Author: Peter Marks

German Mighty Mite works Venice on 40 (video)

In spite of being a bit off frequency, sTef, DL1FDF (aka VY1QRP) has been inducted into the Color Burst Liberation Army. Congratulations sTef! Normally we would requite operation on 3.579 MHz, but sTef has been granted special dispensation because 1) he doesn’t have a 3.579 MHz rock, 2) our stock of this crystal has been depleted, and 3) he actually made a contact with this rig, working II3ICZ in Venice. FB sTef. If anyone has a color burst crystal for sTef, please let us know.
sTef writes:

I would like to say „Thanks” to both of you for your ongoing inspirations in soldering and homebrewing. After 15 years out of ham radio it were you two guys who got me back into the world of -> SOLDERSMOKE. Thanks for that.And belive me been away for 15 years and now getting back into it feels a sometimes a little bit too “digital“ …. ARDUINO or NOT TO ARDUINO ? This is the question….
Anyway…
So what could be more sophisticating than having a MMM ready on the work bench and answering a CQ call on 40m with that thing and be heard.
Yes, the first QSO today with my MMM was for you both.
I worked the Italian Radio Station II3ICZ. I was 559 into Venice with 0.5 watts from the MMM into my full-size triple leg for 40m.

“My Favorite Programming Language is Solder” — Boldport Kits

Look closely at the inscription on that USB stick. Obviously I sympathize. The folks at Boldport have some very interesting ideas and projects. And they operate from a very cool location, just south of the river Thames, not far from my old home in London.

Here is their main site: http://www.boldport.com/blog/2016/2/21/boldport-club-project-1

 Here is where you can subscribe to receive a monthly project (with parts!) from them:
https://boldport.cratejoy.com/

As for the solder quote from Bob Pease, this was discussed before on this blog, back in 2011. We were talking about an intereview that had been done with Alan Wolke W2AEW:

I also liked Alan’s response to the question about his favorite software tool: “Gee, solder is soft, can we consider that software? I use a lot of that!” This is very reminiscent of a quote from the legendary Bob Pease (colleague of Jim Williams): “My favorite programming language is solder.” (That quote was sent to me by Steve WA0PWK. Thanks Steve.)

AA1TJ — On the Air with a Tuning Fork Transmitter using the 2,212th Harmonic and Olive Oil Cooling

The saturable magnetic frequency septupler. The tiny computer memory core is submerged in olive oil (Italian…naturalmente).

Not a very good picture, but here’s the 1600Hz tuning-fork, fork oscillator, SRD pulse generator, PLL S/H phase-detector (diode gate), differential amplifier D.C. amplifier, and part of the 500kHz VCO.


The Wizard (AA1TJ) reports from the Hobbit Hole:

I was pleased to have made the first contact with my tuning-fork transmitter this evening. My contact, N1QLL, runs a pretty B&B on the Maine seacoast, midway between Bar Harbor and Cutler. Jerry was operating a solar-powered QRP station. I found a follow-up email from him when I came up to the house for dinner. He’s asking for a better explanation of my set-up. I can’t wait to tell him about the passive frequency septupler made from an East German computer memory core, heat-sinked in a thimble of olive oil.

My signal was also logged by a number of automated “Reverse Beacon Network” receivers (image attached) located in Ohio, North and South Carolina, Virginia and Pennsylvania…not bad for 90mW on 80m. Please note that my operating frequencies, 3,528.0 and 3,539.2kHz, are the 2,205 and 2,212th harmonics, respectively, of my 1,600Hz tuning-fork frequency reference.
FYI: the third attached image illustrates the block-diagram and tuning-fork reference oscillator circuitry for three common-wavelength AM broadcast transmitters operating in Berlin, Stettin and Magdeburg, Germany from 1928 through the mid 30’s. A central 2,000Hz tuning-fork generated reference carrier was transmitted by landline to transmitters in the aforementioned cities whereupon the 529th harmonic was generated, amplified and broadcast at 1,058kHz. The equipment was designed by the Berlin-based firm, C. Lorenz A.G.. The fourth image details Lorenz’ technique of frequency multiplication via saturable magnetic iron-core inductors. My septupler operates in an identical fashion.
A very pleasant day…

Mike points out that this is a work in progress. He hopes to cross the pond (the Atlantic!) soon. Here is a update from Mike:

A nasty cold has delayed work on the 20 meter implementation, although some of the time I’ve spent crashed on the sofa was put to use redesigning the loop filter network. I think yesterday might have been my “hump” day so I’m looking forward to getting in some quality bench-time over the weekend.

