Category: Electronics

Cloning the Fluke T-Pak

I own a Fluke 87V meter. It has more buttons and features then you could ever hope to shake a stick at. It’s probably an overpowered choice for what projects I’ve done but since I never quite know what I’m going to end up working on, I feel its better to be over rather then under prepared. I bought it because of my dad’s Fluke 83. He’s had that for longer then I’ve been alive and I wanted a one and done meter as well.

One of Fluke’s accessories for their meter line is the Fluke T-Pak, which allows you to hang the meter from any metal surface, by means of magnets.

I was browsing thingiverse, and came upon a clone I could 3d print.

So, I commenced to print the insert. Once I had printed the insert I needed something for the magnets to press in to. I had to try a few different magnets to get the size that I needed, but finally settled on these magnets from grainger. I did have to epoxy & press them into the insert.

The end result is that for about $10 of materials I had successfuly cloned the fluke t-pak. With fluke charging about $45 for theirs, well I definitely had enough left over for a cup of coffee at Starbucks to write this post. What a day to live in. 3d printing is revolutionizing our world, whether we like it or not.

And in action:

Download the Base STL for free. Viva la Revolucion!

Ham Shack-In-A-Box

What’s the point?

Go boxes exist across for a spectrum of purposes. Perhaps you have a sewing box, or a toolbox, or a box with everything required for D&D. By doing this, you have everything needed for that particular task and can be ready to go within a few moments notice – or not have to get everything collected for Friday’s game and you’re already late. Building a ham radio go box is no different – you can grab the unit, head out the door and and once on site have everything you need to operate.

I am primarily a portable operator (as a result of my HOA) who must set up each and every time. With a go box, having all my radios are mounted in a single portable box with the radio gear and power connections set up means I will have much longer to operate – and that much more isn’t left to chance.

I was inspired to build my go-box after joining the Ham Radio Go Box group on facebook. I ended up throwing my new 2m mobile in there as well as a result of starting to run my club’s monday night net. Here are pictures and remarks of the process.

What’s in the Box

Check out the for pictures. In the go-box, I have

  • HF + 2M/440 by the Yaesu 857d
  • MFJ 929 HF tuner connected to the Yaesu
  • 2m/440 + Crossbanding from the Alinco DR-735t
  • Built in illumination for dusk or after operations
  • Built in cooling for both radios
  • Onboard 120V power conversion and a power monitoring system for amp load and voltage (voltage is monitored on battery power)
  • USB Phone charging

Build Log

I drew an initial layout in cad to determine if I should purchase a 4u or 6u rackmount case. The rackmount system comes from the portable audio world and specifies a certain amount of space and a mounting system. Trying different variations, it was decided that a 6u box would provide for all the equipment I had currently, and some future expansion. I decided that purchasing a commercial rackmount would give me better results then building my own box as I have seen some do.

Ultimately, I selected the SKB 6U Roto Shallow Rack unit over a comparable Gator Box (or eurolite) for two reasons. The first was that the SKB features an internal gasket that while it won’t make the water proof, will certainly help keep out the spirit dampening rain storm. The second was that the SKB was better reviewed then any other rack mounts I had found. The additional sturdiness of the unit was worth the additional expense. I avoided the particle board solutions by Eurolite & Musician’s Friend due to the weight. Both the wood and plastic boxes are flight rated so there should be negligible difference in their durability with the weight of the poly boxes being at least half the weight of their wood equivalent. Radios & other things will make the box heavy enough on their own. Then, I needed to go from the vertical pillars of the rackmount system to a horizontal surface to mount the radios, tuner, and other gear. To rack them into the go-box, I ordered 1u racks from Navepoint. By ordering directly from Navepoint I saved about $2 each rack, exchanged an email for another $5 off, and still had free shipping. Much cheaper then purchasing from Amazon

I used the mounting brackets provided by yaesu and alinco for their radios. No reason to reinvent the wheel for a custom solution when what was provided works well. The radios were mounted in the slots in the navepoint shelves with the brackets that came with the radios from their manufacturers. You’ll note that at times the radio shelf is clamped a small masterforce vise. This method of keeping the shelf vertical to work on it works fairly well, especially when you let gravity work to your advantage. This is my go to method for handling the shelf when it is outside of the box.

