Test Equipment

Which DMM would you choose?

September 29, 2015 By Dan KB6NU 12 Comments

fluke_87_5_multimeter — The Fluke 87-V is a professional-quality DMM, but at $400 per unit, it might be overkill for the Ann Arbor District Library’s Makerspace.

In November, I will be teaching a really basic class on how to use a digital multimeter (DMM) at the Ann Arbor District Library, which is setting up a Maker space in the library. Not only are they setting up the Maker space, they plan to loan out some basic test equipment, such as DMMs and oscilloscopes.

When they asked me, “Are there specific DMMs and oscilloscopes you would recommend we get?” I first thought of the Fluke 87-V. It’s a professional-quality DMM, but I nearly choked when I saw the price. It costs nearly $400! I searched around Amazon a little more and found the Fluke 115. This seems like a reasonable price for a reasonably-featured and rugged DMM.

Next, I searched Tequipment.Net for their “top-selling” multimeters and two other options popped up:

BK Precision 2709B Auto Ranging True RMS Tool Kit DMM ($90).
Extech 330 Auto-Ranging Multimeter ($53).

The Extech is not a true RMS meter and seems a bit “cheaper” from the looks of it, but at about half the price, it might be a good option.

What do you think? What other models should I be looking at?

From my Twitter feed: Scope tips, GPS 10 MHz reference, digital voice

September 6, 2015 By Dan KB6NU Leave a Comment

Teledyne LeCroy @TeledyneLecroy

Some everyday #oscilloscope tips from our Test Happens Blog: lcry.us/1NuPZ4X 5 pic.twitter.com/QrYcPcpiNP

Sverre Holm, LA3ZA @LA3ZA

First test of Ublox Neo-7M GPS 10 MHz output as @elecraft K3’s reference seems successful – 12$ #GPSDO, #hamr pic.twitter.com/3cwn8RqH56

Jeff Davis @ke9v

Hams Talk Digital via @hackaday hackaday.com/2015/09/06/ham… #hamradio

From my Twitter feed: DIY bar, EE microscopes, $100 spectrum analyzer

August 27, 2015 By Dan KB6NU 2 Comments

Jeff Davis @ke9v
Proto BuildBar in Dayton Serves Drinks and DIY Electronics curbed.com/archives/2015/… via @Curbed

I hope this place is still open next May when I head down to Dayton for Hamvention…Dan

Electrical_Engineer @Saelig
Give a Nerd a Microscope (like Saelig’s <$60 ones) and anyone can hand-solder SMT systems ubm.io/1LyXxGL pic.twitter.com/mKDGS0E1Zi

I may purchase one of these soon, if I ever got to doing some SMD work. Anyone have any recommendations?…Dan

Dangerous Prototypes @dangerousproto
Specan, a reboot of the W7ZOI/K7TAU spectrum analyzer goo.gl/k35LXM

Just what I need…another project…Dan

More antenna analyzers: one DIY, one Italian

August 9, 2015 By Dan KB6NU 3 Comments

I’ve often wondered why there aren’t more DIY antenna analyzer projects out there. Perhaps it’s because developing measurement circuits isn’t easy. An antenna analyzer has to have a signal source as well.

There is an antenna analyzer kit on the market. The VK5JST Antenna Analyser Kit costs about $110 USD. I actually have the kit, and it looks like a great unit, very professionally done, but I haven’t yet gotten around to building it.

Now, there’s an Arduino-based antenna analyzer project. Here’s a photo:

analyzer

It uses an AD9850 module as the signal source. The approximate cost for all the parts is about $40, and you can experiment with the code, if you like.

While I’m talking about antenna analzyers, let me mention another one that I’ve just found out about: the IW2NDH Antenna Analyzer. This unit has a frequency coverage of 2 – 160 MHz, and can be used as an antenna analyzer, signal generator, and a scalar network analyzer. At only $175, this seems to be a very good deal.

Apparently, this started out as an Arduino project. As Maximo, EA1DDO, pointed out on the radioartisan Yahoo Group, there is source code for this project on GitHub, and a schematic is available on the Union de Radioaficionados Espanoles (URE) website.

Back to Basics Probes Series

July 23, 2015 By Dan KB6NU Leave a Comment

This just appeared in my inbox. Should be worth a look if you have a scope and want to learn more about how to make better measurements….

Choosing and using the right oscilloscope probes can be a confusing proposition. There are many kinds of probes on the market with differing functions and electrical/physical characteristics. This series of Test Happens posts covers some of the salient characteristics of common probe types and provides some tips on which serve best in given circumstances.

