146 MHz RB-TV
UK radio amateurs with Full licences have been given access to an extension of the 2m band between 146 and 147 MHz, but only for experimental modes. This is done on an annual temporary basis and you will need to do an on-line application for a NoV to your current license - see these links:
- NoV Application: http://rsgb.org/main/operating/licensing-novs-visitors/online-nov-application/146mhz-147mhz-nov/
- Additional RSGB guidance on 146 and 71 MHz at https://rsgb.org/main/operating/band-plans/vhf-uhf/vhf-spectrum-release/
The RSGB band plan now includes (and encourages) the use of Reduced Bandwidth Digital ATV (RB-TV) using 500 kHz centred on 146.5 MHz. For more info on Reduced Bandwidth Digital television (RBTV) take a look at this RB-TV special edition of CQ-TV.
RB-TV equipment for 146 MHz
RB-TV on 146 MHz is not possible using "normal" DATV equipment and requires the use of equipment developed specially for the mode. For more technical details take a look at our getting started guide to RB-TV. Getting Started with RB-TV
- The BATC Portsdown is great project involving some simple construction to get on air on 146 MHz - see this introduction page.
- The DATVExpress project offers a versatile and flexible transmit system for 146 MHz.
Due to the very low symbol rate, normal Set top boxes and satellite receivers will not receive RB-TV. The MiniTioune project was developed specifically to receive RB-TV - more details can be found on this wiki page.
Unless you use the new Serit tuner with your MiniTioune, standard satellite tuners will not cover 146 MHz and you will need an upconverter from 146 MHz to L band - you can either home brew the upconverter or use one of the following:
- Roberto Zech Elektronik DG0VE, upconverter, power amplifier, mixer/oscillator module, LNA etc.
- Update Sadly Roberto became SK in 2018; no alternative upconverter suppliers known at present.
You will need a filtered pre-amp before any up converter or tuner.
- The DG8 144 - 147 MHz pre-amp with filtering has proven to work very well on 146 Mhz RB-TV: - http://www.ifwtech.co.uk/g3sek/vhfdx/dg8-preamp-v7.pdf . Note kits were available from G4HUP who suddenly became SK in Feb 2017. Short kits are currently available from SDR-Kits. https://www.sdr-kits.net/DG8-Pre-Amp-2M-Short-Kit
- Minikits in Australia do a pre-amplifier but it may need more filtering. http://www.minikits.com.au/electronic-kits/rf-amplifiers/rf-preamplifiers/2m-RX-Preamplifier
As the VHF spectrum is very crowded and we are operating close to the FM transmitter band and the 2mt amateur band, filters are essential on both transmit on recieve - not only to project other users against spurious from DATV transmissions but to avaoid blocking of the DATV reciever.
Details of suittable filters are listed on this wiki page.
See this wiki page listing considerations and designs for 146 MHz power amplifiers.