Monday, December 30, 2013

Homebrew CW Paddle: Cost $0

So browsing around various email reflectors and online communities I keep hearing about how expensive ham radio gear is.  People keep saying that it costs too much to get into HF.  I wanted to debunk that a little.

I have already built a SWL RockMite-40 kit, but I didn't have a paddle to go with it.  So I wanted to build one, and at the same time show what could be done on the cheap.  The paddle that I came up with isn't overly elegant, other than in its simplicity.  My craftsman ship isn't compliment worthy, other than to say that it works.

The parts list is simple.

  • Base moulding corner block laying around, but any scrap piece of 1x4 would work.  
  • Three inches of scrap of 1x2 white pine left over from a different project.
  • One cheapy kitchen butter knife that I found in a scrap bucket
  • Stereo cable from an old set of headphones
  • Some screws from the "misc fastener" bucket

And that is it.  I used basic tools (as you'll see from the pictures, things like a drill press would have made for a cleaner job), nothing special was required.

My tool list was pretty basic also:

  • Power drill
  • Drill bits
  • Hacksaw
  • Screwdriver
  • Pliers
You don't get much simpler than that.  Now then, on to some pics:

Heck, I even took a short video!  This is me keying CQ into a dummy load.  Imagine that, a dummy on both ends of the radio!  ;-)

And, for the nay sayers, here is a pic of a fully functional HF station, ready to rock on 40m.  Total cost:  ~$50

What's that?  You need a tuner?  Well, at 250mW-500mW, I would recommend a resonant antenna instead of a tuner.  But if you must have one, add in the $65 Emtech ZM-2 tuner (which would happily tune a clothes hanger) and you're ready to go.  Total cost for a flexible HF station: $115

Well shoot, you also don't have an antenna either?  Not a problem, we can cover that too.  A 100ft roll of RatShack speaker wire is $14.  Measure out ~31', split it (use a zip tie to keep it from splitting further) and use the rest as the feedline to your tuner (or just cut it at that length and solder it to some 50ohm coax and go straight to the radio). You can find it elsewhere much cheaper, you just have to look around.  You could probably score some wire for free by doing a bit of dumpster diving or asking a local construction company nicely.

Here is a completely portable ready to go HF station, with tuner and antenna, for a total cost of ~$130.

Now, admittedly, it takes some time to put the kits together, and you need some tools to do so, which also cost money.  But most of the tools needed are already laying around the house with the possible exception of a soldering iron, but those can be had cheap, just look around.  If all else fails, a RatShack soldering iron will get the job done for $10 and it even comes with some solder!

After the tools, it takes the knowledge.  Which is the essence of ham radio.  You don't need a lot of knowledge about electronics to assemble the kits, just follow the directions and you'll be done in no time.  But use it as an opportunity to learn about how the radio works!  Then you'll have the knowledge for next time, and you get tackle a bigger project.  Maybe a BitX or something like that!

Which brings us to the crux of it.  After the tools and the knowledge comes the drive.  The desire to make it happen.  The willingness to put effort into something.  If the desire and drive are there, all the rest will fall into place.  And if it doesn't, call me and maybe I can help!

73 and Happy New Year!

Richard, KK4JDO

Friday, December 27, 2013

Enclosure for KF5INZ "Easy Digi" Sound card interface

To follow up on the last KF5INZ "Easy Digi" post, I wanted to show you the enclosure that I made for it.  This post will be more pictures than typing, because it is easier to show than to type.  Plus I'm feeling kinda muddled this evening and am having trouble typing.  Blood sugar must be messed up again...

I decided to use the venerable Altoids tin for this project.  They work great for this sort of thing.  Plus the mints are delicious!

I decided to use 1/8" Stereo jacks for all I/O ports.  I've done this before on a past project and it works well.

I marked the locations for the audio jacks by putting them in the bottom of the tin and marking the location with a Sharpie.

If you look close, you'll notice that the line is a bit higher than the jack, this is due to the pens thickness and ends up giving a perfect location for the jack with enough room to close the lid.  I discovered this method after messing up and putting one just a bit too high.

