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Tuesday, June 28, 2022

Flip-up Workbench Build -- Possible Application for Our Test Gear

Interesting workbench build.   While his tools were all for woodworking, this got me wondering about using this technique to store bigger pieces of electronic test gear that are not in use every day.  


Monday, June 27, 2022

Pete N6QW's Hybrid Wireless Set -- A Thing of Beauty, with Thermatrons

Pete Juliano is amazing.  He is admirably carrying a very heavy load of family responsibilities.  But  he still can build some really unique and innovative rigs.  He tells us that getting up at 3 am and only sleeping 5 hours per night allows him to do this.

Pete also blames Grayson Evans KJ7UM for this rig, what with the thrematrons and all.  Pete has a 7360 mixer in this rig, something that Grayson had in the 3rd edition of his Hollow-State Design book (get yours here:  https://www.ermag.com/product/hollow-state-design-2nd-edition/).  Pete reports that he first built the chassis for the tube (I mean thermatron) portion of the rig in the 1970s -- it has been in his junkbox ever since.  Grayson admires Pete's compact construction and point-to-point wiring.  

I too noticed very poor conditions on Field Day this year.  

Three cheers for Pete Juliano!  

Thoughts on Homebrew, Makers, DIY, and Hams -- from Lex PH2LB

Sometimes we get a comment that is so good that we elevate it to the main blog page.  That was the case with Lex PH2LB's comment on the blog post of Owen Duffy (yesterday). 


When I started the hobby, it arose out of technological curiosity, the interest in understanding things and the will to make things myself (designing myself was not my main goal). It doesn't matter to me whether it is 100% DIY or a kit (such as Heathkit, Elecraft, QRP-Labs etc) which is modified or not after construction. Just having fun with the hobby and pushing boundaries. And yes I also have some off-the-shelf transceivers (I'm super happy with my FT817ND) and my QO-100 uplink is also a kit (which is then already soldered a little more than average). As far as new tools are concerned: here at home are 2 types of 3D printers, various tools for SMT assembly, and I have a nice workshop equipped with tools and equipment for metal / plastic / wood processing. And every day I try to learn something new, because I stand by the IBEW moto : If you know stuff, you can do stuff.

Am I a maker then? I wouldn't call myself that. Just like I don't call myself a hacker because I'm quite handy with computers, technology and have certain skills. I'm just a hobbyist who wants to do and make things after work.
Lex is a true member of the International Brotherhood.  He is the one who took our beloved stickers onto the European continent and into a Netherlands pub.  He is the one who -- unforgettably -- saw the parallels between ham shacks and the "pleasure room" of "50 Shades of Gray" (See below -- apropos of his current message, we labeled his meme "50 Shades of Homebrew") For more on Lex see: https://soldersmoke.blogspot.com/search?q=PH2LB

Lex's web site (Shack on the Internet):  https://www.ph2lb.nl/blog/index.php?page=hamradio

 Thanks Lex! 

Sunday, June 26, 2022

ZL2BMI Double Sideband QRP Transmitter in SPRAT #191

Very cool that SPRAT had a Double Sideband (DSB)  transmitter article in its current issue (#191 Summer 2022). The author is DSB guru Eric Sears ZL2BMI,creator of the famous ZL2BMI  DSB QRP transceiver. 

I think DSB is a great way to break into homebrewing for phone.  Building a DSB transmitter is a LOT easier than building an SSB rig.  The DSB transmitter can then be converted into a DSB/Direct Conversion transceiver.   

Here is a link to 75 SolderSmoke blog posts about DSB (keep on scrolling, keep on hitting the "older posts" button): https://soldersmoke.blogspot.com/search/label/DSB

Here are a bunch of blog posts that mention ZL2BMI: https://soldersmoke.blogspot.com/search?q=ZL2BMI

Thank you Eric, and thanks to G-QRP. 

Saturday, June 25, 2022

Australian Homebrew: Owen Duffy ex VK1OD now VK2OMD. Are Hams Makers?

