The 52 year old project (Part 2)

In a previous post I described the QRP transceiver project found in an old QST magazine.  I had bought that issue at a radio store while I was studying for my Novice license, and still had it stashed away in my library even after moving five times.

The prototype as described by W6DMK (sadly, now a SK) was built in a rather unique project box (no longer available) which allowed the top, bottom and side panels to be removed for access to the internal chassis or circuit board.  The front and rear panels attached to the internal chassis.  In a previous post, I described how to build a similar type of enclosure from printed circuit board material using an old one gallon paint thinner can as the outside.  However, I found a ‘used’ 7″x5″x3″ Bud or LMB minibox in the junk box, the same size as the enclosure used in the article.

This mini box is of the type made from pieces of sheet metal, each bent into a U shape such that the two nest into and around each other to form the enclosure.  The larger ‘outer’ part would become the bottom chassis part, and the smaller ‘inner’ part the upper ‘lid’ part of the enclosure.  Both of these parts had a few holes already drilled into them from its previous use.  The bottom had three holes in what would be the back panel.  Two of these were drilled out larger to accept a 1/4″ phone jack (for the key), and an SO-239 coax connector for the antenna.  The third hole was just the right size for a Phono jack that would be used for the +12 volt power input.

The top of the box had quite a few holes of various sizes.  These were filled in with JB Weld metallic epoxy.  I first cover the inside of the holes with a piece of metal foil (I used copper foil, but aluminum ‘duct tape’, or heavy duty baking aluminum foil attached with epoxy will also work.  The foil is pressed down with a burnishing tool to remove any bubbles.  The epoxy is then mixed up and applied to the outside.  A putty knife or an old credit card is used to apply a thin layer over the holes, attempting to keep any voids forming in the surface.  It takes the JB weld about 24 hours to harden enough to be sanded.  This is done using medium grade sandpaper wrapped around a small chunk of 2×4.  The surface is sanded down until only the epoxy filling the hole remains.  If there are any voids in the epoxy fill, a second layer is applied, and again sanded, this time with a finer grade of sandpaper.  If necessary (usually only for very large holes) a third application of JB weld is applied.

After the holes had been filled in, I drilled any additional holes required for my use.  Then it was time to paint.  The surfaces of the box were rubbed with extra fine grade steel wool, and then wiped clean with vinegar (a mild acid which helps the paint to stick).  If the box is to be painted a dark color,  I would first spray on a light primer coat.  I used white paint for this on the inside top part which was later painted a flat black.  The bottom chassis was painted white, two coats were used.

Here is how the chassis box came out (I actually did this several months ago):

The labels are made with a Brother P-touch label printer.

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I mentioned in my last post that I was entering the schematics into Kicad.  I have made some changes to the original circuit, mostly to use parts I already have, instead of parts that are no longer available.  The VFO and BFO circuits were the first to be built and tested.  While the QST prototype was constructed on a single large circuit board (the author didn’t provide a PC artwork, but pointed out that his first prototype was built on a vector board), I prefer to divide up the circuitry into smaller modules which can be tested on the workbench and then built into the finished rig.  This is how Charley Morris ZL2CTM builds the rigs he features on his YouTube channel.  He builds small modules onto strip type vector board, and then solders these modules onto a larger un-etched piece of PC board material.  This is what I intend to do.

VFO-BFO

VFO-BFO  (pdf download)

The VFO and BFO circuit schematics are shown above.

P1030039Here is the VFO.  The two transistor circuit is built onto a small piece of vector board which is soldered to the rest of the parts attached to the back of the VFO tuning capacitor.  This 365pf TRF type variable is mounted to the front panel by two threaded spacers.  The VFO is quite stable, it only drifted a few tens of Hertz during an hour of being powered up.

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The BFO is built on another small bit of vector board.  Wiring and parts are on both sides of the board.  You can see the small wire ‘feet’ that will be used to solder the board to the main PC ‘chassis’.  The wire feet hold the board above the PC ground plane so it won’t short out to it.  Sockets were used for the HC-49U crystal and transistor.  This will allow me to try several crystals to find one that will match the two in the receiver IF filter.

keyer

keyer (pdf download)

The transmitter keyer circuit is shown here.  The original used a Germanium PNP transistor to key the +12 volt power to the transmitter.  I’ve converted that to use 2N2905 Si transistors, and I’ve added a switch for the RX +12v as well.  I intend to use a diode signal switch between the antenna and the receiver front end to provide for QSK.  I tried to use the transmitter power switch as a logic inverter for the receiver power switch, but there was too much collector to base feed though from the RX switch that appeared on the TX power line, it would not go below 2 volts on key up!  I therefore added a third transistor to the circuit.

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Here you can see the construction of the keyer switch.  This time I used a pad cutter to create ‘islands’ of copper on a small piece of circuit board.  The cutter was purchased from Harbor Freight.  It is sold as a spot welder cutter.  By overlapping cuts, I can create islands smaller than the size of the cutter.