I found the perfect method (courtesy of Don, K3RLL) for making holes in Altoids tins.  A simple, basic, paper hole punch makes just the right sized hole and leaves a nice clean edge.

You can see where I have tried using a step drill.  Not nearly as clean.  All jagged and full of burs.

Test fitting the jacks in place to verify that the lid would close with the slip ring in place.

 Now to connect the PCB to the jacks.  I started by soldering the wires to the board with plenty of excess wire to reach the connectors.  I then did a test fit to get the proper wire lengths and attached the jacks with the whole mess outside of the tin.  I used heatshrink tube to clean up the clutter.

I used two layers of double-sided tape to hold the board into the tin to avoid any short circuits.  I cleaned the inside of the tin with alcohol before sticking it down.

And the finished product!  The flash made pictures difficult due to the shiny tin, but you can see the cable routing.  This was a quick and easy project from getting to kit to having a completed and usable sound card interface!

Here are the details on the cabling.  The jacks on the left go to the rig, and the jacks on the right go to the PC.  Something like this:

Rig Left (To Rig) Right (To PC) PC
Spkr RX Audio RX Audio Mic
Mic TX Audio TX Audio Spkr
Mic PTT PTT Serial

The columns labeled rig and PC denote what ports the jacks on the interface connect to.

I hope that you enjoyed the little picture show!  Best of luck with your project.  If anyone is interested I will post about how I built the cables.


Richard, KK4JDO

Wednesday, December 25, 2013

Christmas Ham

My wife did the best that she could as far as getting a present for a ham radio operator goes.

A speaker mic for my iPhone!  Who knew that these even existed?  ;-)  What a better way to show off how HamSexy I am than using a speaker mic when talking on the phone!  Of course, now I'll probably ID when on the phone out of sheer habit.  I can see it now:


Mom:  "Hello?"

Me:  "Hi Mom, how are you today?  From KK4JDO"

Mom:  "Ummm, hi, I'm fine?  What were those letters and numbers?"

Me:  "Oh, that was just my call, don't sweat it.  Gotta go!  Love you"

Mom:  "Ummm, love you too dear"

Me:  "Talk to you later, 73, KK4JDO clear"

Mom:  "Uhhhh, bye!"

How absolutely awesome will that be?  I guess it would be less awkward with family than it would be with the doctor or a work call.  Although telemarketers could be fun.  I could give them reception reports and be sure to throw in a lot of hammy slang and abbreviations.  ;-)

Anyhow, what a great present!  I hope that you all had a wonderful Christmas replete with family, friends, and food.  Merry Christmas and Happy New Year to each and every one of you!


Richard, KK4JDO

Wednesday, December 4, 2013

KF5INZ "Easy Digi" Build

Today's post is to cover the quick build of the KF5INZ "Easy Digi" Sound Card Interface.  This was a great little kit.  I can't find the parts separately for what this kit costs.  I can't stress enough what a great value it is at $11 shipped.  The pcb is good quality and the instructions are almost unnecessary it is so easy to assemble.  I think that it took me a total of 15 minutes from opening the package to having a completed board.  I still need to build a box for it, but the board itself was done in just a really short amount of time.

On to the pictures...

The kit came in a typical little yellow envelope, with the parts and pcb in a little zip-lock bag.

The parts are all easy to identify and can be sorted in seconds.

Here is the optoisolator IC and diodes installed .  The polarity of the diode is silk-screened on the board.

Then the resistors.

Then onto the capacitors, all two of them...

And finally the audio transformers.  Quick and easy!

That has it all completed and ready to go, now I just need to build a box for it and build some cables to connect it.  The intent of this board is to connect my 2m rig to my Raspberry-Pi using a USB soundcard to build up an APRS Igate using Xastir and one of the soundcard modems.

I'll do another post once I have it completed.

Thanks and 73,

Richard, KK4JDO

Friday, October 4, 2013

Through the ether...errr....looking glass

Been suffering from the mother of all colds for the last seven days.  Finally feel up to posting anything.

I was working a little PSK31 at QRP power levels the other day, and was rewarded with an email containing a screenshot of my signal.  This is from Michael, CK3NOO, who has quite the interesting website here.  I love getting screenshots of my signal back during a QSO.  It is final proof that I have everything set up right and that I'm not splattering as you see some folks do.