This week I stumbled upon this amazing blog from Australia.  I had to check with Australian friends to find out more about the author.  Owen Duffy has for many years been a rigorous homebrewer who has documented his findings on his blog:  https://owenduffy.net/blog/

For example, Owen asks the question, "Are hams makers?" https://owenduffy.net/blog/?p=122

There is a lot of great material on this blog.  It goes back to 2013.  Peter Parker notes that an earlier version of the blog (before Owen was forced to change his callsign from VK1OD to VK2OMD) goes back even further and is accessible via the Way-Back Machine:  https://web.archive.org/web/*/vk1od.net

Check it out.  Lots of really useful and interesting material there.   Thanks Owen.  And thanks to the Australian friends who provided background info. 

Friday, June 24, 2022

W8ZAP on 40 AM with a Collins 20V3 Broadcast Transmitter

I was on 40 AM yesterday morning and I talked to Jerry W8ZAP (great callsign) out in Michigan.  Jerry was running his Collins 20V3 (above on the right), which was originally an AM broadcast band transmitter.  FB.  

Here is Jerry's QRZ.com page: https://www.qrz.com/db/W8ZAP

Thursday, June 23, 2022

WIRED on the Dangers of another Carrington Event, Solar Cycle 25, Capacitors Could Save Us All

This Wired article has some really interesting info on competing theories about the solar cycle, about the danger to the Earth from solar flares, and about what a flare like that of the Carrington event could do to the transformers we are currently using.  The article points out that large capacitors could protect these transformers from the effects of the flare.  But the power companies are not installing the capacitors. 

I think one of the scientists Pete mentioned in SolderSmoke podcast #238 is mentioned here: 


Wednesday, June 22, 2022

Hammarlund and Homebrew Heroine: Janis AB2RA, HQ-100 Filter Cap Question


I was searching for Hammarlund HQ-100 wisdom when Google pointed me to the Electric Radio articles of Janis AB2RA.  They were in  ER #380 and #381 (February and March 2021).  Lots of good stuff  in there.  

This morning I happened upon a 2014 SolderSmoke blog post (as you do) about my Tuna Tin 2. Turns out that Janis was my first contact with this rig.  And she too was running a homebrew rig. TRGHS. 

I continue to work on my HQ-100.  The AC hum is getting worse so I have ordered a replacement capacitor can from Hayseed Hamfest.   But I was a bit confused about which cap to order.  Hayseed has two caps listed for the HQ-100 -- one (it seems) for the early model of this receiver and one for later models.  Is that right?  Did Hammarlund update the power supply to add filter capacitors?  Take a look: 

Dean KK4DAS is getting ready to work on his dad's HQ-170A.  He too will find lots of wisdom and tribal knowledge on Janis's wonderful web site.  

Her main page: http://www.wireless-girl.com/  (with a vast amount of technical info available through the links on the upper left side of this page) 

About Janis: http://www.wireless-girl.com/AboutMe.html

Thanks Janis!  

The Original Wireless Girl

Tuesday, June 21, 2022

Summer Solstice -- EITs. Solar Tsunamis. Strange Falcon 9 Spirals Seen in New Zealand


Forbes has an interesting article that may help explain the poor Cycle 25 propagation that were talking about in SolderSmoke podcast #238: https://www.forbes.com/sites/ericmack/2022/03/28/an-increasingly-active-sun-is-now-producing-solar-tsunamis-and-sending-flares-our-way/?sh=613e1dd1fbfd 

And Space Weather website has an interesting piece about some really strange SpaceX Falcon 9-related phenonmenon: 

Monday, June 20, 2022

QRP Labs HQ Tour

Really cool to see Hans describe his QRP Labs workshop in Turkey.  Lots of soul in that worshop.  Thanks Hans.  

 And here is a 2022 Turkish media interview with Hans and his team in the workshop:  

Sunday, June 19, 2022

A Great Book on Oscillators (Analog LC Oscillators) by John F. Rider (Free!)


Thanks to Peter Parker VK3YE for alerting us to this wonderful 1940 book.  John F. Rider -- a real hero of electronic literature -- does a great job in discussing the practical aspects of oscillator circuits. 

This excerpt from Rider's foreword gives a sense of the approach taken in this book: 

The book covers a lot of material.  In addition to the standard oscillator circuits, he discussed multivibrators, relaxation oscillators and much more.  There is a chapter on magnetostriction in which he shows that this property is the basis for crystal oscillators AND the mechanical filters that we are familiar with.  In fact he seems to take what we would consider a mechanical filter and put it in the grid circuit of a tube to make an oscillator. 

