QSB-01 (qrp-tech synchronous buildathon) #5 – transmitter build updated @ 21/05/16

Phase 15 – Final RF Power Amplifier Stage

Commenced 02/05/16  Completed 02/05/16

Phase 15 completed

Completed build requiring fitting in an enclosure, setup and alignment

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Phase 14 – Third Driver Stage

Commenced 02/05/16  Completed 02/05/16

Phase 14 testing

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Audio file – Phase 14 testing

https://www.dropbox.com/s/r5u4lidvjgynpmy/Phase%2014%20testing.m4a?dl=0

Phase 14 completed

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Phase 13 – Second Driver Stage

Commenced 02/05/16  Completed 02/05/16

Phase 13 assembly work

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Phase 13 testing

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Audio files Phase 13 testing

https://www.dropbox.com/s/raawuy29mk96134/Phase%2013%20testing%20a.m4a?dl=0

https://www.dropbox.com/s/jlitjs3nqmkjdjm/Phase%2013%20testing%20b.m4a?dl=0

Phase 13 completed

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Phase 12 – Transmit Band Pass Filter (BPF) & First Driver Stage

Commenced 28/04/16  Completed 02/05/16

Phase 12 assembly work

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Phase 12 testing

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Audio file – Phase 12 testing

https://www.dropbox.com/s/bhfaolycjbh8f03/Phase%2012%20testing.m4a?dl=0

Phase 12 completed

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Phase 11 – First Transmit Mixer

Commenced 27/04/16  Completed 28/04/16

Phase 11 assembly work

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Phase 11 testing

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Video file – test operation of the first mixer stage

https://www.dropbox.com/s/sx06ujqmwz6q8kq/20160428_170056.mp4?dl=0

This testing stage is clever in that it is using the receiver to test the transmitter in a feedback loop where the output of the first transmit mixer is fed into the antenna input. This comes with a caveat of don’t do this under any other circumstances else risk destroying your creation! In the above video the audio output of the keyer has been switched off by entering the command mode and disabling it. As such the tones which are heard are those being produced by the transmitter. The technique negates the need for any test equipment which is a bonus for those without those resources to hand.

Phase 11 completed

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I’ve corrected the display unit now by adding the IF frequency to the display’s memory function. Now it adds 6MHz to its received input giving a more accurate and usable reading

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Phase 10 – Keyer & Keying Circuit

Commenced 26/04/16  Completed 27/04/16

Phase 10 assembly work

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Phase 10 testing

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Video file – Keyer Circuit test

https://www.dropbox.com/s/mtlbdey5fdmjr1u/20160427_172713.mp4?dl=0

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Phase 10 completed

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