AF-Amp_Sidetone

AF-Amp_Sidetone (pdf download)

Finally, here is the receiver final audio stage, and transmitter sidetone.  The original QST version used an unijunction transistor oscillator for the sidetone generator.  These devices are now as rare as hen’s teeth, so I substituted a two transistor multi-vibrator circuit.  The transistors are old Germanium devices salvaged long ago from some surplus computer circuit boards (maybe from old IBM 360’s, who knows!).  I added a volume control to the sidetone, something that was missing from the original.

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Again the pad cutter method was used, this time with a home made cutter made from a hex cap head bolt.  To make this cutter I drilled out the cap head of the bolt to make the walls thinner, and then cut 4 ‘teeth’ into it with a Dremel cutoff wheel.  While this type of pad cutter worked, it doesn’t stay sharp long, and soon starts to rip the copper leaving just large holes  instead of islands (you can see two of these failures in the photo).   The HF tool works better, but makes larger islands.

The Keyer switch and the audio board will both be mounted with double sticky tape to the rear and front panels respectively.

Next, I’ll get to work on the receiver circuity.  With the receiver working, this project will really come to life!

 

 

Something old is new again

recently dug out the April 1968 issue of QST from my bookshelf.   Hard to believe I’ve had that issue for over 52 years.  The cover story was on building an electronic keyer using what was then ‘state of the art’ RTL logic circuits.  The article included a printed circuit board layout for those wishing to etch their own.  I’m sure the circuit would perform well today (though it’s missing all of the modern features such as message memories, adjustable weighting, etc), but I don’t know if the IC’s used can still be found.  I suppose one could convert the logic to use available 74 series TTL or CMOS circuits if one really wanted to build the thing (would have to re-layout the PC though).

The first article in the issue was for a QRP CW transceiver for 40 meters.  It was all solid state using discrete transistors and diodes.  Most of the parts are still available (mostly 2N3904 and 2N3906 silicon transistors), though the few germanium PNP and the one unijunction transistor will be unobtainum today.  Still it looked like an interesting build, and I knew I had the older hard to get parts in the junkbox (365pf TRF capacitor and slug tuned coils).

The crystals called for in the BFO and IF filter are available in HC49/u microprocessor clock frequencies, and I have some in the junk box.  I will substitute modern ceramic trimmer caps for the old style compression mica units called for a half century ago.  There are better RF power transistors available today then the ones used in the article, and I’ll re-design that part of the circuit to eliminate the compression trimmer tuned Pi network tank circuit, and use toroid ferrite transformers along with a two or three section LPF instead.  I’m leaning towards an IRF-510 MOSFET in the final, a single transistor will put out more power than the 2N2195 the author used.  I’ll also replace the germanium PNP transistor used in the T/R switch (keying) circuit with a P-ch MOSFET.  The uni-junction audio sidetone oscillator will also go by the wayside, here I’ll probably use an 555 IC, which is almost as long in the tooth as the UJT.

The original rig didn’t have any switching logic for transmit / receive, the antenna connected to both the receiver input and transmitter output.  This worked since the receiver was lightly coupled to the transmitter tank at a high impedance point via a small (10pf) capacitor, and at the 1 watt power level there wasn’t enough RF fed back to blow out the receiver RF transistor.  I will add some diode switching in the signal path, and will switch the receiver power off during transmit.  It should be possible to obtain very good QSK.

It quickly occurred to me that this little rig would also work fine on 30 meters, which might actually be the better band.  If I replace the 5 mhz crystals with 8 mhz ones the circuit will cover the 30 meter band without changing the VFO.  The 5th harmonic of the 2.0-2.3 mhz VFO does fall into the 10mhz band, but it shouldn’t cause any birdies as the actual mixer products seem to just miss the band “by that much”.   I’ll have to use T38-6 cores instead of the T38-2’s to modify the rig for 10.1 mhz.  If I build everything but the VFO, audio amp, sidetone oscillator, and T/R switching logic  on one circuit board, I could try out both versions with the same setup.

I’m working on the new schematics now, and I’m teaching myself how to use KiCad in the process.  I’ll post the schematics here in a later post, and will also provide a link to my Github where I’ll have the KiCad files.   If anyone wants to duplicate my folly, they will find that except for the J.W. Miller slug tuned ceramic coil form,  TRF 365pf tuning cap, and vernier dial in the VFO all of the parts will be ones you can actually buy today.  I am keeping the PNP germanium transistor in the AF output stage to drive a pair of ancient magnetic headphones, but I’ll show how to use an LM386 instead to drive your iPod or cell phone earbuds.  You’ll have to deal with ebay for the VFO parts.

Crystal Control

got my novice class license back in February 1970.  Back then novice class hams were limited to CW operation on portions of the 80, 40, and 15 meter bands.  By this time voice privileges in the 2 meter band had been withdrawn.  The purpose of the novice class license, created in 1951, was to allow the applicant to increase his (or her) CW skills via on the air practice with the goal of upgrading to a general class ticket.  The novice license was granted for a one year period, and was not renewable.

