Comparing RTL-SDR and IC-751A Receivers Using JT65 & JT9 Signals

  Once I had the RTL-SDR radio working as a pan-adapter for my IC-751A, I quickly became interested in seeing what I could do with all of those signals that were apparent on the SDR radio's waterfall.  My first goal was to see if I could receive the complete JT65 and JT9 signal band, with [...]

RTL-SDR Pan-adapter using HDSDR with the IC-751A

There is little doubt that the RTL-SDR tuner dongle radio receivers are the hottest new thing for the amateur radio experimenter.  Re-purposing the $10 tuner dongle to be an extraordinarily wide-band software defined radio is the subject of countless internet articles and videos.  Here I am adding my experiences to the crowd.  What I will describe [...]

Antenna Comparisons using JT65 & JT9 Signals along with NEC Models

True understanding of a problem is confirmed when one can validate theoretical model predictions with measurements.  It is too easy to believe pretty pictures that modeling programs produce, especially when making meaningful measurements is so difficult.  In this article I try to take the bull by the horns and see how close I can come to [...]

Comparing Receivers with Digital Mode Signals

I entered second heaven when I got my second radio.  My original 32-year-old Icom IC-745 got placed on the back shelf when the new 29-year-old Icom IC-751A arrived.  As much as I enjoyed the old IC-745, I was after a little computer control, and the 745 predates the idea that people use computers.  The 751A, [...]

The Off-Center-Fed Dipole Antenna – Design

There are a few ways to build multi-band HF antennas.  These include multiple resonant dipole arrays, trapped dipoles, resonant loops and the off-center fed dipole, OCFD.  I'm going to look at the OCFD because it is relatively simple to construct, yet gets quite decent performance.  I also am fortunate to have some nice tall trees [...]

Ham Lingo

Broadcasting's use of abbreviations and obscure notation started with the original radio-men, when every character required some pain to transmit.  Today's tweeters and texters have invented their own slang for much the same reason, but without the long linguistic history that accompanies radio lingo. When you first enter the ham world, you have to cross the language [...]

Blog post gets Published!

What started out as a bit of curiosity about the time-dependent toxicity of insecticides led to a blog piece I did a little over a year ago titled Time-dependent Toxicity of Imidacloprid in Bees and Ants.  I thought my results were interesting enough to get a comment from other scientists that were looking at the time-dependent [...]