25 May 2008

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Sundays: 08:00 UTC
 7205 kHz
  7082 kHz
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Mondays 19:00 UTC


Listen to what PLC sounds like

Listen to a report on interference at Rooiwal


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UPDATE 8 August 2008

IEC/CISPR Threatens Radio Services by a Planned 18 dB Relaxation of PLT Disturbance Limits

CISPR is the Special International Committee on Radio Interference of the International Electrotechnical Commission IEC with central office in Geneva, Switzerland. It is concerned with the development of standards regarding electromagnetic interference and most of these are adopted by the European Union and many other countries. Disturbance limits for Power Line Telecommunications (PLT) systems are defined by the standard CISPR 22 and its European equivalent EN 55022 entitled "Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement".


A PLT Project Team (PT) was formed in 2005 to produce an amendment to CISPR 22 to cover special requirements for PLT equipment and its first Committee Draft (CD) was issued in February 2008 (doc. CISPR/I/257/CD). However, the comments of 23 IEC members National Committees (NC) and the European Broadcasting Union (EBU) showed insufficient support for the selected approach (doc. CISPR/I/266A/CC) as only 6 NCs supported the draft: Belgium, France, Israel, Italy, Spain and Switzerland. Interestingly, the major European PLT technology providers, developers and manufacturers reside in 5 of these 6 countries.


8 NCs strongly opposed the draft - Australia, Austria, Cyprus, Denmark, Finland, South Africa, Sweden and the United States of America - and some well-founded comments revealed its true purpose: to camouflage an intended 18 dB relaxation of the present PLT disturbance limits by introducing a revised method of measurement with an estimated Longitudinal Conversion Loss (LCL) of 24 dB in contrast to 6 dB in CISPR 22:2005.

Click here for the full document

South Africa's position to the proposed CISPR 22 standard will be discussed at the SABS TC73 EMC meeting on Wednesday 13 August 2008. The SARL will be represented

ICASA is planning to hold public hearing in June

On 7 February ICASA published a notice of intention to make regulations in respect of Technical standards for Power Line Telecommunication (also known as PLC and BPL). A Public Hearing is planned for June.

Down load the draft regulations here

The SARL and Hamnet have lodged an objection to the draft regulations. Read on ..


Submission to ICASA in response to the notice of intention to make regulations in respect of technical standard for power line telecommunications – Government Gazette 30752           7 February 2008

The South African Radio League is the National Body for Amateur Radio as appointed by the Minister of Communication of the Republic of South Africa.

The Council of the South African Radio League has carefully considered the draft regulations for Power Line Communication. We recognise ICASA’s efforts in drafting regulations for PLT in order to regulate its use in South Africa with the minimum of impact on the HF Radio Spectrum. 

We are however of the opinion that the draft regulations do not go far enough to protect the HF spectrum from interference from PLT and therefore object to the implementation of the draft regulations. 

We have consulted widely with our members and the American Radio League Laboratory who have wide experience of the problems that PLT (BPL in the USA) cause on the HF spectrum. The experience of the ARRL is particular relevant as the current South African draft regulations are largely scaled on FCC rules and experience. 

Frequency Band Exclusion (6.2 in the draft) 

During the drafting of the regulation by TC80 WG 6, The SARL insisted that all HF amateur bands be included in the Frequency Band Exclusion clause. This was accepted. However at a following meeting, on insistence of the PLT industry, it was rejected as unpractical and removed from the earlier draft. 

The FCC did not include the exclusion of amateur HF frequency bands in their regulations but paid a heavy price with large number of interference complaints and on going court action. 

It is interesting to note that in the USA, as a practical matter, BPL manufacturers have had to avoid the ham bands and are notching the amateur radio frequencies as a matter of cause. The SARL therefore request again that all amateur bands be included in the table of Frequency Band Exclusion. 

By adding the amateur HF bands to the list of Exclusions ICASA would give sound guidance to the PLT industry to avoid the mistakes made by their American counter parts and avoid going the expensive road of conflict and extensive mitigation processes. 

