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Jeanluck
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Serious interference betwen satellite antenna and omnitik

Thu Jan 03, 2013 8:34 pm

Hi,
I have several omnitik near antennas Satellite, and interference doesn't let view HD channels. The omnitik intereference exists when omnitik is less than 3 meter to satellite antenna.
- Interference is in 1567Mhz, when omnitik is working on 5640Mhz (5.14 version)
- Interference is more extended (almost all hd channels don't work) with 5540Mhz and 5.20 version

I can't move omnitik in all cases...
Why does this happen?
How I can fix it without move omnitik?

Thank's
 
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ohara
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Re: Serious interference betwen satellite antenna and omniti

Thu Jan 03, 2013 9:00 pm

When I asked our satelite dish installer if the dish will interfere with our 5Ghz CPE he mentioned that it may probably work the other way around and the CPE will interfere with the dish. Bear in mind that sat tv is 10Ghz and wifi is 5Ghz which is a huge difference. In our case it has absolutely no impact, though the CPE is directional and in an aluminium faraday case.

The guy also mentioned that sat tv does not work well when 10Ghz radio transmitters are in the neighbourhood. That frequency is widely used in crowded Polish city centres, thus he is always concerned when he gets orders from customers who live in the city centre.

What happens when you turn off the omnitik? Does the interference stop immediately? You could lower the TX power on the Omnitik and increase the TX power on the CPE's. You could also wrap the case with copper tape and leave the antennas, not to mention about painting the case with EMI aerosol.
 
Lakis
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Re: Serious interference betwen satellite antenna and omniti

Sun Jan 06, 2013 5:05 pm

This is interesting are u talking about be-directional satellite antenna send and receive from satellite
or just simple satellite dish antenna just for receiving TV channels - and if its this how can be interference
is there amplifier on this antenna
can u show me photo if u can
 
Jeanluck
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Re: Serious interference betwen satellite antenna and omniti

Mon Jan 07, 2013 12:39 pm

To Ohara:
The interferenciase is due to omnitik. No doubt. If I turn off, the interference stops instantly and completely. Or if it is on, but there is no data traffic, interference also stops. Even when exists interference, the links between omnitik and clients fail often.
It is a serious problem ....

The only solution I've found is to move a minimum of 3 meters omnitik <--> satellite antenna, but there are places that I can't
 
Jeanluck
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Re: Serious interference betwen satellite antenna and omniti

Mon Jan 07, 2013 12:46 pm

To Lakis:
Is a typical domestic antenna like this (just for receiving HD TV channels):
http://www.televisiondigital.es/satelit ... elite.aspx

Is it normal? should notify it to mikrotik support?
 
n21roadie
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Re: Serious interference betwen satellite antenna and omniti

Mon Jan 07, 2013 12:48 pm

Can you post a photo of one the installations which is having issues?
N21roadie,
Network 100% MT for Now?
 
Jeanluck
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Re: Serious interference betwen satellite antenna and omniti

Mon Jan 07, 2013 12:55 pm

Yes, I can. I have no photos now, but I can make photos this week with detail.
I'll upload these days

Thanks
 
ditonet
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 1:14 am

@Jeanluck
I don't know where you live, but in some countries satellite LNB downconverters
have local oscillator which work on 5GHz frequency, e.g.:
http://en.wikipedia.org/wiki/Low-noise_ ... ample_LNBs
In this case Omnitik can be a source of interference.

HTH,
Grzegorz | MTCNA, MTCRE, MTCSE | konsultacje MikroTik Warszawa
It is a book about a Spanish guy called Manual. You should read it. - Dilbert
 
Jeanluck
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 1:23 am

I live in spain, however a spectrum analyzer has verefied a interference in 1567Mhz, when omnitik is working on 5640Mhz (and the omnitik is less than 3 meters away), I don't know why... :(

I will upload photos of installation and satellite antenna soon.
 
ditonet
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 1:33 am

@Jeanluck
Please read whole Wiki article mentioned in my previous post.
Satellite LNB converts frequencies using local oscillator.
If local oscillator works on frequencies similar to Omnitik,
interferences are possible because Omnitik's signal is strong .
It is also possible that interferences are result of 'harmonic frequency' (http://en.wikipedia.org/wiki/Harmonic_frequency)