A Blue Sea Systems 6 Circuit With Coverwas sourced from amazon. This helps protect the radios from short circuits with fusing, as well as providing a neat and clean way of distrubuting the power from whatever source I am using. I should note that its built with metric standards. Because of this, i found it a bit difficult to work with as I have minimal metric tooling. An initial fitting was done to make sure I was on course with the space requirements of everything so far. (I apologize for the potato phone pictures.)

Because of my desire to run the system from a battery, I ordered DC Shunt Monitoring System from amazon. I chose this particular model as opposed to the some of the meters around for its low draw – and that I can shut of the monitor and have no draw at all. The system displays the current voltage of power system, amps in use, watts, and watt hours. I needed a way to encapsulate the shunt, so I designed and 3d printed a shunt box that would allow me to mount the shunt in any orientation. The bottom of the shunt box has two hex hole for a 6-32 nuts to press in. The top has holes for 6-32 fasteners to fit through and tighten via the 6-32 nuts. The center hole is to bolt the shunt mount on the frame with a 1/4-20 bolt. STL below. There are tunnels for the main power wires and the display relay wires.

To mount the monitoring display, the power switches, and a USB charging port, I needed a small panel about the size of a 2u panel (3 1/2″ x 19″). The layout of the switches, power display, USB Charger, and control switches was mostly laid out on the fly. After layout, cutting, and test fits the board was sanded through to 400 grit and stained. Rustoleum Spray Lacquer was used as a protective coating. I found that laying the piece out horizontally and using heavy coats resulted in the best surface finish.

Each function of the box (such as the radios, the usb charging ports, the monitoring display) can be switched on individually. I sourced a number of 13.8 VDC 25A switches from Digikey instead of using lower amperage switches and relays – again with battery powered operation in mind. Because the switches were designed to be mounted in thin plastic, not plywood, I needed a way to engage the locking tabs on the switches on the board. Switch mounts were designed and 3d printed to engage the locking tabs on the switches and screw into the face of the board. The monitoring display was also made to be mounted in thin plastic or steel, so a frame for that was also designed and 3d-printed.

To keep the wiring neat and tidy as I run it to the switches, power supply, and more small wire mounts were designed and printed with my monoprice. An 8-32 nut is pressed into the slot, a #10 fender washer is placed in the top, and then it is bolted onto the tray with a 8-32 x 7/16″ machine screw for wires to run through. This helps keep the wiring tidy and supported.

Adding a feature I probably don’t need, stick-on LED tape was installed around front of the box. First the surface is prepped with isopropyl alcohol and then allowed to dry. The LED tape is applied, leaving the power leads in a supposedly convenient position. Deans Connectors were ordered to allow me to connect the switching panel to the LED tape. With these connectors installed, it becomes trivial to disconnect the lights from the switch board. High quality adhesive shrink tube was applied over the solder joints to protect against shorts.

After this, I began the final fit up and cable management of the wiring inside the case. This was fussy, test, trim, retest, retrim, crimp, retrim, install, remove work that consumed the better part of four days of work. Cable management is an important part of any job and I didn’t want wires hanging in loose bundles looking like garbage – hence printing and installing the wire mounts. Here you can just see the power feeds for the radio fitted over the top of the shelf. They are then fed down through the slots in the trays to each radio. Later, I realized that I needed to open up the slots as an powerpole can’t be pulled back through. Two of the ventilation slots were cut to form a generous slot to pass the powerpoles through. These were cut with a dremel, and then some hand filing to clean up the holes. I also needed to remove a section of the top rack on the side so that wires could pass out from behind the distribution box and make the required connections. Again, this was cut with a dremel and then hand filed.

I had to decide how to hook up the radios – whether I was going to use the factory connectors or powerpoles. I ended up with a mix of the two. I removed the alinco connector and switch the radio directly to Anderson Powerpoles. For my 857, I decided to keep the yaesu connector because of the brown wire (a stupid item imho but best to leave it). Powerpoles were installed on the drops, then a generous coating of dielectric grease was applied. I’ve read that powerpoles corrode quickly so this will help keep them from oxidizing without damaging the ability of power to flow across the tabs.

