All Things Wireless & Letterpress

All Things Wireless & Letterpress

Saturday, November 28, 2015

Ham Radio Horizons: "Building the Fifty Watt Rig", Part 2.

We continue our Educational Review from the Eye of the Printer and Graphic Designer, who also just happens to be a Ham Radio Operator, and who happened to be part of the intended audience of these articles.  We will look at the writing style of the author, the graphics used, the general lay-out of the article and endure some commentary concerning the current state of technical writing from my personal perspective as a former corporate training writer, technical illustrator, and national training director for what was, during my tenure (if you can call anything at the corporate office level "tenure") the largest optical retailing company in the world.

As such . . . yeah, I got a lotta opinions.

Opine No. 1: why don't they write these sorts of articles anymore?  If ever a step by step, one-two-three mentoring piece was ever written that reached out from the pages, took the reader by the hand and actually not only walked him or her through the mechanical process of building a rig to be proud of, but also equipped said reader with the information to academically assess and determine the what and why-for's, this is probably the most exemplary article I have ever read to these ends.  If I still had my training writing team, and we were tasked to create an SOP manual for constructing a widget, this would be our model.  And yes, that is how training curriculii is written, gang.  We borrow examples and massage them.  We hire companies to fill our data banks, and we writers create the links that interconnect the data in such a way that instructs.  Bill Wildenhein, W8YFB (as of 1978) did a marvelous job doing this very thing.  Only, he didn't hire anyone to do anything.  This was his own baby from the get go, and we were fortunate that Mr. Tenney (Skip) had these installments published. 

So, here we go.

I did not see the artist's attribution in these articles, but whoever he or she was, my hat is in my hand.  These were a combination of freehand pen and ink illustration and genuine, old fashioned drafting board layout mechanical drawing.  Nothing was computer generated in this article.  And figure: it was printed in 1978.  Do you know what I was doing in the 70s besides being a novice?  Shooting artwork for a magazine, developing the negs, stripping and pasting and burning offset plates containing this artwork for a local area Orlando magazine (Orlando-land Magazine, to be precise.)  As such, I like to think I know what I am seeing.  This sort of lay-out is called a "duotone", used in magazine publication since the 19th century to great effect.  It makes the page interesting and inviting to read.  The nice thing is that the drawings just happen to be mechanically accurate! What a concept.  An artist that knows what's going on.

I am not a huge fan of the larger formatted magazines, which departed from the older journal sized "almanacs" that was universally used for such publications from the turn of the century up into the mid 1970s.  I believe QST was the first to change over to the large folio sized magazine around 1975.  All the others followed suit.  The smaller magazine was, to me, much more convenient on many levels.  They also seemed more personal, and actually, a bit more authorative.  Just me, I guess.  I grew up on 1930s Red Jacket QSTs and old S-9s that my elmers would dig out of their attics and give to me by the boxes in the 1970s.  I loved them.  I kept a lot of them.  In fact, they were the reasons why I even do these blog installments! Each one was a literary work.  And we can find a fascinating narrative of Ham Radio through the years by doing what we are going right here: reading them and getting a feel for the times, challenges, and technical environment of the average ham in the era in which any particular issue was printed.

Let's take another teckky look at this page: the photo.  It's called a "Half Tone".  The original photo, hopefully a high contrast glossy which photographs well and leaves a great negative, is reduced to dots.  Highlight dots and density dots.  The highlight dots are micro-fine, and appear in the white areas.  The smaller the dot, the whiter the white, but you must always have a dot in there, no matter how white the image field is!  This is how contrast is controlled, and what keeps the printed image from looking like a poor photocopy.  Same goes with the black areas: the density dot is actually a white dot created by the very large halftone dots that eclipse each other.  They space between them is white, from the paper it's printed on, and serves the same purpose as the very fine highlight dot: to balance contrast, and to keep the shaded areas from going full flood black, which looks awful in print....although I have seen this happen with some of the privately published computer printed magazines these days.  I cringe. Oddly enough, ER magazine does a fair job with their imagry, considering the shallow images they have to work with.  They do tend to flood their whites on their covers, but that might be because they use....or used to use....a coloured stock which does not do wonders for contrast.

Remember, would be magazine printers: Contrast.  The three big keys to good printed graphics are 1) - Contrast.  2) - Contrast , and 3) - Contrast.  But never flood your highlights or densities.  Get it?  Got it?  Good.  I can sleep now.

BTW, this is why I stay Letterpress.  And pen and ink renderings.  

