ZX-SSB-II - Multi band homebrew SSB HF transceiver

Updated 2024-03-07

Note:
The ZX-SSB-II has reached a point where it is now considered obsolete and not recommended for new builds with the information being provided here serving only as a historical reference.

For new builds I recommend exploring the MAX-SSB transceiver page , where you'll find details on my latest homebrew SSB transceiver build.

The ZX-SSB-II is a multi-band SSB transceiver based on many homebrew designs I've seen on the web. Ashhar Farhan's (VU2ESE) Bitx20 provided the biggest influence and inspiration, with Pete Juliano's (N6QW) Let's Build Something rig providing the starting point for the Arduino VFO/BFO code and Wes Hayward's (W7ZOI) and Bob Kopski's (K3NHI) white paper entitled 'A Termination Insensitive Amplifier for Bidirectional Transceivers' providing the basis for the ZX-SSB-II's IF amplifiers. Other sources of inspiration and guidance have come from many websites and YouTube channels featuring the works of Peter Parker (VK3YE), Marco (F8VOA), Dan Tayloe (N7VE), Jim Kortge (K8IQY), Arv Evans (K7HKL), and of course Bill (N2CQR), whose SolderSmoke podcast and blog have provided priceless information and the all-essential encouragement to build.

Please note that the ZX-SSB-II's design is a work in progress and still evolving, and the information below is being provided AS-IS and as a way to share my ideas for the advancement of the Radio Art. If you use the information I have provided, you do so at your own risk and must determine if you have the proper skills to do so safely.

Drawings and text may be freely copied and reproduced for non-commercial personal use.



Block Diagram

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The block diagram shows all the modules needed to build the ZX-SSB-II.



Power Management

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The Power Management circuit distributes power



Front Panel (i.e. Microcontroller and User Interface)

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ZX-SSB-II Front Panel Software for Arduino MEGA 2560


The Front Panel (i.e. Microcontroller and User Interface)



Carrier Oscillator BFO VFO

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Carrier Oscillator BFO VFO.



S-Meter

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S-Meter.









Audio / Mic Amp

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Audio / Mic Amp.



Product Detector / Balanced Modulator

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Product Detector / Balanced Modulator.



Amp A

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Amp A. An I.F. amplifier based on Wes Hayward's (W7ZOI) and Bob Kopski's (K3NHI) white paper entitled:
'A Termination Insensitive Amplifier for Bidirectional Transceivers'








Crystal SSB Filter

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Click the following link to learn more about Crystal SSB Filters:
• Crystal ladder filters - By Iacopo Giangrandi (HB9DUL)


Crystal SSB Filter. The crystals and capacitors necessary available from: INRAD (International Radio)





Amp B

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Amp B. An I.F. amplifier based on Wes Hayward's (W7ZOI) and Bob Kopski's (K3NHI) white paper entitled:
'A Termination Insensitive Amplifier for Bidirectional Transceivers'






Mixer

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Mixer



Amp C

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Amp C. An I.F. amplifier based on Wes Hayward's (W7ZOI) and Bob Kopski's (K3NHI) white paper entitled:
'A Termination Insensitive Amplifier for Bidirectional Transceivers'











Band Pass Filters for 160M, 75M, 40M, and 20M

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Band Pass Filter for 160 Meters

Band Pass Filter for 75 Meters

Band Pass Filter for 40 Meters

Band Pass Filter for 20 Meters



PA

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NEW for 2021 - Revised 10-25-2021 (This amp [Module 220-A] is an improved version of the original [Module 220]. The improvements include better input impedance match for 50 ohms, bias rollback on high final temperature (W6JL design), temperature sensor diodes on the finals to feed the Arduino ZX-Front Panel controller, feedback on the finals to lower output distortion and a provision for a fan. The output power specification for this revised amp is only 10 watts (as opposed to the 20 watts on the original), but the output is cleaner with the intention of this PA to be a driver for a higher power external linear amp. Making this amp only 10 watts was inspired by the design philosophy of Hans Summers' 10W HF Linear PA kit from QRP Labs.)
PA 0-10 Watt RF Power Amplifier (New for 2021)



PA 0-20 Watt RF Power Amplifier



Low Pass Filters

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Low Pass Filters - (Build one module for each of the bands: 160M, 75M, 40M, and 20M using L and C values from the table for each of the modules)



RF Power Detector

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• [Video] - YouTube video on the construction of the RF Power Detector module #240

Click the following links to learn more about the Stockton Bridge (tandem match) and SWR:
• The tandem match - a closer look - By Iacopo Giangrandi (HB9DUL)
• How a Directional Coupler in an SWR meter works - Alan Wolke's (W2AEW) excellent video #196
• Calculate VSWR from Forward and Reverse RF Power - Bradley's (KN9B) Digital SWR Meter Project
• SWR Demystified - David Casler (KE0OG) Ask Dave Episode #28
• How To Build An SWR / Relative Power Bridge - Part 1 - Randy's (K7AGE) Pineboard SWR Meter
• How To Build An SWR / Relative Power Bridge - Part 2 - Randy's (K7AGE) Pineboard SWR Meter
• How To Build An SWR / Relative Power Bridge - Part 3 - Randy's (K7AGE) Pineboard SWR Meter


RF Power Detector