WA2EUJ's NXP RF Power Amplifier Design Challenge Entry -- Won First Place Prize!

Congratulations to Jim WA2EUJ.   First Place the NXP Design Challenge. 

You can buy the board here: 

https://sites.google.com/site/rfpowertools/home/nxp-mrf-101

Thanks to Pete Eaton WB9FLW for alerting us to this. 

Mountain Topping in Indonesia -- Very Cool Video

OM Kenji has an awesome video about a mountain topping trip that took place in Indonesia just yesterday.  Very nice.  

I like the use of the neodymium magnets to attach the paddles to the rig.  I may try that with my homebrew straight key and the Samana-uBITX. Or I may have to get a keyer and learn (finally!) to use paddles.  (But simplicity is a virtue and there is nothing more simple than a straight key.) 

Kenji is obviously an amazing cook, even in the field.  I like the coffee-making technique. 

Check out more of his videos (and subscribe) at his YouTube Channel page: 

https://www.youtube.com/channel/UCpfn1viFoqVmWk6x891nKaQ   

Thanks Kenji! 

DK7IH's New HOMEBREW Transceiver Raises the Bar for All of Us

And that, my friends, is a HOMEBREW transceiver.  Wow, amazingly well done.  After I showed this to Pete N6QW (no slouch in the homebrew packaging department), in frustration with his self-perceived shortcomings he threatened to give up on homebrewing and to throw away all his rigs. Don't do it Pete!   

Peter Rachow, DK7IH has carefully documented his project through as series of blog posts: 

Here is Part 1: 

https://radiotransmitter.wordpress.com/2020/01/03/an-experimental-hf-6-band-ssb-transceiver-part-1-basic-outline/

Part 9 deals with mechanical construction, packaging and what George Dobbs used to call "socketry."

Thank you Peter for taking the time to share your project with all of us.  It is really inspirational. 

Junk Box Ethics -- I Plead Guilty! (video)

I cringed when, at about the 32 minute mark,  during a discussion of the moral necessity of preserving old gear, Michael appeared on the screen with a Heathkit Q multiplier sitting right there next to him.  It was as if he was talking about me.  I felt as if I had been hauled into Ham Radio Court, Judge Michael Murphy presiding. 

I have already REPEATEDLY admitted to sacrificing MULTIPLE Q MULTIPLIERS.  But I did it for good reasons:  

1)  I have some objections to use of regeneration, especially in superhet receivers.  After all, Armstrong created the superhet in part to free us from the tyranny of regeneration (that he had also invented).  

2)  This is a case where the parts ARE greater than the sum.  Specifically that variable cap WITH reduction drive.  And that perfectly sized metal box. Those capacitors are currently in service in at least two of my homebrew SSB transmitters. And as I look around the shack, I see one of those boxes housing an Si5351 VFO, and another holding the dual-digital frequency displays for my DX-100/HQ-100 AM station.    

3)  Mike notes that these Q-multipliers are being sold for TWO DOLLARS at hamfests.  At prices like this, temptation is just too strong. 

So I plead guilty, your honor.  But I ask the court to consider the circumstances under which I dismantled this obsolete gear, and the good uses that I made of the parts that I obtained.  Also, I'd like to make note of the fact that I salvaged from a junk pile a Heath VF-1 (I completely rebuilt it) AND I restored to usefulness a Heath DX-40 -- both these devices appeared in the WU2D video.  Finally, if anyone really needs the remaining parts from the now deceased QF-1s, I'd be willing to donate them (in an effort to redeem myself). 

Thanks Mike!  

How to Generate an AM Signal (and DSB!) in LTSpice

Pretty cool and very useful.   You can also do this by using the Modulator symbol, but I found this technique easier and more straightforward. 

But be sure to watch all the way to the end of the video.  Early on, he forgets the step that causes the carrier to stay in the simulation, but then shows how to correct this.  In the process we learn how to create a DSB (suppressed carrier)  signal in LTSpice. 

Lebanon's First Radio Website

I found this site through Paul VK3HN.  He took the AM detector circuit for his AM receiver from one these Lebanese homebrew radios.  

