Clik here to view.
Completely containing switching power supply RFI
In the old days, radio amateurs were concerned with (or should have been) energy from their transmissions getting into devices unintentionally, the classic being televisions, phonographs, telephones,...
View ArticleClik here to view.
YAFP - The mcHF SDR HF Transceiver
Those who know me are already familiar with a four-letter acronym that I've used for many years:YAFPWhich stands for:Yet Another Fu__n_ ProjectWhat, exactly the "F" stands for is up to you, but the...
View ArticleClik here to view.
Assembling the mcHF transceiver boards - getting ready.
If you remember last time, a few of the parts were still on their way - but since then, all have arrived and I have assembled one set of boards and gotten the transceiver operational.But I'm getting...
View ArticleClik here to view.
What to do if your IFR 1200 Service Monitor display just shows "@" signs on...
Figure 1. A properly-working IFR-1200 in receive mode.A few months ago the old IFR FM/AM-1200S service monitor on the bench at work started getting flaky. If you turned it on, cold, it would just...
View ArticleClik here to view.
The "Pointless" 10 meter DSB QRP transmitter
Figure 1:The slightly-modified "Shake Light" and the transmitter. The flashlight portionstill works!Click on the image for a larger version.The annual Homebrew meeting of the Utah Amateur Radio club...
View ArticleClik here to view.
My first coherer
Recently the topic of the meeting of the Utah Amateur Radio Club was on "old" radio. Really old radio, which is to say "radio" in the days before vacuum tubes and even crystal detectors.One of the...
View ArticleClik here to view.
Noisy fan on my Owon DS7102V Digital Oscilloscope
A bit over two years ago I got one of those inexpensive, Chinese-made digital oscilloscopes to supplement my old, trusty (and still working!) Tektronix 465B analog scope. While the old analog scope is...
View ArticleClik here to view.
Update on the mcHF transceiver - Adding features to the original code
It has been a few months since I have posted anything on the mcHF transceiver (my previous post may be found here - link) so unless you have been following the mcHF Yahoo group (link - membership...
View ArticleClik here to view.
Updated version of the "Simple" PWM LED/Laser modulator
A few years ago, for our friends in the Tucson area, I threw together a "simple" PWM circuit for audio modulation of high power LEDs (but it works just as well for laser pointers) for an optical...
View ArticleClik here to view.
A "quiet" 5 volt USB car power supply
Several months ago (see the May, 2014 posting - "How USB car power adapters can ruin 2 meter mobile reception" - link) I wrote about those ubiquitous USB car power adapters that fit in a cigarette...
View ArticleClik here to view.
Using the "RTS.SDR" dongle (with HF upconverter) as found on Ebay
Some months ago I was perusing the wares of a seller on EvilBay and having decided to purchase one of those all-purpose component testers, I was tempting myself with other items on sale. One of the...
View ArticleClik here to view.
Update on the mcHF - Adding more features (Part 2) - Implementing audio...
The front panel display of the mcHF SDR transceiver, an entirelyself-contained all-mode HF transceiver based on open-source software.This is shown not in its 3D-printed case - which is open-source,...
View ArticleIt should have not been BPL that worried us! (And using a separate receive...
About 10-15 years ago - more or less - the ham magazines and press were abuzz with concerns about the impending doom that was "BPL" - Broadband Over Powerlines.Ostensibly, there was good reason to be...
View ArticleClik here to view.
Adding a waterfall display to the mcHF transceiver
Figure 1:The "Grey" waterfall mode of the mcHF self-contained SDR transceiverin "Magnify" mode which shows only 24 kHz total bandwidth.Three - possibly four SSB QSOs are visible in this picture. One of...
View ArticleClik here to view.
A PIC-based audio comb filter to remove AC mains hum
If you have read the Modulatedlight.org page - and realized that I had something to do with its content - you will know that one of my interests is Free-Space, through-the-air optical communications.In...
View ArticleClik here to view.
RIP Gretchen cat
In the summer of 2001, in the courtyard of the apartment complex where my older brother lived at the time a feral mother cat had a litter of 4 kittens: Two males and two females. When they were about...
View ArticleClik here to view.
A Stand-alone ICSP Interface/programming board for 8 and 28 pin AVR...
Several weeks ago I got an "Ultimate 3" transmitter kit from Hans, G0UPL (See the web page http://hanssummers.com for more information) and built it with no problems. As is often the case with a...
View ArticleClik here to view.
First foray into the world of Arduino
Before Christmas I was ordering a few things from Amazon and was somewhat surprised when I was unable to check out with a few smaller items that completed the order. Puzzled, I dug around and...
View ArticleClik here to view.
Low Pass filter for MF/LF (600 meter) reception
About a month ago I fired up the SDR-14 (a wide-bandwidth software-defined "receiver") to "listen" to some longwave signals from some (relatively) high-power stations back east. These stations had...
View ArticleClik here to view.
Analysis of a repeater's antenna pattern
Back in 1997 the antennas on the Utah Amateur Radio Club's 146.760 repeater were relocated and replaced - this, because the original, guyed tower on which the antennas were located was being replaced...
View Article