51 MHz DATV Introduction
The bandplan recommends 51.7 MHz. Probably best to start with 333 kHz DVB-T, QPSK, Guard 1/32, FEC 2/3.
For receive, you can tune there directly with a Knucker tuner and a Portsdown or Ryde. I would suggest a band-pass filter and a preamp (in that order).
For transmit, you can use a Portsdown 4 with LimeSDR, which will give you +1 dBm on 51.7 Mhz with a Lime Gain of 92. Or you can use a Portsdown 4 with a Pluto, which will give you -10 dBm at 0 Pluto Power (the maximum).
Receive upconverter detailed on 71_MHz Wiki page will also make a 451.7 MHz signal if DVB-S or S2 is being fed into a Minitiouner.
The Mini-Circuits RBP-75 band pass filter will pass 51.7MHz. Other low power filters are to be found on the QRP-Labs shop pages for under £5 each
In the 70MHz Filters section of this Wiki G4GUO's low pass filter from CQ-TV-260 intended for 71MHz duty will do also well for 51.7MHz. Note flat top response 50 Hz [spike on left of spectrum] to 75 MHz
A cheap, lightweight antenna for your initial tests is Steve GW&AAV's delta loop Also a combined pair of these antennas are shown on his 4m page.