Axial fans were ordered to provide additional cooling to the radios. The fans from digikey were selected to to provide maximum airflow with a low 38.5dBA noise. If needed, I can mount a rheostat to slow the fans and lower the noise, at the cost of airflow. A fan mount was drawn in cad, and a shop favor called in for the panel to be cut with a water jet. Once it came back from the shop, a coat of rustoleum professional grade primer and then rustoleum gloss black was applied. I refuse to utilize krylon paints in my shop. I broke a fan blade just by tapping with with my finger, so I clearly needed to provide some protection to the fan blades. A fan cover mirroring the style of the grid on the fan mount was designed and printed. I reasoned that the fans could push no more air then they could pull, and mirrored the design of the fan mount. To save print time in the future, I redesigned the guards to have a sleeve and cover. While the sleeve adds slight complexity to the walls and increases their print time, it will save roughly 3 hours should I need to redesign or reprint from breakage the guard grid in the future. Here are the sleeves, and the first & second iteration of the guard. Printing with just shoulders pressing against the fan saves an hour of print time on the monoprice.

Small rubber grommets were ordered and 3/32 holes appropriate for the grommets were drilled. Grommets installed, the wires were passed through the side of the guard, and then wired in parallel to a deans connecter which was then hooked to the appropriate circuit. As will the led lighting, this makes it easier to service various parts of the box. The fans are attached with 6-32 bolts and acorn nuts for a finished look. The fans pull air from the rear of the case and push it towards the front. The user of the go-box experiences a slight breeze.

A “rack” of sorts was designed and printed for the MFJ-929 HF Tuner paired with my Yaesu 857d. This rack barely fit on my monoprice – I had to set the bed size to 121mm x 121mm and get rid of the brim to print these. Taking advantage of rapid iteration through 3d printing, here is the mark 2 version of the tuner mount mount, which loses a mounting hole on the base, and eliminated the need to drill and tap the side of my tuner as I had originally planned. A slot that fits to the center screw on the side of the tuner helps center & retain the tuner in these mounts. Then, a sliding armature was designed that will insure the vertical retention of the tuner.

With the initially printed arms, I had issues with the print warping, and the arms tilting back. I lost some faith in the retention ability of the arms because of this. I initially planned on printing the arms in a way that they couldn’t warp from heat differences as the layers were applied. I changed from the initial arm design to Mk 2.5 to help reduce the print time, and to make things look nicer. After a test print with the arm at about 15° on the print bed I decided I didn’t like the results when I cleaned up the print. So instead, I printed two more arms, gently heated the pla prints, then pressed down with a wood slat to intentionally warp the print so that when bolted onto the mounts, they would squeeze down and against the print. Mk 1 & Mk 2 below.

The fan panel makes it harder to get to the pl-259 jacks on the back of the radios. To make it easier, I ordered and installed some right angle adapters to the radios. The 857 was connected to the tuner with a cable that has a right angle connector.

Closing Thoughts

At this point, I’m posting the build log. I will have to make a few updates for things such as integral power supply, hand mic mounts, and the smaller 2M antenna I’m building to keep in the go-box for deployments. However, the go-box itself is practically done.

There are a few things I will do differently for the next build. I would have a smaller switching section. The parasitic draw of the radios is not enough to justify the cost & trouble. If I was doing a SOTA where I had to hill climb for this, I would take a Yaesu FT-817nd or Yaesu FT-818. Still, for this box I think it all works well and I am in no hurry to tear everything apart to make Mark 2. Even though this is less of a go-box and more of a shack in a box I’m satisfied with the result.


Go Box at Field Day

The go-box’s first deployment was the ARRL’s 2018 Field Day. Note that the tuner is retained by string and that the power supply is external. I simply ran out of time to get everything done.

Operated with my W4KGH End Fed Antenna (Doc 1, Doc 2) with 9:1 Unun, 55’ radiator & counterpoise. Worked well on 40M. 80M was barely able to tune. The noise floor for 80M was S5-S9 though so I was unable to hear anyone.

Random At The Bench

I had an issue with the amperage display reading incorrectly. Here I am verify the wire and testing its reading against my fluke 87V.


Ordered Parts

  1. SKB 6u Shallow Rack
  2. Blue Sea Systems ST Blade Fuse Block
  3. NavePoint 1U Racks
  4. Switches
  5. PowerSupply
  6. DC Shunt Monitor
  7. 12V Warm White LED Strip Lights
  8. 18 Gauge Stranded Hookup Wire, White
  9. 18 Gauge Stranded Hookup Wire, Black
  10. Deans Connectors
  11. Shrink Tubings
  12. Case Fans
  13. 90° PL-259 to straight PL-259 cable
  14. 90° UHF adapters
  15. Rubber Grommets

Printed Parts

Note: I have chosen to provide many of the solid model STLs for the 3D Printed Parts I used. 3D Printing is an incredible technology, and I amazed to be able to use it so easily. However, I provide these STLs without support. I may have suggestions or warnings but they are provided as is. I hope that they are useful to you, but they may not be.

