SSB85 TRX - compact ham radio transceiver

This project is in early development stage and there is no good documentation. Heavily work in progress, making prototypes etc. Please, do not try building this project right now.

This transceiver is an idea sparkled by SSB6.1 kit. It has relatively simple schematic and easy in tune. But it was flawed by several things - it wasn't power efficient and not that compact. Also it was missing 160M band. I wanted to take it to a next level to be able to carry the rig in a backpack and use a power bank as a backup. All that gave me initial set of constraints to work with - most popular ham radio bands, ability to work from 5V powerbank, simple schematics, affordable components.

Name SSB85 speaks for itself: 8 bands, 5 Volts minimal power supply voltage.

Everything on this page is a subject to change!
Project is heavily work in progress.

Ideas for the rig:

  • Mobile/field ready (lightweight, compact, SMD components).
  • Based on SSB6.1 design.
  • +5 V power supply (using typical power bank)
  • Low power consumption in RX
  • High SWR/Shorts tolerant
  • Microcontroller used to switch between frequencies
  • Low frequiencies filter
  • Friendly price
  • Bands: 160, 80, 40, 30, 20, 17, 15, 10 meters.
  • Full complete design (not bunch a of modules as many other)
  • Compatible with existing microphones.
  • QRP but powerful enough.
  • Easy to operate
  • Guided navigation (use software to switch modulation and control modes in different bands)
  • Schematics designed in KiCad.

Theory of operation

Schematic is a classic super-het with 2 frequency conversions.






Click on the image to view zoom in.

Technical characteristics

Power supply, voltage +5V USB 9..14.5V
Power consumption
RX <200 mA
TX < 2 A
Output power 5 W 16 W
Ham-radio bands 160, 80, 40, 30, 20, 17, 15, 10
Modulation SSB: LSB/USB, CW, AM (RX-only)
Size 55x110x160mm
Weight 0.5kg

 

 

List of amateur bands

Band, meters Frequency, MHz BW,kHz Notes
160M 1.8-2.0 200
80M 3.500-4.000 500
40M 7.000-7.300 300
30M 10.100-10.150 50
20M 14.000-14.350 350
17M 18.068-18.168 100
15M 21.000-21.450 450
10M 28.000-29.700 1700

 

 

Lessons learned

  • Initially I choose SA612 as mixers due to their price and power consumption but 5V is not enough to get a good gain from SA612 and I had to switch into better AD831 mixers.
  • Also turns out picking the ceramic resonators was a bad choice for IF/BPF filter. The bandwidth was about 100khz.
  • First I picked up TS4962IQT but it didn't work properly in single-ended configuration. I transitioned to LM386 and I was greatly disappointed by LM386. Even battery powered it has so much noise with grounded input. My next choice SM2211.

Power consumption estimations

AD831 - 45 mA
Si5351  - 35 mA
TCA9406 - 1 mA
BGA2866 - 17 mA
SSM2211 - 20 mA
LT5537 - 15 mA
AD8338 - 8 mA

ATMEGA1284P - 50 mA

S-Levels

S1     = 0.2 μV (rms, 50Ω)  = -121 dBM
S9     = 50.2 uV,   -73 dBm
S9+10 = 160 uV,  -63 dBm
S9+20 = 0.50 mV,  -53 dBm
S9+30 = 1.58 mV,  -43 dbM

4 boards:

1. Main board, contains RX/TX/BPF, LF amp

2. Front panel: Screen, encoder, contorols, processor

3. Power Supply + Switches

4. Amplifier, LPF, SWR Boards connnected using I2C

Main board

Most recent schematics https://github.com/zoonman/ssb85/archive/master.zip

Amplifier board

SSB PA 5V

Synthesizer - NANODDS

This solution supposed to be budget friendly, so far total cost = $10.87.

  • Si5351A https://www.aliexpress.com/item/DC-3V-5V-CJMCU-5351-Si5351A-Si5351-I2C-Clock-Generator-Breakout-Board-Module-Signal-Generator-Clock/32881587285.html
  • 1.8 inch screen ST7735 https://www.aliexpress.com/item/1-8-Inch-128-160-Serial-SPI-TFT-Color-LCD-Module-Display-ST7735-With-SPI-Interface/32818686437.html
  • Arduino Nano https://www.aliexpress.com/item/Freeshipping-Nano-3-0-controller-compatible-for-arduino-nano-CH340-USB-driver-NO-CABLE/32341832857.html Getting replaced with ATMega1284P-AU. More memory = advanced software.
  • The display is connected to Arduino using SPI interface and Si5351A using TWI (I²C).

Source Code and Firmware

Power Supply and Switches

Enclosure

Buy: eBay, AliExpress

Useful resources

  • http://wera.cen.uni-hamburg.de/DBM.shtml
  • https://rf-tools.com/lc-filter/

Credits

SSB 6.1 engineers, community and Nick Strong in particular for help, guides and support.

KiCAD and community for great EDA.

JetBrains for an awesome CLion IDE.

Platformio and Arduino for bootstrap code and toolchain.

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