I upgraded to an Advanced class license within six months of getting my novice license.  The FCC had announced that license fees for the amateur service would be going up for the first time in several decades, from $4 to $9.  With that incentive, I studied the written test questions for both the general and advanced class exams, and managed to copy CW at a solid 15 WPM, a sizable safety margin.  I made the trip down to the NYC FCC office in lower Manhattan on the last day that the $4 license fee would be in force, and I managed to pass the 13 WPM code element, and both the general and advanced class written elements.

Since then, both the novice and advanced class licenses have been eliminated (though anyone holding such  tickets could renew them forever).  The privileges allocated to both of these license classes still apply, how strange that the only way a general class licensee can now gain privileges in the advanced class band segments would now be to obtain an extra class ticket!  I was in a special league here.

Even more recently, the CW requirements for all ham licenses have been removed (thought the CW band segments remain, now shared with new ‘digital’ modes that don’t require CW knowledge).  Since I’d never increased my abilities in CW beyond the 15 WPM plateau (and have probably gotten more than a bit rusty as well), the extra class license had remained an elusive goal.  However with the CW requirement now history, it was within reach.  The written test for the extra was a cinch for me, having a BS degree in electrical engineering.

Nostalgia is a strange beast.  The recent resurgence of home brewing has resulted in many hams building simple QRP rigs.  What is QRP?  Back in the early days of CW when power tubes were scarce and expensive, anything over 100 watts was considered QRO (high power).  If you operated with less than 100 watts, that was QRP.  With the onset of SSB, building a legal limit station became easy.  You no longer needed a heavy, expensive modulator (which was actually a very high powered audio amplifier, about 500 watts worth).  The same tubes that were in the old modulator, plus an additional copy in the final amplifier (2+2 = 4) would run the legal limit, no modulation transformer required.  But it was also discovered just how well SSB cut through the QRM and QRN compared to AM.  You really DIDN’T need the full gallon (most of the time).  The 100 watt output of the average transceiver was more than enough (except for the contest nuts or DXCC hunters).   Today, a new term has come up, QRPP.  If QRP means a 100 watt station, then QRPP would be < 10 watts.

I’ve collected quite a lot of parts over the years.  Even though I’ve pruned my junk box of a lot of the old tube related stuff, I still have a good assortment, including some old NOS octal tubes.  Why not build something that would be a throwback to the novice days?  That would probably mean a crystal controlled transmitter.  There is a problem though, have you checked to see what those old FT-243 crystals cost these days?  Even back in the 1970’s, with quite a few crystal houses still turning out such crystals for the novice class, the supply was mostly made from re-processed WWII surplus.  Needless to say, that supply has dwindled down to a trickle, especially since the demand slackened off following the removal of the crystal control requirement for the novice licensees back in the 1980’s.  As a result, FT-243 crystals on Ebay often fetch upwards of $20 each, especially for those in the heart of the amateur QRP CW band segments.

Looking in my junk box, I see that I have quite an assortment of these old crystals, few of which are cut for amateur frequencies.  I do have some crystals that could end up in an amateur band if used on their second or higher order harmonics (especially for the ‘newer’ WARC bands).  I also have quite a few more that could be made to work by grinding or etching them higher in frequency.  THAT will be my next project.  If I succeed doing this, I will then consider building a simple tube transmitter and receiver (more on that in a future post).

I’ll go into the process of re-working those old crystals in a future post, for now I need a way to test all those old crystals.  I need to separate the good ones from the dead ones.  (Actually the first two ‘dead’ crystals I discovered were only dead because one of the two pins had become electrically ‘open’.  Moving the actual crystal into another case brought it back to life.  I can repair the broken crystal holder).

A search on the web found a project by W5USJ on QRPME.com for a crystal checker.  This gizmo includes a test oscillator, a crystal activity indicator, and a frequency counter.  I didn’t need the frequency counter, I already own an old Leader 250 mhz counter.  I did need the test oscillator however.  The circuit of this tester, as I built it, plus some pictures of its construction are shown below:

CrystalChecker

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The circuit contains an oscillator (Q1), an activity indicator (Q2, two small signal diodes and an LED indicator), and a buffer amplifier (Q3) to drive an external frequency counter.  I added a 5 volt regulator (7805) so I could power the tester from a 9v ‘wall wart’ or a 9v battery.  I built mine on a small copper chassis I made from a scrap of copper plate (from a hobby shop).  The transistors are mounted in sockets (salvaged from old TV set PC boards).  While PN2222 and 2N3904 transistors are specified, really ANY common small signal silicon NPN transistors with an FT of 150 mhz or more can be used.  I have metal cased 2N2222’s in the oscillator and indicator positions, but the 2N3904 would work there as well.

