Homebrew Tiny Space Telescopes from the Netherlands

It is good every once in a while to step back from our electronic work benches and take a look at what other kinds of builders are making.   Hack-A-Day led me to this wonderful video from Holland.  There is great background information on telescopes, but the really great part is the interview with the Dutch fellow who is actually making -- in his home workshop -- these tiny telescopes.  Icing on the cake:  One of them will be used in a student Cube-Sat project in Oregon.  

Be sure to stay to the end for an intriguing presentation by Dr. Liam Fullersheit. 

No Longer On the "Shame Shelf" -- Pete Fixes His KWM-1

 

I think a good troubleshoot is almost as satisfying as a successful homebrew.  And we can sense that high level of satisfaction in Pete N6QW's description of his repair of a Collins KWM-1:   

http://n6qw.blogspot.com/2021/10/resurrection-of-kwm-1-sn-673.html

I liked Pete's troubleshoot/repair story, but -- as is often the case -- I struck by his turn of a phrase.  I think Pete has added something important to the SolderSmoke lexicon: 

THE SHAME SHELF 

Most of us have a shelf like this. I have an HW-101 on mine.  Pete shows us that there is hope -- there is path off of the shame shelf.  You just have to know stuff.... Or have IBEW friends like Pete who can advise you. 

2 Meter Homebrew: The Fredbox (Video)

I predict a rebirth of interest in 2 meter homebrew.  This will probably hit around Christmas time.  The impetus will come out of Hyderabad, India.  At this point, I can say no more. 

I was thinking about all of this today.  I remembered "The Fredbox."  G3XBM's report on this fantastic rig was carried on this blog before it was even a blog.  And the Fredbox goes back much further in time -- back to the mid-1970s.  It must have been great fun to have QSOs with this rig in Cambridge England back in the day.  G3XBM actually crossed the English channel with this 10 mW rig.  FB.  

When I was in London (2003-2007), G3XBM's post on the Fredbox got me interested in 2 Meter AM.  I had a down-converter that let me listen, and I went as far as modifying a Benton Harbor Lunchbox for the proper AM transmit frequency.  I don't think I made any contacts, but I still have the bits and bobs of this rig, so if anyone in the Northern Virginia area wants to get on,  please let me know -- I will blow the dust off this project and will build a 2 meter antenna.  

Here are more details from G3XBM on The Fredbox:  

https://sites.google.com/site/g3xbmqrp3/vuhf/fredbox 

Hans G0UPL got into the Fredbox in 2009 and 2016: 

http://www.hanssummers.com/fredbox.html

SolderSmoke Podcast #233: PIMP, Boatanchors, Novices, MMM, Heathkits, DC Receivers, Mailbag

SolderSmoke Podcast #233 is available. 

http://soldersmoke.com/soldersmoke233.mp3

Travelogue: Cape Cod. SST. Marconi Site.

The WFSRA:   The World Friendship Society of Radio Amateurs.

Pete's Bench:

The Pimp.
The NCX rig.
The Collins.
The many DC receivers built worldwide.
The parts shortages are real! Several key radios on hold. Si5351 sub.
Talk to G-QRP convention

Bill's Bench:

FT-8. Not for me. I tried it.
Novice Station Rebuild.
Globe V-10 VFO Deluxe.
Selenium rectifier removal CONTROVERSY?
Not crazy about my Novice station. Not crazy about CW. 
Mate for the Mighty Midget. Again. 
Mike W6MAB -- Detector problems LTSPICE Check
One more mod for MMM RX. Ceramic filter at 455.
Dropped screw inside tubular cap on Millen 61455 transformer. 
Talk to the Vienna Wireless Society
Thinking of a Moxon or a Hex beam.


