Another uBitx Add-on PCB.
Im loving the cheap and easy EasyEDA/JLPCB boards and simple web designer.
This time its a CW filter similar to the QCX and HiPerMite. I take no credit for the design, just copied it and added a switching relay. I ordered 10 boards at $10 posted. love it! 73, Nick VK4PLN.
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Kelly Jack
Nice. Are you selling these boards?
Regards Simon VK3ELH
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Maybe, if they work ill put the extra ones up with my RadionoI2C boards....
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Just FYI:
Center Frequency: 700 Hz Bandwidth: 200 Hz DC Power: 5VDC GAIN: Upto 20dB via R11 and R12 + trimpot. Resistors 1206 SMD: R1 33k R2 33k R3 1M R4 47k R5 47k R6 36k R7 36k R8 10k R9 750k R10 10 R11 100K R12 100K Capacitors 1206 SMD: C1 0.1u 104 C2 47n 473 C3 36n 363 (33n + 3n3 mount on side together) C4 1n 102 C5 39n 393 (33n + 5n8 mount on side together) C6 1n 102 C7 2n2 222 C8 2n2 222 C11 0.1u 104 C14 220u Electrolytic Other: IC TLC274 Relay OMRON G6S-2-DC5 200K/100k trimpot R11 and R12 are optional to parallel the 200k trimpot to make it a logarithmic 100k. Or just use a linear 100k pot. Use a switch connected to 5V to turn on the filter. This powers the opamp and switches the relay feeding the audio into the circuit. When off the relay just passes the audio straight through unfiltered 73
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PeteWK8S
Thanks for the suggestion Nick,
BTW... I’ll buy one of those boards if you sell em. I’d considered tacking a relay onto a Hi-Per-Mite but yours would be more elegant. Let me know. Pete WK8S
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Peter, please see: https://vk4pln.blogspot.com.au/2018/03/vk4pln-ubitx-add-on-boards.html
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HI All.
Boards arrived today, I will assemble one and test. Hoping to feed it into an audio spectrum analyzer to provide some idea of its exact performance/response. I will ship them out to folks who have ordered ASAP. Might be a delay, we have an impending cyclone in the area and I've taken down my antenna, I'd like to test it in the uBITX with a real signal... Thanks. Nick
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Ok, some results:
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To my ear the lm324 gave a better result than the TLC274...
I'll start posting out the boards. 73...
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Board complete:
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