Operation is simple, connect power (the red LED should light), and plug a crystal into the socket.  If the crystal is oscillating, the two diodes will rectify the signal and develop a turn on bias for Q2, which will the conduct lighting the green LED.  Transistor Q3 along with the diode from its base to ground will square up the signal to provide a clean waveform to drive a frequency counter.  The circuit as designed by W5USJ included a PIC microcontroller programmed as a frequency counter good for up to (at least) 10 mhz.  He didn’t provide the source code, but I’ve seen other examples of PIC frequency counters on the WEB if you need one.  (https://sites.google.com/site/vk3bhr/home/fm2)   I just use my Leader LDC-823S I bought used many years ago.

Note that 6740 khz crystal in the socket.  I intend to try and move that (and a few others like it) into the 40 meter CW band.  Many years ago as a novice, I did mange to move one surplus crystal a few hundred khz higher in frequency.  Several others were ‘bricked’ in the attempt.  I’ve later read about using an etching solution to chemically thin down crystals, a process that should offer a higher rate of success.  We’ll see.  I have some etching solution on order.  I’ll report on how this all works out in a part two.  Stay tuned.

 

The Art of Soldering (PL259 to RG8/U)

The other day I finally installed the 2 meter J-Pole I’d bought late last year.  I made use of a run of coax that had been used for a dipole antenna, and I had cut the run shorter to use the minimum amount of cable between the shack and the antenna.  So, I had to solder a new connector to the feedline in the shack.

Technically, it’s not RG8/u, but rather RG/213U, which is the modern part number.  Still, old time hams have been calling the cable RG/8U for decades, and as both part numbers look the same from a few feet away,  a rose by any other name ….. to quote the Bard.

Attaching the common PL259 UHF connector to this 1/2″ cable looks simple, until you actually try to do it.  The cable is thick, and not very flexible, and difficult to handle.  The operation of striping the insulation and tinning the copper braid is a messy operation with the thick cable fighting you all the way.  Over the years, I’ve figured out a method of taming the beast, and produce a good strong and perfect electrical and mechanical connection between the ancient connector and the coax.

I really don’t know why new amateur (and CB) gear continue to use this relic from WWII, but the PL259 (and it SO-239 mate) just refuse to die.  You’d think that the superior N type connector would have supplanted it by now, but alas no.  Not that the N connector is any easier to attach to coax, but it is simpler to solder to, and has a lower SWR bump, especially above 30 Mhz.

Anyway, the first thing I do is to strip about 1.5″ of the outer insulation off of the cable to expose the copper braid.  Normally, you’d then cut the braid back to size (about 1/2″) and the tin it, however that will leave rough loose ends of braid about, ready to end up inside of the completed assembly to short it out.

So what  do is to tin about an inch of the braid from the outer insulation towards the end of the cable.  First smear a good amount of rosin flux on the braid and then melt a thin layer of solder on it.  Use a Weller soldering gun, NOT a wimpy pencil or iron.  A 140 watt or higher gun is ideal, though I have been able to get good results with my old 100 watt Weller Junior gun.

After tinning the braid, I file off the excess solder to leave a smooth evenly tinned braid with no solder lumps.  Now we will cut the braid back to 1/2″ in length.  The ideal tool to use here would be a tubing cutter.  I’ve used  a pipe cutter for this with good results, but you have to be careful to only cut through the braid, and not all the way though the insulation to the center conductor.  I’ve also got good results with a hack saw, or a jewelers saw.

Next peel away the rest of the braid to leave the center insulation and conductor.  About 1/16″ from the end of the tinned braid cut away the center insulator to expose the inner conductor.  Twist this some and then tin the end and cut it just long enough to stick out of the connector.  Use the connector as a size guide.  Now slip the connector clamping ring over the cable (with the open end towards the end of the cable!), and screw the connector on to the cable.  You should see the tinned braid through the four holes though which you will solder, and the center conductor should be sticking out the front by at least 1/8″.

File or sandpaper the connector where you will be adding solder to remove any corrosion that would result in a bad solder joint, and then wipe on some rosin paste flux.  Use a small vise to hold the cable while you solder the connector to the cable at the four body holes, and the center connector.  Trim the excess center connector off, and touch up the soldering here.  Now screw on the clamping ring (You DID remember to slip it on on the cable the right way didn’t you?), and the job is done.  A thing of beauty forever.

 

Computer Build part 2

So my parts arrived and I’ve done the initial POST test.  Hurrah, it all works.  I’ve downloaded the current Alpha build of the future Kubuntu 20.04 LTS (the final release will be sometime in April, as the release version name indicates).  That seems to work too.  I’m still not too sure about the video card though.

I bought two different cards, the first was a 2GB Radeon R7-250, and the second was a EVGA GeForce 8400 GS.  Both are older, single slot cards that while no longer recommended for gaming, will handle the usual office applications and Youtube videos just fine.  They both also have enough resolution for CAD work, so I’m covered here.  I wasn’t interested in building a gaming rig.