  1. Switch Plates
  2. Wire Guides. Note – max capacity is 4 12 gauge automotive wires. A 8-32 x 7/16″ bolt will rack these perfectly with no interference to the wires with a .050″ fender washer and a 14 gauge steel shelf.
  3. DC Shunt Box STL’s
  4. Fan Sleeve
  5. Fan Cover
  6. Tuner Mounting Fixtures

Creative Commons License
These STL’s are licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. I do not certify anything other then loosing your beer money over these. They may or may not be useful. Remember, only Hu can Prevent Florist Friars!

Building a Ham Radio Power Supply

Ham Radio Isn’t Cheap

Much like shooting, ham radio is expensive. I think all fun hobbies are. But after spending $820 for the radio, I wasn’t in the mood (or the financial state) to drop another $100 to $150 on an Alinco Power Supply. Slick as spit, but not worth it.

So, here is what I came up with:

My power supply has the following features:

  • Hacker cred. I put it together, and it looks nice and works great, on 2M at least.
  • Dual USB ports, for keeping a phone topped off.
  • A cigarette lighter, for powering/charging a baofeng or anything 12V compatible.
  • Dual Anderson Powerpoles on the rear, for the ham’s favorite 12V connector
  • Uses a standard computer power supply cable.

So, here is my Bill of Materials:

A few build notes:

  • I crimped the powerpoles using my standard channelock wire strippers and then soldered them with my hakko. This gives about as good as a connected as you can get.
  • I used standard spade connectors (though mine are from Menards), again crimped and soldered, to connect everything to the power supply unit.
  • Most ham radios expect 13.8VDC, instead of the 12V this one was outputting. That’s okay, there’s a dandy reostat you can use to adjust the output power. I had mine set for 13.81V and its drifted to 13.84/5. I suspect it has to do with the construction and actually powering the unit up. However, my 857 will tolerate a +/- 10% range, so eh. I’ll adjust it again the next time I fire it up.
  • Take care when making the AC Mains connections. I am using a cut\trimmed piece of a PC power cord, with crimped and soldered spade terminals connected to the socket and to the power supply unit. I used some push on connecters to make a removable/solid connection to my socket, then put heat shrink over the arrangement to make sure I had removed and electrocution hazard, as best as possible. 14VDC will tickle, 120VAC will kill, and hurt the entire time.
  • Cut outs for the Chassis mount and PC powersupply socket were done with an x-acto knife, a ruler, and a little bit of caliper work. Everything fits perfectly. Lay out the holes you need, then visually check the marks are in the right place. Make light passes with the x-acto to cut through the plastic of the dry box.
  • This is such a gadgety thing, but it makes doing zip ties so much easier, tighter, and with practice the cut offs cleaner.

The total cost of the arrangement? Not counting the sundries I had on hand, $54.04. Not bad, a third of the cost and quite a bit more fun. You could do this even cheaper if you skipped the power powerpoles and the other features, but charging phones is good. When I first made it, I had the radio and a cut off power cord running directly to the power supply unit. It worked, and worked well, but I wanted to make things cleaner for sure.

Questions? Comments? Leave them below. 73, and good night all.

Edit: I posted this to /r/amatuerradio and generated a fair response. I would like to highlight Megas3300’s RF Choke. This is probably needed for mine as well, but so far I’ve only used this on VHF. A proper HF antenna system awaits.

Icom IC-W32A: A Work in Progress

This is contingent to my “Workin’ the Birds” Series. However, it is a more technical discussion of amateur radio equipment. The primary purpose of this blog is preserve information I want for later. However, I feel that the information contained in these posts may be found edifying for others. If you can’t look up edifying, you are not the target audience of that secondary purpose. A third purpose is a demonstration of my technical skills and abilities as well as communication. It is not working as well as I would like.

I wanted an upgrade from my Baofengs for multiple reasons and the Icom IC-W32A is the radio that I ended up choosing. The W32A is well regarding within the Amateur Satellite Radio community as one of the best. After my post on the high price and poor selection of equipment available at this time, I ended up back tracking into the early 2000’s for my “new” gear. This HT is well loved. Wear spots, but no nicks or gauges. Used, but not abused. The only thing that was missing from what I wanted (better receive, reasonable price, better channel management, S-Scale) was better channel management, though there is the option of skip programming which may prove useful.