It is really easy to get a screenshot if you are using DM780, all you need to do it hit Atl+PrntScrn and DM780 will save a copy of your screen to a "DigitalMaster780" folder under "My Pictures".

A few weeks before that I was tinkering around on SSTV during the Sunday night Reddit net.  One of the people on the net (I think it was Jeff, NT1K) was kind enough to post the image that I had sent via HF.

I'm not much into SSTV, but it was neat to be able to send this to him sans internet connection, and extra interesting to get to see it as he saw it.  Here is the original as I sent it (before adding callsign):

You can see that HF wasn't kind to it.  Someone else on that net received it in almost original condition and posted that, but it appears that I have lost that one.

Well, that's it for this post.  Time for more meds and sleep.


Richard, KK4JDO

Tuesday, October 1, 2013

And more mesh cross-posts...

September 24 at 5:56pm

The antennas arrived today! 2 x 9dBi and 2 x 5dBi outdoor dual-band antenna (2.4/5.. Now I just need to score some RP-TNC to N adapters. I have enough 5' LMR-400 jumpers with RP-TNC connectors to get all four hooked up. I need to find some nema enclosures to pole mount the APs.

So the question becomes, do I eschew diversity and go with one antenna per AP, or do I hook up two APs with two antenna each. I'm leaning towards one antenna per AP since I'm not going to be serving mobile clients. What does everyone else think?

September 24 at 6:14pm

Today's arrival brings me to the following inventory:

HSMM Mesh "Go-Package":

Site 1:
Cisco/Linksys WRT54G v2 running v1.0 firmware
Cisco 7961G-GE IP Phones running 8.5.4 SIP firmware
Cisco 7914 Extension Module (14 extension sidecar)
Cisco 2940 8-port Managed Swich
Cisco ATA 187 two line ATA
Grandstream HT-286 ATA
Raspberry Pi running Asterisk and Prosody
9dBi outdoor collinear antenna
Rubbermaid Roughneck 18gl Container

Site 2:
Cisco/Linksys WRT54GL v1.1 running v1.0 firmware
Cisco 7961G IP Phones running 8.5.4 SIP firmware
APC NetBotz 420 IP Camera and Environment Sensor
9dBi outdoor collinear antenna
Rubbermaid Roughneck 3gl Container

Site 3:
Cisco/Linksys WRT54GL v1.1 running v1.0 firmware
Cisco 7961G IP Phones running 8.5.4 SIP firmware
APC NetBotz 420 IP Camera and Environment Sensor
5dBi outdoor collinear antenna
Rubbermaid Roughneck 3gl Container

Site 4:
Cisco/Linksys WRT54GS running v1.0 firmware
Cisco 7961G IP Phones running 8.5.4 SIP firmware
5dBi outdoor collinear antenna
Rubbermaid Roughneck 3gl Container

eBay, here I come.  I still need to find:

One more 2-line ATA
Two more NetBotz cameras
Three more PoE injectors to power the APs
Three more data switches
Four nema boxes to pole mount the APs
Four phone patches of some description
Four sturdy collapsible poles
Four power strips

Once that these are found I will have a deployable mesh solution for Field Day or EmComm duties that will support Voice, Video, and Data at four locations (assuming line of site between the antennas or additional mesh hops).

I will keep looking for more WRT54G routers and antennas for mesh infrastructure duties. Although I would suggest something like the Cisoc 1552e APs for actual mesh backhaul. I worry about having a WRT54G atop a tower.

Saturday, September 21, 2013

Emtech - ZM-2 ATU Build

As you have probably figured out for yourself, I have finally gotten a chance to post my build pictures for the last couple of projects.  This topic of tonight's post is the Emtech ZM-2 QRP antenna tuner.

This is a "Z" match tuner,  basically meaning that it has two variable capacitors with no tapped inductor coil.  It does however have a neat built-in 1W dummy load and SWR sensing circuit.