The Radeon card came from Ebay, as a Dell overstock item.  It has two outputs, one DVI and one Displayport.  In theory, it should drive both outputs, but so far I haven’t been able to get anything out of the DP  I’ve read online that the card defaults to the DVI output until a driver is loaded, and at least in my case the MB bios does not display anything out the DP, even when its the only one connected.

I haven’t yet tested the GeForce 8400 yet in this regard.  Obtained from a B stock sale on EVGA’s website (for only $10 and free shipping), it has three outputs, one HDMI, one DVI, and one VGA.  With monitors connected to the DVI and VGA  ports I only get output under the BIOS setup from the DVI, but I didn’t try that with ONLY the VGA connected.  I do get dual head operation under Kubuntu, so even the open source drivers can handle this.  I don’t yet know if I can drive both digital outputs (DVI and HDMI) at the same time in dual head mode, I’m still waiting for another HDMI cable in the mail to try that.  I did get an HDMI to DVI adapter, but it won’t plug into the card along side the DVI cable as the sockets are too close together.  I can always use the DVI and VGA outputs, as my monitors will handle that, but I’d rather not use the VGA inputs as they probably lose a little bit in signal quality over the Digital inputs in full HD resolution.

I also have the older Nividia dual head card that’s in my current computer.  It only has 512gb of ram, but does drive dual DVI outputs to full HD.  It’s good enough, but I was hoping to get a cheap, more modern GPU running on the new machine.

Now to answer the question of why I chose the other stuff that I did.

1: CPU:  Short and simple, I’ve always liked AMD for being a bit better in the bang for the buck, and for being a smaller target for the malware writers.  Their new Ryzen Zen processors are currently the best price vs performance available, sorry Intel.  The Zen 2, Ryzen 5 3600 is actually at the bottom of the current heap (except for the Ryzen 3 3200G, and the Ryzen 5 3400G APUs).  I drew a $250 line in the sand, and the CPU I picked clocked in at $180.  The next one up was the slightly faster Ryzen 5 3600X, offering a bit higher base and boost clock rates, but not worth the extra $50 IMHO.  The Ryzen 7 CPUs which have 8 cores and 16 threads (vs the 5’s 6/12) start at about $310.  If I ever need more power later on I can upgrade to this point, and then there are the Ryzen 9 processors that go up to 12 or 16 cores!

2: Motherboard:  My price line in the sand was about $100.  This pretty much limited me to a B450 chipset, and a uATX format, but I’d already settled on the smaller sized board because I wanted to use the case that I’d salvaged from an old Lenovo machine.  There are plenty to chose from with these parameters from MSI, Gigibyte, ASRock, and ASUS.  Most of these will have one M.2 PCIex4 SSD slot (usually with this chipset if there is a second M.2 SSD slot it will be SATA3 based).  I chose the MSI board mentioned as it fit my price range, and also included board headers for both a COM port, and a PARALLEL port.  Both of these are useful for driving micro-controller development tools.

3: Memory:  As I wasn’t going to sink extra money into a high end video card, or a more powerful processor, I decided to get the most/best memory I could afford.  I budgeted about $150 for the ram.  I did run over that by $10, but spent only $80 on the MB, so we’re not over budget.  Crucial recently (just a week before I placed my order) announced a new line of their Ballistix gaming memory in 2667, 3000, 3200, and 3600 mhz speeds, with and without RGB LEDs (WTF?).  AMD recommended 3200 mhz speed ram as the sweet spot for the Zen 2 processors, so I decided to go with that.  I ordered a 32gb kit (two 16gb modules) which is probably overkill by double what I REALLY need.  However, I do intend to run Windows 10 in a VM under Linux, and having the cores and ram to throw at it I’ll be able to run any micro controller development tool that isn’t available for Linux in a large enough sandbox.  Atmel Studio, that means YOU (you G-D resource hog!).

 

 

Building Computers

First of all, I’m sorry for being off the blog for an extended period of time.  I’ve been recovering from mitral valve repair heart surgery (in November)

Since 1995 or so, my ham shack personal computer has been one I’ve built from purchased parts, rather than an off the shelf machine.  During this time I’ve mostly used AMD processors, though a few machines did use Intel CPUs.  My current computer is a factory reconditioned Dell purchased from Ebay (Intel Core-i7), although it’s been upgraded with a new video card, power supply larger hard disk, and an SSD boot drive.  (Running Kubuntu Linux, it has the net-name of “ThePenguinInTheDell“)

The first PC I ever built was an upgrade to a PC-XT clone.  On that one I changed out the mother board for one with an 80386SX processor (I later moved everything into a larger case).  I then progressed to an AMD K6-233 in an AT Tower case, later upgraded to an Intel Pentium III-500 (mother board swap).   My next build was an Intel Pentium-III 833mhz this time in an ATX format ( later upgrading the processor to a 1 Ghz version). The next few builds were AMD Athlon and Athlon-64 based, with the final in this series using the Phenom-II 4 core processor.

