These devices are coming to Europe the container load.
The NanoTeam pulls these little beasties apart, prostrates their innards in order for you to see what makes them tick, and how we can make them sound a little nicer
Since December the 8th 2006, subject to interface requirements, nanotransmitters have been legal to use in the UK!
http://www.ofcom.org.uk/media/news/2006/10/nr_20061005
http://www.ofcom.org.uk/consult/condocs/exemption/statement/
Such devices come under the category of 'Licence Exempt Short Range
Devices' and need to meet the minimum requirements set out in UK Interface Requirement 2030 under the section Wireless Audio Applications.
Other existing requirements such as Directive 1999/5/EC also apply.
The maximum permitted power level in the UK is 50nW e.r.p.
Yes that's 50 nano Watts or 50x10-9 Watts!
0.00000005 Watts ERP !!!
We're talking modulator
power levels here, barely transmitter power levels at all.
Ofcom's original research started out by testing a power level of 10nW which they
found would only just work in a room with a portable receiver at less than 3m distance and almost certainly
wouldn't work at all if the tuner was using a roof top antenna. They proved
that because of metal obstructions, it would be very hit and miss in a car. They
further reasoned that given the lack of selectivity of a typical receiver, you would
need to be tuned 250-300kHz away from even a fairly weak broadcast receiver in
order to avoid interference to the SRD user.
They then tried 250µW and concluded that this worked really well but were
concerned that when really close in proximity and frequency to another receiver
tuned to a another broadcast, some poorer receivers would give problems.
They then bought two commercial micro transmitters and tested their EIRP levels
which they found to be about 15nW and 50nW. They then tried them out with three cars.
The 15nW device only worked satisfactorily in one of the cars as this had an
antenna combined with the heated rear windscreen.
They found that even the higher power device had signal nulls with one of the cars.
They then tried them both out in a domestic environment and found them to work
ok if in the same room but not if a rooftop antenna is used.
They named all the test equipment used, even the three cars, but not the two
commercial SRDs. They described them, however, and one matches the specification
and description of the Belkin TuneCast II.
They suggested, also that this 50nW device would not meet the Part
15 FCC regulations as it was too 'powerful'
And in conclusion, they decided that if they can walk around a micro transmitter
on a lawn for a few meters carrying a Grundig Yacht Boy, and the signal fizzled
out after a few metres, then a conservative 50nW seemed like an appropriate
power level to suggest. Read the full Ofcom publication here
Identification is surprisingly difficult with these devices. Many of them can look practically identical to each other, and it's not until you open them up do you notice that they are completely different. There are three visible features which mark them apart and go some way to establishing a family resemblance.
There are frequent and radical internal differences which can be catagorised by ...
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ChaoYu are easy to identify as the manufacturers name appears at the top left of the LCD display. |
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Externally very similar to the ChaoYu 668A minus the torch. Internally, it's a completely different animal. |
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Goldfly GF-ES2007 and similar 3 memory button transmitters No torch and simple display. Three 'cursor' type memory buttons. |
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No torch and simple display. No bottom buttons at all. |
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This is the really angular looking thing. Absolutely unique in its design approach. |
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It has a feeble range but sounds OK |
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The current device under test
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Picture coming shortly  |
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