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Lab Tests Reveal Truth!
The EMC legislation relies upon the quality of the tests undertaken by laboratories and to this end, labs with the authorisation to test to the harmonised standards are called Notified Bodies. The personnel responsible are highly trained and the results definitive. We have just published a set of results for a Comtrend PLT adapter from one such Notified Body. The result speaks for itself.

<< Test Results Here >>

Ofcom Commissions Report
Due to criticism from many fronts including the RSGB and from the Industry Association the EMCIA and Summit Group, Ofcom have commissioned yet another report into PLT. .

Originally scheduled to  be published at the end of November 2009 it was to cover the existing PLT 'standard' of 2 - 28 MHz but was adjusted to include VHF in light of the new gigabit PLT standard which will pollute up to 300 MHz. A freedom of information request has determined it is scheduled for publication in April.

300 MHz in the FOIA >>
Urgent - 300 MHz is live!
We recently purchased a Belkin "Gigabit Powerline HD Starter Kit" model F5D4076uk.

The units were installed per the manual and the emissions inside the house effectively wiped out most radio reception from:-

 0.1 MHz to 370 MHz.

The units have been sent away for examination and testing to the current harmonised standards. The preliminary test results are in and it does not look good.

Belkin Field Test Results
The Test Results from a Notified Body. . .

 Shortly after putting up this website I was sent a batch of Compliance Test results for a Comtrend 200Mbps Powerline Adapter. The results are very revealing.

 This test was conducted by Hursley EMC who are a Notified Body with international Accreditation, including Military. The test results from an organisation such as this are indisputable. Let's take a look at the results and see what they have to say. . .

.

 

Test Number    :06
Customer       :JOHN RALLEY

Details of Equipment under test

  SYSTEM UNIT  :   200Mbps Powerline Adapter                         

                   P/N: 301104-092                                   

  Mfg          :   Comtrend                                          

  S/N          :   08011006455A                                      

  VOLTAGE, FREQ:   230v 50Hz NEUTRAL                                 

  TEST BY      :   M.T                                                

 

Test Limit                     :CISPR "B" Av
Test Loaded                    :2008/12/04 at 16:16
Completion                     :100% 2008/12/04 at 16:36
Report printed at              :2008/12/04 at 16:36
Software level                 :1075262254
Test specification file        :CONDUCTED EMISSIONS9_45.DCF
Test Sequence file             :CONFIGS\CON_COM.DCF
Spectrum Analyser definition   :INSTRUMENTS\SPECANL\HP8568B_8.DCF
Transducer Correction          :FACTORS\CONDUCTEDD.DCF
Source table file(s)           : C:\PROFILA\FACTORS\CEFAC.TXT C:\PROFILA\FACTORS\COND CABLE FACTOR.TXT
Test Receiver definition       :INSTRUMENTS\RX\ESH3_4.DCF
Transducer Correction          :FACTORS\CONDUCTEDD.DCF
Source table file(s)           : C:\PROFILA\FACTORS\CEFAC.TXT C:\PROFILA\FACTORS\COND CABLE FACTOR.TXT
Plot is filed as C:\PROFILA\RESULTS\JOHN RALLEY\08CE0526_06.WMF

SIGNIFICANT PEAKS

 Frequency    Absolute   Amplitude  Test limit    Detector  

              Amplitude  relative  to limit                           

 779.950 KHz    41.27dB   -14.73dB  CISPR "B" QP  Quasi Peak

 779.950 KHz    28.77dB   -17.23dB  CISPR "B" Av  Average   

 1.36940 MHz    39.64dB   -16.36dB  CISPR "B" QP  Quasi Peak

 1.36940 MHz    27.34dB   -18.66dB  CISPR "B" Av  Average   

 2.65710 MHz    90.52dB    34.52dB  CISPR "B" QP  Quasi Peak

 2.65710 MHz    75.42dB    29.42dB  CISPR "B" Av  Average   

 5.92820 MHz    89.95dB    29.95dB  CISPR "B" QP  Quasi Peak

 5.92820 MHz    75.25dB    25.25dB  CISPR "B" Av  Average   

 8.03570 MHz    88.84dB    28.84dB  CISPR "B" QP  Quasi Peak

 8.03570 MHz    68.04dB    18.04dB  CISPR "B" Av  Average   

 12.2312 MHz    89.95dB    29.95dB  CISPR "B" QP  Quasi Peak

 12.2312 MHz    70.25dB    20.25dB  CISPR "B" Av  Average   

 17.2732 MHz    88.35dB    28.35dB  CISPR "B" QP  Quasi Peak

 17.2732 MHz    67.25dB    17.25dB  CISPR "B" Av  Average   

 23.1193 MHz    89.93dB    29.93dB  CISPR "B" QP  Quasi Peak

 23.1193 MHz    69.53dB    19.53dB  CISPR "B" Av  Average   

 27.5088 MHz    87.98dB    27.98dB  CISPR "B" QP  Quasi Peak

 27.5088 MHz    69.08dB    19.08dB  CISPR "B" Av  Average   

 



Well well. That doesn't look very good. So Mr. Ofcom, please tell me again how this conforms to 2004/108/EC / EN55022???