Building your own computer might sound like rocket science, but it’s not.  The only tools you will need will be a #1 Philips screwdriver, and maybe a suitable sized nut driver.  An anti static wrist strap (which might be easier to use on your ankle) is also a good idea.  The hard part is in selecting compatible parts that will actually work together.  Obviously you must use a motherboard that has the socket and chip set that is compatible with the processor you intend to use.  The on board BIOS version must support the version of the processor, or you will need a way to update the BIOS.  You must also select suitable memory.  Any motherboard purchased today will be using DDR4 memory (unless you are building a ‘retro’ machine with an older processor and motherboard).  Getting the right memory process isn’t enough, the speed, voltage, and timing parameters must match the processor and chipset being used.  Sometimes memory that works on an Intel board won’t play with an AMD one (and visa versa).  If you buy your memory from Crucial, their website can help select the correct modules for the motherboard/process you are using.

Recently I decided that it was time to look at moving on to newer tech in the computer department.  AMD now has their Zen Ryzen processors in the third generation, with the fourth gen parts due out this summer.  The Ryzen 5 3600 processor I selected is a 6 core, 12 thread CPU with clock speeds starting at 3600 Mhz, and capable of being burst mode, and overclocked past 4 Ghz.  I selected Crucial’s new Ballistix memory at 3200mhz speed, getting 32 gigabytes (two modules).  Ebay provided a nearly unused M.2 256gb SSD for the boot disk, and I’ll probably transplant the 2gb SCSI III hard drive from my current computer to the new one (which contains all my user data files).

I selected an MSI B450M pro-vdh-max mother board, and I had a suitable mATX mini tower case salvaged from an old Lenovo Think-Center computer.  I know that Chineseium computer cases can be had for cheap, and the new case designs do offer improvements in air flow, and cable management, but the old Lenovo case is a ‘looker’, and it sports two 5.25” drive bays suitable for an optical drive, and a built in SD card reader / USB hub.  I had both of these items salvaged from previous computer upgrades.

The final item needed was a new video card.  I could use the current 256mb dual DVI PCIe card in my current computer, but I found an EVGA “B” stock Gforce 8400 GS on sale (on EVGA’s website) for only $10, with free shipping.  This card sports 1GB of memory, and DVI / HDMI outputs.  It will take an adapter thing-a-ma-gig to connect the HDMI output to my monitor’s available DVI or DP input, but otherwise it should work fine.

Kubuntu will release their 20-4 LTS version sometime in April, and that will be the OS I’ll install on the new PC.  In the meanwhile, I’ll be testing everything to make sure it all works.   I’ve already managed to do the initial power up and POST tests.  It all worked, except for the AMD R7-250 video card that I had originally planed to upgrade my current machine with (to fix a driver problem with the Nivida card).  It seems that this AMD card defaults to the DVI output, and won’t drive the DP output without the proper driver setup.  The motherboard BIOS doesn’t know how to talk to the DP output.  I could probably get this to play eventually, but I now have the option of using a Nivida card that should work.

 

Heathkit GC-1006 Clock Assembly Log

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Packed in a plain cardboard box inside of a Priority Mail shipping box, awaiting my attention.

P1020648.JPGOn top the famous Heathkit assembly manual, and a note congratulating me on my purchase.  Strangely enough, this is called a “First Edition” kit, even though it’s been in production for some two years now.

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Inside, several envelopes containing the parts.  The white box has the 9 volt “Wall Wart” power transformer.

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We begin by going through the parts list, making sure that nothing is missing (nothing was).

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There are two circuit boards, joined at the hip (will snap them apart later on).  Here I’ve started to add parts, resistors, capacitors, and diodes.

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The Siamese twins have been separated.  Top board is the microprocessor, bottom board is the display.  An Atmel ATtiny processor holds is the brains.  It communicates via a serial bus to the LED display driver board.  A photo resistor in the lower right hand corner of the display instructs the processor how bright to shine the LEDs depending on room brightness.

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The two boards are now connected via a ribbon cable, and the battery holder has been added.  6 AA cells can power the clock for over a week during a power outage.

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Another view of the two married circuit boards.

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The two circuit boards and the battery holder have been mounted to the bottom plate of the case.  It’s now electrically finished.

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Sideways view of the almost completed clock.

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Powered up and being tested.  The final step will be to add the wood sides and the top, then it will look just like the photo on the Heathkit Web site.   I just may buy the Heathkit 144/450 mhz antenna kit next.  Wish they would make a QRP SDR ham transceiver kit.

Heathkit Clock

Sometime in the late 1970’s or early 1980’s I built my last Heathkit, the GC-1108 digital alarm clock.  I still have it and it still works.  I did have to replace the alarm on/off switch on top with a slide switch from RatShack when the original went bad.  Now the three position set time/ set alarm/ run switch is going bad, resulting in the clock loosing the time setting when the switch is operated if I apply any inward pressure on it (carefully sliding it  is OK).

