Saturday, December 9, 2017

Cryptocurrency and Blockchain

Here are some informative links about cryptocurrency (Bitcoin is the first and best-known) and the enabling Blockchain technology.

The introduction and Overview in this article provide a good quick view of the topic, including the concept of a production cap that limits the ultimate amount of the currency in circulation.

Cryptocurrency Mining
In the early years of Bitcoin, computer users were able to run software to "mine" new Bitcoins. Over time this has become much harder, requiring great amounts of electrical power and computer processing power. This article from 2015 describes the  futility for an average PC user.

Update - January 11:
The large-scale mining of Bitcoin was explored in a visit by CNBC to the Wenatchee, WA location of Salcido Enterprises. This facility takes advantage of cheap electrical power to operate 1800 servers that mine 5 to 7 Bitcoins per day. The current power consumption is 7.5 MW, costing $200,000 per month. The CEO hopes to mine 50 Bitcoins per day by July, consuming 40 MW. Salcido is one of 12 companies in the area who are mining Bitcoins. Four companies have requested 100 MW of electrical power from the local utility.

You can view one of the CNBC video segments at this link.

This is probably the best-known site for exchanging ordinary currency into Bitcoin and other popular cryptocurrency.

Special Report: Blockchain World
This series of articles from IEEE Spectrum has LOTS of detail on the subject and its application to transactions far beyond cryptocurrency

Tuesday, October 31, 2017

Test of blog post from outside email

Test of blog post from outside email. Sent by John on 10/31/17.

Test of email post to blog

Test of posting to blog via email. 10/31/17



Thursday, September 28, 2017

WiFi Analyzer Apps

Here is a collection of some links to apps that enable you to analyze and troubleshoot your WiFi configuration and coverage at a given site.

Network Analyzer - wifi scanner, speed test, tools
For iOS devices, but does not have all the WiFi details that are available on other platforms

Mac OS
7 Best Wifi Analyzers for Mac OS

Windows and Mac
9 free Wi-Fi stumbling and surveying tools
Slides 3 and 9 are Mac apps

8 Best WiFi Analyzer And WiFi Scanner Apps For Android


Also see:
How to Find the Best Wi-Fi Channel for Your Router on Any Operating System

Thursday, August 24, 2017

VOACAP 7191 kHz - Aug 24 at 0715

Best signal would be indicated by green and blue contour lines, but they are missing today. Not the best conditions.

Thursday, June 1, 2017

HF Radio Propagation Modeling

Below is a series of cropped screen shots I collected at 0830 CDT today from the VOACAP map feature of the KE9NS PowerSDR software that I am currently using. My station location is marked with the red star. The predicted signal level scale ranges from blue (strongest) to green to yellow to orange to gray (weakest). Only the 30 m plot has gray contour lines. The 60 m plot has vertical lines that mark two of the defined frequency channels.

During earlier discussion of this topic, Tom KQ5S told us about the VOACAP propagation modeling presented on the K6TU web site. The link I provided here gives an overview of what's needed to run the model program on the web site.

A little web searching today about "do-it-yourself" VOACAP usage brought the following article from 2004:

Two other search results raised my awareness of the VOACAP dependence on sunspot data and how it is defined and published:
My searching today reminded me that the VOACAP capability is also a plug-in built into the 4nec2 antenna modeling software that I use. I've seen it in one of the program menus, but have not digested the documentation enough to use it.


Monday, April 24, 2017