RXP2600: Contest TCVR - HIGH Performance CW only

Superhet + SDR

9 Mc IF + 2 xAD603 + FST3125 IQ detector

H-mode mixer

FSA3157 + ET1-6TSM20

Low cost D.D.S.

Si5351 + custom low pass filters

Hilbert digital F.I.R.

Teensy 4.1 with custom code.

Digital sampling A.G.C.

Arduino nano + AD8307

7 or 10 " touch display.

Nextion display + own code

Elecraft cat code emulator

N1MM interfacing

Part 1 - Local Oscilator

Si5351 + Low pass filters + Autolevel @ 0,5Vpp.

Si5351 is not the greatest PLL in the world, but is cheap and accessible.
Output signal is not sinewave but almost rectangle, and lots of strong harmonic signals visible on output.
Easy to use on arduino code style, easy to manipulate it but strongly advice against using more than 1 output to avoid crosstalking.
Fix 1: Ad603 with 40dB gain driven by MCP4725 via i2c bus for autolevel
6 x low pass filters, one for each TX band and another 3 for RX + 9 Mhz IF
More than 60 dB harmonic rejection.
Reed relays for switching instead of diodes.

Part 2 - Bandpass filters, RF Mixer and 15dB Preamp / ATT.

6 bandpass filters, Chebyshev 5th order.
Relays switching
15 dB Att or 15 dB Preamp.
FSA3157 H-Mode Mixer Module

Part 3 - 9 Mhz I.F. + IQ Detector

2 x AD603, 80dB gain + AGC line
1 x 600 Hz IF crystal filter
1 x 3 Khz Noise crystal filter
1 x 15 dB postmixer preamp with an old 2N5109
2 x FST3257 IQ detector
2 x AD8599 audio preamp and 0-200 Hz cutoff filter
Teensy 4.1 m.c.u. with 2 x 200 Hilbert coefficients I/Q for LSB / USB side suppresion.
SI3551 2x 9Mhz @ 45 degrees offset.

Part 4 - Audio codec, MCU board - To be continued

Arduino DUE MCU
SOTA BEAMS VARI DSP
AD8703 logarithmic ACG detector
Noise pulse detector and gate for N.B.
Noise reduction
Elecraft K3 CAT codes emulator for N1MM.
Nextion 7″ touch screen display

2 Comments

Emily · January 8, 2026 at 5:41 am

Hi Charlie (Gabriel, n.r.),

Your RXP2 transceiver project is a solid and practical DIY radio build,showcasing your expertise and talent.

This is Emily from PCBWay, and I’d love to explore a pontential collaboration by sponsoring your project with free PCB prototypig.

A brief review would be appreciated in return. Would you be interested in collaborating?

Looking forawrd to your early reply.

Best regards,
Emily

yo8rxp · January 29, 2026 at 8:20 pm

Yes Emily, I would really like to explore a potential collaboration with PCBWay. That would be not for money but to spread the joy for DIY.
Please instruct me via email how do we do that !
Regards, Gabriel

RGO One, better than MOST expensive TCVR's

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