Heathkit went out of the kit business, and then disappeared after my purchase of that kit.  I’ve since purchased several already-built Heath products, including a tube tester, solid state curve tracer, and a signal generator.  Their test equipment and ham radio gear were usually designed at the perfect level of performance vs cost for the hobbyist, and being kits they gave the owner a sense of pride and accomplishment once assembled.  They were also fun to build.  Needless to say, I do miss Heathkit.

As of 2015, Heathkit is back, sort of.  I’m not sure just who the new owners of the brand name are, if there is a real, direct connection with the new Heathkit and the old, or if this is just a case of a new entity having purchased all of the IP and Logos of the former company.  They are no longer in Benton Harbor, Michigan, the new company is shipping product from Ottsville, PA, and I’ve heard that their engineering office is somewhere in California.  At the moment their website store lists only four kits, an AM Radio-Tuner (available in no solder and solder versions), an Alarm Clock, a Dual Band J-Pole type antenna for the Amateur 144/440 Mhz bands, and a SMT practice soldering kit (code practice oscillator on a ruler).  They also list a precision RF meter that seems to be stuck in pre-order hell.  I don’t know if it will EVER be available.

I hope the new Heathkit will eventually add more stuff to their catalog.  I had been eyeing their new “Most Reliable Clock” kit ever since it was announced, and I finally decided to order one and relive the Heathkit building experience again.  Unfortunately, Heathkit seems to be running hand to mouth on their inventory, building kits on order.  As a result, there is a backlog of about a month from order to shipment.  You will get an order number once you place your order, and will get an email when the kit actually ships.  Mine was sent USPS Priority Mail and shipment took three days.

So far, I’ve only opened the box and verified the contents.  I’ve just started reading though the manual.  The new Heathkit assembly manual is just as good as the old ones (maybe better).  The manual is spiral bound to lay flat open to a single page.  While there is new artwork appropriate to the current date, there are also many illustrations lifted right out of older Heathkit manuals from the 60’s-80’s.

I hope to document the build of this new clock kit and report on it here.   I don’t think they have added a 24 hour mode to the clock, which would be nice for use in the ham shack (though I intend to replace the GC-1108 on my night stand with the new one).  I got the Green LED version, that’s more pleasant to the eyes at night (same color as the GC-1108).   This is going to be fun.

Cutting the Cord

A few days ago my wife noticed that our local CBS station was missing from Direct TV. It seems that Nexstar, the troll that owns distribution rights to CBS (and other local stations) is holding AT&T up for ransom in order to get more money out of them for the right to carry the local stations. While we do have an antenna, and can bypass the satellite to receive CBS’s programming, we can no longer use the DVR feature on our Direct TV receiver. We were planning on cutting Direct TV’s cord when our contract ends sometime next year, at which time we’d get an OTA DVR. Thanks to Nexstar, I decided to get one now.

There are a few different options out there for OTA DVRs. Being a geek, I had thought of building my own MythTV box. There are several different Linux compatible TV tuners for this, with the SiliconDust HdHomeRun being the current favorite. However the Mythbuntu Linux distribution is no longer being supported, making it necessary to configure the Mythtv packages around one of the Ubuntu or Mint distros. Then I’d need to build up a micro ITX computer box to run the back end, as well as get the required tuner. An off the shelf solution wouldn’t be as versatile as MythTV, but I can always revisit the idea later.

Mention TV DVR’s and one of the first ones that comes to mind is Tivo. Tivo is a decent product, but it’s no longer the only game in town here. A quick Google search narrowed the options down to two different products, Amazon’s Recast, and Tablo. Both of these products are available in two or four tuner versions (meaning the ability to record two or four different channels at the same time). Both use a networked streaming connection to your TV, no HDMI cords. This of course, means that you need either a streaming device connected to your TV to watch the output of the DVR, or to use a ‘smart’ TV with a suitable app installed.

If you go with the Recast, you’ll need an Amazon FireTV or Fire Stick as the Recast ONLY works with Amazon branded equipment. The Tablo will connect to the FireTV / Fire Stick, but will also play with Roku streaming devices, Samsung and LG smart TV’s, Android and Apple devices, and computer web browsers.

As we have a Samsung 65” TV in one room, and a Fire Stick in another, the Tablo was the logical choice. We ordered a second Fire Stick for a third TV.

We got the Tablo Quad, which is the four tuner model. This is the latest and greatest version, which can use WiFi-AC, and has a built in SATA compartment to install the required hard disk. You can use any 2.5” hard disk (rotating or SSD) up to 8tb, but it must be 7mm or less thick to fit inside the unit. External USB hard disks can also be used (USB 2.0 or 3.0 are OK). I selected a Seagate 2tb Barracuda drive.

Setup was easy, I accessed the DVR from my Linux PC by setting my browser to my.tablotv.com to access the web app. From here I was able to scan for available channels, register the unit with Tablo, and start my 30 day free trial of their on line schedule subscription.
Yes, just like Tivo, they do charge you a monthly fee to access the schedule info (though if you’re OK with manually entering record schedules by channel, date, time, once-repeat, you can live without the subscription).   I’d have to pay for a similar subscription to schedulesdirect.org if I built a MythTV box.   Tablo does give you a discount for buying the subscription for a full year, or you can pay them $150 once and you’re good for the rest of your life.

