Minima build log #2 – Testing switches and AF stages

Read first! I am no longer building this transceiver. Please check other interesting projects from Farhan on the discussion group, like HF-1 Transceiver, the replacement of the Minima and some cool RF jigs, Specan and Sweeperino. Also, since I’ve lost from both server and my drive the Eagle files of the PCBs, they will be no more available. Minima has become discontinued, check the group for more details. I will still keep the pdf files here for download for anyone still interested in hacking the rig.

Today I did some first tests on Minina, and the results were promising.
So far:
– AF amplifier;
– R/T switch circuit;
– LPFs switch circuit;
– BFO switch circuit;
– Microphone amplifier;
– AF Preamplifier;
– CW Tone generator.

Minima Transceiver

Minima Transceiver – Switch circuits and AF stages

Remaining the RF circuits:
BFO, Bi-Di Amp and Mixers, maybe next week when the crystals will arrive from China.

I did also a video with the smoke test. As you can see at the end, the CW tone has a very low level. Not sure if this is normal. It can be heard well into some headphones perhaps, but on an external speaker is weak. I will investigate that later.

Minima Transceiver Testing Video

In the meantime, Sandeep’s PCBs finally arrived! And they look wonderful! Happy to see my Minima preliminary PCB design machine made.

Minima PCBs from Sandeep, VU3SXT

Minima PCBs, factory made by Sandeep, VU3SXT

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One Response to Minima build log #2 – Testing switches and AF stages

  1. mvs sarma says:

    Hi, Adrian,
    i saw y day on net, some one sorting out the audio volume level by changing the final capacitor to speaker as 470uF instead of 50uF.. He hasd normal volume thereafter. of course the series resistor from 12V power could be say 10 ohm or less.

    mean time can you try final stage transistors like what sandeep suggested to use Darlington s. say BC5117 and BC516.
    what are the future prj on the anvil !!
    All the best to you
    regards sarma

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