance) crawls fast through the picture,
> >> accompanied by a chopping noise, about 8-10 chops per second. The
> >> stripe scrolls fast through the picture, about 2-3 times per second,
> >> downwards.
> >> A classical interference. PAL operates at 25cycles per second, German
> >> power at 50Hz, what does this tell about the interference spectrum/
> >> freq?
>
> >> Yes, we have a variety of other wireless devices in the house,
> >> including a Fritz! WLAN, 22.4GHzphone bases (5 mobile phones),
> >> several wireless weather stations, a Razr cell phone.
> >> I pulled ALL plugs of all known *wireless devices, unscrewed fuses
> >> wherever needed, NADA! The noise remains, as strong as before.
> >> I even put all wireless phones into a metal box and carried it out of
> >> the building, still no change.
> >> Meaning that all my wireless devices do NOT have any impact at all,
> >> the other noise is the main problem. WHERE THE HELL IS IT COMING
> >> FROM?
>
> >> The received video signal is rather weak, moving the receiver around
> >> yields interesting spots of "almost" no noise (about 1ft apart).
> >> Interesting to note: the noise gets typically more solid if the
> >> overall picture is better and clear/strong. Meaning if I settle for a
> >> grainy video, then the stripe is almost invisible (yet noticable in
> >> the audio part as the mentioned fast 'chop chop chop' noise)
>
> >> I am at the end of my wits. Cannot analyze freq sprectrum nor do I
> >> have other tools handy to investigate. Am a left handed physicist,
> >> not an electrical freak, hence my plead for support here!
> >> What could cause this strong interference, a neighbor, the power
> >> line, the antenna from *the satellite/cable (even switched off the HF
> >> amplifier for TV)?
>
> >> What else should I try to isolate the problem? Cut the power line of
> >> all my neighbors?
>
> >> Thanks a bunch!
> >> michael
>
> Poor weak signal - do a test move the receiver to the same room as the
> transmitter *(3ft of stone)...
> Chris
>
> --
> Superb hosting & domain name dealshttp://dn-22.co.uk
> The Handymanhttp://www.looker.me.uk
> The FlatPack Manhttp://www.flat-pack.info- Zitierten Text ausblenden -
>
> - Zitierten Text anzeigen -

I do agree that the signal strength is low, mainly caused by the 3
thick walls and floors.

But I DO have success, sort of:
the transmitter allows to select 4 different broadcast channels, and
in one (D, the highest?) I noticed that the wide speckled and running
bar disappeared. It was replaced by 2 very narrow and absolutely
static ones! That was actually good news, as it was a DIFFERENT
interference, one I quickly identified as being from my own wireless
base station, located in the same room as the 2.4GHz receiver. That
one can be unplugged anytime; also I am considering to disable/cut
the
transmitter or antenna - the base is not actively used, it only
serves
as a charger for one cordless phone.
It produces a very sharp, whitish bar, in synch with the receiver for
some reason
(overtone or fraction of the xmit frequency I suppose?), no audio
interference noticable.
I am quite convinced that the other broad noise is indeed from a
neighbor's WiFi/WLAN system. What is baffling is that the plentitude
of my own wireless devices (with the exception of the one phone base
in the same room) have absolutely no impact on the xmitter/receiver
signal, and this bastard HAS, from 100ft away, through several 1foot
mason walls. What is he using??
Anyways - thanks for the ideas, hints and suggestions, highly
appreciated!
michael