He discussed the modulation of oscillators. He describes the Heising modulator that caused young Jean Shepherd so much teenage heartache.  

Download the book here: 

Friday, June 17, 2022

Video of SolderSmoke #238

For details and audio podcast see: 

SolderSmoke Podcast #238 -- SolderSmoke Shack South, Cycle 25, Chiquita Banana Radio, RCA, HQ-100, Mate Mighty Midget, Sony SWL RX , Mailbag

SolderSmoke Podcast #238 is available:  http://soldersmoke.com/soldersmoke238.mp3


Cathartic decluttering:  Bill preparing for future winter travel to Dominican Republic.  Will build SolderSmoke Shack South.  Dividing everything up:  Rigs, parts, tools, supplies, antennas, test gear.  Everything.  

OUR SPONSOR:  Parts Candy.  
https://www.ebay.com/usr/partscandy  Premium quality test leads! Hand cut, hand crimped, hand soldered, these will become your new favorite test leads GUARANTEED!


-- Cycle 25 better? – Out here on the left coast – it is not evident
-- Chiquita Banana and the US Navy in early ‘wireless” operations.  Why RCA was created by the US Navy in 1919.
-- Update on the MAX2870 –someone has written the code to make it work with the Raspberry Pi and the QUISK SDR software
-- Field Day prep

Bill needs your help:  
-- Please watch his YouTube videos.  The longer the better!  Success based on hours watched. Great to have on while you are working in the shack. Just go to YouTube and search for the SolderSmoke channel. Or:  SolderSmoke - YouTube
-- Please put links to the SolderSmoke blog on your websites and blogs. 
-- How to USE the SolderSmoke Blog: Propagation, shopping, other sites... 
-- Please put comments under the articles on the SolderSmoke blog.  We like comments and dialogue. 


-- Repair of the Sony ICF SW1 shortwave receiver.  Bad electrolytics.  Number Station receiving device? 
-- HQ-100   Q-Multiplier. BFO Switch. AVC.  Noise Limiter limitations.  Dave K8WPE: Old Radio Lessons.
-- MMMRX: Detector circuit. Alignment. Muting. On the air (40 AM with DX-100) 


-- Bob Crane W8SX -- Great interviews at FDIM. On the SolderSmoke Blog. Thanks Bob! 
-- Dave Bamford W2DAB -- Stickers on the Upper East Side of Manhattan.  FB Dave! 
-- Farhan VU2ESE:  LADPAC software now available through W7ZOI' site.  
-- Lex PH2LB: Stickers in a Netherlands pub.  
-- Dave K8WPE Michigan Mighty Mite links.  Old Smoke idea. On the SolderSmoke blog. 
-- Rich WB4TLM was in the electronics class of CF Rockey W9SCH. FB. 
-- Dean KK4DAS Working on  his dad's HQ-170A. VWS maker group on mixers. 
-- Grayson KJ7UM -- Mixology article in ER. 
-- Pete Eaton -- Farhan's new analog rig: Daylight again!  Standby for more info from Farhan. 
-- Will KI4POV New HB Al Fresco single conversion superhet.  FB. 
-- Alvin N5VZH. Shep's "I Libertine."  Yes.  I laughed, I cried,  It changed me. 
-- Chuck KF8TI.  Mr. Wizard!  
-- Steve N8NM on the mend after some routine maintenance. 
-- Ben AB4EN is listening and likes the podcast -- Thanks Ben. 

May 1939 QST

Thursday, June 16, 2022

Watch Mr. Wizard! 1952 Program on Electromagnetism. And more! (video)

Wow.  This is a very thought provoking program.  It is kind of like "Mr. Roger's Neighborhood," but with science. The lessons provided by Mr. Wizard are really good, but one shudders to think about doing the these experiments with kids (or even with adults!) in today's world.  Here are a few of things that would cause trouble today:  

-- Liquid mercury.  
-- A big power supply. ("Here Willy, you hold the positive terminal.") 
-- Even the sprinkling of iron filings would probably require masks at a minimum.  
-- In the end, letting poor Willy drop to the floor when Betsy turns off the electromagnet that was holding his swing in the air.  
-- And of course, poor old Mr. Wizard's affinity for the kids would stir suspicions. 