There is some really great information on this wonderful website.  It has been online for some 20 years -- I wish I had found it earlier.  The author shares his Knack story -- this is a wonderful example of the International Brotherhood of Electronic Wizards (IBEW). 

http://www.midcenturyradios.com/index.html

And he has very cool schematics, really well done.  Click on image to enlarge: 

Wild Woody WARC Keys

From the NAQCC newsletter: "The key is Dave's own unique invention called the WILD WOODY WARC KEY, and each key is consecutively serial numbered. (My key is number 476). WILD WOODY WARC KEYs have a place of honor in the ARRL Headquarters, and in the offices of Kewnwood, Icom and other such places. Dave, as some of you may know writes a monthy column for CQ Magazine and is the author of several books on keys, QRP operation and other subjects. The WILD WOODY WARC KEY is pictured below. Ingenous simplicity -- a true work of wonder. Thank you Dave."

I post this for several reasons.  

1) A friend recently complained that telegraph keys are getting expensive.  "Ha!" I said.  This proves me right.   Clothes pins are not expensive. 

2) I think we should make more use of clothes pins in ham radio.  They were used in my 20/15 meter dipole in the Dominican Republic. 

3) I worked K4TWJ several times -- twice from the Dominican Republic, and once from Virginia using a homebrew transceiver that he had inspired.  He was pleased.  It was cool. 

4) As a little kid, I liked Woody the Woodpecker. 

4) On Thursday morning my wife and I saw a Pileated Woodpecker (just like Woody!) in our neighborhood.  TRGHS. 

Mr. Carlson's Lab Attacked by Dangerous Canadian Snow Static! (Video)

Even when describing something as simple and basic as snow, Mr. Carlson is electronically awesome.   This video made me realize that in the event of an EMP, his will probably be the only lab to survive.

The SolderSmoke Daily News took up the topic of snow static back in 2011.  Be sure to read the comments, especially the one from KC7IT about the QUARTER INCH ARCS that woke him up in the dorm at MIT.  Check it out: 

https://soldersmoke.blogspot.com/2011/10/snow-static.html#comment-form

I've got to get one of Mr. Carlson's 2020 calendars! 

  

Hack-A-Day and Copper Tape

https://hackaday.com/2020/01/15/the-flexible-permanence-of-copper-tape-circuits/

and

https://halestrom.net/darksleep/blog/039_coppertape/

The End Fed Half Wave Antenna and EFHW Tuners

In the SPRAT 179 (Summer 2019) article describing their Peregrino (Pilgrim) transceiver,  Joan EA3FXF and Eduardo EA3GHS recommend the use of an End Fed Half Wave (EFHW) antenna. Their circuit incorporates an EFHW tuner and an SWR indicator.  As I planned my trip to the Dominican Republic with a uBITX, I had this antenna system idea in mind.  I was attracted by the possibility of avoiding having to carry coax with me.  And it seemed that an EFHW antenna would be easier to get up in the air than a coax-fed dipole. 

When searching for schematics for EFHW tuners I came across the QRPguys tuner kits.   

https://qrpguys.com/end-fed-half-wave-sota-antenna-tuner

This looked like just what I needed, so I ordered one.  But I placed my order kind of late, and I started to worry that I might not get the tuner kit in time.  So I decided to homebrew my own (just in case!) 

As it turned out, QRPguys got the kit to me in plenty of time. It went together very quickly and is a really useful piece of gear.  My homebrew version works fine, but I prefer the QRPguys device. 

You can check out the manual here: 

https://qrpguys.com/wp-content/uploads/2019/09/efhw_40m_tuner_assy_090119.pdf

The circuits are interesting.  The EFHW antennas present an impedance not of 50-70 ohms, but of 3000-5000 ohms.   The Peregrino and the the QRPguys circuits use a matching transformer to change the high impedance to 50 ohms.  In both circuits polivaricon capacitors are used to tune for resonance. The QRPguys circuit uses an N7VE LED absorption bridge -- I found it very satisfying to put the circuit into "tune" mode and then just adjust the capacitor until the LED went out.  That means the antenna system is presenting 50 ohms to the transmitter. 

SOTA beams has a good explanation of the EFHW antenna here: http://sotabeams.co.uk/efhw/
I did use a counterpoise.