Naked Science Forum
Non Life Sciences => Technology => Topic started by: neilep on 12/09/2009 12:02:10
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Dearest USBologists,
Hope you're well !..it must be fun being a USBologists..I bet ewe get up to all kinds of whacky and crazy things....like exchanging a model USB80123 for a model USB80123a in someones laptop without telling anybody eh ?....ewe crazy crazy mad people !!
As a sheepy I of course enjoy wireless laptop luff but can't understand why this:
[ Invalid Attachment ]
A USB Sticky Thingy Thing
Should interfere so much with the signal being received by this
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A DAB Radio Thing Being Well Interfered With !
Ewe see...what I don't get is that the USB Sticky Thing is a receiver yes ?...so why on earth does it make my DAB radio sound like it's underwater ?..why ?....
Please assist, I am in need of assistance !!..that's what people say !
Hugs & Shmishes
mwah mwah mwah mwah !
neil
USB Stick Investigator
xxxxxxxxxxxxxxxxxx
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Er, well, I think your USBstickything is probably a radio transceiver, which is technospeak for something that transmits and receives. So, perhaps it's interfering with your radio while it's transmitting.
However, it's very difficult to figure all of this from a remote location, so I suggest you pack your radio, laptop and USBstickything in a well padded cardboard box and send it to me so I can investigate further. I'll message the shipping address to you.
Cheers!
Honest John RF Investigators, Inc.
Purveyors of RF thingys to Rich People
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Dongle. No it's not a term of abuse, your USB thingy is a broadband wireless dongle.
So it's essentially the same as a mobile phone, (which transmits and receives radio signals).
http://en.wikipedia.org/wiki/Dongle
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Assuming that your USB thingy is a wireless LAN adapter, it's a bit strange that it seems to be interfering with your DAB reception as they operate in different bands: wireless LAN uses either the 2.4 or 5 GHz bands whereas the DAB in the U.K. utilises frequencies between 209-230 MHz.
DAB, and especially the way it has been implemented in the U.K, has a few serious problems. In the U.K, for example, a BBC R&D white paper stated:
A value of 256 kbit/s has been judged to provide a high quality stereo broadcast signal. However, a small reduction, to 224 kbit/s is often adequate, and in some cases it may be possible to accept a further reduction to 192 kbit/s, especially if redundancy in the stereo signal is exploited by a process of 'joint stereo' encoding (i.e. some sounds appearing at the centre of the stereo image need not be sent twice). At 192 kbit/s, it is relatively easy to hear imperfections in critical audio material.
Yet, in July 2006, the BBC reduced the bit-rate of transmission of Radio 3 from 192 kbit/s to 160 kbit/s, and the way that the U.K. government has licensed the spectrum has resulted in many broadcasts being below 128 kbit/s, and sometimes down to 64 kbit/s for monaural speech radio.
With such low bit rates the poor error correction techniques used in DAB (as opposed to the later DAB+ standard, which is not used in the U.K.) frequently result in the gurgling you hear whenever you get a poor signal.
Another broader problem with DAB, and DAB+ too, for that matter, is that DAB receivers use much more power than ordinary FM radios because of the additional digital processing overhead. This typically means that DAB receivers use between 6 and 12 times more power than FM receivers.
For a full list of the problems with DAB have a look at:
http://en.wikipedia.org/wiki/Digital_Audio_Broadcasting#Criticisms_of_DAB (http://en.wikipedia.org/wiki/Digital_Audio_Broadcasting#Criticisms_of_DAB)
Anyway, back to your specific problem.
If you're using a wireless LAN adapter in your lappy, you must also have either a wireless lan home-hub or router, or another wireless LAN equipped PC or lappy (or you're using your neighbour's bandwidth which, based upon how often he has 'helped' you with your experiments in the past, is quite likely), so try removing the USB thingy from your lappy and then put your DAB box near your home-hub/router or your other wireless lappy/PC and see if you get the same problem. If another wireless LAN device doesn't cause problems, and it's only the new USB thingy that does, then perhaps there's a fault with it such that it's broadcasting (noise) outside its alloted band.
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If the dongle is mobile wireless (http://en.wikipedia.org/wiki/Broadband_wireless_access#Mobile_wireless_broadband) (not WLAN) then it operates at mobile "cell" phone frequencies ...
