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

Saturday, April 22, 2017

160 m Dipole - Old and New

Here is a series of plots that compare the radiation patterns of two versions of multi-band dipole antennas at KB0BH:
  • Old dipole: 240 ft end-to-end, 35 ft high, 450-ohm balanced line feed
  • New dipole: 230 ft end-to-end, 60 ft high, 450-ohm balanced line feed
Modeling for the old dipole includes the fact that 20 ft on each end hangs down vertically.
The graphics below include horizontally polarized pattern in the horizontal plane and vertically polarized pattern in the vertical plane. Three frequencies were analyzed (1.9, 3.7, 7.2 MHz). The frequencies are identified near the upper left corner of each plot.

In all cases the antenna structure is oriented from left to right on the plots. 

Each plot shows the patterns for both antenna cases, for comparison. The color legend is shown at the lower left corner of each plot. Numerical markers for maximum gain and beam width are for the new dipole. Click on any image for a full size view.

The software can provide additional types of radiation patterns.

Monday, March 13, 2017

Map of QSO participants

I updated a pair of Google Earth map views to show the locations of participants in our morning round table QSOs on 75 m. These are extensions of the earlier maps I made a few years ago of participants in the Saturday Bell Ringers Net. Click on either graphic below for a full-size view. The place marker dot, not the call sign label, represents the location of each station.

The view above shows frequent and infrequent participants. Four range circles, centered on W4BXI, are labeled with each radius in miles.

This second view is zoomed in to better display the stations within 100 miles of W4BXI.

Monday, March 6, 2017

Baluns -- Under the Hood

Below are views of 3 baluns that I own, with their covers removed to see the internals. The first photo shows 2 LDG baluns that are rated for 200 W. The one on the left is a 1:1 current or choke-type balun. The one on the right is a 4:1 balun that appears to be a voltage-type balun.  For some in-depth discussion of balun types, see this article by W7EL.

LDG baluns

1:1 Current Balun
4:1 Voltage Balun

Above are schematics of the two LDG baluns, using graphics from the W7EL article.

The next 4 photos show the internals of a DX Engineering balun DXE-BAL050-H10-AT that is rated for 5 kW CW and 10 kW SSB.

-  John