By the way, my PLL-based transmitter frequency stabilizing circuit has much in common with a garden-variety frequency-synthesizer. Obviously, the tuning-fork frequency reference is the main point of departure. My sampling phase detector, for example, was old hat by the mid-1960’s. Nevertheless, this has been a fun project.

That Time We Were Re-Transmitted on 487 THz On a Red Light over Salt Lake City….

Some of you may remember this from back in 2012:

http://soldersmoke.blogspot.com/2012/09/soldersmoke-in-red-light-zone.html

Fast forward to November of last year. By this time I’d forgotten about the Utah light beams. Ron Jones, K7RJ, was kind enough to send me a wonder-filled bag of electronic parts. I have been slowly sorting them. All kinds of great stuff is in there, but I noticed a lot of stuff that you don’t normally find in ham shacks — lots of optical stuff, lots of LEDs and photo transistors, little transistors with lenses on the top. Cool stuff all, but not the kind of parts you’d use for a 40 meter CW rig. What the heck was Ron building? I wrote and asked. Here is his reply.

I’m like you, Bill, I’m a jack of all trades and master of none. I dabble in this and that. I always have a hand full of half finished projects on the bench.

The optical stuff probably fell on the floor when Clint (KA7OEI) and I were experimenting with “through the air light communication” a few years back. Clint in the real guru in that particular project. We made optical contacts over what we think is a world record – 173 miles! That meant packing in optical gear to the top of remote Utah mountains, but what a great time we had! We used a high power LED – NOT a laser. Lasers really suck for super long range communications. They are great for wide band across a parking lot, but not for voice communication over tens of miles (in our cast 173 miles) over the air. We did over 100 miles with a laser pointer – can you believe that? A $3.00 laser that you torture your dog with… 100 miles! But, that is a different topic. If you do say anything about the optical stuff, be sure to mention Clint, he really engineered the optical communication project.

By far, most important thing that we did with optical communication was on one of our short tests (only about 50 miles) when we broadcast one of the Solder Smoke episodes for anyone who cared to “look in” on our red beacon. I think Clint sent you a picture from his side of the path a few years ago.
If there are any parts in that pile of junk that you are particularly interested in, I may be able to find more data and/or circuit ideas I had. But, honestly, a lot of that is stuff that is as strange and wonderful to me as it is to you. Fun as heck to look at, but needs to be put in the “YAFP” pile (Yet another .. project).
Thanks for doing the podcast. It is always an inspiration for me to keep my soldering hot.
73
Ron K7RJ
Very cool. So Ron had been at the other end of Clint’s Red Light beam, the light beam that was carrying a SolderSmoke podcast across Salt Lake City. And it appears that some of the parts involved in that amazing project have ended up in my junk box. The Radio Gods like this sort of thing and may have been at work here. Thanks Ron.

DD4WH’s Fantastic Teensy SDR Receiver (Videos)

This is almost enough to make me abandon my analog, discrete component, HDR fundamentalism. Check out that display. And that StereoAM mode in which the upper and lower sidebands go to the left and right headphones “useful for CW”… Wow, that’s seems like a step beyond binaural.

Don’t miss Parts 2-4 –They are all on YouTube and will appear in the right hand column when you are watching Frank’s videos. But I couldn’t resist embedding the video that shows the hardware. Note: the oscillator is an Si5351! Yea! And the LP filter board comes from Hans Summers.

Beautiful work Franz! Thanks for making the videos. 73 Bill

From Paul Darlington M0XPD: A Book!


Our friend Paul Darlington M0XPD is a member in good standing of the International Brotherhood of Electronic Wizards. His AD9850 Arduino shield propelled me into the world of I and Q. His “Shack Nasties” blog is a valuable resource for all of us. And now he has written a book. Paul was kind enough to let me read it before it was published — I enjoyed it very much. It is the story of a very personal journey. At one level it is about Paul’s trip to the Dayton Hamvention. But the trip goes much further than Dayton, both geographically and personally. I especially enjoyed Paul’s observations on the United States — our British cousins often see things we ourselves overlook. I’m really pleased that George Dobbs wrote the foreword — he is the ideal person to do this for Paul’s very philosophical book.

We give “Getting There” our highest review: the coveted FIVE SOLDERING IRONS. And we are nominating Paul for a Brass Figlagee with Bronze Oak Leaf Palm.

Read Paul’s description of the book here:

Buy the book here:
Congratulations Paul!

Antennas and National Monuments

We started SolderSmoke 185 with a brief description of my recent ascent to the top of the Washington Monument. A few days later I was visiting George K9GDT’s wonderful web site
http://www.qsl.net/k9gdt/radio/radio.htm and in the humor section came across the above Gil cartoon from 1959. That is the general idea.