By the way, if you noticed above, I have highlighted the measurement which was highest in the group at 34.52dB. On another page on the site I have stated that a single PLT device can emit interference at the level of 1,000 barely legal units. I would like to point out that 34.52dB is equivalent of 2,830 barely legal devices. . .

Sorry Ofcom, I didn't quite get that, ? Thought there might have been an apology, guess not.

Well I suppose since "there is no significant harm arising" that makes a device which fails the internationally agreed legal limits for conducted emissions perfectly OK.

Oh but hang on, this could be a 'faulty' unit not representative of the product line. That's OK, I've got another unit's test results here:-

 

Test Number    :07
Customer       :JOHN RALLEY

Details of Equipment under test

  SYSTEM UNIT  :   200Mbps Powerline Adapter                         

                   P/N: 301104-092                                   

  Mfg          :   Comtrend                                           

  S/N          :   08011006455B                                      

  VOLTAGE, FREQ:   230v 50Hz LINE                                    

  TEST BY      :   M.T                                               

 

Test Limit                     :CISPR "B" Av
Test Loaded                    :2008/12/04 at 16:16
Completion                     :100% 2008/12/04 at 16:47
Report printed at              :2008/12/04 at 16:47
Software level                 :1075262254
Test specification file        :CONDUCTED EMISSIONS9_45.DCF
Test Sequence file             :CONFIGS\CON_COM.DCF
Spectrum Analyser definition   :INSTRUMENTS\SPECANL\HP8568B_8.DCF
Transducer Correction          :FACTORS\CONDUCTEDD.DCF
Source table file(s)           : C:\PROFILA\FACTORS\CEFAC.TXT C:\PROFILA\FACTORS\COND CABLE FACTOR.TXT
Test Receiver definition       :INSTRUMENTS\RX\ESH3_4.DCF
Transducer Correction          :FACTORS\CONDUCTEDD.DCF
Source table file(s)           : C:\PROFILA\FACTORS\CEFAC.TXT C:\PROFILA\FACTORS\COND CABLE FACTOR.TXT
Plot is filed as C:\PROFILA\RESULTS\JOHN RALLEY\08CE0526_08.WMF

SIGNIFICANT PEAKS

 Frequency    Absolute   Amplitude  Test limit    Detector  

              Amplitude  relative                           

                         to limit                           

 468.500 KHz    45.62dB   -10.92dB  CISPR "B" QP  Quasi Peak

 468.500 KHz    35.62dB   -10.92dB  CISPR "B" Av  Average   

 3.01290 MHz    91.94dB    35.94dB  CISPR "B" QP  Quasi Peak

 3.01290 MHz    75.04dB    29.04dB  CISPR "B" Av  Average   

 5.62430 MHz    90.63dB    30.63dB  CISPR "B" QP  Quasi Peak

 5.62430 MHz    74.33dB    24.33dB  CISPR "B" Av  Average   

 8.92120 MHz    88.17dB    28.17dB  CISPR "B" QP  Quasi Peak

 8.92120 MHz    72.37dB    22.37dB  CISPR "B" Av  Average   

 12.2271 MHz    91.65dB    31.65dB  CISPR "B" QP  Quasi Peak

 12.2271 MHz    76.05dB    26.05dB  CISPR "B" Av  Average   

 16.0399 MHz    89.83dB    29.83dB  CISPR "B" QP  Quasi Peak

 16.0399 MHz    63.23dB    13.23dB  CISPR "B" Av  Average   

 17.7996 MHz    84.86dB    24.86dB  CISPR "B" QP  Quasi Peak

 17.7996 MHz    61.26dB    11.26dB  CISPR "B" Av  Average   

 24.5304 MHz    90.25dB    30.25dB  CISPR "B" QP  Quasi Peak

 24.5304 MHz    70.95dB    20.95dB  CISPR "B" Av  Average   




Oh my word, look at 3 MHz. 35.94dB above the specified limit. That is equivalent of 3,930 barely legal devices.