The unit seems to work nicely. The FireTV app is rather slow, it takes about 4 minutes to start up after opening the app (including the amount of time the Fire Stick takes to boot up after tuning on the TV, selecting the HDMI port, and hitting the home button on the Fire Stick remote). But this is a version 1 Fire Stick, hopefully the new version 2 I have on order will be faster (dual core vs quad core). The Samsung TV app is much faster, it starts almost instantly, ditto for the web app on the computer. Once you select a channel to watch in the live TV section, there is a 5 to 7 second buffer delay before play starts (regardless of the device used to connect). Video quality is good, but not all of your OTA stations are in HD (mix of 480p, 720p, and 1080i). The default setting of the Tablo is 720p, but you can bump this to 1080 at the cost of eating up more disk space.

So FSCK-you Nexstar!  I wonder if I can get a reduction on my DirectTV bill by asking them to drop all of my local channels, since I don’t need them anymore to get them?

Home brew Arduino

The Arduino controller boards are easily the most popular ‘go to’ for quick and dirty microcontroller based projects.  The Arduino Uno, with the Atmel-Microchip ATMega328P processor is the most popular, costing less than $23 US for the original version, and under $10 for clones and ‘mini’ bread board friendly versions.

For projects, you’ll probably want to just build the raw processor chip into your design, but you’ll still need the Arduino setup to download your code to the chip.  This means providing the USB to Serial interface, and programming the bootstrap onto the chip.  You’ll also have to provide the required oscillator crystal and resonating capacitors.

Depending on what I’m doing, I’ll either lash up a simple breadboard to develop my projects code, or skip that step and solder up a perfboard with the minimal circuit.  An example of the former is shown below:

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The Atmega328P controller chip in a QFTP-32 package is shown soldered to a DIP adapter board.  These adapter PCB’s are available from overseas suppliers on Ebay cheaply, if you buy them in bulk you can get several for a dollar.  These boards come in several flavors as shown below:

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The ‘Quad’ styles are four sided and have single or double rows of pins.  The single row style can be used with breadboards by populating two parallel rows with bread board pins, and Arduino style sockets connectors on the other two rows.  For the ATmega328 only one such socket connector will be required as the other row only has two I/O connectors on it.  The other pins go to VCC, GND, and the crystal.  Wire fly leads can be soldered to the needed connectors and plugged into the breadboard.
The other ‘quad’ style board while not suitable for breadboard use, will more easily fit into your completed project.  This particular board is made to hold either a 32 pin style IC (ATmega328) or a 44 pin style chip (ATmega324, Atmega644, or Atmega1284).  These larger ATmegas are 3 to 6 times more expensive than the Atmega328, but if your project is memory or I/O space challenged on the smaller processor, they are a welcome option.

The dual inline style board has solder pads on the bottom for chip resistors or capacitors for bypass or pull downs.  I used them to bypass the VCC leads to ground, and to mount the crystal resonating capacitors.

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Atmel-Microchip recently introduced the ATmega328PB version of the ‘328.  This chip is only available in the QFTP and QFN style packages (both can be soldered to the adapter boards shown, but the QFN packages are a bit harder to solder, they will require the use of solder paste and a hot air soldering tool).  These parts have a few more I/O pins, and extra serial ports.

If you are using ‘bare’ AVR chips in this fashion, rather than the Arduino Uno, there are special Arduino board profiles available here.  The Minicore profile supports all of the 28/32 pin processors including the new ATmega328PB.  The MightyCore profile adds support for the 40/44 pin AVR chips, and the MegaCore profile adds support for all of the 64/100 pin variants.  There are a few other profiles available for some other less used AVR controllers.  The MegaCoreX for the Xmega parts looks interesting.

The link to the various ‘core’ profiles includes sample wiring diagrams.  There are several speed options available including the usual 16mhz, as well as 8mhz, 7.3728mhz, 14.7456mhz, 18.432mhz, 20mhz, and a few others.  The ‘oddball’ frequencies are special ones than divide down exactly to standard baud rates.  Crystals for these frequencies are quite common.  The frequencies above 16mhz are overclock rates for some of the older AVR processors (but still might work).

You’ll need some kind of programmer to flash the bootstrap onto your chip, which will require you to wire up the standard Atmel 6 pin ISP connector (see the sample wiring diagram provided with the core profiles).  For any of the AVR chips with 64K flash or less I recommend Adafruit’s USBtiny for $22.  If you want to use the larger AVR procssors with 128K or more flash, or any of the XMegas,  you’ll have to buy a programmer from Atmel-Microchip, or a suitable clone.  Another option is to use the Arduino Uno with a suitable sketch as a programmer (example on the Arduino website ).   However if you really need that much flash space, maybe you should be considering one of the ARM based Arduinos, but that’s another story.