<-[[.:start]] ====== 30m Phasing Rx ====== I recently found an old project that had been left in the junk box unfinished. It's a direct-conversion phasing receiver for 30m. Inspired by my current binge-listen to the Soldesmoke Podcast [[https://www.soldersmoke.com/]] archives (I'm starting at the beginning and listening to them all.. currently I'm at around Episode 30) I thought I'd restart the project and build it into the planned-for 30m CW transceiver. There's a 5W PA strip that's recently been used in my [[qrss_tx| QRSS MEPT]] but I'll build a new PA for the MEPT and use the original one for it's original purpose. I repaired a few broken wires and dry joints and the RX is working. I've checked that the phasing opposite-sideband rejection is working and given it a tweak to check that the adjustments are doing the right things. All looks good. I'll document the circuit later FIXME Here are some photos {{:public:radio:topics:arduino:img_20260716_213549.jpg?direct&400|}} {{:public:radio:topics:arduino:img_20260716_213409.jpg?direct&400|}} {{:public:radio:topics:arduino:img_20260716_213531.jpg?direct&400|}} {{:public:radio:topics:arduino:img_20260716_213540.jpg?direct&400|}} {{:public:radio:topics:arduino:img_20260716_213553.jpg?direct&400|}} There's a Makertube video of it receiving its first signals... [[https://makertube.net/w/4xeject7Vtk6E9zxuJqxsd]] ===== The design ===== Coming soon.... FIXME The basic format is * Band pass filter for 30m * RF amplifier * Signal splitter to feed the RF ports of a pair of home-made passive 4-diode balance mixers * the 2 mixers are also fed with 90° I & Q local oscillator signals from an arduino/Si5351 IQ VFO * The outputs of the 2 mixers is a pair of baseband audio signals in quadrature which then pass through the phase-delay circuits * The 2 paths combine such that the audio from the unwanted sideband is cancelled and audio from the wanted sideband is presented to to an op-amp audio BPF centred on 700Hz. * Then there's a audio amplifier that can drive a speaker. ===== Further Information ===== Page created : 16/07/26 22:57 BST Page updated : ~~LASTMOD~~ {{tag>radio cw homebrew arduino}}