Pete then sent me this:

Pete originally had a three element Yagi coming out of Teddy Roosevelt’s head, but that just wasn’t right. I asked that it be changed to a 17 meter Moxon. Thanks Pete.

I would like to note for the record that I have no intention of using the Washington Monument, the Statue of Liberty, Mount Rushmore or any other national monuments as supports for any Yagis, Moxons, Cubical Quads, Ray Guns, Lazy H’s, Inverted L’s or any other type of electromagnetic wave launcher.

75 and 40 Meter AM on my HQ-100 (Videos) + Digital Display

And here is how I sample the oscillator frequency for the digital counter. I use an old trick: I wrap some wire around the oscillator or mixer tube. I made the coil out of an old coil form. I had to play around with the number of turns to get suitable pickup on both 160 and 40 meters. The San Jian board allows for IF freq offset. I use a similar arrangement on the transmit side with the DX-100. By the way, the box that houses the two displays is the carcass of one of the Heath QF-1 Q multipliers from which I heartlessly pulled the nice reduction drive variable caps for use in my BITX rigs.

Add caption

Sputnik Replica Transmitter, an “Error” in the Sputnik Schematic, and Why 20.005 MHz?

Mark K6HX pointed me to very interesting Hackaday article on Frank PA3CNO’s Sputnik transmitter replica. As blog readers will recall, we went through a period of Sputnik-mania a few years ago: http://soldersmoke.blogspot.com/search?q=sputnik Chief Designer Comrade Mikhail Rainey AA1TJ sent me some of the Russian tubes (like those pictured above).

The Hackaday article pointed to our post reporting that Oleg RV3GM had found the schematic:
http://soldersmoke.blogspot.com/2013/04/sputnik-schematic-found.html Stefan reports that PA3CNO found “an error” in the original Soviet schematic:
http://www.radio.cc/post/Franks-power-supply-for-sputnik A mistake you say? HAH, I say! Hah! This must have been part of a sinister commie plot to prevent the capitalist imperialists from ever being able to reproduce the glorious transmitter of the Soviet people. They almost succeeded.

Just kidding.

In the course of looking through our old Sputnik posts, I came across a question I posted:

I have a question: OK so the crafty Soviets picked 20.005 MHz for some good reasons: Being so close to the WWV freq, it would be easy for hams and SWLs to find it with precision. In the November/December 2007 issue of “Break In” (from NZ — thanks Jonathan-san!) ZL3DW notes that this frequency selection would allow a receiver set to exactly 20 MHz to “produce an audio tone plus or minus the Doppler shift without ever going through zero beat.” But zero beat with what? Most of the receivers out there would not have had BFOs, right? So the Soviets wouldn’t have been using ordinary CW, right? Were they using AM, with the beeps produced by an audio oscillator modulating the carrier?

Was their diabolical plan to use WWV as the BFO for those using ordinary AM SW receivers? If so, a 5 kHz separation from WWV seems to be too much right? Especially when the Doppler shift on approach would push the frequency up a bit. Maybe they just chose this freq to make it easy for listeners to find — just a bit above WWV. Comrade Rainey surmised that they were keying the PA stage — the oscillator “backwave” was at times audible on the ground.

What do you think Comrades?
DSW and 73.

“Hot Iron” New Issue, Great Articles

I was very pleased to find Tim Walford’s “Hot Iron” journal in my e-mail this morning. Lots of great articles in this edition, including one by a fellow we know: Pete Juliano! Pete writes about our esteemed dual gate MOSFETS. All hail the 40673! There is also a nice article about superhet receivers using a 6 MHz IF and a very convenient analog LC (yea!) oscillator arrangement. Another discusses how to use Huff and Puff stabilizers to take care of VFO drift. N4HAY describes his initial foray into the world of homebrewing and how EMRFD helped him.

Hot Iron is free. Tim writes:

“Hot Iron is published by Tim Walford G3PCJ of Walford Electronics Ltd. for members of the Construction Club. It is a quarterly newsletter, distributed by e mail, and is free to those who have asked for it. Just let me know you would like it by e mailing me at electronics@walfords.net“

Thanks Tim!

SolderSmoke Podcast 185 — SPECIAL FEBRUARY ANTENNA SHOW

SolderSmoke Podcast #185 is available

 22 Feb 2016

 http://soldersmoke.com/soldersmoke185.mp3

 Travelogue: 550 feet above Washington DC

 Bench reports
Pete: Simpleceiver update. Adventures in Raspberry Pi SDR.
Bill: A daring but failed attempt at divide by 2 I&Q.
Audio Mods on the Hammarlund HQ-100.
Dual Digital Readout for the AM station.

