Alan Wolke Looks at Diode Ring Mixers

Bill,   I remember in your Soldersmoke book that you had difficulty for a long time trying to understand how a mixer created the sum and difference frequencies, and how this was accomplished in a diode ring mixer.  I know that you've got it all sorted out now, but I thought this was a good topic for a video anyway.  

Here's my video on the subject:

https://www.youtube.com/watch?v=junuEwmQVQ8

73,

Alan

Alan:  Thanks.  Great stuff. Yea, I've been looking at the innards of mixers for a long time. In my book, I try to explain how I have come to understand the physics of the mixing action -- how the use of a non-linear element causes two signals to "multiply" and how this "multiplication" results in sum and difference frequencies.  I tried to go beyond the trig functions because for me the trig didn't really explain anything. 

In the book I was looking at the classic two diode mixer (beloved of Doug DeMaw!).  A few years later, on the blog, I was looking at the action of the diode ring.  I concluded that there is a big difference between how the diode ring works and how the two diode mixer works.    RSGB provided a great diagram: 

http://soldersmoke.blogspot.com/2009/04/are-diode-ring-mixers-fundamentally.html

73   Bill 

-----

I guess one way of describing the difference between a two diode mixer and a diode ring would be to say that the more simple mixer multiplies the signal by 0 and 1 (if it is operating in "switching mode), while the diode ring multiplies by 1 and -1.   

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SolderSmoke Podcast #164 Ancient Tribal Knowledge: Tube and Tube-like Radios

SolderSmoke Podcast #164 is available:

August 16, 2014

http://soldersmoke.com/soldersmoke164.mp3

ANCIENT TRIBAL KNOWLEDGE -- TUBE AND TUBE-LIKE RADIOS

Workbench Updates: 
-- Pete's Arduino Keyer Project
-- Bill Builds (and LIKES!)  a REGENERATIVE RECEIVER
-- The Joys of Regen Shortwave Listening
-- Grayson Evan's Tube (Thermatron) Book
-- Book review:  "The Joy of X"  (It's about math).
-- Shameless Commerce:   A Plug for Bill's Book
-- Pete discusses tube projects
-- Making your own enclosures from Home Depot flashing
-- Amplitude Modulation
-- Compactrons, Nuvistors and other unusual tubes
-- BANDSWEEP:   Radio Havana on Bill's new regen 


Bill's Mate for the Mighty Midget Receiver
3 6U8 Tubes on a Benton Harbor Lunch Box Chassis


Nuvistor 2 meter down converter


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Voice of Vietnam on Old (New!) Regen Receiver

I'm having a lot of fun shortwave listening with the reborn British regen.  This is the Voice of Vietnam. 

I rebuilt the regen using the old Eddystone variable capacitors, the original coil form, the original wooden chassis (now covered with copper flashing) and the original front panel and knobs.  But the old triode was replaced by an  MPF-102 JFET.  And the AF amp tube was replaced by an LM386. Something old, something new... The circuit is the old Armstrong circuit, with a tickler coil and throttle cap.  Thanks to Charles Kitchin for all the regen wisdom in his Nov/Dec 1998 QEX article (available on-line). 

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Some Progress on the Old Regen

That's Radio Havana Cuba.

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Jim, WB5UDE's Knack Story

Hi Bill! ...

Of all the Amateur Radio related podcasts I've sampled, SolderSmoke has

been my favorite.  The reason is because of the passion you (and Mike,

too, in the beginning) bring to us each and every episode.  I've been

passionate about radio since I was 10 years old, and electronics in

general since I was about 8.  Many of the other podcasts seem to lack

this quality, or worse, try to have a "how to do things in Amateur Radio

the right way" focus.  I suppose their thinking is that hams listen to

podcasts to learn, so they assume their job is to tell someone how to

get started doing this or that.  However, the result often comes off

being preachy-- that there is a Right Way to do things, and that it's

important to do things that way, so they'll work out best.  That's not

what Amateur Radio is about!  Amateur Radio is about doing something

because you're passionate about it.  Even where your own passions are

concerned (e.g. individual analog components, no chips!) you acknowledge

that the other approaches are equally valid, and that we should all

do what we enjoy.  You're not shy about branching off into your other

technological passions, about space, RC aircraft, etc., which as you

rightly observe, so many of us have in common.

We share a passion for learning and understanding about radio/electronics.

Where we differ is in the depth of understanding we crave.  Actually,

I have experienced enough of that desire for total understanding to know

exactly what you're talking about, but I'm usually content without it.

