Frequency coverage is from 5,7MHz up to 22,5MHz. That might seem a lot, but with a 10 turn tuning pot it is quite acceptable. The foot print is 10 x 15 cm.
AF board on the left, audio pot and 10 turn tuning pot center front, and pre selector and oscillator coils on the right hand side. In this test setup I have separate batteries for the tuning voltage, the receiver and frequency display module.
A closer look at the coils:
Schematics: the TDA1072 is as shown in the data sheet.
Pre selector circuit:
Audio amplifier, schematics and frequency response (voltage amplification factor as function of frequency). The values shown are suitable for approximately 50mV plus/minus input signals.
The TDA1072 radio chip has an output for frequency counter which works perfectly with a cheap counter module found on ebay. The counter module has programmable IF offset which makes it easy to display receive frequency.
All in all I really like the TDA1072. It makes building a fairly good receiver doable. Using varicap diodes for tuning is very flexible and does away with a lot of the mechanicel headaches that comes with traditional variable capasitors.