Would you accept this?

[UndeadDevil]

I've had this issue for well over a year, so far no Satalite Profesional has been able to diagnose and fix this issue. I am on a Communal Dish that serves 6 flats.

 

Only 11642 V has this issue, every other transponder is perfectly fine from all 4 28.2e Satalites.

This morning (6AM) these channels were fine for the first time ever in a long time. This lasted until 9:20AM when suddenly they became un-watchable!

 

Anyone have any ideas? I do not have WiFi or a Cord-less Landline Phone. However my neighbour has a BT-HomeHub Router which also includes a DECT phone. I've read via Google that the BT HomeHub is well known for killing these channels. Is this likely? I could only find posts about this on 1 Forum site so not sure weither to believe it.

 

I wouldn't care if the Teleshoping channels were on this transponder, however this Transponder serves all the decent FTA Music Channels!

[Kat-CeDe]

Hi,

speak with your neighbor and test it together with him. If it´s not the router you must search again. If it´s the router you can find a solution together.

 

Ralf

[UndeadDevil]

I'm not able to find which neighbour has the router (It could be one of 8 flats! 5 in this building, plus the building right next to this one) and I'm not even sure it is that. Can something sold in a shop really do this amount of damage to TV Channels? Surely if it was the BT HomeHub I would have heard about it from the Media?? ("BT HomeHub kills Satalite TV")

 

I've uploaded a recorded TS, could you please look at how bad it is and tell me if you honestly think this could be caused by a device at least 5-10 meters away with several walls/ceilings in the way.

I do not understand how this interfearence was completly gone until 9AM if it was a router, and why a DECT phone would constantly be transmitting.

 

http://usa.d3vi1.com/06-21_20-06-03_Scuzz_.ts - 5 mins of video, yet only 46.6MB

[uglyned]

Is that the transponder with NME TV and Chart Show channels on?

 

If so, it's highly likely that it's a DECT phone doing the damage.

[Griga]

Only 11642 V has this issue, every other transponder is perfectly fine from all 4 28.2e Satalites

Anyone have any ideas?

Maybe it can be solved by changing LOFSW from 11700 to 11640 MHz (see DVBViewer channel editor, select the root entry representing the satellite position). This will move the transponder (and all other transponders between 11640 and 11700 MHz) from the low band to the high band, thus changing the intermediate frequency used by the LNB for sending the signal to the receiver.

 

Most LNBs and DVB devices will tolerate a 60 MHz LOFSW deviation. My TechniSat Multytenne and Hauppauge Nova S2 HD can cope with it (just tried).

 

Another possibility would be an antenna cable with a better shielding, provided the intermediate frequency is jammed from outside, not in your PC (did you consider that? There are a lot of high frequencies...).

[Benarty]

Pro7 had the same problem, dect phone disortions, they moved to another transponder to fix this.

[UndeadDevil]

Is that the transponder with NME TV and Chart Show channels on?

 

If so, it's highly likely that it's a DECT phone doing the damage.

 

Yep, but I still don't see how they could interfear from 5-10 Meters away through Walls! Everyone whos had problems with there own DECT phones always just moved them slightly further away and the problem was solved.

 

Most LNBs and DVB devices will tolerate a 60 MHz LOFSW deviation. My TechniSat Multytenne and Hauppauge Nova S2 HD can cope with it (just tried).

 

Another possibility would be an antenna cable with a better shielding, provided the intermediate frequency is jammed from outside, not in your PC (did you consider that? There are a lot of high frequencies...).

 

I did this and notice no difference. I am however using DVBViewer Server from another machine due to my Twinhan not working in Windows 7. Would this matter?

 

My Sky TV Box has the same issue, does that rule out the PC generating RFI? I'm not sure how good this cable is, but chances are the stuff inside my walls going to the Co-Ax Out socket on my wall is much lower quality. (This place was built on the cheap, ADSL gets a huge amount of RFI here as well, yet 200 meters away on another road its perfect. Literally double the sync rate!)

[Griga]

I did this and notice no difference.

Additionally check the per channel settings in the channel editor. After applying the work-around the editor should show Tone = 22 khz and LOF = 10600 MHz for the affected 11642 MHz channels (like POP). And you need to retune the channel, of course.