I realized back when I was a teenager that some things would click for me

right away, and some others, I'd always struggle with.  I made peace with

that very early.  Still, I have wondered more than I could find ultimately

adequate explanations for about things like, OK...exactly what ARE these

radio waves?  More often, though, I am content to gain a sufficient depth

of understanding that I feel comfortable knowing how I might achieve a

particular thing.  I have great sympathy for your struggle with "holes" in

transistor theory.  That actually clicked for me, but not immediately--I

had to chew on it just a bit, but then it did gel.  If that "?" floating

over my head had refused to disappear, I might have found that a little

frustrating.  But to me, the really frustrating thing is that books so

often begin by talking about electrons and holes and depletion zones and

so forth.  I have found that a much simpler explanation is sufficient

for my tastes--I'm content to understand that there are N-doped and

P-doped sections, and that this allows the silicon to control current

in a certain way.  Knowing how we arrange the electronics around a

transistor to get it to behave in its own useful way in a circuit is

really all I've ever cared to know.  And furthermore!... I'd rather

have the whole presentation be top-down...I'd rather start with what a

transmitter and receiver are, and what their stages are, and what kind of

circuits go into those stages, then eventually, down to what components

make up those circuits.  It's all a natural progression, for me, of, "OK,

I understand that--now, how exactly does that part work?  Give me more

details, please."  The whole thing of just learn all these fundamentals,

and we promise we'll eventually tie them together into something useful

doesn't work well for me as a way to learn.  Worse than that, it doesn't

thrill me to the core the way gaining a gradually deeper and deeper

understanding does, as I drill down into more and more detail about

things I've caught an interest in, and remain content with a shallower,

surface knowledge of things I just want to know well enough to use,

when I need them.  So, I don't have the same burning desire to get down

to the bottom foundation in first principles all around that you do,

but I do love to learn, and understand.

I got my start in electronics when I was eight years old, and read a

book my parents had bought me about electricity.  I suddenly realized

that things like flashlights and motors didn't have to be a strange

mystery, but were things I could understand, and even try for myself.

I began reading everything I could find at school about electricity.

Meanwhile, over the next couple of years, I began appreciating music.

Reproducing music was something very special that electronics could do.

Even more special, radio electronics could bring you this music from

far away.  That whole combination, bringing communication from far away,

including things I found enjoyable, and doing it with this wonderful

magic of electricity, which it was possible to actually understand, was

(and still is to this day) quite thrilling.

When I was ten years old, I realized that, lo and behold, it would

actually be feasible for the amount of money my parents would be able

to spend for a Christmas present, to buy a pair of toy walkie- talkies.

I set a new level of obnoxiousness leaving the catalog open to the

page with the walkie-talkies, and finally, just flat out telling them

that's what I wanted.  I then exceeded that level of obnoxiousness when,

I'm ashamed to say, I absolutely chewed them out when they didn't take

the hint.  Instead, I got a tape recorder.  I actually enjoyed that, too,

but continued to campaign for the walkie-talkies, and when I still wanted

them a year later, my parents decided I meant it, and bought them for me.

(My dad knew a thing or two about radio himself, and my mother later

told me that my dad had been concerned that the walkie-talkies would be

fragile, would perform poorly, would chew up batteries like you couldn't

imagine, and would have a very disappointingly limited range.  He was

right about all those things, but it turned out I was right, too--in spite

of all that, I loved those walkie-talkies as much as I'd known I would.)

Meanwhile, I got a 100-in-1 electronics set for my birthday.  My parents

had wanted to find one that was about individual components, but all

they could find was one that was based on projects using a pre-built

audio amplifier, radio receiver, speakers, and battery holders.  Its only

component-based aspect was an apparent afterthought, an AM BCB transmitter

built on a cardboard circuit board.  This was really a bit too "appliancy"

for me--I would rather have been learning how to make components work--but

I still learned a lot from that.  I also bought an AM clock radio for

less than a dollar at a garage sale.  It didn't work very well, but this

was really good, because I learned that I could make it work much better

by wrapping a few turns of wire around its built-in loop antenna, and

attach that to various antennas I got to experiment with.  Months later,

I found a very nice tube-type AM/FM Zenith table radio at another garage

sale, and bought it for $5.  That radio went home with me strapped to

the back of my bicycle, then went on the bookshelf on the headboard of

my bed.  I learned to work its knobs backwards, reaching behind my head.

I listened to AM radio stations from all over the US until all hours of

the night, and my addiction to radio grew even deeper roots.