The image on the above shown page is actually quite shallow, and the guy that shot the neg went to a 600 line screen to hold what detail he could.  And I say, he deserved a raise.  This was no computer evaluated half-tone, it was done by eye, by densitometer, and by skill.  Another reason why I like old publications.  

Another reason is because I love the movie "The Secret Life of Walter Mitty".  Watch it, fellow commercial dark-room rat!  (if you haven't already.)

Bill the Author lays down simple theory and a bit of math, once again, for the benefit of the reader to understand how and why they are metering the screen and grid of the final.  The approach is classical. "Ethics Rise from Dogma", which means before you task anyone to do anything, you first lay out why!  The Apostle Paul even wrote his Epistles following this paradigm!  Before he tasked the reader to any sort of behavour he laid down chapter after chapter with Doctrine, and provided a link with the word translated "Therefore".  It is a basic writing technique. One I see less and less of these days.

Can't find the meter that reads the scale you need in mA?  You don't have to.  Here, the author teaches the reader how a meter functions and how to build a resistance network based upon the meter's own metrics to indicate the desired scale you want!  Have you ever seen this sort of detail in a construction article before?  I mean, really!  That's why it took three installments to publish this piece!  And the odd thing: as of my last perusal, this article appears nowhere on line, which I think is a crime.  Well . . . it is, now.  As an Educational Review, but it's here, nonetheless.  If you really want this article to have and to hold, contact CQ magazine.  I think they bought out Ham Radio Report, the parent publisher for HRH.  They may have ALL six or so years of HRH.

On page 37, the author walks the the reader through the controls, following the same mode of communication.  Here is also where be begin to see more actual mechanical drawing, and some of this probably came from clip art.

Ever wonder why they call it "clip art"?  Well, glad you asked:

Technical Illustrators draw a lot, but we didn't draw everything.  There were some areas where a lot of repetition of imagery was required. There was really no need to redraw each and every arrow, circle, this thing or that.  Sometimes, people were needed to populate, say, a landscape scene.  We don't care who they are, we just need people.  At one time the engraver engraved each and every man, woman and child on the printed image . . .to be used for one run only!  Early on, when the photographic process began to be used in the 1870s, standardized images began to be cut and pasted into the artwork, and then shot for plating.  Such images were drawn, and later printed, on large sheets that could be easily cut and used in the past-up room.  The Paste up room is where each page of a magazine was laid out, the text on printed paper, the high contrast line are was oriented, &c.  The negatives were shot and "stripped" on a sheet of "goldenrod", UV-proof paper, and set up according to the "paste-up", and the plate for the page or pages were then "burned" and taken to the press-room.  So, repetitive images, normally small elements that feed the whole image, were "clipped" from a sheet and pasted in.  We do this today with clip art books, too.  So, I guess it's pretty obvious where the term comes from, but I thought I might engage in a bit of history as well.  That's why I write these pieces after all.

It also keeps this blog entry an Educational Review.  So, bear with me, ok?

These are pages 38 and 39, each containing what I believe to be a hand rendered bit of artwork.  If it indeed clip work from the paste up room, they had access to clip are that I did not have!  I think what they did was draw the shells, and one contact, which was then duplicated and then pasted all around.  Rapidograph touched up the seams.  We used to do this sort of thing for Orlando - land magazine as well.  I was not present for the printing of this magazine so I don't know for sure, but I do know what technology was available in 1978.  A lot of hand work went into these pages, trust me.  The illustration in the upper right of page 39 has a combination of hatch and stipple shading.  That baby was drawn by Rapidograph.  When I illustrated the training manual for Pearle Vision, Inc., I drew many of these detail images.  In fact, they were kinda fun to do once you got the pencil down.  Stippling is something that is rather cathartic to me.

What was described above is also true here as well.  These are not clip art inserts from the paste-up room, these are hand drawn images, likely executed with old school drafting ages.  The braiding of the coax shown on page 40 (left) is hand rendered.  All the cross hatching and stippling work was likewase drawn in either by Rapidograph pen or mapping pen.  Does anyone do this anymore??  I purposely shot these images such that they can be downloaded and enlarged so you can get the detail!  

You know?  Novices like me needed all the help we could get, and the more realistic the images are, the better chance we had at understanding what was going on!  This was why such lengths were taken in the day, by this publisher, to ensure great visual communication.  Even with our computerised illustrations today, I still detect a certain homogenization that serves to prevent such detail, even though we are capable of off-the-map detail.  Perhaps it's because the artists and designers did not grow up in a truly detailed hand rendered visual environment?  Who knows.  It costs to have excellent artwork made, perhaps that's part of the problem.  I might note that I am only illustrating on the side, and that for my own company, Paper Wren Press.  By profession, I am a Licensed Optician.  Huh . . . what does that say??

