UBITX Build Part 3

The assembly of my suitcase radio is almost complete and I have started the testing phase.

The radio powered-up first time. The receiver is lively and the tuning is very smooth. Pressing the tuning knob gives access to the simple menu system. When listening through headphones it is wise to have one hand on the volume control. As there is no AGC on this radio, a strong station coming on the frequency can be ‘deafening’!

The UBITX AF power amplifier does not have enough ‘grunt’ to effectively drive a speaker (I am using the R4 PCB). Therefore I made use of the audio amplifier salvaged from the donor record player.

I measured the CW RF output on all of the amateur bands:

80m - 13 Watts

40m - 6 Watts

30m - 7 Watts

20m - 12 Watts

17m - 6 Watts

15m - 8 Watts

12m - 5 Watts
10m - 5 Watts

Supply voltage for the measurements was 13.3 volts.

Talking into the microphone on SSB mode reassuringly deflects the RF power meter, although I have yet to try it out ‘on the air’.

Future posts will cover further testing and give more detail on the design and assembly.

To be continued.

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