But since Ofcom state they are legal, Ofcom MUST be correct, non? Well, er, no. Here we have definitive proof from an Internationally Accredited laboratory which clearly demonstrates that the devices tested do not conform to the internationally agreed legal limits.

These results at the time of writing are over a year old but yet 6 months after they were available, Ofcom pays Taxpayer's money to a commercial entity to compile a report on whether there is a problem with the technology.

Once upon a time I held Ofcom in high regard however, for a regulator to blatantly ignore verifiable test results from a respected laboratory who must by definition of their Notified Body status remain completely neutral, confounds me

At this point I feel ashamed to be British and associated by virtue of my nationality with an organisation so completely inept and unfit for purpose.

Finally I provide Comtrend unit 'B's' final result I almost missed it but there is an even higher reading:-
 




Test Number    :09
Customer       :JOHN RALLEY

Details of Equipment under test

  SYSTEM UNIT  :   200Mbps Powerline Adapter                         

                   P/N: 301104-092                                    

  Mfg          :   Comtrend                                          

  S/N          :   08011006455B                                      

  VOLTAGE, FREQ:   230v 50Hz NEUTRAL                                 

  TEST BY      :   M.T                                                

 

Test Limit                     :CISPR "B" Av
Test Loaded                    :2008/12/04 at 16:16
Completion                     :100% 2008/12/04 at 16:54
Report printed at              :2008/12/04 at 16:54
Software level                 :1075262254
Test specification file        :CONDUCTED EMISSIONS9_45.DCF
Test Sequence file             :CONFIGS\CON_COM.DCF
Spectrum Analyser definition   :INSTRUMENTS\SPECANL\HP8568B_8.DCF
Transducer Correction          :FACTORS\CONDUCTEDD.DCF
Source table file(s)           : C:\PROFILA\FACTORS\CEFAC.TXT C:\PROFILA\FACTORS\COND CABLE FACTOR.TXT
Test Receiver definition       :INSTRUMENTS\RX\ESH3_4.DCF
Transducer Correction          :FACTORS\CONDUCTEDD.DCF
Source table file(s)           : C:\PROFILA\FACTORS\CEFAC.TXT C:\PROFILA\FACTORS\COND CABLE FACTOR.TXT
Plot is filed as C:\PROFILA\RESULTS\JOHN RALLEY\08CE0526_09.WMF

SIGNIFICANT PEAKS

 Frequency    Absolute   Amplitude  Test limit    Detector  

              Amplitude  relative                           

                         to limit                           

 2.83200 MHz    92.13dB    36.13dB  CISPR "B" QP  Quasi Peak

 2.83200 MHz    77.03dB    31.03dB  CISPR "B" Av  Average   

 5.51085 MHz    90.33dB    30.33dB  CISPR "B" QP  Quasi Peak

 5.51085 MHz    74.63dB    24.63dB  CISPR "B" Av  Average   

 8.66075 MHz    87.56dB    27.56dB  CISPR "B" QP  Quasi Peak

 8.66075 MHz    67.66dB    17.66dB  CISPR "B" Av  Average   

 12.3164 MHz    88.06dB    28.06dB  CISPR "B" QP  Quasi Peak

 12.3164 MHz    68.86dB    18.86dB  CISPR "B" Av  Average   

 17.2730 MHz    89.85dB    29.85dB  CISPR "B" QP  Quasi Peak

 17.2730 MHz    69.55dB    19.55dB  CISPR "B" Av  Average   

 19.7734 MHz    88.79dB    28.79dB  CISPR "B" QP  Quasi Peak

 19.7734 MHz    68.79dB    18.79dB  CISPR "B" Av  Average   

 22.8161 MHz    91.63dB    31.63dB  CISPR "B" QP  Quasi Peak

 22.8161 MHz    71.83dB    21.83dB  CISPR "B" Av  Average   

 25.6250 MHz    90.56dB    30.56dB  CISPR "B" QP  Quasi Peak

 25.6250 MHz    68.66dB    18.66dB  CISPR "B" Av  Average   

 

 




In this final test, the first result in the series is a record breaker. At 36.13db above the internationally agreed limits for Conducted Emissions, this represents a staggering 4,100 times the interference of a barely legal unit.

I have now got around to putting up the results for the Advent 200Mbps PLA's which can be found on the following page. They are also quite interesting, with some results peaking over 40dB above the limit.
 



 

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