We also see a sad and very early example of the influence of advertisers and what they call today "product placement."  Note the fairly obvious plug (via Morse Code!) for breakfast cereal.  In the credits you will see that the program was sponsored by "The Cereal Institute."  What next kids?  Cigarettes? 

But there is a lot of virtue in this program:  The development of the telegraph key, Morse Code,  CW sidetone.  Unlike many of the Box Top Extras of today, young Betsy was not afraid to wind a coil.   

We should all embrace the spirit of Mr. Wizard.  We are, after all, the International Brotherhood of Electronic WIZARDS!  These experiments reminded me a lot of the Trivial Electric Motor that my son Billy and I made when he was around Willy's age (thanks for the idea Alan Yates).  

Thanks to Chuck KF8TI for alerting us to this show.  Chuck says this program was an early influence on him, and was one of the things that provided a connection between the theory he was learning in college and the real world of electronic devices. 

Many more great programs like this can be found on Mr. Wizard's YouTube Channel: 
https://www.youtube.com/user/MrWizardStudios   Please let us know if you find other videos (on this channel or elsewhere)  that will be of special interest to the IBEW. 

Finally, color TV in 1952?  That seems a bit early for color.  What do you folks think was happening here? 

Tuesday, June 14, 2022

Hans Summers G0UPL Wins FDIM 2N2222A Power Out Challenge -- 4.1 Watts from Two 2N2222As

Farhan told me how cool this was.  And he was right.  It looks like a lot of fun.  Congratulations Hans! 


Monday, June 13, 2022

SolderSmoke FDIM Interview with Keith W. Whites -- Teaching Electronic Design to EE students using a QRP Transceiver designed by Wayne Burdick

When I first listened to Bob Crane's interview at FDIM with Keith Whites, I thought of the book "The Electronics of Radio" out of CalTech by David Rutledge.  Keith Whites told me that the difference between his effort at University of Kentucky was that Rutledge's course was designed for freshmen at Cal Tech, while White's course was aimed at Juniors and Seniors.  

I told Keith Whites that I had struggled to understand the Gilbert Cell and the NE602, the device that lies at the heart of the rig used in both courses:  The NE-602 Gilbert Cell Mixer used in Wayne Burdick's NORCAL 40A. Here is how I came to understand the device:  https://soldersmoke.blogspot.com/2021/11/how-to-understand-ne-602-and-gilbert.html

Here is Bob Crane's interview:  http://soldersmoke.com/2022 Whites.mp3

Here the slides that Keith used at FDIM: http://soldersmoke.com/2022 Teaching NorCal40A.pdf

Keith's students obviously got a lot out of this course.   Keith has kindly offered to make his course notes available to those who need them. 

Thanks to Bob Crane, Keith Whites, David Rutledge and Wayne Burdick. 

Saturday, June 11, 2022

Putting the "Mate for the Mighty Midget" Back to Work -- With a DX-100 on 40 Meter AM

After working on it for a while I got so fond of my old Hammarlund HQ-100 that I moved it from the AM/Boatanchors operating position over to a more convenient spot right next to my computer.  This left a big gap on the receive side of the AM station.  

I briefly put my HRO-ish solid state receiver above the DX-100, but I'm afraid that receiver needs some work.  More on that in due course. 

I thought about putting my SOLID STATE Lafayette HA-600A atop the thermatronic DX-100, but this just didn't seem right. The Radio Gods would NOT approve. 

So I turned my attention to the Mate for the Mighty Midget that I built in 1998 and have been poking at and "improving" ever since

This receiver worked, but not quite right. It received SSB stations well enough, but when I turned off the BFO I could no longer hear the band noise. I wasn't sure how well the RF amp's grid and plate tuned circuits tracked.  And I had serious doubts about the detector circuit that Lew McCoy put in there when he designed this thing back in 1966. 

As I started this latest round of MMMRX poking, I realized that I now have test gear that I didn't have in 1998:  I now have a decent oscilloscope.  I have an HP-8640B signal generator (thanks Steve Silverman and Dave Bamford).  I have an AADE LC meter. And I've learned a lot about building rigs. 