The bad is being an ebay radio (and 10 years old), I knew I would be needing a new battery. With this particular auction I didn’t get a charger either. At this moment in time, the charger missing is a bad thing. I don’t know if the radio will even turn on. While I was willing to risk what I did on the auction, I wasn’t ready to double the bill to fail. I need to know if this thing will power on and transmit. I was able to get around this though, with an adapter from RadioShack. Two options:

Since I have all of components for option 2, I went with that. The primary reason was the low cost – $3.50 and a bit of wire and solder. You could buy an official Icom Charger, but if this thing functions well, I’ll be switching to this lithium-ion battery pack. What a waste to get the official Icom option when I’ll use it … once.

After looking around the manual and talking with people on reddit and the AmSat mailing list, I was able to determine the polarity and power output of the plug. 12V, center positive.

After charging, the radio powered up! Oh joy. I at least have a reasonably priced scanner now. Except tuning to a NOAA Weather station, I do not have audio output. Plug in some headphones, and I have sound. Great. This could be either a broken speaker, or a broken headphone jack. Without the headphones, I have a working mic. With the headphones, I do not. For now, the solution is to find a reasonably priced handset to plug in. This will work until I have checked everything else out, and insure that the radio is worth my time to repair further. It will also provide inexpensive replacement parts. The replacement will be here Monday (4/18) and I will attempt to check into my ham club net with the radio that night.

That’s all I have for now. I’ll leave this post linking various resources and information that I found while waiting and getting the radio to function to this point.




Borrowing from my podcasts, this post is not sponsored by our employers, employees, who or what have you. All opinions expressed have been, are, and always will be our own. Said opinions expressed on the show are believed to be well reasoned and insightful. If you find a topic mentioned on the show interesting and decide on further action, then it is your responsibility to research, consult your doctor, lawyer, significant other, etc and understand the full risks of such an action. Providing a link to a resource online does not certify the usefullness, safety, or reliability of the content or providers on the other side.

The information in this post is semi-technical and capable of damaging\ruining\destroying your prized transceiver. It’s not my fault if you turn it into and efficient boat anchor.

Minor Update

I’ve found that filling a bit off the bottom of the plug from radio shack makes it connect more reliably.

Fixing Over-modulation in a Cheap Throat Mic

I purchased this throat mic back in April. When I hooked it up to the UV5R, it was reported that I was over-modulating the mic. In layman’s terms, the mic was so sensitive that it was picking up my voice so well it was “overdriving,” or clipping the audio. You can see a fair example at the beginning of this youtube video:

So how to deal with the over-modulation in mics? If you have your Technician’s license, you know that this is one of the questions on the Amateur Radio Technician’s test. The answer is to move the mic further away from your mouth. But throat mics use a piezo element which translates vibration into an electrical signal. So, to work, they have to be touching the source of the vibration.

The solution is to dampen the vibration. One way to handle this is to rotate the throat mic about your neck so its not directly setting over your voice box. But, in my case, it wasn’t enough. To much low end in my voice, I suspect. In the end, the solution I employed was to put some theraband between the cup wall and the piezo element in the cup.

Theraband is basically rubber banding. Removed from sunlight, it doesn’t break down like a regular rubber band will do – an excellent quality for our intended use. Jorge Sprave uses it for his ridiculous launchers. I had some left over from a previous infatuation. If you don’t have theraband, you can use foam sheeting. I actually wanted to use the foam sheeting, much like this amazon product, but all I had was theraband. The idea was to reduce the amount of vibrations that the mic can “feel” by adsorbing some of the vibrations produced by speaking.

In the photo of the throat mic, the piezo element is located in that left hand cup. You can take it apart by removing the two Philips head screws on the inside of the band and gently pulling the cups apart. Then cut a piece or theraband or foam sheeting into a circle (a nickle is about the right size) and place it in the cup in between the piezo element and the inner wall that will be contacting your throat. Put the cups back together and then screw the screws back in. Be careful – the cheap plastic strips easily. I ended up needing to use some black electrician’s tape to hold mine together because I managed to strip out the screw holes and then lose one of the screws. I actually only needed a single piece of theraband to bring the mic into a usable range.

I used it to check into the local repeater net earlier, and heard no complaint. I’ll have to check with the fellow that pointed it out, but if I’m still over-modulating I’ll just place another coin sized piece of theraband between the cup and the piezo element. This is probably my favorite mic system to use. The acoustic tube makes for discreet listening and the mic needs to be directly on the sound source so it won’t pick up background noises.