Here, we come to the end two pages.  Page 42 features another drawn image showing the critical components as real images of correct proportion.  The accompanying text describes the purpose for wiring these components as such. I can look at these drawings forever.  I might make mention of the tube sockets: there was something we did in the darkroom, which was simply laying a specific screen with a desired dot size over the negative.  This was not the same as half-toning, which indeed uses a dot screen, but the exposure is entirely different, and involves another process.  In screening, we just shot the image by wrote, through the screen.  This gave the effect of "tinting" or "graying" a solid area.  The same was done in the burning process, where we might expose a negative to the UV while burning a plate, with a transparency dot screen under the negative to achieve the same effect, only by direct burn to the plate.  These tube sockets were shaded in the same manner: not by hand, but by an equally arduous process, by screening.  Screening could be a nightmare in the stripping room where the negs are opaqued and laid out on the goldenrod for plating.

On last observation: page 43.  Yeah, Palomar paid for that add to appear on that page.  And it is fairly interesting from a graphics standpoint.  This is a duo-tone, with no screening, although I might have pushed for screening the colour in the actual product image.  See how sharply contrasting the red shading is in the product image?  They do that to add effect: it's a graphics way of underlining, or bold-facing.  To attract attention to a specific area.  I think it looks positively ugly, but hey....even when I did this professionally, the voice of the darkroom seldom was heard in the front room where such decisions were made.  We just bit our lips and did what the work order commanded.  Yeah....our lips bled a lot.

Well, here ya go.  Another installment and graphical assessment of a great and what I opine to be a Classic Article, from a very good author, printed in a very special Magazine, Ham Radio Horizons.

The last installment covering the last section, Part 3, will be forthcoming.  And folks, especially you hams so inclined: Novice Rig Round-up happens in February.  Go to our FaceBook Page for details if you'd like to participate, and possibly even build this very transmitter!!

73, es CUL - de wd4nka

Thursday, November 26, 2015

Revisiting the "Fun-Mitter", a Goof Proof RF Project from 1981

Note: these photos were uploaded in large format.  To enlarge, click on the images, and download from the link by right clicking on the link image and selecting  "save image as". You should be able to at least double the image size.

I'm always a little nervous whenever something comes my way that claims to be "goof proof".  I am the one goof they didn't consider. When Mark Oman, WA0RBR wrote this article, a whole generation of QRP enthusiasts was just getting off the ground.  This was a group that preferred simplicity, something that could be made from readily available parts, something that could be made in a couple hours.  At the time, even the "simple" receiver and transmitter projects in the newly formatted ARRL handbook tended to be quite involved to build.  The DC receiver was the home brew receiver of choice, regen receivers were not even on the radar.  It was a time quite different from today in some respects, yet not all that different in others.

In the era of the 1980s, Radio Shack still somewhat appealed to hams and home-brewers.  They actually carried broadcast caps, all sorts of chokes, and the ever popular 40673 dual gate mosFETs, MPF-102s, 2n3904s and 2n222a type transistors and FETs.  And as well, a selection of power transistors, such as are used here.  And while these power transistors may not be available through RS,  they are still available via cross referencing NPI products, and I am sure, other manufactures as well.  The ones I located on line averaged about five dollars per transistor, all such transistors benefiting by heat sink mounting.

Heat sink mounting is advised in this article published by '73.  The photos show "Dyna Labels" in use for labeling.  Gosh, remember the Dyna-Label guns that punched them?  I always considered them along the lines of an over-stuffed chair on a front porch.  But they served the purpose!

These transmitters ran on 24 volts, which the author explains is easier to use to obtain 5 watts input.  I noticed in the power supply schematic that LM-317 is not included in the shopping list of parts, yet is clearly shown on the schematic.  It is a linear voltage regulator, available today, which handles an adjustable range of voltages from 3 - 40v.  Of course, two 12-vdc lantern batteries will do the trick, and probably last a number of hours.

Notice the handy transmit receive switch!  The front panel sports a VXO.  You could probably rubber about 1.5 kc out of the xtal.  Now, when we say "rubber", know it means from the xtal frequency up or from the marked frequency and down.  VXOs are rarely a spread range going from one side to the other.  It can be done, with a combination L and C, both variable, but usually the VXO is provided just in case you find yourself at zero beat to a signal, you can "slide to the side" a little, to be heard.

