07-11-2024, 08:30 PM
(This post was last modified: 07-11-2024, 08:44 PM by Mike Watterson.)
See data for ET13X300A, Etoms UHF ASK/OOK superhet.
I bought a bunch of these maybe nearly 15 years ago. SMD, so I used cheap ready made PCBs to Adapt to DIL for stripboard.
RX is set by a 4.3 MHz to 7 MHz crystal. For USA 315 MHz "licence free" it's 4.754695 MHz and for Europe 433.92 MHz "licence free" it's 6.6181 MHz, assuming a cheap 10.7 MHz ceramic filter. Can be used for AM and to measure signal level.
I found a drawer with them and one IC soldered to adaptor PCB tonight while looking for a TTL to serial over USB IC. Which I didn't find. It's not as simple as the Philips designed 70 kHz IF VHF-FM Superhet that uses a PLL so that 250 kHz deviation can be received (RDS and stereo decoders work). That IC now made by Chinese makers too and runs off a couple of AAA for weeks or months. Rotary tuner or up/down buttons. It's easy to make up. Edit TD7088 and compatibles. No crystal, IFTs or ceramic filters. Just one critical 78 nH coil (wind 6t on 3mm drill bit and adjust spacing).
I bought a bunch of these maybe nearly 15 years ago. SMD, so I used cheap ready made PCBs to Adapt to DIL for stripboard.
RX is set by a 4.3 MHz to 7 MHz crystal. For USA 315 MHz "licence free" it's 4.754695 MHz and for Europe 433.92 MHz "licence free" it's 6.6181 MHz, assuming a cheap 10.7 MHz ceramic filter. Can be used for AM and to measure signal level.
I found a drawer with them and one IC soldered to adaptor PCB tonight while looking for a TTL to serial over USB IC. Which I didn't find. It's not as simple as the Philips designed 70 kHz IF VHF-FM Superhet that uses a PLL so that 250 kHz deviation can be received (RDS and stereo decoders work). That IC now made by Chinese makers too and runs off a couple of AAA for weeks or months. Rotary tuner or up/down buttons. It's easy to make up. Edit TD7088 and compatibles. No crystal, IFTs or ceramic filters. Just one critical 78 nH coil (wind 6t on 3mm drill bit and adjust spacing).