The MMRX has a tuned circuit in the grid of the RF amplifier, and another in the plate circuit of the RF amplifier.  There is a ganged capacitor that tunes them both.  They need to cover both 80/75 and 40 meters. And they need to "track" fairly well:  over the fairly broad range of 3.5 to 7.3 MHz they both need to be resonant at the same frequency.  

McCoy's article just called for "ten turns on a pill bottle" for the coils in these parallel LC circuits.  The link coils were 5 turns.  No data on inductance was given.  Armed now with an LC meter, I pulled these coils off the chassis and measured the inductances of the coils.  I just needed to make sure they were close in value.  They were: 

L1 was .858uH L2 was 2.709         L3 was .930uH  L4 was 2.672

Next I checked the ganged variable capacitors.  At first I found that one cap had a lot more capacitance than they other.  How could that be?  Then I remembered that I had installed trimmer caps across each of the ganged capacitors. Adjusting these trimmers (and leaving the caps connected to the grid of V1a and V2A, I adjusted the trimmers to get the caps close in value.  I think I ended up with them fairly close: 

C1: 63.77-532 pF          C2 64.81 -- 525.1 pF

I put the coils back in and checked the tracking on 40 and on 80/75.  While not perfect, it was close enough to stop messing with it.  


I've had my doubts about the detector circuit that Lew McCoy had in the MMMRX.  In his 1966 QST article he claimed that the circuit he used was a voltage doubler, and that this would boost signal strength.  But I built the thing in LT Spice and didn't notice any doubling.  And consider the capacitors he had at the input and output of the detector:  100 pF.  At 455 kHz 100 pF is about 3500 ohms.  At audio (1 kHz) it is 1.5 MILLION ohms. Ouch.  No wonder years ago I put a .1 uF cap across that output cap just to get the receiver working. 

Scott WA9WFA told me that by the time the MMMRX appeared in the 1969 ARRL handbook, the second "voltage doubling" diode was gone, as were the 100 pF caps.  Now it was just a diode, a .01 uF cap and a 470,000 ohm resistor.  I switched to the 1969 Handbook circuit (but I have not yet changed the 1 meg grid resister to 470k -- I don't think this will make much difference).  Foiled again by a faulty QST article, again by one of the League's luminaries. 

6U8s out, 6EA8s in 

We learned that the 6U8 tubes originally called for by Lew McCoy are getting old and not aging well.  So I switched all three to more youthful 6EA8s.  This seemed to perk the receiver up a bit. 

MUTING from the DX-100

My K2ZA DX-100 has a T/R relay mounted in a box on the back of the transmitter.  When the Plate switch goes up, it switches the antenna from receiver to transmitter.  The box also has a one pole double throw switch available for receiver muting.  I put the common connection to ground, the normally connected (receive position) connect the ground terminal of the AF output transformer to ground -- it is disconnected from ground on transmit.  The other connection (normally open) is connected to the antenna jack -- on transmit this connection ground the receiver RF input connection.  These two steps mutes the receiver very nicely. 

Replacing Reduction Drive

Over the years I have had several different reduction drives on the main tuning cap.  I had a kind of wonky Jackson brothers drive on there that needed to be replaced.  I put in a new one -- this smoothed out he tuning considerably. 

Ceramic Resonator

I never could get McCoy's 455 kc two crystal filter to work right.  So at first I made due with the two 455 kc IF cans.  This made for a very broad passband.  Then I put a CM filter in there.  This was more narrow, but with a lot of loss.  There may have been others.  But the filter spot is currently held by a 6 kHz wide ceramic filter.  This one is my favorite so far. 

Digital Readout

When I was running the DX-100 with the Hammarlund HQ-100 I built a little frequency readout box.  The box was from a Heath QF-1 Q multiplier (I am sorry about this).  The readouts are in Juliano Blue and come via e-bay from San Jian.  I now have it hooked up to the DX-100's oscillator.  I haven't tapped into the MMMRX's oscillator yet. 

Friday, June 10, 2022

SolderSmoke FDIM Interview: Adam K6ARK and his 2.6 gram Mini-Pixie SMD Transceiver

I've not bee a big fan of the super-simple Pixie transceiver, but Adam K6ARK could make me a believer. 

