Category: Electronics

Electronics: circuits, making, commercial and home-brew

Ham Radio

CQ CQ CQ de N9QQB… Say what?

“CQ” is the ham radio signal meaning “I’m looking for someone to talk to.” and N9QQB is my FCC-assigned callsign, for ham radio. So it means, hey, let’s talk. My wife has her own callsign.

Amateur Radio is an exciting hobby with a huge array of modes and bands to explore. You can chat with others around town from your home or vehicle, or converse with people in other countries. Voice modes are popular, with a variety of types available. Morse code enthusiasts abound- there’s no better way to punch a signal through huge distances and difficult atmospheric conditions. But the requirement to learn Morse code to get a ham license was done away with years ago. Many hams use various digital modes, which also travel very far, and even digital voice modes. Hams are also allowed to transmit images and video too.

Are you a volunteer? Several organizations specialize in assisting public service, law enforcement, and disaster relief organizations, providing communications support in impacted areas.

Amateur Radio is a hobby, but one that requires a license. Amateur radio is regulated under FCC Rules Part 97. Getting a license requires passing a multiple-choice test, but you find the questions (and the answers) online, so you can study. There are hundreds of study guides available for the various license classes. Each class requires its own exam, and each entitles you to more privileges on the air.

Technician Class: This is the entry-level license type. There is a pool of 650 questions in the exam, and when you take it, you will be asked 35 of those questions. The entire pool is published, and available to study. The fees associated with the licensing process are small. The bands and modes available to the Technician Class licensee are used mostly for local, statewide, and regional communications, and under good band conditions, can cross the continent.
General Class: This next level license allows a lot of privileges on bands well suited to world-wide communications, as well as the Technician Class ones. You must hold a Technician Class license first, then take an additional 35 question exam. All possible questions are published and freely available.
Amateur Extra Class: This license class conveys all available U.S. Amateur Radio operating privileges on all bands and all modes. Holders of a General Class and Technician Class license and take a 50 question exam, and if passed, receive the Amateur Extra license. The entire question pool is published.

More information: The American Radio Relay League is the education and advocacy resource for Amateur Radio, and is a vast trove of information. Their Licensing, Education & Training section is an excellent place to start.

Computing Electronics Technology

USB3 Extension Box

Newer computer cases often have all the USB connections on the back. That’s fine for some, but I have a very crowded lab, and it’s a pain to reach back there and fumble around trying to plug/unplug equipment. So I created this USB 3.1 capable extender box.

I started with a search of Tiger Direct, Amazon, eBay, and several other of the usual suspects. I was looking for a relatively high density way to mount female USB jacks. They had to be mounted in something with some mass to it, so it won’t skitter around when I try to plug things in, and it needs non-skid rubber feet too. Ultimately, I took the guts out of an old 2400 baud modem. Remember those? You’re dating yourself. That provided the box to mount the USB jacks into. A little aluminum plate, some machining with a drill, punch, and file, and some specialty USB jacks, and Bob’s yer uncle.

BATIGE Dual Ports Square USB 3.0 Panel Flush Mount Extension Cable

These are what the panel-mount USB cables look like; Amazon has them in both 3 and 6 foot lengths.

This is what I used:
https://www.amazon.com/gp/product/B078LXX3MD.

After considerable machining (by hand) of some scrap aluminum…

The final product looks like the photos below.

Tags computing, electronics, USB3

Electronics Technology

Power Supplies 1

Inexpensive Chinese Smart Power Supply Modules

I’ve been playing with small power supply modules you can get from BangGood.com and other Asian retailers. What I’ve found is that you can build a bench power supply that’s lightyears more advanced than my old Elenco Precision Dual Power Supply, for an affordable cost, provided you understand their limitations and use them accordingly. Here’s a once-over on the RD6012. I’ll post another article about operating a little later. I also have a DPS8005, a much less expensive ($35), much smaller 5 amp model. I’ll write that one up too.

The Riden RD6012 is an upgraded version of their RD6006 model. The former is the 60 volt / 12 amp version of the 60 volt / 6 amp product, and now there’s an 18 amp version, the RD6018. Like most of these modules and boards, they feature DC-to-DC conversion, switching regulation, and require a voltage source. This means that they don’t plug into a wall outlet and accept 120 volts AC. A power supply brick designed for LED lighting makes a good voltage source. I have one that produces 60 volts DC at 17 amps, and another that does 60V/10A.

It comes in two flavors, the base unit pictured above, the same thing with a USB connectivity and Bluetooth module included. I bought mine that way, and paid about $90 for. I see it on sale now for $64 in places, You can also buy a custom-desgined housing for it for about $35.

The unit is about 6.5″ wide, 3.35″ high, and 2″ deep, but of course you’ll need a lot more clearance than that at the back. It’s got a cooling fan, so you need air space behind it to keep it cool, and you need some cable clearance.

In the photo above, the WiFi/Bluetooth module is at the lower right. It’s supplied, if you buy it that way, but you have to finagle it into the tiny space allotted for it. I have yet to get the cooling fan to run, even at heavy load, something others have reported too. There’s an input and output fuse soldered in, each next to an empty fuse socket. If you fry one, you can install the provided spare. The input terminal provides two plus and two ground wires, to enhance current carrying capability, and a screw terminal block is included with the kit. The black wire exiting from the top in the photo has a thermistor on the end of it. The unit has a battery charging circuit (that’s what the green binding post on the front is for) but I don’t know if the thermistor is for sensing battery temps while charging, or if it’s an ambient temp sensor. Either way, the temperature is shown in the display.

In any event, you’ll need a DC source, that can supply the current you want, and has an output voltage just above maximum voltage you want to supply. I bought a 10 amp, 60 volt unit under $40 and a 17 amp / 60 volt one for a different project, $65 or so. Look around, there’s hundreds of sellers on eBay selling this kind of thing.

17 amp: https://www.ebay.com/itm/AC-110V-220V-To-DC-60V-17A-Switch-Power-Supply-Driver-Adapter-LED-Strip-Light/333786254482?hash=item4db7360c92:g:BdoAAOSwunJfq63d

10 amp: https://www.ebay.com/itm/AC-110V-220V-TO-DC-60V-Switch-Power-Supply-Driver-Adapter-For-LED-Strip-Light-3D/333783376357?hash=item4db70a21e5:g:ebgAAOSwNNFfqS4o

10 amp: https://smile.amazon.com/gp/product/B079D9KTF7/ref=ppx_yo_dt_b_asin_title_o05_s01?ie=UTF8&psc=1