BOOK REVIEW Chuck Penson WA7ZZE New Heathkit Book. http://wa7zze.com

Mailbag

-- New SPRAT is out! Hooray!
-- Todd K7TFC sent me copy of Shopcraft as Soulcraft. FB.
-- Dean KK4DAS building an EI9GQ 16 W amp. FB.
-- Jack NG2E Getting close on Pete's DC receiver.
-- JF1OZL's website is BACK!
-- Tony K3DY sent link to cool books. 
-- Sheldon VK2XZS thinking of building a phasing receiver.
-- Peter VK2EMU has joined the WFSRA. FB!
-- Ned KH7JJ from Honolulu spotted the Sideband Myth in the AWA video.
-- Chris M0LGX looking at the ET-2, asks about the variometer.
-- Pete Eaton Nov 64 anti HB rant in november 1964 QST. Wow.
-- Josh Lambert Hurley spreading FMLA stickers in the UK. FB
-- Stephen VE6STA getting ready to melt solder.
-- Got a great picture of Rogier PA1ZZ back on Bonaire.
-- Farhan reading the manual of Hans's new digital rig.
-- Paul G0OER wonders if FMLA getting ready to move on 5 meters.

Recent Homebrew Projects from Jan PA3GSV (of "Mate for the Mighty Midget" Fame)

 

Recent talk of the Mate for the Mighty Midget receiver and Pete's PIMP SSB transmitter brought me back in contact with the work of Jan, PA3GSV.  I took a look at his QRZ.com page and found that he has some projects that rival even his seemingly unbeatable MMM RX project. 

Check it out for some real homebrew eye candy: 

https://www.qrz.com/db/pa3GSV

Bill's 52 year-old Apollo 11 Time Capsule -- What Should I Do?

 

When I was a kid, I was an Apollo 11 fanatic.  I was ten years old when they landed on the moon.  I was convinced that the newspapers and magazines from that event would someday be worth A FORTUNE! So, as a ten year-old, I double or triple wrapped a bunch of them in plastic and put the package up in the attic of my parents' house.  Where they sat undisturbed for more than half a century.  

We were recently getting ready to sell the house, and I asked if my Apollo 11 newspapers were still up in the attic.  They were!  So the time capsule has come back to me after all these years (see above).  It remains unopened.    

Obviously this is not worth the fortune that my ten year-old self thought it would be worth. (Hey, I was 10!)  But it is worth something to me.  I know we have a lot of fellow space geeks reading the blog, so let me ask for advice:  What should I do with this?   

Another M^3: The Michigan Micro Mote

Move over Michigan Mighty Mite and Mate for the Mighty Midget.   There's a new M^3 in town.  And it is SMALL. 

Hack-A-Day had an article on this today, and while it seems only tenuously connected to ham radio, I found it intriguing.  

Check it out.  Who knows, someday people may be operating in "dust mode":  

https://hackaday.com/2021/10/04/snails-sensors-and-smart-dust-the-michigan-micro-mote/#more-498450

Dean KK4DAS Builds an EI9GQ 16 Watt RF Amplifier (and Noodles in the Process)

 

I really like Dean's description of the building process, especially where he describes the need to sit down with paper and pencil for some noodling.   We see that in the picture above.  Too often we hear from guys who seem to be looking for detailed, step-by-step instructions, and then get frustrated and stuck when this kind of detail isn't available. Dean shows what to do in this situation:  noodle! 

Check out Dean's blog post on this project: 

https://kk4das.blogspot.com/2021/10/ei9gq-16-watt-power-amp-start-to-finish.html

Dean's post made me think about the origin of the verb "to noodle."  We know it has its origins in music.  Google provided this interesting explanation: 

To noodle around on something, while it does make use of the noodle (head), may derive from the regional German nudeln, to improvise a song, or from the late-19th-century Scottish sense of noodling as humming a song to oneself. By 1937, to noodle was to fool around with notes to create music.

We noodle around with parts and schematics to create rigs. 

Scott WA9WFA's Mate for the Mighty Midget Receiver is WORKING! (Video)

Wow, Scott got his Mate for the Mighty Midget receiver to work and he is obviously overjoyed with the result.  All of us who have struggled with a homebrew project know just what this feels like.  And it is very cool that Scott got some useful guidance from Charlie Morris in far-off New Zealand.   Congratulations Scott.  I'm really glad you stuck with it.  

