Video of my Barebones Superhet

I literally blew the dust off this thing last week.  I posted the schematic a few days ago (scroll down).   This morning I finished re-building the CW transmitter that went with it.   I am running out of rigs to re-build, so I suppose I will now have to start building some new ones.  Maybe a BITX-20?  Or a BITX-75/20? 

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The Southern Appalachian Radio Museum

Chris, KD4PBJ, of SMT Solutions, sent us a thumb drive with pictures and videos of his visit to the Southern Appalachian Radio Museum.   What a great collection of radios!   I saw many old friends on those shelves.

There is a lot of radio history in that museum, and much of it is conveyed by the photos and videos that Chris took.   Here they are, all 111 files:

https://picasaweb.google.com/116927941005026017464/SARM#

The museum is in Asheville, N.C.  http://www.saradiomuseum.org 

Thanks Chris.  And thanks to the curators of this fine museum.

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A Beautiful Receiver by W1DN

I wish my prototypes (or final products!) looked this good.    I like the way Lee puts the switches onto the prototype board.  Very nice.

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Wow! Raspberry Pi as an RF Transmitter

https://github.com/threeme3/WsprryPi

This site shows you how to use a $35 Raspberry Pi Computer as an RF transmitter for the WSPR (Weak Signal Propagation Reporting) System.  All you need is a simple low pass filter and an antenna. (Oh yea, and a ham radio license.)  The site says you can get 10 milliwatts out.  That's enough for WSPR!   Very cool. 

This looks like a real international effort:

Credits goes to Oliver Mattos and Oskar Weigl who implemented PiFM [1]  based on the idea of exploiting RPi DPLL as FM transmitter. Dan MD1CLV combined this effort with WSPR encoding algorithm from F8CHK, resulting  in WsprryPi a WSPR beacon for LF and MF bands. Guido PE1NNZ extended this effort with DMA based PWM modulation of fractional divider that was  part of PiFM, allowing to operate the WSPR beacon also on HF and VHF bands.

For more info on WSPR:  http://soldersmoke.blogspot.com/search/label/WSPR

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Podcast Noise Explained; Mic advice from Germany

Hello Bill,

This might be down the drain for you, but I only listen to your podcast very few months:

The background hiss you mentioned in Soldersmoke 148 definitely was a crosstalk from the switching voltage converters for the CPU in your laptop. The CPUs these days are operated with voltages in the .7 V to  2 V range,with currents from several Amperes up. A high-performance CPU may dissipate150 W which can easily mean supply currents of 100 A an more. The CPU operating voltage, especially in a laptop, might change several 100 times a second. I think you can imagine the rest.

Why is that voltage adaption so important? This is within your domain: The biggest heat source in digital electronics these days is charging and discharging capacitors. Unless you use a resonant circuit (which you cannot do on a chip) you dissipate P = 1/2 C U^2 with every discharge. Yes: Power depends on the square of the supply voltage. And at a clock frequency in the 2 GHz range you charge and discharge all those capacitors quite often. Each of these has a capacity in the fF (.001 pF) range, but you have billions of these...

Over the time you had quite some complaints about your whistling s. In former times this was definitely made worse by some technical problems. But this is a problem long gone. An Soldersmoke 149 I believe the remaining problem simply was the tooth gap you described a few years back.

BTW: You could easily reduce the file sizes of your podcasts by at least 50% with a few simple measures:

- You should record the podcast as you do now, with a 44 or 48 kHz sampling rate, that's fine. I would even record in wave format.

- Afterwards downsample your recording to a sampling rate of 12 or 16 kHz. This provides ample audio bandwidth for this purpose. See e.g.http://forum.audacityteam.org/viewtopic.php?f=28&t=19705

- Then create the MP3 file with a signal rate of 48 or 64 kbit/s.