Cellular mobile services operate within the frequency ranges 872-960 MHz, 1710-1875 MHz and 1920 - 2170 MHz.
http://www.sitefinder.ofcom.org.uk/mobilework.htm
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Er, well, I think your USBstickything is probably a radio transceiver, which is technospeak for something that transmits and receives. So, perhaps it's interfering with your radio while it's transmitting.
However, it's very difficult to figure all of this from a remote location, so I suggest you pack your radio, laptop and USBstickything in a well padded cardboard box and send it to me so I can investigate further. I'll message the shipping address to you.
Cheers!
Honest John RF Investigators, Inc.
Purveyors of RF thingys to Rich People
Thank ewe Geezer !...I am humbled by your kind offer to give my equipment a ' once over '.....thing is...I'm a lazy sheep and to get it to ewe will take some effort. I will have to unplug it all for start....phew !!...just thinking about collapsing the DAB aerial has got me perspiring. I have a simple and effective solution.
If ewe perchance can see your way to sending me some tickets (first class of course including limousine transportation to and from)..i will see my way to coercing the kids to pack everything away for me. I will then travel all the way to ewe for what I am sure will take a good four weeks diagnosis....I may have to go on a tour to allow for your careful consideration of my communication problem.....for which I am sure you'll be happy to compensate me (pro forma of course)...yes..yes..I am sure this will work and I am very grateful !
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Dongle. No it's not a term of abuse, your USB thingy is a broadband wireless dongle.
So it's essentially the same as a mobile phone, (which transmits and receives radio signals).
http://en.wikipedia.org/wiki/Dongle
Ah !..Thank ewe RD....as also mentioned by that trustworthy Geezer fellow....I see now that my "dongle " does indeed transmit.
I will get my dongle and wave it about to see how transmittable it's effects are ! [;)]
Thanks for the link...very interesting.
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Assuming that your USB thingy is a wireless LAN adapter, it's a bit strange that it seems to be interfering with your DAB reception as they operate in different bands: wireless LAN uses either the 2.4 or 5 GHz bands whereas the DAB in the U.K. utilises frequencies between 209-230 MHz.
DAB, and especially the way it has been implemented in the U.K, has a few serious problems. In the U.K, for example, a BBC R&D white paper stated:
A value of 256 kbit/s has been judged to provide a high quality stereo broadcast signal. However, a small reduction, to 224 kbit/s is often adequate, and in some cases it may be possible to accept a further reduction to 192 kbit/s, especially if redundancy in the stereo signal is exploited by a process of 'joint stereo' encoding (i.e. some sounds appearing at the centre of the stereo image need not be sent twice). At 192 kbit/s, it is relatively easy to hear imperfections in critical audio material.
Yet, in July 2006, the BBC reduced the bit-rate of transmission of Radio 3 from 192 kbit/s to 160 kbit/s, and the way that the U.K. government has licensed the spectrum has resulted in many broadcasts being below 128 kbit/s, and sometimes down to 64 kbit/s for monaural speech radio.
With such low bit rates the poor error correction techniques used in DAB (as opposed to the later DAB+ standard, which is not used in the U.K.) frequently result in the gurgling you hear whenever you get a poor signal.
Another broader problem with DAB, and DAB+ too, for that matter, is that DAB receivers use much more power than ordinary FM radios because of the additional digital processing overhead. This typically means that DAB receivers use between 6 and 12 times more power than FM receivers.
For a full list of the problems with DAB have a look at:
http://en.wikipedia.org/wiki/Digital_Audio_Broadcasting#Criticisms_of_DAB (http://en.wikipedia.org/wiki/Digital_Audio_Broadcasting#Criticisms_of_DAB)
Anyway, back to your specific problem.
If you're using a wireless LAN adapter in your lappy, you must also have either a wireless lan home-hub or router, or another wireless LAN equipped PC or lappy (or you're using your neighbour's bandwidth which, based upon how often he has 'helped' you with your experiments in the past, is quite likely), so try removing the USB thingy from your lappy and then put your DAB box near your home-hub/router or your other wireless lappy/PC and see if you get the same problem. If another wireless LAN device doesn't cause problems, and it's only the new USB thingy that does, then perhaps there's a fault with it such that it's broadcasting (noise) outside its alloted band.