Scott's success comes at a good time:  Pete N6QW is building W4IMP's three tube "IMP" SSB transmitter (also from the 1960s).   I accept responsibility for naming Pete's project:  It will be known as "Pete's IMP" or, memorably,  "The PIMP."  For a look at Pete's rig go here: 

http://n6qw.blogspot.com/2021/09/lets-build-something-with-vacuum-tubes_23.html

Scott had problems getting Lew McCoy's 455 kc crystal filter to work.  So did I.  It turns out that this is a very old problem, going back to World War II.  In Don Stoner's 1959 "New Sideband Handbook" on page 54 he writes of homebrew filters in the 400 to 500 kc range:  

"Inexpensive crystal filters constructed from war surplus FT-241 type low frequency crystals are very popular with the 'do it yourself' hams. These CT cut crystals have been plentiful and relatively cheap for a number of years and are in the hands of many Amateurs. The general run of war surplus crystals may or may not be good. Experience has shown that one out of four of these crystals are usually defective in one way or another." 

Stoner was writing just 14 years after the war.  Add another six decades to the age of these crystals -- often decades spent in musty basements -- and you can imagine the percentage of bad 455 kc FT-241  crystals increasing.  So I think Scott is wise to seek an alternative to McCoy's crystal filter. 

Scott's original build of the MMMRX receiver is just so nice.   In the video he says he plans to go back to it after he gets the expanded version fully functional.  He should definitely do that -- his  original version looks so good.  I think it is probably very close to working properly. 

Thanks Scott, and again, congratulations OM. 

Selenium RECTIFIED

Selenium rectifiers. The name kind of sounds like Dilithium crystals, possibly related to flux capacitors. 

Anyway, there were two of them in the Globe Electronics V-10 VFO Deluxe that I recently bought.  Obviously they had to go, so I took them out yesterday, replacing them with a 1N5408 silicon rectifier.  

The new diode had a significantly lower voltage drop than the selenium rectifiers -- this pushed the output voltage from the power supply up to around 200V.  It is supposed to be around 185 V.  So I put a 470 ohm,  5 watt resistor (found in the junkbox) in series.   This brought the output voltage to 167 V.  Close enough.  VFO seems to be working fine.  

I'm glad I did the extraction before these aging components released their nasty toxic smoke. 

W3HWJ has a good article on replacing these nasty old parts, with some interesting info on their history:   http://www.w3hwj.com/index_files/RBSelenium2.pdf

Backgound on the element Selenium:  https://en.wikipedia.org/wiki/Selenium

Chuck Penson's Amazing New Book about Heathkit Amateur Products

 

I was very pleased to read that Chuck Penson WA7ZZE was publishing a book about Heathkit's amateur radio products.  His book is a really great guide, providing a lot of fascinating information, stuff that even those of us who have spent decades with pieces of Heath gear didn't know.  For example, I never knew that an after-market dial had been available for the HW-101.   And I didn't know that the Indian names used for many of the Heath rigs (Comanche, Apache, etc.) resulted from a suggestion from Roger Mace's wife, who was Native American. 

Chuck's book arrived just as I was putting my DX-40 novice transmitter back on the air after almost 50 years.  TRGHS.  Who knew that there were TWO versions of the DX-40?  I didn't, but Chuck did, and his book explained how to spot the difference (flashlight through the side vents -- I have the very slightly more modern version). 

When I opened the book for my first peek inside, the page opened to the QF-1 Q multiplier.  I immediately felt guilty about having brutally cannibalized several (well maybe more than several) of these things.  But right there in the text Chuck repeats my justification for the carnage:  He notes that the tuning cap has a nice 14:1 turns ratio.  Exactly.  How could I NOT pull those beautiful variable caps out of that old regen device, for re-use in superhet receivers and BITX transceivers?  

This is a wonderful book that belongs in the workshop libraries of all those who have used and loved Heathkits over the years.   

Order yours here:  

https://wa7zze.com/amateur-radio

Thanks a lot Chuck for making such a great contribution to the radio art and to ham radio literature. 