As the "Fun-Ceiver" did a few months later, this article provides an actual size foil side pc board layout so the builder could purchase the copper clad board, the Sodium Ferric Chloride, both of which Radio Shack sold, and make a pc board right there in the shack.  However, most just used plain ol' Perf Board.

The last page shows the inside physical layout, which is amazingly spacious. Here, you can see the heat sinks, which are recommended by the author, and were not available at Radio Shack.  Today we can get these items from Digi-Key or Mouser, probably even at  The transistor finals (RS 2038) are obsolete and difficult to cross reference.  I might suggest a 2n3553, which carries a 7w dissipation spec, and is also an NPN type.  The RS 2033, also NPN, can be replaced by an NTE-123AP.  It might even be replaced by a 2n2222a.

Try one out for Novice Rig Round-Up this coming February!  Let us know how you fare!

-73 es CUL, de gary / wd4nka

Revisiting another Home Brew Classic: the One Transistor Rig for 40 meters.

For this classic, we step back a few years further to April of 1978.  The magazine featuring this article was Ham Radio Horizons, singularly the best magazine ever printed for beginners, novices, and the Not-So-Novice.  "HRH" was the daughter publication of Ham Radio Report, and had a very respectable authorship.  Jim Fisk, Skip Tenney, Nagle, Orr, and more of this ilk of writers all had a contributory hand in authorship. This particular article was co written by Ed Marriner,  W6BLZ and John Merideth, K5GXR.  It's a shortie, only a couple pages.

The best way to view these images is to click on it, and then save the image from the linked location.  You should be able to enlarge the image considerably.

The project itself appears to have begun as a curiosity.  Looking over the schematic, I might conclude the "curiosity" must have had something to do with how few parts one can assemble and still have a respectable transmitter!  It seems to be a Xtal Pierce, keyed at the collector, and inductively coupled to the outside world through an Amidon ferrite toroidial inductor, a T-97 type.  Of course, a traditional hand-wound output tank would do, really.

This rig has the feel of the famous (or alternately, "infamous") QSL-40, which was another very spartan, bare-bones single element transmitter dating to 1938.  Whereas the QSL-40 made use of the then two year old 6L6G beam power tetrode, this one takes advantage of a transistor designed for television service, the 2n3553.  Oddly enough, I still have a couple of these transistors. 

I am very curious how these little rigs sounded!  The author(s) recommended an old car battery and trickle charge arrangement to power this little 2.5 watt marvel.  My suspicion this rig has considerable current flow.  Figure about three watts output at 12.6 vdc - probably a loaded average of 250 - 300 mA at key-down.  Definitely a battery burner.  

You probably will not tear up 7050.  But it might be fun for Novice Rig Round-Up this February!  After all, that is the collective group to which this article was aimed: the Novice Home-brewer of 1978.  Which included . . . me!  What fun building our own gear was.  And while I did not build this particular transmitter (I was still working on my 6AG7-6L6G MOPA!) - it was articles like these that kept our interest and excitement with Amateur Radio whetted.  We learnt early that the most satisfying contact is a Home Brew contact!

This concludes this little jaunt down memory lane.  I am hoping soon to post the matching transmitter to the recently posted "Fun-Ceiver".  

73 es CUL, de gary // wd4nka.

Blast from the Past Revisited: the Fun-ceiver! (from '73 magazine, July 1981)

Opening note: to view enlarged images, click on the photos.  Save image from the link location by right-clicking and selecting "save image as".  These photos download at approximately 50%, and can be doubled in size on your computer.  I use Irfanview as my go-to viewer.

1981 was a pretty good year for projects, really.  At least for '73 magazine.  Along with this featured article by Mark Oman, WA0RBR, '73 magazine also covered a tube regen and matching transmitter, breaking an almost twenty year silence on such "hollow state" technology!  And indeed, such an article did engender it's share of criticism.  In this blog installment, however, we will review an equally fascinating project, only this one is a classic of another genre: solid state!

In 1981 when this article came out, I was living up in Jacksonville, my first time living away from my home town of Winter Park, Florida.  I was a broke, newly licensed Dispensing Optician at the ripe age of 26.  The last thing that I could do was pop off a couple hundred bucks for a small QRP rig. I was living an a sub-let condo that did not permit an outside HF antenna.  I had my trusty Kenwood TS-520SE with me, and to be sure, I did eventually put a disguised antenna up, but I also wanted something far more portable to take with me to the beach or at least to the St. Johns River where I could sit and watch the big transport ships roll into port with their holds loaded down with Hyundai and Toyota automobiles.  There was a park on the campus of J.U. where I could set up on a picnic bench, toss up a wire, and work some QRP . . . or just listen in on the band.

