Radio amateurs are serious about the rising RF noise floor

May 4th, 2017, Published in Articles: EE Publishers, Articles: EngineerIT


Radio amateurs are serious about tackling the problem of RF pollution and the resultant increase in the radio frequency noise floor. Since the beginning of the year interest groups have sprung up in various countries around the word and national amateur radio organisations are taking a serious stand and in several countries are accusing their spectrum regulators of not doing enough about it.

The Radio Society of Great Britain (RSGB) has recently  taken issue with assertions by telecoms regulator Ofcom that the agency “advises and assists spectrum users to help resolve harmful interference.” RSGB said that, while Ofcom does advise complainants from the amateur community and elsewhere, it is “usually only to the extent of advising that they can do nothing and have no further interest in the case.”  The regulator apparently rarely uses its statutory powers to assist.

The situation in the UK somewhat mirrors that in the US, where the FCC has cut back the number of personnel available in the field to handle complaints. RSGB noted that when Ofcom took over responsibility for UK spectrum management in 2003, there were 100 field technical personnel dealing with interference and enforcement work, supported by other enforcement and engineering personnel.

The spectrum has become steadily more polluted as the number of non-compliant and faulty pieces of electronic apparatus and equipment has risen, coupled with Ofcom’s reluctance to act against them, while spectrum use has continued to grow. Instead of rising to the challenge, Ofcom has in fact constantly reduced staff until it now claims to have just 30 field engineers for the whole of the UK.  The RSGB’s view is that this is short-sighted and inadequate.

Fig. 1: A typical screenshot of a SDR system showing the noise floor. (Screenshot by Henry Chamberlain ZS1AAZ)

Ofcom has masked this inadequacy, RSGB contends, by raising the noise threshold for technical assignments for commercial licensees, something it cannot do for the amateur service. Meanwhile, the sources of interference to radio amateurs “are manifold and increasing. The RSGB said more recent developments such as  wind farms, domestic solar arrays, and very high bit rate digital subscriber line (VDSL), which are the cause of severe problems are on the increase. RSGB said Ofcom’s typical response is “to merely check that the individual components are CE marked” and don’t acknowledge that the electromagnetic compatibility (EMC) regulations require that apparatus must be compliant when it is first put into service.

Over many years, the RSGB has been urging Ofcom to update its interference regulations, which can be used to stop interference from a wide range of apparatus when it is in use. “ While we welcomed the updating that took place in 2016, we pointed out several flaws in the regulations. These were not accepted by Ofcom”, the RSGB said.

In addition, another group of users of the radio spectrum in the UK  are urging candidates in the snap general election coming up in June 2017 to include action against radio frequency pollution  as part of the election manifesto. UKQRM is a volunteer-led collective of radio-spectrum users drawn from the public and from industry. Formed in 2008 in response to the radio-spectrum pollution devices known as power line technology, they aim to help all users of the radio spectrum where unnecessary man-made radio-spectrum pollution is experienced.

UKQRM has now taken the issue a step further by urging candidates to include  RF pollution in their election manifesto:   “The radio-spectrum users of the United Kingdom of Great Britain and Northern Ireland  want  parliamentarians  in the first Parliamentary session following the general election to  seek to enact primary legislation that dissolves the NGO known as the Office of Communications (Ofcom) and pass its functions to other government departments and enact primary legislation that creates a new radio-spectrum protection authority operating  as an independent body reporting to the Cabinet Office only.” More about their demands can be found on their website at .

The South African Radio League (SARL) held a workshop on 22 April 2017 to form a working group to address RF pollution problems in the local context. “While we all know that the problem exists and is in fact is escalating, we need to establish the level at which it occurs and the rate at which is escalates.”  Nico van Rensburg, the league’s president said.  “We all know the energy saving lights, solar panel controllers and a host of other electronic equipment are the culprits but we cannot generalise. For example, some LED lights are not causing interference while others do. Take two similar LED lights – when you break them open you will find that one has a full interference printed circuit  fitted while the problem one also has the protection printed circuit board, but it is not populated with the required components and did not meet the specification. It is all about making more profits”.  As in the UK and in many other countries it is a question of compliance enforcement which lies at the door of the spectrum regulators.

The SARL workshop resulted in the formation of a workgroup to develop guidelines on how to identify RF interference and pollution and to involve as many radio amateurs as possible to monitor specific frequencies over a period of time, as well as to observe the general increase in the RF noise floor using a dedicated system such as a dongle configured as a software defined radio.   The workgroup is planning a follow up with a workshop in the July/August 2017 time frame in order to report back.

Fig.1 depicts how the monitoring and taking of snapshots weekly over several months will enable a clear picture of what is happening to the RF noise floor. There are other factors to consider such as seasonal variation, ionospheric noise etc. For example, should someone in the neighbourhood put up an electric fence without  complying with the accepted installation standard (which often happens to cut costs) the interference will show up and can then be acted upon. The problem with RF pollution is that it is cumulative. One bad LED may not be a major problem but install ten or 20 in your home or office, and it will be a different story.

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