N2CQR (WN2QHL) Novice Station Re-Created

 

There it is.  The 2021 re-creation of the WN2QHL Novice Amateur Radio Station.  This is what I had when I first went on the air in April 1973 from Congers, NY. 

-- I got my first Lafayette receiver (WITH JEWELED MOVEMENTS!) for Christmas in 1972.  My mom drove all the way into New Jersey to get it for me. 

-- I bought my first DX-40 and the Globe VFO Deluxe from someone in the Crystal Radio Club.

For this re-creation station: 

-- I got this recently acquired Lafayette free-for-pickup from a very kind SWL in the Shenandoah valley.  (I've discussed this receiver extensively here.) 

-- The DX-40 is the result of a couple of junkers that I bought in a hamfest some 23 or 24 years ago.  It might have been the Timonium Hamfest.  I cannabalized one of them and made one good DX-40 out of the two.  Parts of the cannabalized unit carry on the good fight as pieces of my balanced  antenna tuner (the coils were useful there) and as the chassis for my first SSB transmitter. 

-- The Globe VFO Deluxe was harder to recover.  There are just not a lot of these things around.  I actually put up a plea for one of these on the SolderSmoke blog.  Not even the IBEW could come up with one of these things.  But then, last week on Facebook I came across a fellow who was selling one.  Deal!  Check our the nice Juliano Blue light indicating 40 meter operation. 

Putting these three devices together was more challenging than I thought.  To get them to work together decently three different things had to happen as the result of throwing one switch: 

1) Antenna had to switch from receiver to transmitter. 

2) Receiver had to be largely muted (leaving some key-down signal for sidetone).  

3) VFO had to be turned on (I left it running and just keyed the DX-40).  

Fortunately I have almost 50 years more experience than I did when I first set this station up.  So I was able to do this better in 2020 than I did in 1973.   I had a 3PDT relay that I had built for a DX-60 station.  I was able to use it to do all three things described above. 

Muting the Lafayette was a bit tricky.  On the back octal connector they have two post  (1 and 3) that are normally connected.  Disconnecting 1 from 3 completely mutes the receiver by cutting off a needed ground connection to the RF amplifier and to an IF amplifier.  The Lafayette manual tells you to connect these terminals to the "muting voltage" presented by your transmitter.  The DX-40 doesn't have such a voltage, and I was reluctant to connect any voltage to this terminal for fear of blowing up the RF and IF amplifiers.  I figured that just putting a big resistor across 1 and 3 would mostly mute the receiver.  The 3PDT relay shorts this resistor on receive, un-muting the receiver. I use a 500,000 ohm resistor.  It works well, but the sidetone is chirpy while the actual signal is not.  This is a bit annoying. 

I re-capped the DX-40 when I got it back in the late 90's.  Those caps are still good. 

The Globe VFO had also been recapped.  But it still has selenium rectifiers in there.  I will change them ASAP.  Also, the Globe VFO had a somewhat mysterious second transformer in there.  I wondered what that was.  I measured the output:  6.3 V.  That is a filament transformer.  My guess is that the filament winding in the main transformer went open, maybe as a tube failed. Instead of replacing the whole transformer, they just popped in a replacement filament transformer.  That's fine. 

I've been on the air with this rig, mostly on 40, as I was as a Novice.   I can work anyone I hear on 40 meter CW and my CQ's are heard in Europe (as shown by the RBN). 

I'm struck by how physically BIG these pieces of gear are.  Much bigger than our beloved BITXs. 

Regarding T/R switching:   There was a line in the 1973 ARRL Radio Amateurs Handbook that really got to me back in 1973:  Page 640, in the chapter entitled "Assembling A Station:" "

"In any amateur station worthy of the name, it should be necessary to throw no more than one switch to go from the 'receive' to the 'transmit' condition." 

By this standard, my station was probably unworthy of the name.  I don't remember how I handled T/R changeover, VFO keying, receiver muting and sidetone,  but it almost certainly involved throwing more than one switch.  But now, I am happy to report, my novice station is finally up to the ARRL's high standards.  As Pete says, "When you know stuff you can do stuff."