The popular SDRs that are used to transmit DATV at higher frequencies are the Adlam-pluto and Lime Mini. The pluto does not work below 70MHz and while the Lime Mini does cover 29MHz natively, in practice the spectrum it generates in this region is not sufficiently clean to use on the air. To get round these issues, Mike G0MJW has designed a simple 149 to 29MHz transverter. It is designed to fit into a standard Hammond 1590B 'stompbox' die-cast box.
Building the transverter
PCBs is stocked in the BATC shop.
The gerber files are available here: File:DVBT_Transverter_rev5.zip
BOM and schematics
The BOM version by G4KLB is available for download: File:Transverter BOM.xlsx
The schematics are available here:Media:DVBT_Transverter.pdf
5 crystal oscillators are available here for about £13 delivered. https://www.ebay.co.uk/itm/202891111938