Our correspondent Bob Crane W8SX interviewed Adam at FDIM.  You can listen to the interview here: http://soldersmoke.com/2022 K6ARK.mp3

The video above shows Adam's tiny Pixie in action in the California desert.  His rig is about the size of a postage stamp and weighs about 2.6 grams. FB Adam. 

Adam did a lot better with his Pixie than I did with my far larger and more complicated SST transceiver. He also did better than I did on 40 when I was using my ET-2 (two FET) transceiver. 

I liked how Adam recorded in the field the CW from his rig, I also liked his key (!) and his EFHW antenna and "tuner."  Adam's ability to cope with no CW sidetone was also admirable.  

Adam's YouTube channel is here: https://www.youtube.com/c/K6ARKPortableRadio

Thanks to Adam and to Bob Crane.  

Wednesday, June 8, 2022

SolderSmoke FDIM Interview: Jack Purdum W8TEE on the Challenges of Decoding CW by Software


In his interview with SolderSmoke correspondent Bob Crane, Jack Purdum made some very interesting comments about the challenges of decoding CW with software. He notes that W1AW's code practice CW is perfect, but that below 18 wpm, they deliberately insert a "Farnsworth Delay" that increases the spacing between words -- this complicates automatic CW decoding.  

Jack also talked about the distinctiveness of different CW operators.  Jack  noted that W1AW has no real "fist" in this sense:  "It has the personality of a stick!" 

Jack mentioned that Pete Juliano had been reading book on SDR radios that Jack and Al Peter recently published:  https://www.amazon.com/Software-Defined-Radio-Transceiver-Construction/dp/B09WYP1ST8/ref=sr_1_1?crid=2KPYAMPOW5P6J&keywords=DR.+Jack+Purdum&qid=1654598559&sprefix=dr.+jack+purdum%2Caps%2C40&sr=8-1  

Here is our correspondent Bob Crane's interview at FDIM 2022 with Jack Purdum: http://soldersmoke.com/2022 W8TEE.mp3

Thanks Bob.  Thanks Jack.

Tuesday, June 7, 2022

Sticker Spotted Near the Old NYC Home of E. Howard Armstrong


Thanks Dave! 

SolderSmoke FDIM Interviews: A BRAVE HAM! Grayson Evans KJ7UM Presents a 50 Watt Amplifier to THE QRP GROUP!

Wow, talk about walking into the lions' den!  Grayson Evans, author of "Hollow State Design" and guru of all things thermatronic, went to FDIM and made a presentation TO THE QRP GROUP on how to build a 50 watt amplifier with a 6146 thermatron.  In New York that would have been called chutzpah.  The QRP ARCI guys seem to have tolerated this QRO-heresy; I'm not so sure the zealots over in G-QRP would have been quite so tolerant.

Grayson gave a nice shout out to SolderSmoke's Pete Juliano.  

And he offered some sage advice to those who live in fear of high voltage:  "Don't touch anything with high voltage on it."  Words to live by my friends.  He even managed to call those who shy away from high voltage "wimps."    This was all very reminiscent of the unforgettable safety advice he offered in his August 2021 interview on Ham Radio Workbench: "Try not to swallow anything, and don't sit on the thermatrons." I mean, who can argue with that? 

You can listen to Bob Crane's interview with Grayson here (about 6 minutes total): 

http://soldersmoke.com/2022 KJ7UM.mp3

Check out Grayson's  Hollow-State Design Book 3rd Edition: tinyurl.com/hollowstatedesign3

Check out Grayson's technical blog:kj7um.wordpress.com

Thanks Bob and thanks Grayson. 

Monday, June 6, 2022

SolderSmoke FDIM Interviews: Hans Summers G0UPL Talks about the QDX and His New Balloon Tracker


Thanks to Bob Crane W8SX for getting us this wonderful interview with Hans G0UPL.  Its really amazing to hear Hans talk about how many QDX rigs and Baloon Trackers have been sold by QRP Labs, and how quickly they sell.  Really great.  Hans's comments on the realities of the parts shortage was also very interesting. 

Listen here (about 7 minutes):  http://soldersmoke.com/2022 G0UPL.mp3

U4B Balloon Tracker 

SolderSmoke FDIM Interview with Farhan VU2ESE -- The sBITX is Coming!

