Malahit ATU-100 Antenna Tuner Box atu100 Shell ATU100 1.8-50MHz case

Kit is not for the novice! But, if you have several builds under your belt, that should suffice for this level. Winding inductors/ toroids and soldering experience a must! The review from Scouter III was detailed, informative ans spot on to the issues you may face, and I concur with him 100%. Some parts had no use in this kit, and others parts are not supplied at all. Not the end of the world, just be ready to hit the spare parts drawer to complete the tuner. I did add some FT37-43 toroids and 100 nf caps across the buttons and changed out one of the diodes to a 1n5711 on the swr bridge as per the suggestion by one YouTuber. This is a great tuner for the money if you are willing to do some slight modifications. It's usable without the mods, but much better with them. All in all, it was a fun build which provides you with a nice portable tuner for very little money.

I FINALLY got my ATU-100 Antenna Tuner kit and this Tuner Box built after watching several YouTube videos done by previous builders. The Tuner works great and this box makes the whole unit look fabulous! However, I had to re-work some wiring errors I made due to the lack of detailed instructions and the fact that I am not an Electronics Assembly Expert. The difficulty is that there are no detailed Step-By-Step Instructions for this kit. There is adequate information on the document along with the Schematic to enable an experienced kit builder to assemble the kit. However, a relatively new or first-time kit builder probably will not be able to get it assembled. Here are a few things I learned (some the hard way!) - Unless you have SUPER eyesight, use a large magnifying glass/light before you attempt to build this kit. 1. For the Malahit ATU-100 Antenna Tuner Box, the image of the wiring on the back of the green Tune Switch is incorrect. The wire connecting half of the Auto, BYP and Tune switches together goes to GROUND, NOT the + wire as shown in the picture that comes with the Tuner Box. The OTHER side of the Tune switch gets the + wire. 2. The hookup wire necessary to fully assemble the ATU-100 kit does NOT come with the kit! You will have to provide the stranded insulated hookup wire yourself (NOWHERE is this mentioned on Amazon NOR the single Instruction sheet!). A. I used some 18 ga. stranded insulated wire for the initial power connector but the hole in the PCB made it tough to fit that size wire in the (-) PCB hole. The other wire (+) goes to the On/Off Power Switch so there was no issue there. B. I used 22 ga. stranded insulated hookup wire (very flexible!) for the other hookup wire connections that were necessary. C. The Yellow and White wires needed to connect the Auto and BYP switches to the BACK SIDE of the Printed Circuit Board (PCB) must be VERY small to fit into the two tiny PCB holes they must be soldered into. You will need to be very careful soldering these two wires to the back of the PCB because the solder pads are so small and so close together! 3. This is a very compact kit. Use a very small pointed Soldering Iron to prevent overheating the PCB or the already installed SMD components. 4. As another Amazon customer suggested, I recommend building and installing the Toroids FIRST. I also would add to build and install them in their numbered order. Trying to install the Toroids AFTER the Relays are soldered onto the PCB will be a nightmare. 5. Pay close attention to the size and LENGTH of the wire required for each Toroid as stated on the Instruction sheet. 6. As suggested in the instruction sheet, I used Allen Wrenches the described diameter as described to wind the three air core windings. 7. Take your time and be sure you understand EXACTLY where each component and wire should be soldered to the PCB. I initially soldered the four light yellow enameled wires for the Tandem Match Transformer "binocular" toroid into the WRONG 4 holes (underneath it!). They actually go into the four SMALL holes just outside the "binocular" toroid's diagram outline on the PCB. 8. The Electrolytic Capacitors have a very distinct mark on one side. Be sure that side of those Capacitors goes into the PCB hole that shows the white mark on the edge of the circle images on the PCB. 9. Examine the picture of the vertically installed diode as it is shown on the Instruction sheet. Be sure the white ring mark is at the TOP when you solder it into the PCB (you will have to bend that end of the diode's terminal wire down toward the other wire end to install it vertically). 10. If you buy the Tuner Box, BEFORE YOU SOLDER THE SLIP ON TERMINALS ONTO THE OLED, be sure you draw yourself a diagram showing which terminal on the OLED display module is which connection (i.e., Gnd, VAC, SCL and SDA). After you solder the slip-on terminals to the OLED display module, you will no longer be able to read those markings on it! 11. If you buy the Tuner Box pay close attention to how the four green mounting tabs are oriented in the Instruction sheet picture when they are attached to the PCB. 12. If you buy the Tuner Box, when pushing the On/Off Power Switch into the end panel, do your best to keep the switch even and press it straight into the rectangle hole (i.e., NOT one side in before the other!). 13. If you buy the Tuner Box, I suggest sticking a piece of electrical tape or other insulation material onto the back side of the front end panel. This tape will insulate the inside of the front box end panel. This is BETWEEN where the OLED display's soldered slip-on connectors are located and the inside of that box end. This should keep those solder connections from contacting the inside of that metal box end. The Instruction sheet does not mention this. It just didn't make sense to me to risk those solder connection points touching the metallic box end panel and potentially shorting out. I actually used a small file to flatten the sharply pointed solder points to make their thickness narrower and less likely to punch through the tape and contact the metal end panel. As I said, my completed ATU-100 Tuner and Tuner Box works great (the box looks great too!). However, my language during the build process was not fit for human ears! I hope this was helpful to others considering to buy and build this kit and that they have a much better experience building their kit. 73!

Well constructed but need better instructions.

Good quality, all parts included.

Not only did it arrive late, the nuts and spacers to mount the display are missing. The screws to attach the front and back panels are supposed to be black matching the enclosure and the picture but they are chrome. Only 2 nuts provided where 4 are needed for the PL259. 2 solder lugs included for the PL259 but missing for the ground connection. No instruction on how to mount the display and missing spacers, nuts. Otherwise it looks good and nice finish.

I had a sense of trepidation when I bought this case set and the tuner kit: at that price would it really work? Now, months after assembling the tuner and putting it into this case I am delighted. I think this is an excellent tuner for a portable 100 watt or less mobile HF radio. I leave it connected and turned on all the time. I hear it automatically tuning when I change bands for FT8. The display has developed some dim spots, but they're still legible. The case fit perfectly. Only one thing to be aware of and that is to plug in the power plug before turning on or connecting the power supply, otherwise you may burn the fuse.

Both kits lack ANY real instructions for assembly! You better be able to follow schematics and guess where parts go. Color coded wires, forget about it, colors in the pictures do not match. There are NO wires included as indicated in the pics for hookup. Fasteners, nuts and bolts, can be an issue as no sizes are mentioned length wise and if you guess wrong, you will be taking it apart to replace them. IMO this is not for a beginner! Good soldering skills are a must as well as a good soldering station.

Nice box with everything you need to mount your ATU-100. My only complaint is there is no back plate options for the SMA version of the tuner but I knew this before I purchased it. I just made the holes wider to clear the connectors until I make a new plate for now. When wired properly this works just as described.

Was a gift