[MLB-WIRELESS] OT: RF emissions of Grandstream Budgetone 102 VoIP phones.

[vak]

I agree that the ideal solution to this problem would be to separate 
power and coax by at least 600mm (if you have the luxury of performing a 
renovation).

If you rerun it, I suggest you use quad-shield RG6. This will help keep 
unwanted interference out.

Also, you might want to check if you've got stray currents on your roof 
(injecting into the mast -> antenna). I *HAVE* measured potentials of 
over 60V on some tin roofs (after feeling a buzzing feeling through my 
hands).

The other possibility is using a bandpass filter on the input to the TV, 
this won't keep out interference *IN* the VHF bands, but it will reduce 
outlying harmonics which can disturb TV images - The ACA actually put me 
onto a company who designed and manufacture these devices locally. From 
memory their solutions were between $50 and $100 (or there abouts). Give 
the ACA a call, they had some very competent techs who assisted me when 
I first put up my mast (my neighbour claimed I was causing her TV image 
to snow).

It is also worth determining which circuit your TV is on, turning all 
devices on that circuit off and then switching them on one by one. If a 
particular device (or combination of devices) is causing the problem, 
fit ferrites to its power lead.

It is also worth checking that the TV/Aerial socket is not damaged or 
improperly terminated - There's a chance that if it is not grounded 
properly (or oxidisation of the pins/shield/termination has occured) 
then that can also cause noise.

Also in a perfect world, you'd have the option to mount your AP away 
from the TV antenna.


Tony Langdon (ATC) wrote:

>>I have a power point right next to a TV aerial outlet. I 
>>suspect the power and aerial lines run right beside each 
>>other for some distance inside the wall. The TV picks up 
>>interference from devices plugged into that power point. Some 
>>devices generate more interference than others. Using a 
>>better quality cable between the TV and the wall point 
>>helped, but it is still visible, particularly on channel 9.
>>
>>I'm wondering what I could do to reduce the interference. 
>>Would wrapping the power cable through a ferrite inside the 
>>wall help? Any hints as to the best part to use?
>>    
>>
>
>The best solution would be to re-run the TV feedline and get some separation
>between that and the power wiring.  Depending on the frequency (in this
>case, it's VHF, so a good chance it'll work), you can get rid of some
>interference by using a clamp on ferrite or two on the power wiring, or
>alternatively on the wiring of offending appliances.
>  
>
>>(Trying to bring it back OT). The TV aerial has an AP in a 
>>box about 1m above it. I don't seem to get any TV 
>>interference from it. However, another person with a similar 
>>setup thinks he might be getting some TV interference. Would 
>>a ferrite around the ethernet help here?
>>    
>>
>
>It may, or it may not.  I have an AP that generates a bit of interference on
>channel 2.  I just live with it, the picture's still watchable. :)  Maybe
>after moving to the new place, I'll look at doing something more serious. :)
>
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