BTW: Last weekend at a ham flea market I got a variable transformer. Now I can try to revitalize my Drake TR4C that has not seen any electricity for some 30 years. I bought it when I got my shortwave license in 1975. At that time I lived with my parents. Then I could operate it during my military service. But after that I got an electronics engineer and lost all possibilities to erect any kind of SW antenna. Only three years ago I got my own house near Munich. But I'm hardly at home and I nearly exclusively operate from my car. I will not try this with any kind of boatanchor :-)

vy 73
Alexander
DL4NO

------------------------------------
Von: solder smoke [mailto:soldersmoke@yahoo.com]
Gesendet: Dienstag, 19. März 2013 09:49
An: DL4NOAlexander
Betreff: Re: Soldersmoke 148: Background Hiss

Thank you Alexander.  That is very useful information.   I have switched to a new computer and I think the hiss  problem is gone.   The gap in my teeth remains however!    I am thinking about getting a better microphone.  Any advice on this?   I am glad to  hear that you are back into ham radio.  My Elmer (the guy who helped me get started as a novice) was an immigrant from Germany (Hilmar,  WN2NEC).  He was an excellent technician.   I still use some of the things he made for me.   73  Bill ------------------------------------------------ Hello Bill,   about a microphone: Think about a headset, possibly a wireless one. I would search forums about dictation software for advice.   A headset fixes the position of the microphone relative to your mouth. At the same time the microphone is near your mouth so any ambient noise is suppressed. A wireless [Bluetooth] headset would allow you to move around freely. Unless you come near a larger hard or soft surface or leave the room the sound should not change much. You could arrange the materials for your next podcast around the room and move from "chapter" to "chapter". And as the digitizing happens in the headset all weak analog signals are safe away from any voltage converters and digital electronics.   I had never left ham radio, I just reduced and modified my activities. 2m or 70cm FM were always possible. Here in Germany we have more than 1,000 repeaters. Many of these repeaters have Echolink capabilities. For the last 15 years I have more or less exclusively worked from my car while driving. In my car I have a FT-857D. For shortwave I use monoband antennas on a PL mount at on the roof of my car. For pictures see http://www.dl4no.de/thema/amateur1.htm. The schematic in http://www.dl4no.de/thema/mobil-st.htm shows how I ensure that my TRX gets its 22 A peak from the 12V outlet in the trunk of my car: I buffer it with a 1 F capacitor - really 1,000,000 µF! The mean supply current during SSB transmit is less than 5 A.   A quite important role in my ham life play the local chapters of our German ham radio society DARC. There are more than 1,000 of them, each with its own DOK. So wherever my customers are, at least one local ham meeting a month is not far away. I participate in their activities, give a lecture from time to time. This is a big help as I mostly work at my customers and these are scattered all over southern Germany.   Just a short story with some local connection for you: Peter, DL5NC, spent quite a few years in the Washington, DC area. He has a US call, but please don't ask. He was born some 50 km from my home town. Formally this area, Franconia, has been part of Bavaria since 1806. Nevertheless we believe that the Bavarians have no clue how to brew beer.   One Friday morning (your time) he was on his way into Washington, DC. Through Echolink he connected to a Munich repeater while I was in the afternoon rush hour on my way to a beer garden. I told him that this was one of the few places in Munich where you could get a decent beer. And otherwise I had my own beer at home imported from Franconia. He threatened to never again talk to me because of mental cruelty. In the meantime he returned to Germany and got a neighbor. We drank a few Franconican beers together in the meantime :-) vy 73 Alexander DL4NO

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DeMaw's Barebones Superhet

A recent e-mail got me thinking about Doug DeMaw's Barebones Superhet.  June 1982 QST.  Mostly 40673 Dual Gate MOSFETS (this one's for you Dino!).  Barebones indeed.  Check out the schematic.

I literally blew the dust off my version and fired it up on Sunday.  It sounds really great.   I had lowered the values of the caps in the ladder filter to widen it out for phone.   Also, I see that I used LM386 instead of the op amp AF Amp prescribed by W1FB.   I notice that my version has much better audio than another version of this RX (with the op amp) that I'm using on 17 meters.  Could the difference be the LM386 vs. op amp?  There is a lot more audio with the 386, and the AF response seems wider.  

I feel the urge to put this receiver to use.  I am rehabilitating the W1VD CW transmitter that used with it during the late nineties, but I'm a phone guy now, and I feel compelled to use this RX as part of an SSB rig.  Of course, I could build a standalone SSB TX, but how about a diode switching scheme to make use of the Barebones' filter, the VXO and the BFO in a transceiver?

Here is my article on the original build of this receiver: http://www.gadgeteer.us/HBHOME.HTM

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

A Beautiful Workshop in Scotland

A nasty Coronal Mass Ejection hit our magnetic field at around 0600 UTC today.  The HF bands are now in poor shape.  What better time to visit a really impressive workshop in Scotland? 

Ian has an interesting site: http://www.ianjohnston.com/

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Vanguard!

Wow, Vanguard even looks like a QRPp satellite. 

