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Tuesday, May 30, 2017

The Transistor! 1953 Bell System Film -- Great Stuff!



Thermatron fans beware!  There is some trash talking of tubes in this 1953 Bell film.  But there is also a lot of recognition of the contribution made by our beloved valves.  I especially liked the report on the historic 1915 phone transmissions from Arlington, Virginia. ( I drive past the transmitter site every work day).  FIVE HUNDRED TUBES combined to send the human voice from Arlington to both the Eiffel Tower and to Pearl Harbor, Hawaii.  FB OM!  59!

I was disappointed, however, that this film failed to recognize another momentous 1953 achievement in sold state electronics:  In that year, 11 year-old Pete Juliano built his first solid state amplifier -- an audio amp using a CK722 transistor.  Read about it here: http://soldersmoke.blogspot.com/2015/03/pete-juliano-homebrwing-with.html

The fact that Pete was homebrewing solid state circuits at the time that this film was made is a reminder of the vast experience that he has, and of how much technological progress we have made in such a short period of time.

Farhan gives me a Spectrum Analyzer and W2AEW Provides the Tutorial (Video)



At Dayton, Farhan very kindly bought me a Tektronix Spectrum Analyzer.  (I joked during his visit that this device might help me stay in the good graces of the FCC.)   This morning I decided to learn more about this device.   I Googled "Tek 1401A" and was immediately directed to a YouTube tutorial.  I was pleased to see that it was from our old friend Alan Wolke W2AEW.  I knew that the Tek analyzer and I were in good hands. TRGHS.  Alan expertly laid out the functions of the device.  I am confident that I will soon be analyzing the spectrum of my homebrew rigs, and that they will all be found COMPLETELY FREE of spurious emissions.

Alan's tutorial is instructive for all those getting started with spectrum analyzers. 

I need to find a manual and schematic for the 1410A.

Thanks Farhan.   Thanks Alan.   And three cheers for Beaverton, Oregon!

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:  https://www.theheathkitshop.com/index.html

Listen to the interview with Mike here:


KEEP THAT GREEN FLAME BURNING MIKE!

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:  https://www.qrz.com/db/W8TEE   

Listen to Bob's interview with Jack here:

http://soldersmoke.com/FDIM17W8TEE.mp3

Thanks Jack! Thanks Bob!

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

http://soldersmoke.com/W8TEEschematic.pdf

http://soldersmoke.com/W8TEEmanual.doc

http://soldersmoke.com/W8TEEbom.doc


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 …

73s,


Thursday, May 25, 2017

VU3XVR's BEAUTIFUL Morse Keys


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:

http://vu3xvr.blogspot.com/p/morse-key.html
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column