HTH,
Grzegorz | MTCNA, MTCRE, MTCSE | konsultacje MikroTik Warszawa
It is a book about a Spanish guy called Manual. You should read it. - Dilbert
 
Jeanluck
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 1:54 am

I will read the articles in depth, thanks!
It appears that here are used 10GHz. Maybe a problem of harmonic ... (5640/1567 = 3.6 exactly)
 
ditonet
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 2:17 am

Harmonic frequency is 5640*2 = 11280 MHz.
European satellites (Astra and HotBird) have frequency range from 10714 to 12731 MHz.
Astra sends on 11258.50 MHz some HD TV channels for Spain.
Do you have problem with: Canal+ Liga Campeones HD, Fox Crime HD, Canal+ 2 HD, Canal+ Golf HD???

Regards,
Grzegorz | MTCNA, MTCRE, MTCSE | konsultacje MikroTik Warszawa
It is a book about a Spanish guy called Manual. You should read it. - Dilbert
 
Jeanluck
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 2:34 am

Yes!, with 5640Mhz "Canal+ Liga Campeones" can not be seenn, and with 5540 can not be seen more hd channels. So it's a harmonic problem... at least the problem is located!
What I can do? Try different frequencies 5500-5700? any ideas?
 
Lakis
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 7:32 pm

Yes!, with 5640Mhz "Canal+ Liga Campeones" can not be seenn, and with 5540 can not be seen more hd channels. So it's a harmonic problem... at least the problem is located!
What I can do? Try different frequencies 5500-5700? any ideas?
I m so surprised about that
Also under the ETSI regulations u can use 5150-5350 MHz (up to 200mw) /5475-5725Mhz
can u do a test and see the difference?
 
Jeanluck
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 7:47 pm

Yes, in few days I will make extensive tests changing frecuencies, and I'll post results here
 
ditonet
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Re: Serious interference betwen satellite antenna and omniti

Tue Jan 08, 2013 11:22 pm

According to list of Astra's frequencies (http://en.kingofsat.net/pos-19.2E.php),
OmniTik's frequencies below 5300MHz should be OK. Give it a try.

HTH,
Grzegorz | MTCNA, MTCRE, MTCSE | konsultacje MikroTik Warszawa
It is a book about a Spanish guy called Manual. You should read it. - Dilbert
 
WirelessRudy
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Re: Serious interference betwen satellite antenna and omnitik

Thu Apr 23, 2015 1:33 am

Just came across this old tread by accident.
But I can underwrite about interference from 5Ghz wifi stuff on satellite HD receipt.
We had mayor problems receiving HD TV on a dish that worked for years with SD TV even under the harshest (heavy rain, thundering clouds) circumstances.
Last winter we installed a new TV set and upgraded our ASTRA subscriptions to receive Dutch TV channels here in Spain in HD quality.
Me and some skilled technician with pro satellite frequency and alignment tools worked for 2 days to find the reason why HD channels were very poor to almost impossible to receive.
We replaced and measured everything; coax, 3 x different LNB, 4 different receiver, etc.

Until one moment I thought about my tower with about 8 different 802.11an antennas (some that were receiving high signals from the other end of a link. These signals sort of 'looked' straight into the sat dish parabool too..) at only 5 meters distance.

So we decided to hang the sat dish on the side of the house. Out of sight of the wifi tower and also completely obscured from remote antenna beams... Gone were our problems. Rock solid signal now.....

So yes, 5Ghz definitely has an impact on the receipt of satellite digital HD TV signals...
Show your appreciation of this post by giving me Karma! Thanks.

Rudy R. Puister

WISP operator based on MT routerboard & ROS.
 
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Bergante
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Re: Serious interference betwen satellite antenna and omnitik

Thu Apr 23, 2015 2:13 pm

I wonder if you are using a high TX power which would probably cause distortion, making it transmit spurious signals in harmonic frequencies.

Try lowering the transmission power (if possible).
 
jimmyz
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Re: Serious interference betwen satellite antenna and omnitik

Thu Apr 23, 2015 5:03 pm

Just remembered the cordless phone devices, they interfere with the satellite receiver's tuner as well (when they are close). From memory I recall the Prosieben case (Astra 19°E, 12544,75 Horizontal).

Anyway, for the roof problem, one could shield the LNB from the CPE. Even more, connect this shield to house's Earth-GND.

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