Bob Crane W8SX --  our correspondent in Dayton/Xenia --  once again collected interview with FDIM presenters. Thanks Bob!  Here is his talk with our friend Farhan:  

http://soldersmoke.com/2022 VU2ESE.mp3

Here is a great post on the sBITX (May 30, 2022) from Farhan's web site: 


Here is Farhan's amazing presentation on the sBITX at the 2021 FDIM: 


Sunday, June 5, 2022

JFET (Junction Field Effect Transistor) Video -- Part 1

Good video.  I like how he related the real-world device to the Igs graph. Also, note the big variation in MPF-102 parameters.  Stay tuned for Part 2. 

Friday, June 3, 2022

Phase Noise and all that

Our friend Dave K8WPE has been listening to old podcasts.  He recently came across those in which Pete and I were talking about phase noise.   He asked for some resources on this topic.  Here is what I sent him: 

 Receiver performance expert Robert Sherwood explains it this way: 

Old radios (Collins, Drake, Hammarlund, National) used a VFO or PTO and crystal oscillators to tune the bands. Any noise in the local oscillator (LO) chain was minimal. When synthesized radios came along in the 70s, the LO had noise on it. It is caused by phase jitter in the circuit, and puts significant noise sidebands on the LO. This can mix with a strong signal outside the passband of the radio and put noise on top of the weak signal you are trying to copy. This is a significant problem in some cases: You have a neighboring ham close by, during Field Day when there are multiple transmitters at the same site, and certainly in a multi-multi contest station. You would like the number to be better that 130 dBc / Hz at 10 kHz. A non-synthesized radio, such as a Drake or Collins, has so little local oscillator noise the measurements were made closer-in between 2 and 5 kHz. 

Rhode and Schwarz have a good oversight video with great graphs that explain the fundamentals,  See above or here:  https://www.youtube.com/watch?v=hfgaEjf1154 

I think a lot of the fretting about advanced receiver performance measurements are really kind of over-the-top, and mostly of interest to advanced builders who want the very best performance from their receivers.  Most of the rest of us are happy if we can hear the band noise and separate the desired signals from the QRM.  But I must admit that as time goes on, I find myself getting more and more finicky.  I start to worry about gain distribution and dynamic range.  But I don't worry so much about phase noise because I am more of an LC oscillator guy and don't make much use of the PLL devices (like the Si5351) that do produce more phase noise. 

I've had many articles on the blog about about phase noise.  Here they are: 

Thursday, June 2, 2022

The Amazing Workshop and Test Gear of Tony Albus PE1ONS

This is almost too much.  This makes me want to go out and buy some more test gear, maybe another scope, or a spectrum analyzer, or at least another DMM.  I mean Tony has at least three of everything. 

This is really amazing.  Tony is obviously a test gear guy, but he also has a ham call PE1ONS.  He says he is not too active, but we should encourage him to get more involved with ham gear.  We need guys like him working on ham gear.  And he seems like such a happy person.  

Here is his QRZ.com page: https://www.qrz.com/db/PE1ONS

Here is his awesome YouTube channel: https://www.youtube.com/TonyAlbus

Wednesday, June 1, 2022

Marconi the Fascist

For obvious reasons Marconi stories pop up in my news feeds.  This morning an article  from Wales reminded me of a very dark and disheartening aspect of Marconi's life:  his fascism and his participation in the persecution of Jews. 

There have been at least 14 stories in SolderSmoke extolling the technological virtues of Marconi.  I even met his daughter Elettra while in Rome and wrote it up for the blog.  But it is just wrong to sing Marconi's praises while ignoring his fascist involvement. 

His fascism wasn't even separated from his radio work.  He won fascist honors and he won his appointment to Mussolini's  Academy of Italy  because of his radio work.   Take a look at this quote: 

He became President of Mussolini's Academy of Italy -- and it was in that position that he participated in the persecution of Jews.  He was a member of the Fascist Grand Council.

If you have doubts about this, just take a look at the short clip (above) from Marconi's 1937 funeral procession.  Note the fascist salutes, note Mussolini himself marching in the procession. 

The article from Wales: 

Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column