From their website:

"ZM-2 ATU (Antenna Tuning Unit) - Order The ZM-2 is a state of the art Antenna Tuning Unit. It is not just another standard tuner circuit repackaged. The ZM-2 has no inductance switching to mess with, just two variable capacitors to tune. And most times that is 1 to 1 SWR where other tuners only get close.

Just What Will It Tune?

The ZM-2 tunes wire antennas: Random, Long, Short, "that's all I had"... It tunes BALANCED fed antennas such as Loops, Deltas, Dipoles, Verticals, V's! From field reports it has tuned: House Gutters, Window Frames, Swing Sets, Bedsprings, etc. It tunes out mismatch in COAX fed antennas to make the radio happy.

Is It An AutoTuner?

No, the ZM-2 is not an autotuner. But it still tunes fast! Approximate tune time on a strange new antenna is less than a minute!

What Bands Will It Tune?

The ZM-2 will tune all bands from 80 to 10 meters.

Is It Hard To Build?

An evening project for many, maybe two evenings for others. Easy pictorial assembly instructions. 

There is one large toroid to wind, and one small one to wind, but they are probably some of the easiest ones you'll ever do.

What Is Included In The Kit?

Everything but the elbow grease, solder, and tools! All parts are furnished including a front panel label as shown and either BNC or UHF (SO239) connectors. We include large knobs to help tuning because the ZM-2 tunes so sharp.

How Much Power Will It Handle?

Maximum Power is 15 Watts.

What About Weight And Size?

The ZM-2 is a compact 5-1/16" x 2-5/8" x 1-5/8" and weighs only 8 oz. Great for backpacking."

So, on to the build:

The kit comes with a Radio Shack style project box with a pre-punched aluminum plate, which through me off at first, but it turns out pretty nice.  The components are bagged for easy identification.

The part that will give some people heartburn is that you have to wind some toroids, and one has a lot of taps which makes it a bit tricky.  However, I was able to do it have never wound one before in my life.  And if I can do it, believe me, so can you!

There are two toroids with this kit, the one pictured below, and another smaller one that I didn't get a build picture of.  It was far simpler than this one even if a bit smaller.  The included instructions walk you through it step by step, although I think that it would have been much easier had it been a color picture.

Here is a picture of the second toroid already in place in the kit.  Not much to it as you can see.

There are no PCBs in this kit to worry about, it is all "point-to-point style".  Which means that you connect the lead of one part to the lead of the next one directly.  It can get cluttered, but it works.


More pictures of the assembly.

Different angle of the BNC side of the kit.

And a different angle of the balanced line side.

The front of the tuner is covered with a paper label.  I was fairly disappointed with it to be frank.  It is a typical Avery mailing type label.  Normal paper, not laminated.  The instructions suggest a layer of clear lacquer, but how many folks have that laying about?  I ended up using two layers of clear packing tape and it turned out fairly well.  In any case, you need to be REALLY careful when tightening up the components that you don't twist the paper.

But it looks pretty good when you get it completed.

And, just for a size comparison, here is a picture of it next to my Pixie and RockMite-40 radios.  Consider the pictures of my wife and Grandmother in the background a familial bonus and just ignore the clutter on the rest of the desk.  ;-)

The kit is fairly easy to construct, even for the novice.  It is a bit different due to the whole "point-to-point" style technique used, but it turns out alright if you keep a close eye on what goes where and making sure that there are no shorted out leads.

I connected it to my G5RV and was able to get a match on 7.040MHz with the RockMite-40 in just a few minutes.  Just like any tuner, tune for max noise first, being sure to check each of the three added capacitance settings (there are only three options with this one, +0pF, +250pF, +500pF).  After you have max noise, switch into tune mode and key up with low power and tune the two capacitors until the LED gets dim or goes out.  Be careful as the tuning is sharp and the LED might only blink briefly if you twist the knobs too fast.  Once you have the dip, switch back to operate and have at it!

It also worked great on a EFHW on 40m with my FT-817ND, which is a feat as these types of antennas can be a challenge to some tuners.  I was also able to load that wire up on 15m (of course) and 20m as well.  
In summation, it is a fun kit to put together and a nice break from more traditional kits.  Don't be afraid of winding toroids, they are not that bad.  For $65 you can't beat it for price and it works a treat.


