KB6NU's Ham Radio Blog

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From my Twitter feed: DMM tutorial

Posted: 08 Feb 2017 05:01 AM PST
http://feedproxy.google.com/~r/kb6nu...m_medium=email














HamRadioFeed @HamRadioFeed

Great multimeter tutorial for aspiring Hams ift.tt/2kgW67c#HamRadio









UD6ACWÂ*@ud6acw















Download this book for free!Dan


Signal Processing @DSP_fact

Think DSP book greenteapress.com/thinkdsp/ by @AllenDowney




The post From my Twitter feed: DMM tutorial appeared first on KB6NUs Ham
Radio Blog.


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From the trade magazines: EM model of the human head, vintage electronics
history

Posted: 07 Feb 2017 04:57 PM PST
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Create an EM model for a human head. A model of the human head was created
for studying specific absorption rates of EM energy from wireless sources.

Concern for the growing use of wireless devices, such as mobile phones,
that expose a user’s head to electromagnetic (EM) field energy has
motivated a number of studies on the effects of EM radiation on the brain.
An important part of that research is to develop accurate models of the
human head for simulating the effects of EM radiation on human tissues.

Amateur radio operators need to be concerned about RF safety—if only to
debunk all the misconceptions that are floating around out there. With that
in mind, I found this to be an interesting read.Dan

Electronics through the ages: A history of vintage technology in pictures.
The history of consumer electronics goes back to the early 20th century,
most precisely the 1920s. It was then when radio broadcasting incorporated
the first major consumer product that went to mass production: The
broadcast receiver.

Ready to start programming and configuring that Red Pitaya open instrument
platform? Heres a new blog series to help. The Zynq-based Red Pitaya open
instrumentation board gives you a programmable platform like an Arduino or
a Raspberry Pi, but with the added kick of high-speed ADCs and DACs for
analog instrumentation projects.

The post From the trade magazines: EM model of the human head, vintage
electronics history appeared first on KB6NUs Ham Radio Blog.


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How dangerous are the new batteries?

Posted: 07 Feb 2017 11:21 AM PST
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On the KX3 mailing list, somone wrote:

For anyone who would like to know why Lithium batteries can be so dangerous
I ran across this interesting video from PBS Nova. If you have not seen it
yet take a look. It should be worth you time.



Another guy replied:

None would think lithium batteries were so dangerous were it not for what I
call internet reporting. No one will much remember a story about a cell
phone where the battery got hot and had to be discarded. If it blows up now
thats another story.

Ive never understood how a cell phone can catch fire in someones pocket.
Lithium batteries dont get hot and blow up under a light load. And they
dont all of a sudden blow up. Hot pocket? Take it out.

The batteries in the hoverboards caught fire because of poor design. The
battery not having the capacity to deliver the current required or the
charger being faulty. Why would you keep both feet on the hoverboard if you
noticed something wrong. Like getting hot, smells funny, hoverboard slows
down or stops.

Lithium batteries are very tough and reliable if used according to specs
and charged correctly.

In any case the flat packs seem to cause the most trouble. I see them sort
of like a small dog vs. a big dog. Both can have aggressive and hostile
tendencies. Small dogs dont scare me. Big hostile and aggressive dogs do.
Lithium batteries are little dogs.

Im not a battery expert, but from what Ive read, it seems like they can be
dangerous, so handling and charging them with care seems appropriate. What
do you think?

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Radio Blog.