Following a request by RSGB last year, Ofcom announced on 1st February that it would extend the validity of the NoVs issued Amateur Radio Full licensees to operate under a Special Research Permit between 501 and 504 kHz until 28th February 2009.  Further, they agreed to the Society's request that the permitted maximum radiated power be increased; Ofcom are allowing an ERP of up to 0 dBW (1 watt).

Special Research Permits under a Notice of Variation to the Licence may be made available to holders of Full Amateur Licences on a case by case basis to applicants who can demonstrate a genuine interest in experimentation at these frequencies and provide adequate supporting documentation for assessment.

Due to the usage of the spectrum around 500 kHz, applicants should pay special attention to demonstrating technical and operational competence in terms of transmitting within the frequency and Effective Radiated Power (e.r.p.) parameters agreed with Ofcom. Previous experience at 73 kHz as well as 136 kHz will be considered desirable in this respect to ensure adequate steps are taken to limit any potential interference. 

Ofcom will monitor any interference reports with a view to limiting numbers in the use of the band if necessary. In general, considerably lower ERP levels than that permitted in the 136 kHz band are likely to be favourable and this will only be permitted where it can be demonstrated that increased powers are necessary for research. On no account will an e.r.p. level of greater than 0 dBW be permitted under any circumstance.

The standard application form (OfW306) for a Special Research Permit can be downloaded at:

http://www.ofcom.org.uk/radiocomms/ifi/licensing/classes/amateur/applications/ofw306.pdf

  Form OfW306 is also available on request from the Ofcom Licensing Centre at:

Ofcom Licensing Centre
Amateur Radio
Riverside House
2a Southwark Bridge Road
London SE1 9HA
Tel: 020 7981 3131  

Recommendations in considering and completing an application for the SRP

Ofcom's SRP form is a generic form to cover a range of possible research reasons that require operation outside the terms of the Amateur FULL Licence.  For this particular application it is important that prospective applicants consider the following and ensure that they follow the recommendations re RFI assessment and include information on the following points in their completed SRP form, either on the form itself or through attaching additional sheets: 

a) some form of research reason that confirms that the person is really keen to use the NoV;

b) an explanation of experience at LF/MF, e.g. 73 or 136kHz experience or equivalent as a marine officer.  Where 73/136kHz experience is lacking an explanation as to why the desired experience cannot be gained on 136kHz first, and perhaps any alternative design, construction or operating experience that is thought to be relevant;

c) an explanation as to how one is proposing to determine frequency and measure the e.r.p. of the station.

d) Whilst the standard SRP form requires a RFI field-strength assessment to be made at the property boundary and at the nearest neighbour's premises the nature of the long-wavelength at 501kHz makes this a difficult task for those where the boundary or the neighbour's premises are within 100m (which is termed the near-field zone, see our details on Radiation Theory for further information).  Because of Ofcom's limitation with respect to e.r.p. of -10dBW it is recommended that the distances be filled in on the SRP form, but that the applicant undertakes no detailed assessment, but in operation, must ensure that interference will not be caused to other users of radio or electronic equipment.  For those applicants where the boundary/neighbour is within 5m of any part of the aerial a scaled plan-view sketch of the proposed aerial, with boundaries and neighbour's premises shown, must be submitted along with the SRP application.

Note: Potential licensees should be aware that in all frequency bands, high intensity RF radiation may be harmful and safety precautions should be taken, particularly in locations to which people have access. Advice concerning safe levels of exposure to RF radiation is provided by the Health Protection Agency.  

Useful links

There are many other website of those operating on 136kHz that have valuable information, so would appreciate e-mails to the webmaster below on useful URLs to add that would be of assistance to those about to experiment on this frequency.

RSGB LF Group Reflector

An e-mail reflector has been operating for many years now to help encourage those wishing to experiment at LF.  In the early days it concentrated on 73kHz and 136kHz as well as occasionally other LF aspects; with the demise of 73kHz (in the UK) the reflector is one of the main Internet recourses available for coordinating operating and exchanging technical knowledge on 136kHz.  Now that we are experimenting on 501-504kHz many are using the reflector for advice and support for the early contacts - it is recommended that the numerals 500 be put into the subject line so that people can filter the e-mails coming from the reflector.

Anyone is free to join the reflector by sending an e-mail to Majordomo@blacksheep.org with the "subject" field blank and the following message in the message field: 

subscribe rsgb_lf_group

To unsubscribe from the reflector a similar e-mail is sent but with the slightly different message: 

unsubscribe rsgb_lf_group