Richard, KK4JDO


Special thanks for Steve, WB6TNL, for giving me a better understanding of how this circuit works and correcting my errors on build terminology!  Here is a copy of his extraordinarily helpful email:

"Hello Richard,

I checked out your blog and the photographs of your ZM-2.  Nice work on the tuner and the photography.  I'm certain there are plenty of QRPers out there who have wanted to see just what's inside the ZM-2 and your well illuminated and close-up photographs certainly do that.

There are a couple of nits I'd like to pick, however:

You said that a Z-Match tuner basically means that it has two variable capacitors with no inductor coil.  It does have an inductor; that is what the larger of the 2 toroidal coils is for.  More accurately, the primary, resonant winding of the Z-match inductor does not have multiple, switched taps hence it requires no switching to select bands.  The central theory it is based upon is that of the old "multi-band tuner" circuit (which was not an antenna tuner) made popular back in the 1950s and 60s.  Back then, multi-band tuners were very often used in mobile tube-type transmitters for interstage tuning and final amplifier plate matching networks.  The reason that no band-switching is required is that the ganged, 2-section tuning capacitor and the main coil winding are selected so that the resonant point of the circuit only hits one ham band for a particular setting of the tuning dial.  The larger winding resonates on the lower frequencies and the smaller winding the higher.  Impedance matching is performed by the switched input variable and fixed capacitors.

You described the construction as "dead bug".  Actually, that method of wiring is called "point-to-point".  "Dead bug" commonly refers to construction using integrated circuits (and sometimes transistors) where the components are glued to a substrate with the leads (legs) pointing up, like a dead bug.

Actually, tuners and QRP mix very well since it is extremely important for us to get maximum power into the ether and matching the transmitter to the antenna system is paramount.  Sure, some tuners are not as efficient as others but the Z-Match is not one of them, provided that the impedance of the antenna system falls within its transformation ("matching") range (typically 30 to 500 Ohms depending upon the load reactance).

Anyway, thanks for sharing the great blog page and best of luck with your tuner.

73.......Steve Smith WB6TNL
           "Snort Rosin"

Friday, September 20, 2013

Small Wonders Labs - Rockmite-40 Build

Since I posted about my Radi0Kit-140 build-out yesterday, I figured that I would post pictures of my Rockmite-40 build today.   For those not familiar with the RM-40, it is another QRPp CW only radio.  It is crystal controller (in this case, the crystal is for 7.030MHz) hence the name RockMite.  Again, being a QRPp radio means that it puts out less than one watt.  In the case of this radio, about 750mW.

Unlike the Pixie, this transceiver has a sidetone so that you can hear your code as you send it, as well as an adjustable transmit offset.  I decided to go ahead and get the connectors/controls option, PicoKeyer upgrade by Ham Gadgets, and a MityBox by American Morse Equipment at the same time that I ordered the kit.

About the transceiver kit from SWL's website:

"The Rock-Mite is a crystal-controlled direct-conversion transceiver available for 80M, 40M, 30M or 20M.   It features an on-board 8-pin PIC microcontroller which controls a T-R offset on key-down. A brief tap of a pushbutton control switch reverses the offset to yield a second operating frequency. Pushing and holding on the pushbutton activates the speed adjustment routine for the built-in Iambic keyer. If you'd rather use an external keyer or straight key, there's a 'drop-through' mode which allows use of an external keying source.

You'll note in the image above that the Rock-Mite uses two crystals. The first is used in the local oscillator for transmitter and receiver. The second is used as a receiver front-end filter. This crystal significantly reduces the SWBC energy present at the receiver mixer; as a result, unwanted SWBC reception is dramatically reduced.

The Rock-mite uses one surface-mount part with fairly large spacing. There are no toroids to wind, so assembly should be a snap! The Rock-Mite uses subminiature epoxy-encapsulated RF chokes instead of toroids."