In rule 6.5 a notch depth of 20 dB is recommended. This has proven to be inadequate. The state of the art of the technology is that notch depth is at 35 dB as a minimum.  Having a 35 dB requirement would not be a major burden on the industry but would avoid most major interference problems if coupled with Amateur band exclusions. 

 Comments on section 4 of the draft regulations 

The draft regulations are largely modelled on the FCC BPL regulations which have not proven to be a model for success.  The high permitted limits that are tens of dB greater than the present noise levels, permitted conducted signals that are tens of dB higher than the present conducted emissions limits and flaws in test methodology and required filtering notch depth have resulted in numerous complaints of interference in the US. 

It seems unwise for South Africa to follow this route. 

Comment on limits 

In CISPR 22, two sets of limits and test methods are set.  One limit applies to noise conducted onto the AC mains.  This is tested through an Artificial Mains Network (AMN), differentially from the hot and neutral conductors to the ground plane reference.  These limits are intended to indirectly control radiated emissions and to protect other equipment connected to the AC mains from excess conducted noise.  These limits are as outlined in Table 2 of the draft. 

The second set of limits and test method is related to the signals that would be conducted out the signal port of an ITE device, ie onto an Ethernet or DSL cable.  Limits on these signals are intended to indirectly control only radiated emissions, because normally, other devices are not connected to the Ethernet or DSL cable.  The test methodology measures ONLY the common-mode signal present on the signal ports, with no attempt to control or measure the differential mode signal, ie the desired Ethernet or DSL signal. These limits are as outlined in Table 4.

 The limits for the signal port are higher than the limits for the AC mains. 

In the developing drafts for CISPR 22, for BPL/PLC devices, the PLT port and AC mains port are one and the same, so the attempt to define a separate PLT port, with the ensuring higher limits and the measurement of ONLY common-mode signals on the "PLT port" is an attempt by the PLT industry to not have to meet the Mains Port limits, but instead, to be able to measure and control only common-mode signals.  This is inappropriate on several levels.  Any regulations that permit PLT signals to conduct noise onto the AC mains in excess of the limits in Table 2 will be presenting other devices on the AC mains with a much stronger noise level than they are seeing right now. 

The SARL recommends that the regulations must require that PLT devices meet the limits of Table 2 AND Table 4, and that it measure the differential noise conducted onto the AC mains from each phase to the ground reference plane. 

4.2.1. Radiated limits below 30 MHz. 

The permitted levels of 30 dBuV/m at 30 metres are tens of dB greater than the present median value of man-made noise.  PLT signals continuously occupy large swaths of spectrum and usually occupy that spectrum for long periods of time. PLT systems also occupy large geographical areas. The premise that the limits that serve to some degree to control emissions from devices that emit only locally can also serve to control emissions from an emitter that could be as large as an entire city is fundamentally flawed.  Note 2 at the bottom of the table in 4.2.2 should be added to the table for 4.2.1 as well. 

4.2.2 Radiated limits above 30 MHz.

The same issue applies -- these levels are much higher than the median values of man-made noise.

7.  Complaint – Resolution processes 

The "mutually agreeable schedule” is not a workable practice and could lead to extended periods to reach agreement. If the industry has the mechanism to respond to public-safety complaints within 24 hours, there is no reason not to apply that standard to all interference complaints.  

7.5 The draft regulation states: “The standard ICASA complaints resolution process must be used for reporting cases of interference.” 

No such procedure has been published in the public domain. Current experience has shown that interference complaints on HF are seldom resolved and ICASA has often to be reminded of outstanding cases. The usual comment from ICASA staff is that the Authority is not fully equipped to deal with interference on HF frequencies. 

8. PLT Database 

The SARL is concerned that ICASA does not currently have the infrastructure or personnel to execute a PLT database and update information within 3 days. This statement is based on the long delays in updating the ICASA website. The reasons often given are excessive workload and lack of capacity. 


The draft regulations fall short of stipulating that only legally acceptable measurement results would be those that were obtained by an independent SANAS accredited testing laboratory with accreditation for testing to the CISPR 22 standard. While this is standard ICASA policy, the SARL believes that it needs to be entrenched in the PLT Standard to avoid possible misunderstanding on this issue. It is already suspected that most of the initial PLT interference measurement results in South Africa were not obtained from tests that were performed by such accredited facilities. 