I suspected that something was up:  I noticed that Mike Rainey, AA1TJ has recently been crossing pond with a QRPp Germanium rig...  Then Steve "Snort Rosin" Smith clued me in: The next period of  Vanguard QRPp Activity Days begins tomorrow.  "Club 72" has a nice write up, and a nice collection of pictures of the Vanguard rigs that have been built around the world:

http://www.club72.su/vanguard.html

Go Germanium!  Go Vanguard!

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QRP SSB with a New Rig

Kelly, WB0WQS, was trying out a new KX3 that his wife had given him as a present.  The radio gods must like that low-power rig because, in what seems like a deliberate demonstration of the awesome power of QRP phone, Kelly's first QSO was with another QRP operator:  me!  The sun was going down and taking 17 meters with it, but neither of us missed a word.  We talked about SolderSmoke and our mutual friend, Jerry, NR5A -- Kelly had known Jerry when they were teenage hams. Good luck with the new rig Kelly!

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Kludge: Rube-Goldberg Heath-Robinson Ad-Hockery

Wow!  "Ad-hockery... verging on being a crock."  That sounds like my building technique!  I thank Kevin for sending this, but I admit to now being more confused than ever.

Bill:

A snippet from my kluge research.  This was a word I learned from my dad who told me he had heard it first used in the 1930s.  Here is where I find a divergent meaning with the new word kludge which I have often heard pronounced as rhyming with sludge.  I was asked why I pronounced it with the d as silent.  I asked why I should pronounce a letter which was not even in the word.  Thus my introduction to the new word kludge which means something very different than what I had learned from my father.  While a kluge is something clever a kludge is an ad hoc and usually buggy hack. 
I found a little supporting evidence for the etymological timeline. To whit:

Source: The Free On-line Dictionary of Computing (2003-OCT-10)

kluge

   /klooj/, /kluhj/ (From German "klug" /kloog/ - clever

   and Scottish "kludge") 1. A Rube Goldberg (or Heath

   Robinson) device, whether in hardware or software.

   The spelling "kluge" (as opposed to "kludge") was used in

   connection with computers as far back as the mid-1950s and, at

   that time, was used exclusively of *hardware* kluges.
 

   2.  A clever programming trick intended to solve

   a particular nasty case in an expedient, if not clear, manner.

   Often used to repair bugs.  Often involves ad-hockery and

   verges on being a crock.  In fact, the TMRC Dictionary

   defined "kludge" as "a crock that works".
 

   3. Something that works for the wrong reason.

   4. (WPI) A feature that is implemented in a rude manner.

   In 1947, the "New York Folklore Quarterly" reported a classic

   shaggy-dog story "Murgatroyd the Kluge Maker" then current in

   the Armed Forces, in which a "kluge" was a complex and

   puzzling artifact with a trivial function.  Other sources

   report that "kluge" was common Navy slang in the WWII era for

   any piece of electronics that worked well on shore but

   consistently failed at sea.

   However, there is reason to believe this slang use may be a

   decade older.  Several respondents have connected it to the

   brand name of a device called a "Kluge paper feeder" dating

   back at least to 1935, an adjunct to mechanical printing

   presses.  The Kluge feeder was designed before small, cheap

   electric motors and control electronics; it relied on a

   fiendishly complex assortment of cams, belts, and linkages to

   both power and synchronise all its operations from one motive

   driveshaft.  It was accordingly tempermental, subject to

   frequent breakdowns, and devilishly difficult to repair - but

   oh, so clever!  One traditional folk etymology of "klugen"

   makes it the name of a design engineer; in fact, "Kluge" is a

   surname in German, and the designer of the Kluge feeder may

   well have been the man behind this myth.

   TMRC and the MIT hacker culture of the early 1960s seems to

   have developed in a milieu that remembered and still used some

   WWII military slang (see also foobar).  It seems likely that

   "kluge" came to MIT via alumni of the many military

   electronics projects run in Cambridge during the war (many in

   MIT's venerable Building 20, which housed TMRC until the

   building was demolished in 1999).

Source: Jargon File (4.3.1, 29 Jun 2001)

kluge /klooj/ [from the German `klug', clever; poss. related to Polish

'klucz' (a key, a hint, a main point)] 1. n. A Rube Goldberg (or Heath

 Robinson) device, whether in hardware or software. 2. n. A clever 
 programming trick intended to solve a particular nasty case in an 
expedient, if not clear, manner. Often used to repair bugs. Often

  involves ad-hockery and verges on being a crock. 3. n. Something

  that works for the wrong reason. 4. vt. To insert a kluge into a

  program. "I've kluged this routine to get around that weird bug, but

  there's probably a better way." 5. [WPI] n. A feature that is

  implemented in a rude manner. 

