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:

February 26 at 10:55pm ·

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:

http://m0xpd.blogspot.co.uk/2016/03/a-new-book.html

Buy the book here:

http://www.amazon.com/getting-there-Paul-Darlington/dp/1523452196

Congratulations Paul!

Radio Row, New York City, 1929

Check out this video:

https://vimeo.com/109197452

and more here:

http://www.radiodiaries.org/radio-row/

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.

The Power and Potential of Small Computers (Quad Copter Videos)

Start by looking at this one: 

https://www.ted.com/talks/raffaello_d_andrea_meet_the_dazzling_flying_machines_of_the_future

Then, for more details, look at these:

"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