The South African Radio League rejects the draft PLT regulations as inadequate to protect the HF radio spectrum from interference from PLT installations and propose that ICASA goes back to the drawing board or holds on till the international standards are finalised. Until such time no PLT installations should be authorised. That includes pilot sites. 

If pilot sites are authorised under the general regulations, all stakeholders in the HF spectrum should be notified ahead of the pilot and if interference to the HF spectrum occurs, the pilot must be switched off within 24 hours of a complaint reaching the operator of the pilot and ICASA. 

No PLT operator should be allowed to advertise their equipment until such time as regulations have been agreed and gazetted and equipment type approved following the review of test results from an SANAS accredited test laboratory.  

Submitted on behalf of the SARL Council

Hans van de Groenendaal
SARL Councillor Regulatory Affairs


Submission to ICASA in response to the notice of intention to make regulations in respect of technical standard for power line telecommunications – Government Gazette 30752           7 February 2008 


HAMNET is the emergency communications division of the South African Radio League.  Hamnet serves on the sub-committee of the South African Search & Rescue Organisation and also provides emergency communication for organisations like the Off Road Rescue Unit, the Mountain Club of South Africa, the K9 Dog Unit, The N.S.R.I and many Emergency Medical Service Units around South Africa. 

HAMNET services are not restricted to the above.  Any organisation in South Africa or internationally may at their discretion call on Hamnet to provide alternative means of communication in any emergency situation.  Hamnet as an example serve on the IRESC – the International Radio Emergency Support Coalition that make extensive use of dedicated emergency channels as listed below. 

In December 2007 the Global Forum on 'Effective Use of Telecommunications and ICT for Disaster Management: Saving Lives' launched two important initiatives, the ITU Framework for Cooperation in Emergencies and the ITU Network of Volunteers for Emergency Telecommunications. The ITU Secretary-General also established a High-Level Panel for Emergency Telecommunications consisting of Mr Eui Koh, Mr Jay Naidoo, and Mr Olof Lundberg.

The ITU Framework for Cooperation in Emergencies (IFCE), formally launched at the Forum, is designed to make telecommunications/ICT resources available for use by government agencies responsible for disaster relief, humanitarian personnel as well as victims of disasters through its technology, finance, and logistics clusters seeking to ensure that reliable, easily transportable and technology-neutral systems are deployed in a timely manner whenever and wherever disasters may occur. The IFCE is an integral part of ITU's other activities undertaken at all phases of disaster management, such as disaster preparedness, early warning, and rehabilitation of telecommunications networks.

Radio Amateurs are an important part of this ITU initiative and as such seek protection of dedicated frequencies. As disasters happen unannounced, radio amateurs may be called to any part of the country to render their services. If PLT interference is present on the listed emergency channels, the emergency communication efforts would be severely impacted or even rendered unusable. 

There are many documented instances where radio amateurs were first on the scene to provide much needed communication. In South Africa the Laingsburg disaster and tropical storm Demoina come to mind. Internationally the Tsunami, Hurricane Katrina, earth quakes in India are some examples of where radio amateurs world-wide rendered assistance. Their HF capability allows a network to be set with the minimum of delay overcoming adverse propagation conditions by setting up alternative relay paths. 


Hamnet therefore seeks the addition in rule 6.2 the following frequencies for exclusion. These frequencies are worldwide coordinated frequencies by the International Amateur Radio Union 

21 360 kHz Global emergency centre of activity

18 160 kHz Global emergency centre of activity

14 300 kHz Global emergency centre of activity 

7 060 kHz Region 1 emergency centre of activity

3 760 kHz Region 1 emergency centre of activity

10 149.3 kHz APRS emergency monitoring frequency for yachts at sea

We trust that ICASA will consider the above request for modification of the draft regulations with the same respect as amateur radio’s contribution to disaster management communication is held by the ITU and other world bodies.

Yours sincerely
Francois Botha
National Director HAMNET

Emergency communication division
of the South African Radio League





Read reports from Radio Amateur driving through Rooiwal, listen to the interference and judge for yourself