About the PicoKeyer from their website:

"Here are the main features of the PicoKeyer-RM:
  • Low current operation - typical sleep current well under .1µA, only 1-2mA when keying.
  • Direct replacement for your Rock-Mite's or Hi-Mite's original keyer chip, no modification to your Rock/HiMite is needed.
  • Simple one-button "menu" interface
  • Setup and message entry using your paddle
  • Speed adjustable from 5 to 45WPM from the paddle - or add an optional speed control pot!
  • Variable pitch audio sidetone
  • Adjustable weight
  • Selectable Iambic Mode A, Mode B, Ultimatic, semi-automatic "bug" or straight key operation
  • Automatic straight key detection. Both message memories are available for playback even with a straight key! (You will need a paddle to record messages, though.)
  • Beacon mode! No switch or jumper required for beacon mode, just insert a special prosign character into your message. Great for calling CQ!
  • Message pause with auto-resume - You can insert a pause to manually send RST or other information in the middle of a saved message.
  • Auto-incrementing, resettable QSO/serial number can be inserted into your messages for contests. Send them with or without cut numbers (0 and 9 only) and leading zeros!
  • Greatly improved tuneup mode for hands-free steady carrier or 50% duty cycle pulsing.
  • Two message memories hold up to 100 characters each. Message memories can be chained to make one 199-character memory.
  • Paddle switching - effortlessly select left or right handed operation without switching wires or turning the key upside down.
  • All settings and message memory is maintained in non-volatile memory, even with power off.
  • "Factory Reset" option to restore all default settings to your PicoKeyer-RM.

The PicoKeyer-RM uses FLASH and EEPROM memory to store all settings and message memory, meaning NO backup batteries and NO lost settings."

And finally, about the Mity Box, from their website:

"Custom CAD/CAM engineered CNC hogout enclosure for the Small Wonder Labs Rock Mite transceivers
  • CNC machined from Aircraft Aluminum billet
  • Designed specifically around the Rock Mite boards
  • Absolute minumum size & weight - 2.2x3.3x.875 inch, under 2 ounces
  • Beautiful Blue Anodized finish - very durable
  • Uses standard miniature off-board components
  • Pre-drilled for all components - board & cover hardware included"

And now, for the build-out:

This first thing that I added was the one surface mount IC.  I keep reading about how easy it was, but it was a serious pain in the butt for me.  To the extent that I had to touch it up after completion of the kit due to a bad solder joint.  But I finally got it!

Adding the IC and some capacitors

Adding the resistors

Adding the sockets for the non-surface mount ICs.

Adding the diodes

Adding more diodes since I forgot some...

Adding the RF chokes

Adding the transistors and some more capacitors

Adding even more capacitors

Adding the crystals

And finally, after adding the ground connections for the crystals, Finished!

Unlike the last post I was so excited that I didn't get any video of the initial smoke testing and subsequent irritation as I tracked down the bad solder joint on the surface mount IC.  I have only minimal test equipment, by which I mean I have one off-brand multi-meter and an off-brand capacitor tester.  But the build documentation is absolutely stellar with this kit, TO INCLUDE a really great troubleshooting section.  It walked me through the testing and verification step-by-step until I had a working radio!

Another great resource is the builder community for the RockMites and Minimilist QRP Radios in Yahoo Groups.  I can't say enough good things about the guys and gals on that email reflector.  Great bunch of folks that are always willing to lend a hand with building tips and troubleshooting ideas.

All-in-all this is an amazing radio, especially for the price!  With the connectors/controls, upgraded keyer chip, and enclosure, I am in for about $77 not including shipping.  For that price you get a radio with tons of upgrade potential, a top notch case, and more fun than you can shake a stick at!  Build-out can be completed in an evening (although it took me about three).  The soldering is a little more challenging than the Pixie, but very doable with a little patience.

The receive on this radio is really good, way better than the Pixie in my last post.  It is much less sensitive to BCI overloading, though not immune, due to the crystal acting as a filter on the front-end.  The only downside that I could find was that it is sensitive to microphonics.  If you tap the case you can hear that tapping in your headphones.

The Mity Box case makes for a really nice and sturdy package for the radio, but be forewarned, it is TIGHT in there.  Plan ahead as much as possible when you are ready for final assembly.

To close out this lengthy post, I really do recommend that you get this kit if you are looking for a fun project.


Richard, KK4JDO