Thank Ewe LeeE very muchly for all this very great information. I really do appreciate it.
It's definitely a LAN wireless thingy. Unfortunately it's simply impractical to move the DAB radio next to the wireless router...but not impossible !...I may try this as some form of empirical research !
Hmmm..bad error correction eh ?..I have noticed that I do not get the best of signals but everything is fine until I turn the lappy on !
I have to say that when I do use the FM instead of DAB I do experience more warmth...I think this may be akin to vinyl against Cd..or valves against transistors perhaps ?. I know in the early days there was lots of contention regarding the quality of DAB verus FM....it's a shame it's still relevant today
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It depends on the design techniques used in the wireless LAN thingy. As Lee says the frequency bands are different from DAB, however the LAN thingy's receiver may well be some sort of superhet design requiring the second Local Oscillator (2LO) to be around the DAB frequencies. This would be a very poor design for the UK market, and even poorer if inadequately screened, but this is certainly possible. The 2LO will radiate if inadequately screened and this could interfere with the DAB signal.
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Thank ewe Geezer !...I am humbled by your kind offer to give my equipment a ' once over '.....thing is...I'm a lazy sheep and to get it to ewe will take some effort. I will have to unplug it all for start....phew !!...just thinking about collapsing the DAB aerial has got me perspiring. I have a simple and effective solution.
If ewe perchance can see your way to sending me some tickets (first class of course including limousine transportation to and from)..i will see my way to coercing the kids to pack everything away for me. I will then travel all the way to ewe for what I am sure will take a good four weeks diagnosis....I may have to go on a tour to allow for your careful consideration of my communication problem.....for which I am sure you'll be happy to compensate me (pro forma of course)...yes..yes..I am sure this will work and I am very grateful !
No problem Neil. Tickets have been dispatched by wagon train and express tea clipper. Do you have a woolly coat? You may need it.
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..I have noticed that I do not get the best of signals but everything is fine until I turn the lappy on !
In that case, it looks as though the interference from the USB thingy is either due to bad design, as graham.d suggests, or a fault. If it's still under warranty you should try getting it replaced.
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..I have noticed that I do not get the best of signals but everything is fine until I turn the lappy on !
In that case, it looks as though the interference from the USB thingy is either due to bad design, as graham.d suggests, or a fault. If it's still under warranty you should try getting it replaced.
If he can find the guy who sold it to him out of his car boot [;D]
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Thank ewe Geezer !...I am humbled by your kind offer to give my equipment a ' once over '.....thing is...I'm a lazy sheep and to get it to ewe will take some effort. I will have to unplug it all for start....phew !!...just thinking about collapsing the DAB aerial has got me perspiring. I have a simple and effective solution.
If ewe perchance can see your way to sending me some tickets (first class of course including limousine transportation to and from)..i will see my way to coercing the kids to pack everything away for me. I will then travel all the way to ewe for what I am sure will take a good four weeks diagnosis....I may have to go on a tour to allow for your careful consideration of my communication problem.....for which I am sure you'll be happy to compensate me (pro forma of course)...yes..yes..I am sure this will work and I am very grateful !
No problem Neil. Tickets have been dispatched by wagon train and express tea clipper. Do you have a woolly coat? You may need it.
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Looks like North London ! [;)]
Looking forward to receiving the tickets Geezer...I hope they are not dodgy Geezer !! [;)]
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..I have noticed that I do not get the best of signals but everything is fine until I turn the lappy on !
In that case, it looks as though the interference from the USB thingy is either due to bad design, as graham.d suggests, or a fault. If it's still under warranty you should try getting it replaced.
Thanks LeeE....It's probably bad design...it was an Ebay El-Cheapo special !!..there's probably no shielding whatsoever !
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..I have noticed that I do not get the best of signals but everything is fine until I turn the lappy on !
In that case, it looks as though the interference from the USB thingy is either due to bad design, as graham.d suggests, or a fault. If it's still under warranty you should try getting it replaced.
If he can find the guy who sold it to him out of his car boot [;D]
Car Boot sales happen far too early in the morning for a sheepy to attend !.... [::)] [:D]