Dorji 808/818 are a series of FM transceiver modules based on RDA Micro’s RDA1845/6 chipsets (yes, the ones in the Baofeng / Pofung handhelds). They offer either VHF (134-174MHz) or UHF (400-470MHz) coverage, 0.5-1W RF power output, CTCSS/DCS and -122dBm sensitivity in a a package about the size of a coin (19mm*36mm).
It really is a wonder of technology, packing the transceiver, DSP module and PA section in such a small footprint, that only retails for US$12:
Basically you only have to add a few parts to have a complete transceiver, so not need to wonder anymore how does Baofeng manage to manufacture and sell handhelds for US$30 and still make a profit. You can probably do it yourself for even less: US$5 microcontroller, US$3 LCD, a US$2 audio amplifier and you can make your first QSO.
There are 3 models out there:
– DORJI 808M, based on RDA1845, lacks DCS and DSP audio filter, UHF only
– DORJI 818U, based on RDA1846, has DCS and audio high-pass/low-pass/pre-emphasis, UHF
– DORJI 818V, based on RDA1846, has DCS and audio high-pass/low-pass/pre-emphasis, VHF
More details on the Dorji website.
Must be well suited for an APRS transmitter!