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Saturday, January 17, 2015

Colin Finishes His BITX

Wow, that is one beautiful BITX.  Nicely done Colin.  But I must say that you are exhibiting an almost inhuman degree of patience!  Who needs a case?  Fire that thing up and make the traditional "still-on-the-workbench" initial contact. 

Hi Guys,
I loved the last SolderSmoke, it was another great episode. It really does amaze me, that a few years ago, hams were saying that it was too difficult to build your own gear that would be anywhere near to the commercial stuff, but here we are with Arduinos etc bringing powerful functionality to the masses. I couldn't have imagined building an SSB rig with a pretty and functional LCD screen when I started in ham radio.
Bill, first regens, now SDRs? Amazing! I exchanged a few words with George Dobbs about your change of heart towards regenerative receivers, he seemed genuinely pleased. :)
Pete, your Si5351 work with the pretty displays is cool, I can see me getting pretty hooked! I have the Si5351 board, Paul M0XPD advised me to buy it. I'd love to build another SSB rig in a smaller box for regular SOTA activating. I must look into the pretty little displays and have a play with the Si5351. I notice that Hans Summers has now put out a cheap Si5351 based kit, handy for us guys in Eu. http://www.hanssummers.com/synth.html
I finished building my BITX board yesterday but wanted to have a sleep before applying power! Today I carefully checked the circuit for errors and found none, phew! I fired the rig up gently, watching the current carefully. I wound up the TX bias to 50mA as stated in the MKARS80 instructions, all went well. I plugged in the mic and spoke - BANG! - Everything went off. Oops - I had used a 500mA fuse for initial safety and forgot to swap it for the bigger one! I fitted a 1.6A fuse and hey presto, all was fine. I was absolutely amazed and to be honest, rather proud of myself. I think the TX is a little bit too hot, my meter is showing about 6W on voice peaks- eek! The rig seems to be perfectly behaved though, no wierd effects seem to be happening. I can just turn the bias down a bit, right?
Anyway, I was happy with my progress so I finished for the day. I still need to investigate and probably tweak the carrier suppression.
I spent a short while talking into a dummy load, using my FT817 to monitor the transmission. My 2yr old son was interested in my voice coming out of the 817'sspeaker!
Thanks for all the guidance and help along the way, I'm elated that I've built a voice rig that works! I've attached a pic of my finished board, I only just squeezed the circuit on, but isn't she pretty? :-)
Can't wait to get the rig built into it's case and score that first QSO.
73, Colin, M1BUU

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  1. I agree with Bill. That is a beautiful rig and congrats on your electronic skills! What is the actual size of your printed circuit board you used?

    Al N8WQ

  2. e molto bello :))) very nice rig with i2c lcd wow ,congrats ,9a3xz.

  3. Size of board is about 2.3 RockMites by 1.3 Rockmites :-)


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