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Monday, May 29, 2017

Indonesian BITX: Check out the BRITX

Pretty cool,  don't you think?

Here is the Google translation of the "about" portion of OM Dian Kurniawan's blog:

Electronics is something very interesting. In it are stored many miracles of His creation. The almost limitless opportunities for creativity make electronics an art medium. Countless things are ultimately made easy and possible with electronics.... Feel free to start. Life starts from a cell. Let's keep working for a better life. Salam.

It is obvious that OM Dian has THE KNACK and is a member of the International Brotherhood of Electronic Wizards.   Does anyone know his callsign?

There is a lot of very cool stuff on his blog, including some mind-blowing applications of small, color displays.  Check it all out:

Sunday, May 28, 2017

FDIM: W8SX Interviews Mike Bryce WB8VGE

Mike Bryce's many contributions to the radio art and QRP definitely puts him in the Homebrew Hero category. I have Mike's "Hotwater Handbook" (about the legendary HW-8) on my bookshelf.  Our intrepid SolderSmoke media team (Bob W8SX) spoke to Mike at FDIM 17.  His comments on the joy of a good troubleshoot, and on the pernicious, unfixable nature of many recently marketed appliance radios really resonated with me.   

Mike has special expertise on Heathkit gear:

Listen to the interview with Mike here:


Saturday, May 27, 2017

FDIM: W8SX Interviews W8TEE on Facelifts for SSB Rigs

Our intrepid correspondent Bob Crane interviewed FDIM speaker Jack Purdum W8TEE.  Jack made some very intriguing comments on his efforts to enhance the beloved BITX transceiver.  CW! AGC! Speech processing! Woo hoo!  We await more details on how to acquire the board that Jack describes.

Jack is a very accomplished guy who has made many contributions to the radio art, most recently on Arduino microcontroller projects:   

Listen to Bob's interview with Jack here:

Thanks Jack! Thanks Bob!

Here are is the manual, bill of materials, and schematic for Jack's board:

Friday, May 26, 2017

Homebrew Peppermint BITX: KC1FSZ Goes Scratch-built and Sweeps a Filter

Hi Bill/Pete:

Congratulations to Bill on the award.  Very well deserved!  

I just watched the video that Bill made with Farhan and I really enjoyed it.  As usual, lots of useful information there.

Farhan’s demo of the Sweeperino was particularly timely because this past weekend I was doing something very similar.  

As I’ve mentioned to Bill before, I am working on a scratch-built BITX to accompany the Peppermint BITX-40 module rig that I’m running right now.  I took Pete’s advice and started from the audio end.  After building the audio amplifier, product detector, and first/last pair of IF amplifiers, I was able to connect the VFO where the BFO is supposed to go and enjoy a pretty reasonable direct conversion receiver.  It works great!!  My first working receiver.

So my next step was the crystal filter.  I puzzled over all of the different articles, tried to follow the G3UUR method, sorted crystals, etc. and finally put the whole thing together.  But all along I’ve had this doubt that I could have possibly followed all of the steps closely enough to achieve the precision needed for a 3.5 KC SSB filter - it just didn’t seem possible.

Last week I decided to try to “sweep” the filter.  This was a multi-day undertaking in itself.  I pieced together the microprocessor, an AD9850, a TIA amplifier, the RF power detector from the SSDRA book, and some software that generates the necessary frequency sweep and collects power readings.  The picture of the test rig is included below.  It’s not much to look at.

With low expectations (and wires that are too long), I ran a few seeps and then downloaded the data onto my computer for analysis.  No fancy software here, I’m just using Excel.  When I put the data into a line chart in Excel, what emerged from the jumble of seemingly random numbers was a thing of beauty: a 3.5 KC passband right below 12 MHz. It’s the next stage beyond the Joy of Oscillation:  The Joy Of Selectivity!

It’s even showing about the right insertion loss.  Note the setup is very primitive and noisy so the fact that I can’t measure anything below -8dB isn’t surprising, you can ignore that part.

But I’m starting to get the feeling that this might actually work.  Onto the diode mixer …


Thursday, May 25, 2017


Truly a thing of beauty.  Farhan gave me one of these.  They are crafted by VU3XVR.  It is enough to turn a phone-guy like me back to CW.  Thanks Farhan!  

Here is VU3XVR's site:

Wednesday, May 24, 2017

FDIM: Listen to Bob Crane Interview Hans Summers, G0UPL

Bob Crane, our intrepid correspondent at the 2017 Four Day in May event, caught up with Homebrew Hero Hans Summers G0UPL.  Hans's amazing web sites have been the inspiration for many projects in my shacks.   My favorite so far was his QRSS transmitter using an LED based multivibrator circuit to generate a shark fin pattern on grabber screens.  That was fun.  I am now really tempted to send one of Hans's WSPR transmitters into the stratosphere using party balloons. 

Listen to the interview here:

Visit Hans's QRP-Labs here:

Thanks Bob!  Thanks Hans!

Monday, May 22, 2017

Video: Farhan in the SolderSmoke Shack! BITX, JBOTS, McDonald Straw Sig Gen, uBITX, Sweperino and more!

Thanks again to Farhan for visiting us.  It was great to see his reaction to my humble implementations of his great designs.  I got him to sign my BITX17.  This was really a fantastic day for me and for my family.
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column