The Fun-Ceiver shown above seemed to be right up my alley.  Very low parts count and what parts this receiver required were readily available at the local Radio Shack up in Regency Square, near the Pearle Vision Center where I worked.

This article is amazingly concise and very detailed, especially for the builder of 1981.  The only thing I wish was that the author include substitutes for the active components, which are referred to only by their Radio Shack designations.  The same is true with the "Fun-Mitter", which will be the next installment.  But thankfully, unlike 1981, we have the Internet and Google.  All these references can be cross-referenced.
For our purposes with this particular article, the active components used are the 3n211/ 40673 Dual Gate mosFET, the MPF-102, and the 741 op amp. I purposely digitized these scans of the article such that they can be clicked on and enlarged.  Of interest here is the mixer circuit itself, here being operated such as to produce an audio difference (Direct Conversion) - can also be used at the RF level as an RF mixer with only a couple component changes.  I will discuss this down-range.

You might notice these pages are worn and quite marked upon with my own construction notes from countless replications and slight revisions.  I found the variable diode set up for main tuning in this article was very drifty, so I replaced them with a conventional tuning cap which helped considerably.  While the modified Radio Shack 10uH chokes were fine, I opted to wind my own from scratch using powdered iron cores from the local surplus.  Later I used T-50-2 and T-50-6 Amidon Toroids. 

Looking back on this project, I have to note that in the midst of it's "bottom line" minimalist approach, the author included an active 741 op amp cw filter!  In fact, one of the reasons why I am revisiting this article is because I plan to use this filter in a project for Novice Rig Round-Up!  Googling these op-amp active filters, I find that several can be cascaded to achieve differing levels of filtering.  This is something I found to be characteristic about the circuits shown in this article: they can not only be easily duplicated, but also cascaded with little or no modification.  For instance, the mixer/ local oscillator in this project can be operated not only to produce an audio difference frequency, but also a much higher radio frequency differences.  I made a 40 meter down converter using this very circuit with one capacitor change in the output, substituting a 100pF SM cap.  The local oscillator was a xtal pierce 2n2222a circuit.  This RF mixer fed, in turn, a duplicate mixer using a VFO local oscillator, producing an audio difference output. (a BFO/ Product detector.)

A superhet in it's most basic of elemental form.  Simply from cascading what basically amounts to this receiver.

A decade or so later, this very circuit became the experimental down-converters for my prototype Regenerodyne.  They worked fabulously feeding a regenerative detector which had more than enough Q to select the untuned output of one of these mixers, perfect to tune about a 500 kHz wide "IF Window", which became the heart and soul of the Regenerodyne.  All thanks to this little 3n211 mixer and an ultra simple xtal LO!   Once I "road tested" the regen-converter scheme, I built down converters using a 6J7 or 6K7 pentode and a 6C5 xtal LO....just to keep things "all hollow state" - but rest assured, these little minimalist mixers shown in this article as a Direct Conversion mixer, and used my myself at RF, work very well for the purpose, in fact, possibly with a lower S/N level!  Today we live in a post-3n211 world, which in itself has become about as scarce and expensive as many tubes/ valves!  Even the then-popular CA3028 vhf mixer IC which found use in many HF DC receivers is become unobtainum.  But the devices that substitute for them these days are far more silent, thus if you are interested in trying these mixer circuits, try out these modern substitutes!

Radio Shack sold Sodium Ferrichloride in sufficient strength to safely etch a circuit board.  Some of the surviving Radio Shacks still around, most of which are franchises, may still carry boards and etchant.  "Instructibles" on Line also has articles on how to produce your own.  The above page shows the foil side of both the receiver and the 741 op amp filter.  I etched the board for the receiver, although I never did make the filter.  Later I built successive receivers and modified down converters on regular perfboard and sometimes even drilled masonite!  Just about any insulating surface works, even plexiglass!

The author chose not to include an audio board or an audio circuit, though one can be easly made around an LM-386, which is what I recommend.  The suggested audio section for this project was Radio Shack's amplified speaker, which is what I also used, and what the photo in this article shows.  And to be sure, it was quite effective.  Making your own LM386 audio final does allow the builder to shape the audio, add bass, and any level of gain desired.  So for the builder of today, I'd say take advantage of the web and google the many simple audio circuits out there.  Later I will post one to this blog as well.

That's it.  Next project posted will be the "Fun-Mitter" from Febuary 1981's '73 magazine, which was actually the first in this series.  I posted the receiver first because I actually built it.  I never did make the transmitter, but we will give it a once-over as well, together.

de gary // wd4nka