Part I

The way in which you connect your ground lead can have a big impact on the real-world bandwidth and response of the probe.

Part II

It’s important to pay attention to the inductance added by the leads to the circuit created by the probe’s contact with the DUT.

A Variety of Probes

To speak of an oscilloscope probe is to open a fairly large can of worms. There are many kinds of probes on the market, with differing functions and characteristics. Let’s take a brief look at the four basic probe varieties in this short video.

From the trade magazines: LabView, DigiKey, mixers

July 22, 2015 By Dan KB6NU 4 Comments

30LabVIEW_200x DIY Makers, Hobbyists, and Experimenters Get Professional Software. National Instruments has come out with a $49 version of LabView. According to the article, “Called the LabVIEW Home Bundle, this is a fully operational version of the core NI product that can be used to speed up and simplify experimentation by making programming less of a problem.” I’m not having much success with the software bundled with my new digital scope (more on that later, but it’s been very disappointing), and I know LabView is quality software, so I’m seriously thinking about purchasing this package. NOTE: If you’re a student, you can buy a Student Edition of LabView for as little as $20!

Q&A: Digi-Key’s Larson Looks Back—And Ahead. I found this interesting as DigiKey actually started out as a place for hobbyists to get parts. The CEO says, “In the early days, Ron was a graduate student at the University of Minnesota, and he was a very active ham radio enthusiast. While he was still in school, he put together a kit [of electronic parts] for sending Morse code, and he would sell these kits at ham radio fairs.” Now, of course, it’s a major electronic components distributor.

Understanding Mixers and Their Parameters. While written for engineers, not radio amateurs, it’s not heavy on the math and just might give you a better understanding of mixers and some of the terminology associated with them.

From my Twitter feed: Exploding DMMs, videos for kids, weather sat images

July 9, 2015 By Dan KB6NU Leave a Comment

hackaday @hackaday
Exploding Multimeter Battle Royale wp.me/pk3lN-FTz

Freetronics @freetronics
Harnessing discarded VFDs for Arduino-powered clocks – freetronics.com.au/blogs/news/369… #Arduino

Make: @make
@adafruit introduces super fun video series for kids to learn electronics (w/ Adabot)! ow.ly/Pn62a pic.twitter.com/y7Mku9AkfO

DIY Engineering @DIYEngineering
NOAA Satellite Signals with a PVC QFH Antenna and Laptop – This instructable covers everything you’ll need to get … ow.ly/31bLCg<

From my Twitter feed: RPi laptop, ionosphere, homebrew antenna analyzer

April 21, 2015 By Dan KB6NU Leave a Comment

DIY Engineering @DIYEngineering
Raspberry Portable Pi Laptop – Hi guys! This is a really quick and easy project with a great outcome. The Portable… ow.ly/2X9Yv5

Sverre Holm @Sverre_Holm
Sir Edward Appleton: Unveiling Earth’s Ionosphere – IEEE – The Institute theinstitute.ieee.org/technology-foc…<

OK1RIG @OK1RIG
Si5351A Antenna Analyzer appnotes.etherkit.com/2015/04/si5351… prostřednictvím @etherkit #hamradio #hamr

Learn measurement fundamentals

March 27, 2015 By Dan KB6NU 1 Comment

back-to-basics-dvd Keysight, which used to be Agilent, which used to be Hewlett Packard, is offering a free DVD aimed at providing “a strong foundation in basic measurement techniques.” Here’s what they say about the DVD:

This complimentary “Back-to-Basics” DVD includes more than 50 new application notes as well as new and updated webcasts and videos that cover a wide variety of topics from design simulation to digital and modular instrumentation. The resources on this disc will help you brush up on the basics and get your job done more efficiently and effectively.

The list below is just a sampling of what’s new and updated for 2015. Click here to see EVERYTHING on the DVD.

Webcasts/Videos:

• 10 Oscilloscope Innovations You Really Want
• Fundamentals of RF Design
• Network Analysis Fundamentals
• Spectrum Analysis Fundamentals
• Signal Generation Fundamentals
• Why Calibrate? What is Calibration?

Application Notes:

• ABC’s of Arbitrary Waveform Generation
• 8 Hints for Making Better Digital Multimeter Measurements
• Test-System Development Guide Computer I/O Considerations
• Solutions for Measuring Permittivity and Permeability w/LCR Meters & Impedance Analyzers
• PXI Interoperability – How to make PXI-based test work for you
• Why complex modulated optical signals?
• 10 Practical Tips you Need to Know About Your Power Products
• USB Coaxial Switches for RF & Microwave Test and Measurement Application

And MORE!