 

I am however using DVBViewer Server from another machine due to my Twinhan not working in Windows 7

I don't know how the DVBViewer server works (shame on me), but I suppose the LOFSW shift has to be applied where the receiving DVB device is located. That's something Lars can tell you...

 

My Sky TV Box has the same issue, does that rule out the PC generating RFI?

Most likely yes.

[CellZapper]

I have the same problems with (my own) interfrerence from a dect phone,it is on the same channels and similar frequenies on other satellites.

 

I have the problem with sky digibox, technomate 5400, echostar receiver, and a pc PVR.

 

the only cures I have found are

switch of the dect phone, best result.

move the DEct phone to a less interferring location.

Get a better signal level down the cable, (I can test this but unfortunately I have a long cable run so can't get a permanent improvment to the signal level).

 

You have no beef with your neighbours as the interference is from the allowed transmission of radio signals in the 2.4 ghz band used by dect phones, wifi networks and bloootooth ( the later being usually so low power as not to be a problem, and I note that wifi does not seem to cause the problem allthough it is nearby on pvr and laptop)

 

BT offer solutions (google for them) in the form of BT telephone face plates,(thinking about it I believe it is to keep the interfrence out of the BT cables) but first find the cause/source you or a neighbour (i assume you use wifi with you computers)(maybe more than 1 source causing a build up of intererence)

 

you can also replace your TV and satellite wall face plates for properly RFI shielded models (logitek offer some, see screwfix catalogue) I am about to try this when time allows. (my telephone cables run next to my coax runs, can't move the telephone cable due to the hose being on top of them, inconvienient to move coax......)

[CellZapper]

My Sky TV Box has the same issue, does that rule out the PC generating RFI? I'm not sure how good this cable is, but chances are the stuff inside my walls going to the Co-Ax Out socket on my wall is much lower quality. (This place was built on the cheap, ADSL gets a huge amount of RFI here as well, yet 200 meters away on another road its perfect. Literally double the sync rate!)

 

I just read the above, The coax cable is critical to this, if it is running in a duct with the telephone cables from the neighbours, that could be the point of interference insertion. the quality of the cable is all that separates you from the interference.

 

the types of installation used for multi drop satellite instalations need to carried out by skilled technicians to prevent these problems, I am not qualified to comment about that, and people who have more than just an "opinion" are going to be dificult to find (and expensive).

 

You could absail down the building with a test cable.......just joking.

[Griga]

@UndeadDevil: No support via PM - read the forum rules! But an explanation here:

 

A frequency like 11642 MHz can't be transported through a cable. That's why the LNB converts it to a lower intermediate frequency. It is done by mixing the original frequency with the local oscillator frequency (LOF) of the LNB: 9750 MHz for the low band (transponder frequencies below 11700 MHz) and 10600 MHz for the high band (transponder frequencies above 11700 MHz). The 22 khz signal sent by the receiver to the LNB switches between those two LOFs (22 khz on = high, off = low).

 

The intermediate frequency arriving at your receiver is the original transponder frequency minus the LOF. For 11642 MHz as low band frequency (22 khz tone off, LOF = 9750):

 

11642 - 9750 = 1892 MHz

 

and when you shift it to the high band (22 khz tone on, LOF = 10600):

 

11642 - 10600 = 1042 MHz

 

The intermediate frequency is the one that can get jammed on its way to your receiver. It's quite unlikely that a terrestrial source affects the original frequency. However, a neighbouring satellite position may cause disturbances if your dish is not adjusted well and/or if it is a very small dish (below 60 cm) that doesn't focus so sharply.

[UndeadDevil]

Thanks for the detailed explanation Griga, do you have a job in the Satalite industry? I haven't had the slightest issue in 5 hours now! Not even 1 discontinuity! I'm not getting my hopes up that its completly gone yet but it seems that your advice worked perfectly. (I did initially re-tune by changing to another transponder and then changing back, this didn't make a difference. However I had to reboot my PC and since I did the transponder is coming through perfectly.)

 

For the record I've been trying to get this issue solved for over 2 years, had the "satalite experts" out several times but they gave up. Thank you for this solution Griga!

Edited June 24, 2009 by UndeadDevil