 SPECIAL FEBRUARY ANTENNA DISCUSSION
Why we build antennas in February.
Why hams should concentrate on antennas.
The importance of noodling.
Pete’s beam project.
Pete’s Lazy H.
The pernicious influence of automatic antenna tuners.
Bill’s Ray Gun Antenna.
Bill’s Moxon and his 160 inverted L.

MAILBAG
Tom Gallagher NY2RF (new ARRL Exec VP).
Mike Rainey AA1TJ on the air with a unijunction transistor.
Dale W9DKB sends me 160 meter book.
Alan Wolke W2AEW builds a Mighty Mite.
Daniel HK4DEI builds a DSB rig in Medellin.
Chris KD4PBJ modulates an AD9850.
Charlie ZL2CTM Builds a Teensy Superhet.
Jim W8NSA — a Tek 465 goes toes up.
Thomas KK6AHT has roof, needs antenna!
Grayson TA2ZGE homebrewing crystal filters in Ankara.
Ian G3ROO and I had QRP QSO in 2001!
Steven G7VFy sent me a box of VALVES.
Frank KM4AXA repairs a rig and thus adds SOUL to the machine.

Design Wisdom from Allison, KB1GMX

Allison KB1GMX has helped me out of numerous battles with recalcitrant amplifiers. She provided an interesting contribution on the r2pro mailing list thread that I referenced yesterday:


Interesting thread…

I see Rick as having provided the basis and tools and it up to the collective ‘US” to use them to
create that next generation radio. All you have to do is decide the performance and
then go about looking at the means to do so. All the blocks are there.

Dynamic range, how much is enough? When I’m portable or mobile raw sensitivity is
more useful as the antenna is usually a compromise. Overload is easy to handle with
switchable attenuator. The exception to this was a radio designed for contesting in a
hostile environment (a KW user 800ft away) if you burn power you get overload
performance. Its not a battery friendly radio (RX power is over 1A for headphone output).
Look at what you need and not what you want.

TX power is just adding stages. I’ve worked MOSFETs, LDMOS, GaN FETS and there
are some pretty cool devices out there and some not designated for RF are cheap.
If all else fails the IRF510 gets both raves and derision. At 12V its a tepid device
but at over 20V and at 24V it starts to wake up and really perform. I’ve run The WA2EBY
design for a few years at 45W level using two of those push pull at 28V and its clean and
solid and the original pair are now over 6 years old! I also run 8 of them (4x4push pull)
at 32V at 6M for a cool 210W with good IMD. I’d add all the good (high gain, low IMD)
power fets perform better at 28 or 50V. For those into CW consider class E as I’ve
worked with this and using GaN fets have generated 15W with 82% efficiency at
13.56mhz (includes driver and osc) and using the lowly IRF510 at 12V a full 10W
with 85% efficiency. Class E can be amplitude modulated.

As to the thermionic FETs, a 6AU6 crystal osc driving a 5763 for 10W gets a lot of raves
on 40M from a buddy that runs CW. The same deal plate modulated can sound good
at 5-6W AM on 75M. For those that want more a 6C4, 6aq5, 6146 will get you over
50W on CW and 25W AM. Change the bias a little and inject IQ SSB into the driver grid
and be running 50-80W PEP. A 12BY7 or 6CL6 driving a pair of 6146 will get you into
the 180-200W DC input range for about 100W. Remember the hybrid radios solid state
low level and rugged tubes for the heavy lifting. The Pi network (or Pi-L) will load anything
from about 28 to 100ohms more if you use enough taps and variable caps. That and DC-DC
converter for the HV are not terrible at 80% or better (even the 1960s transistor designs
were better than 75%).

In the end it all starts with the receiver. For that you can always start with a 1T4 RF and
a 1R4 converter and a 1T4 as regen driving a 3V4 audio. Power it with 45V (five 9V battery)
and a C cell and go portable. It should run for a very long while. Hollow fets run well at low
drain currents. 🙂

Allison

Words of Wisdom from Rick Campbell, KK7B

Rick Campbell KK7B recently responded to a question on the r2pro mailing list. His answer was so good, and so full of design wisdom that I asked Rick for his permission to post his message here. Here it is:

I have designed and built several new single band HF rigs for my own use since the R2pro, but have not done any complete transceiver designs intended for others to duplicate. The R2pro was specifically designed as a set of modules so that a designer can combine an assortment of those modules with others and come up with a transceiver optimized for a particular, personal application. Much of my recent most design work has been for instrumentation at VHF and UHF, so it doesn’t really lend itself to the “high performance at HF” realm. The R2pro design still holds up well in 2016.