Then, when I was 13, I found a Zenith Transoceanic portable at a

garage sale, for $15.  I raced my bicycle home as fast as I could.

(This radio was a little too big for the bicycle.)  I got my mother to

drive me back there (urging her to hurry!  before someone else bought it),

and brought that one home....  then spent that whole evening driving my

parents nuts by running into the room where they were every few minutes,

excitedly exclaiming something like, "and NOW I'm getting a station from

GERMANY!" and then running back to see what I could get next.  Of course,

I had even more fun with it after I put a decent outdoor antenna up.

When I was 16, I finally met an Amateur Radio operator.  I'd read an

ARRL book about becoming a ham, and building one's own station, but the

books were a little expensive, and I wasn't sure how to go about it all.

Pat Barge, WB5OEB, about one year older than me, had earned his license

about a year before, and was eager to pass along the favor of showing

the ropes.  I got to listen as he operated his station, and he told

me which books would give me the specific knowledge I'd need to pass

the tests.  I was 17 when I got my first license.

While I was learning what I'd need to get my first license, I got my

next great receiver--this time, an RAL-7 regenerative receiver.  You and

I very much see regenerative receivers differently, but then, I had

the pleasure of learning on the best regenerative receiver ever made.

Back in those early days, I'd sometimes hear the opinion that the RAL-7

was not merely the best regenerative receiver ever, but the best receiver

ever, period.  I think all those old-timers have died off, though.

I've enjoyed building a bit over the years, too.  I haven't found nearly

as much time for it in my adult years, so I think to this day, about

half of my building was done as a teenager.  I haven't done anything

impressive, but I have made contacts using things I've built myself, and

what a thrill that is!  I've built more than a dozen projects (but fewer

than two dozen).  The most fun I've had was several years ago, following

the advice of a post to the Glowbugs list, I began experimenting with

crystal radios, then slowly began to ramp the circuits up, adding tube

amplifiers, tuned circuits, etc.  My favorite successful project was

a SWL converter to feed a car radio.  I built a doubly balanced diode

ring mixer and a crystal oscillator.  I used a 3-gang air variable

as the foundation for a 3-stage front end filter.  I had an 8.x MHz

crystal that put signals from (depending on where I tuned that 3-gang

air variable) either the 49 m or 31 m shortwave broadcast bands in the

tunable IF provided by the AM car radio, which fed a nice 3-way speaker

from a stereo, for the most beautiful sounding SWL listening of my life.

Like all my projects at that phase, it never left the breadboard stage,

but it stayed on the breadboard for a long time, while I paused in my

building to enjoy listening for a while.

I serve as one of the net control stations for a local two meter FM net

that meets weekly to discuss technical topics.  We got our start back

before most folks had Internet access, and served a very useful role as

the place where hams who had a problem to solve or wanted to ask how to

get started in a new phase of Amateur Radio could come and get answers to

their questions and ideas about how to do things.  In these days where

it's easier to Google for answers, we've morphed into more of a general

discussion session among a small, dedicated group, but it's still a lot

of fun.  It gives me a chance to do what I enjoy the most consistently

in Amateur Radio, which is to understand, talk about and explain things.

In fact, that's often all I find time for.  Other than the weekly net,

I sometimes go a long time without actually getting on the air.

When I do get on the air on HF, it's almost always CW.  I've always

struggled with Morse, which has never come easy to me, but I enjoy it.

Every time I return to HF after having been away for a while, I think,

"This time, I'm going to do some SSB" but every time I actually sit down,

I think, "But tonight, I'm going to do CW."  I can't explain why I like

it better, but it just seems to me to be a particularly special part of

the magic of radio.

Before closing, I'd like to finish by responding to something you

mentioned in episode 162.  You told about a member of the audience at a

talk you gave, who was asking about how much time it had taken you to

build a particular radio, seeming to suggest there was a price to pay

by investing all that time.  I love to explain to people that there is

a whole different economics to Amateur Radio.  In my professional life

in IT, I'm always promoting the idea that we should deploy and install

systems so that we will expect them to work trouble free throughout

their anticipated lifespan.  People balk at the expense of doing it

that way, but it's my job to remind them that the cost of having it

fail, in lost productivity, is far greater than the expense of doing

it right in the first place, not to mention the fact that coming along

later and remediating an inadequate deployment usually costs more than

it cost to do it wrong the first time, let alone the incremental cost of

doing it right.  Similar ideas prevail with radio.  We see professional

radio installations where many thousands of dollars are spent doing

things that we hams rarely even consider.  For many of us [raises hand]

we must do Amateur Radio out of a meager budget for entertainment,

or not at all.  But even more importantly, if we enjoy doing these

things, then the time spent laboring at our projects--transmitters,

receivers, antennas, etc.--is not a liability at all; it is an asset!