  Nowadays this term is often encountered in the variant spelling

  `kludge'. Reports from old farts are consistent that `kluge' was the

  original spelling, reported around computers as far back as the

  mid-1950s and, at that time, used exclusively of _hardware_ kluges. In

  1947, the "New York Folklore Quarterly" reported a classic shaggy-dog

  story `Murgatroyd the Kluge Maker' then current in the Armed Forces, in

  which a `kluge' was a complex and puzzling artifact with a trivial

  function. Other sources report that `kluge' was common Navy slang in the

  WWII era for any piece of electronics that worked well on shore but

  consistently failed at sea.

  However, there is reason to believe this slang use may be a decade

  older. Several respondents have connected it to the brand name of a

  device called a "Kluge paper feeder", an adjunct to mechanical printing

  presses. Legend has it that the Kluge feeder was designed before small,

  cheap electric motors and control electronics; it relied on a fiendishly
  complex assortment of cams, belts, and linkages to both power and

  synchronize all its operations from one motive driveshaft. It was

  accordingly temperamental, subject to frequent breakdowns, and

  devilishly difficult to repair -- but oh, so clever! People who tell

  this story also aver that `Kluge' was the name of a design engineer.

  There is in fact a Brandtjen & Kluge Inc., an old family business that

  manufactures printing equipment - interestingly, their name is

  pronounced /kloo'gee/! Henry Brandtjen, president of the firm, told me

  (ESR, 1994) that his company was co-founded by his father and an

  engineer named Kluge /kloo'gee/, who built and co-designed the original

  Kluge automatic feeder in 1919. Mr. Brandtjen claims, however, that this

  was a _simple_ device (with only four cams); he says he has no idea how

  the myth of its complexity took hold. Other correspondents differ with
  Mr. Brandtjen's history of the device and his allegation that it was a

  simple rather than complex one, but agree that the Kluge automatic

  feeder was the most likely source of the folklore.

  TMRC and the MIT hacker culture of the early '60s seems to have

  developed in a milieu that remembered and still used some WWII military

  slang (see also foobar). It seems likely that `kluge' came to MIT via

  alumni of the many military electronics projects that had been located

  in Cambridge (many in MIT's venerable Building 20, in which TMRC is

  also located) during the war.

 The variant `kludge' was apparently popularized by the Datamation

  article mentioned above; it was titled "How to Design a Kludge"

  (February 1962, pp. 30, 31). This spelling was probably imported from

  Great Britain, where kludge has an independent history (though this

  fact was largely unknown to hackers on either side of the Atlantic

  before a mid-1993 debate in the Usenet group alt.folklore.computers over

  the First and Second Edition versions of this entry; everybody used to

  think kludge was just a mutation of kluge). It now appears that the

  British, having forgotten the etymology of their own `kludge' when

  `kluge' crossed the Atlantic, repaid the U.S. by lobbing the `kludge'

  orthography in the other direction and confusing their American cousins'

  spelling!

  The result of this history is a tangle. Many younger U.S. hackers

  pronounce the word as /klooj/ but spell it, incorrectly for its meaning

  and pronunciation, as `kludge'. (Phonetically, consider huge, refuge,

  centrifuge, and deluge as opposed to sludge, judge, budge, and fudge.

  Whatever its failings in other areas, English spelling is perfectly

  consistent about this distinction.) British hackers mostly learned

  /kluhj/ orally, use it in a restricted negative sense and are at least

  consistent. European hackers have mostly learned the word from written

  American sources and tend to pronounce it /kluhj/ but use the wider

  American meaning!

  Some observers consider this mess appropriate in view of the word's

  meaning. 

I hope this further muddies the definitional waters for you :)

   73,

      Kevin.  KD5ONS

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Almost forgot! Happy Pi Day!

3-14   Get it?

And happy birthday Albert Einstein! 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Autographed SolderSmoke Books

I have some books left over from Winterfest.   Please let me know if you'd like a signed copy.  Some folks are ordering them as gifts for fellow Knack victims.  I will inscribe them with whatever you'd like me to write (within limits, of course!)

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20