Regarding being inspired to design a new high performance transceiver, I find complete transceiver designs uninspiring, hi. I personally enjoy coming up with a particular application that isn’t well served by anything currently available, and working on some unique design for that particular niche. Occasionally it has been a large enough niche that I’ve worked with someone like Bill Kelsey to come up with a commercially available kit of parts, but more often I just design and build a few to fill the immediate need in my lab. Sometimes that “need” is just a whim, and some of my most enjoyable and technically rewarding work has been to satisfy some personal curiosity or other.

Regarding your wish list:

“Best Sounding Audio Possible” is still the same as it has been since my first receiver with diode ring mixers to do the frequency conversion before any gain, followed by a serious audio amplifier string drawn from the audio recording industry. In most of my recent work, starting with the R2pro, the limitation on dynamic range inside the audio channel is set by the op-amps. About 80 dB from the noise floor to non-harmonic artifacts is relatively easy, but you have to be careful. If the noise floor at your receiver volume control is 80 dB below a volt, that’s about 100uV, and well below what you can see on an oscilloscope. These are very old principles. Though they haven’t been common in the communications receiver field, no breakthroughs are needed, just careful design. The R2pro is better than it needs to be.

“Good Dynamic Range” is an interesting concept. I like to design receivers that have good enough dynamic range, which is different for every application, on every band. Unlike during the 1970s, today most of our receivers have enough dynamic range, in the same sense that cars have had enough wheels since designers figured out that 3 was not enough. Once you have enough, adding more is not an improvement.

Some of my recent receivers have had a crystal filter between the antenna and first active stage. Those are stellar, but that’s not usually needed. They do illustrate the point that if you find yourself operating in a hostile EM environment with many very strong nearby signals, there are other ways to address the problem besides in the receiver circuitry. Ever since I achieved “good enough” for all my personal applications a while back, I’ve focused on other receiver performance measures. In particular I try to avoid sacrificing something important to make an improvement in a specification that is already good enough. I have never been on a hilltop with Wes Hayward when anyone missed a contact because of inadequate dynamic range, but I have been when we missed contacts because the batteries died.

“SCAF type filtering.” I’ve played with switched capacitor audio filters and other commutating signal processing since the mid 1970s. Each time I’ve built one into a receiver I’ve run into problems with that danged clock. I tend to listen at and below the noise floor, and one of my pet peeves is when I can hear anything at all other than pure thermal noise when the receiver is terminated with a room temperature 50 ohm resistor. Since I routinely record signals for post processing in a DSP system, it is disheartening to discover that some harmonic of the SCAF clock beat against the LO at a particular frequency, ten dB below the noise so you didn’t hear it when you made the recording, but 10 dB above the noise floor in your FFT waterfall plot. So I have avoided such things for my last few decades of instrumentation-grade receiver designs. When I have a digital dial, I include a switch so it can be turned off when I’m recording weak signals. None of this applies to you–please continue to experiment with SCAF filters, embedded processors and other generators of digital noise that may well be far beneath the threshold of signals and antenna noise for your particular application.

“Audio output power.” In my lab I generally find about a half watt is more than enough for a radio tuned to a ham band. In other applications I go as high as 40 watts of audio at the threshold of detectable two-tone IM products. All of that is nicely covered in the audio literature, and there are a number of good designs available on the web. The R2pro audio amplifier in EMRFD works well driving a compact, efficient speaker in a quiet room. For more power output, use bigger transistors and raise the supply voltage up to about 24. Above that, you need to add Darlington drivers, as in the original R1 and R2 circuit, and you can then raise the voltage up to around 40v with NE5532 op-amps and get more than 20 watts of superb clean audio. That R2pro audio output stage in EMRFD has been borrowed and modified for more than one very high end professional audio application.

“RF Power” For either audio or RF power, I encourage experimenters to use higher voltages than 12. Within a few years we should have available some nice GaN transistors that will allow us to use supply voltages up around 80, which really makes it easy to generate many watts of power into either 50 ohm or 8 ohm loads. If you don’t want to wait for GaN, there are some huge N channel depletion mode FETs that run the electrons in vacuum and will easily handle many hundreds of volts on the drain. They need a separate low voltage supply at an amp or so to generate the electron stream, but are capable of astounding performance, particularly in narrow band applications. If they hadn’t been invented 100 years ago, we’d be all excited about the possibilities now. A 6146 would just idle along at 5-10w out and last forever.

For my most recent contacts on 40m CW, I used an R2pro and ran a very stable premixed JFET Hartley VFO driving a 6C4 and 6AQ5 output stage.

Enjoy the experiments.

Best Regards,

Rick KK7B

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