If assembling a kit, or planning and building some unique project, or

putting up a different antenna every six months, is something we truly

enjoy--even LOVE doing--then that time spent is no hardship at all.

Thanks, Bill, for the time and effort you put into providing us with

an episode of SolderSmoke from time to time.  All my life, I'd wished

for TV and radio shows about Amateur Radio, and now, they're finally at

my fingertips.  Your gift to the hobby is deeply appreciated.

73,

Jim  WB5UDE

Moonlight Moxon

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Video: Regenerative Receiver Project!!!

Pete Juliano and Grayson Evans are luring me back into the world of tubes and (gasp!) regen receivers.  

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

M0XPD Goes 3D with Boxed BITX with Digi-Hinge!

Paul, MOXPD, has put his BITX-based rig in a proper box.  In spite of his recent collaboration with famed miniturizer Pete Juliano, Paul used a BIG box.  It is not quite milk carton size, but it is getting there. Well done Paul.   I really like the way Paul kept the digital and analog elements in different dimensions.  The digi bit is sort of floating above the main analog board (almost in a "cloud"!).  In SolderSmoke 163 Pete Juliano mentioned a downside of this kind of stacking:  it makes it hard to get to the main board.  Paul ingeniously solved this problem by putting the digital board on a hinge.  Excellent.  This will prevent you from becoming "unhinged" when the time comes to fix or modify the main board.    

Here are all the details on Paul's project: 
http://m0xpd.blogspot.co.uk/2014/07/boxing-clever.html


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SolderSmoke Podcast #163 Pete Juliano! Tribal Knowledge Part 3 "Sideband Sidecars"

Crystal Filters built by WA7MLH

SolderSmoke Podcast #163 is available: 

http://soldersmoke.com/soldersmoke163.mp3

Saturday July 26, 2014

Part III with Pete Juliano:  Tribal Knowledge -- Sideband Sidecars

-- Moxon Update "A Thing of Beauty"
-- Pete is Building Peter Parker's Knobless Wonder
-- Ladder Filters
--Construction Practices for SSB rigs
-- Essential Test Gear
-- Junk Box development and parts storage

Next time:  Tubes, Valves, Termatrons, Firebottles. 

Thanks to Bob Crane and the FDIM musicians for this episode's musical opening. 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

EXCELSIOR! Jean Shepherd's Birthday

Bob Crane (and, I think, Garrison Keillor) alerted us to this important birthday:

It's the birthday of humorist Jean Shepherd (books by this author), born in Chicago, Illinois (1921). He's remembered for the autobiographical stories he told on the radio about a boy named Ralph Parker growing up in Hohman, Indiana. One of his stories was made into the movie A Christmas Story (1983), which he narrated. It's about a boy who wants a BB gun for Christmas, even though every adult in his life says that he'll shoot his eye out.

The stories Shepherd told on-air were always improvised, but he later wrote them down and published them in collections like In God We Trust: All Others Pay Cash (1967) and Wanda Hickey's Night of Golden Memories and Other Disasters (1972).

Jean Shepherd said: "Some men are Baptists, others Catholics. My father was an Oldsmobile man."

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

My Moxon on Hackaday!

I was really pleased to see my Moxon on Hackaday.  Their write-up was a lot of fun.

http://hackaday.com/2014/07/23/fishing-for-radio-signals-with-the-moxon-antenna/ 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

WA7MLH's RD16HHF Amplifier

OK, so now that I have the MOXON in the air, my thoughts are turning to amplifiers and a possible winter project. Hey, even QRP guru Doug DeMaw conceded that every once in a while a fellow needs a few more db. And the sunspot count will be dropping.  

On the BITX group there has been an interesting discussion of using RD16HHF MOSFETs in place of our familiar IRF-510s.  I thought these devices were new, but some Googling this morning led me back to the wonderful website of QRP giant (hey, he is IN SSDRA!) Jeff Damm,  WA7MLH.   Jeff has been using these devices for quite some time.  As with all of Jeff's projects, I find his EXTREME UGLY building methods to be inspirational and reassuring.  Even if you have been there before, you should visit his site:

http://www.neoanderthal.com/wa7mlh1.html

Even his QRZ.com page makes you want to build something:

http://www.qrz.com/db/wa7mlh

Thanks Jeff! 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20