146-147 MHz Usage and Band Planning FAQ

New Ways of Amateur CommunicationsThe new 146-147 MHz allocation is available to UK Full licence holders from October 31, 2014. The RSGB have issued a FAQ document which answers some of the common questions about the new allocation.

They say in terms of enabling innovation and experimentation it might have been preferable if Ofcom was prepared to grant 146 MHz NoVs to holders of all classes of UK amateur licence. However, the Ofcom view was that because Full licensees have demonstrated a greater comprehension of the interference aspects, NoVs will only be available for holders of full amateur licences.

Map illustrating where 146 MHz cannot be used

Map illustrating where 146 MHz cannot be used

It is expected the allocation will be used for wideband digital transmissions. Bandwidth tailoring will be imperative to ensure no RF extends into the weak signal satellite segment at 145.8-146.0 MHz (the Lunar 4M JT65B beacon uses 145.980 MHz). Narrow band users in 147 MHz must also be protected from any increase in the noise floor.

The FAQ says:

The 146‐147 MHz band is ideal for testing new forms of medium bandwidth data transmission that can surpass traditional methods such as amateur AX25 packet data. Some higher speed data modes used by amateurs on microwave frequencies produce a very wide transmitted spectrum and are clearly not suitable for the 146‐147 MHz band. Even the 128kbps medium data rate D‐Star ‘DD Mode’ used on the 1296 MHz band fills up over 500 kHz of bandwidth at 60dB down on the peak transmitted power. However we do expect that amateurs will be able to develop solutions compatible with the spectral constraints of the 146‐147 MHz band.

146 MHz Spectral CompatibilityIn the initial 146‐147 MHz band plan there is a recommendation that wider bandwidth data modes should be centred at 146.500 MHz to make sure that all of the sidebands are contained within the 146‐147 MHz band. For initial experiments the recommendation is to use data rates of no more than 350 kbps and measure the total bandwidth at the transmitter output in order to ensure maximum protection of other users at the 147 MHz band edges and amateur satellite users below 146 MHz. As amateur radio access to the 146‐147 MHz band has been granted on a non‐interference basis, it is important that all amateurs adhere to these guidelines in order to ensure that there is no interference with users of adjacent bands. In the longer term it might be possible with bandwidth tailoring and pre‐distortion techniques to produce cleaner transmitters to permit greater data rates with sharper spectral slopes.

Apply now for your NoV at http://rsgb.org/main/operating/licensing-novs-visitors/online-nov-application/146mhz-147mhz-nov/

The application asks you for your Licence Number which appears on page 1 of your licence. If you don’t have it simply login to the Ofcom licencing page and download a new licence PDF at https://services.ofcom.org.uk/

RSGB 146 MHz http://rsgb.org/main/operating/band-plans/vhf-uhf/vhf-spectrum-release/

FAQ PDF http://rsgb.org/main/files/2014/03/146-147MHz_FAQ.pdf

146 MHz talk slides http://rsgb.org/main/files/2014/03/RSGB_146-147MHz.pdf

UK radio hams start 146 MHz development

New UK Amateur Radio 146 MHz allocation