Tuesday, July 28, 2020

Faraday Tour

I missed it - may try to catch the next one.

Cognitive Radio

Via Slashdot.org: Neural Network-Enhanced 'Cognitive Radio' Communicates With ISS

To understand Cognitive Radios, you have to understand that the term Cognitive Radio came directly from Joseph Mitola's research in the mid to late 90's.

He was well known for being a software guy who got into RF. His early research was in software radios and the term "Cognitive Radio" was coined in 1999.

To understand why "cognitive radio" became a thing, one has to understand why "software radios" became a thing.

First, virtually all radio systems (even those developed now) are done by deciding the spectrum, modulation, and propagation methods up front. You do this so you can decide what the link budget (bandwidth) of your connection is, determine whether the signal is analog or digital, pulsed or CW, the modulation, demodulation, filters, mixers, noise floor, sampling, amplification, antennas, etc. This is why you typically see new wifi and cellular systems determined "by spec". The spec informs the hardware design and vice versa. This is also why you often hear about bandwidth allocation as a hot topic - not only is bandwidth fundamentally "squatters rights", so that organization and adherence to rules is important, the bandwidth allocation also fundamentally informs which physics are important and therefore the hardware of the radio system itself.

Second, the digital theory of information fundamentally transformed radio, and was in the process of transforming radio for several decades. There was a lot known about the digital equivalence of physical devices like filters, and phenomenon like noise, and ideas like channel capacity, but due to the nyquist theorem, it was actually very difficult to take advantage of any of the knowledge gained because computers were simply not fast enough to perform the necessary mathematical operations quickly to convert voltages to bits, compute, modify the bits, then convert back to voltage - especially at higher and higher frequencies. (Notice how your communications devices get faster and faster data rates over time? You can thank the fact that computing hardware is getting faster and faster.)

With the advent of fast computational devices (DSPs, mostly) it became possible to implement a lot of the theoretical advantages of digitized waveforms.

Third, RF designers started to look at the fundamental hardware building blocks of a radio, especially the filtering, modulation/demodulation. and mixing stages - which were often analog components that were "off the shelf" and fixed quantities, and created theories around how to create generalized digital representations of these devices. Once the fundamental building blocks became well understood in terms of how to build software representations of these devices, and hardware became fast enough to implement some of these software representations of once fixed hardware devices (in practice, this is still extremely primitive - even in 2020 terms), researchers began to earnestly look at how one might be able to create dynamically reconfigurable RF systems.

And the representation of these dynamically reconfigurable RF systems? Of course, it is done as a language, and therefore, programmed in software. Hence the field of "Software Radio."

Now that you realize how radio got into the software domain, you have to understand that the term "cognitive radio" is just any software radio that implements Mitola's Congitive Cycle, which is basically just a feedback loop, where a radio listens to its environment and then adapts its RF operation to best reach the receiver.

There was a program in 2012 called COMMEX (Communication through Extreme Interference) by DARPA that was ultimately won using a Cognitive Radio approach.

This is just a vastly simplified explanation. To really understand the concept of how AI can be used to steer the software radio system to receive receivers through difficult links / signal paths, you have to understand that AI is just a combination of linear algebra and statistical mathematics being used to solve objective functions. But now, maybe you have more to explore in terms of why AI and Cognitive Radio became a thing, and why it might be useful for this kind of situation.

Thursday, July 23, 2020

Garmin Hit by Ransomware

I couldn't upload my run this morning... turns out Garmin is dealing with a ransomware attack.

Wednesday, July 22, 2020


Being on-call has been part of the job for as long as I can remember... first carrying pagers then alpha-numeric pagers then Nextels then Blackberries. However, I'm not sure I would have any interest in a recent job posting that included this:

"Be available as needed to rectify IT emergencies. Must answer all forms of communication immediately."

Friday, July 17, 2020

Intellectual Discourse - Ham Radio Reddit

First - Baofeng Bucks:
"Chinese communist party takes your Baofeng bucks and puts them right in the 'turn America into one big concentration camp' fund. They don't want you dead, they want your whole life. Call me crazy, see what happens.

EDIT: Changed 'Baofeng dollars' to 'Baofeng bucks' because it's funnier."

"Japanese anime porn artists take your Yaesu Yen and put them right into the "get Americans addicted to tentacle hentai" fund. They don't want you dead, they want your whole life. Call me crazy, see what happens."

The Screwtape Letters

C.S. Lewis' The Screwtape Letters is on sale for $1.99 as a Kindle ebook. It's an easy, but thought provoking read. 

Wednesday, July 15, 2020

International Space Station

We watched the ISS go overhead last night. I was surprised by how bright it was.

You can track it here and find times when you might be able to see it.

"The crew can operate the 2-meter packet radio in unattended mode, and hams can make contacts with the ISS station when the crew members are working. Hams can also communicate with each other using the ISS packet (computer) radio mode, or receive slow scan television mode images. It all depends on what equipment is in service in space. 
A typical ground station for contacting the ISS station includes a 2-meter FM transceiver and 25-100 watts of output power. A circularly polarized crossed-Yagi antenna capable of being pointed in both azimuth (North-South-East-West) and elevation (degrees above the horizon) is desirable. But successful contacts have even been made with vertical and ground plane antennas."

Knoxville Utility Board Considers Offering Broadband

Chattanooga's EPB has done a great job with providing municipal broadband. I'd love for KUB to follow suit.

They own all the poles and I'm sure there are lots of SmartGrid advantages, too.

Monday, July 13, 2020

Eclectic Tech Podcost

I'm gonna give the ARRL's Eclectic Tech Podcast a try. The episodes aren't very long and it comes out biweekly.

Ham Radio is Dead, Long Live Ham Radio

From the "News for Nerds, Stuff that Matters" set, a discussion on the future of ham radio.

Since I've been working form home, I've been at the desk with my radios. I've not been spinning the dials on any HF bands, but scanning the local repeaters on 2m has turned up very little rag chewing. I thought folks might be talking more if they are stuck at home.

Saturday, July 11, 2020

On-Line Streaming Costs


Friday, July 10, 2020

ABP - Always Be Performing

I've heard people suggest C-SPAN, cable news, and the internet have lead to too much transparency. Compromises don't happen because politicians are always performing for their base. If they don't maintain their extreme positions, the mob attacks. That's how you get this...

via Gfycat

Thursday, July 9, 2020

Bad Router

Slashdot.org: Over 100 Wi-Fi Routers Fail Major Security Test -- Protect Yourself Now

My ASUS AC3200 isn't on the list, but as always the best practices apply:

  • Change the default password
  • Disable remote administration from the internet*
  • Turn off UPnP
  • Update your firmware and automate it if possible**
* You lose some convenience since you can't make changes from anywhere, but I rarely need that ability.
** Be aware that automatic updates my introduce new bugs.

Monday, July 6, 2020

$9 Wireless Charging Pad

I need to add another wireless charging pad, since I'm working from home and I end up using different rooms depending on who is in the house.

Nerds Know the Answer to Fake News?

I've been reading Slashdot.org for years. I have a fairly respectable UID under 50000. (You kids get off my lawn!)

It would probably be better than "unfollowing" and "snoozing", but not as good as avoiding it all together.

Sunday, July 5, 2020

Another 10 Years

I had to renew my ham license. The online process was painless. I had my FCC Registration Number (FRN) documented with my usual reference materials, so it meant I didn't have to go digging for it and avoided that headache.

I'm good for another ten years. Maybe I should actually get on the air again.