keskiviikko 24. lokakuuta 2018

Handheld 2...30MHz SSB 5W plus 50MHz and 70MHz

Technical data

 Dimensions: 35 x 115 x 230 mm
 Operating voltage 12V 3 pieces lithium ion batteries 3.8V / 3Ah

 3.5MHz to 30MHz performance
 Sensitivity: -130dBm is audible
 Power out flat 5W :

50MHz performance
Sensitivity -130dBm is audible
Power out 5.1W

70MHz performance
Sensitivity -120dBm is audible
Power out 2.6W

Circuit description

Direct conversion polyphase SSB modulator / demodulator receiver and transmitter with CW mode.
Most of RF section is own version of OH7SV juma TRX2 circuit
Display is Nextion touch screen and processor is Arduino Nano. Band switch is controlled with i2c bus with 8 channel extender board.
Local oscillator is si5351
Software is hand made with lot of borrowed code. Source code is available at request.
I got lot of help from OH7SV with RF questions. Hans Summers G0UPL explain, how to get clear frequency change without clicks and how to get I/Q 90 degree working
Power amplifier circuit is copy of FT817 PA. That because it is so wide from 2...70MHz
VFO tune coder is HRPG-ASCA. optical encoder with 120 step per round.
Radio have only 3 control knobs, af volume, VFO coder and PTT switch plus CW key connector
D connector is for charging batteries and later options for e.g control PA amplifier.
Everything else is controlled  in touch screen.
Most of components are SMD and as you see, this is prototype and not easily reproductable.

For questions: oh2btg (at) sral . fi
73 Eero OH2BTG

First QSO's with prototype

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