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"TDOA" direction finder systems - Part 1 - how they work, and a few examples.
Next to using a directional antenna, one of the simpler ways to determine the direction of a received signal is to use what is often referred to as the "TDOA" system which stands for Timed Direction Of...
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On the winding of power chokes and transformers: Part 2 - A filament transformer
Having wound the choke described in the previous installment about chokes - (link)- I decided to proceed with the next logical step in the project: Winding a filament transformer.Figure 1:The...
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Repairing the power switch on the Kenwood KA-8011 (a.k.a. KA-801) amplifier
Back around 1990 my brother mentioned to me that there was an amplifier, in a box, in pieces, in the back room of the home TV/electronics store where he worked at the time and that if I made an offer I...
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On the winding of power chokes and transformers: Part 3 - The plate (high...
This is a follow-up of two previous posts in this series:On the winding of power chokes and transformers: Part 1 - Chokes - linkOn the winding of power chokes and transformers: Part 2 - A filament...
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A simple push-pull audio amplifier using russian rod tubes and power...
As one sometimes does, I was perusing EvilBay a while back and saw some ex-USSR sub-miniature pentode tubes for sale. In looking up the part number - 1Ж18Б, which is usually translated to "1J18B"(or...
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A low power PSK31 transmitter using a Class-E power amplifier and envelope...
Back in 1999, not too long after the first appearance of PSK31, I decided that I wanted to construct a beacon transmitter that would operate using this mode but at the time the only practical means of...
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An A/B Battery replacement for the Zenith TransOceanic H-500 radio with...
A friend recently gave me an old Zenith TransOceanic (ZTO) H-500 and after re-aligning it to get it into proper working condition I decided that I wanted to build a battery pack for it - both for...
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A novel APD-based speech bandwidth optical receiver
In a previous posting I wrote about a novel application of a JFET - (Read about that in the article "Gate current in a JFET - The development of a very sensitive, speech-frequency optical receiver" -...
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Fun with self-oscillating TV flyback transformer circuits, arcs and high voltage
A few weeks ago I ordered a few things from The Electronic Goldmine and one of the items that I picked up was a small flyback transformer (Stock #: G20787, manufacturer part number BSH12-N406L) as...
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The 1J37B as a replacement for a 1L6?
The rarity of the 1L6:Owners of the classic Zenith Transoceanic radios from the early-mid 50's will probably be aware of the pain involved if they have to buy a 1L6 tube (or "valve") for their beloved...
View ArticleA (somewhat convoluted) means of locking a "binary" (2^n Hz) frequency to a...
DDS (Direct Digital Synthesis) chips are common these days with small boards containing an Analog Devices AD9850 board being available on EvilBay for a cost lower than one is likely able to buy the...
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A daylight-tolerant TIA (TransImpedance Amplifier) optical receiver
While the majority of my past experiments with through-the-air free-space optical (FSO) communications were done at night, for obvious reasons, I had also dabbled in optical communications done during...
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An RV "Generator Start Battery" regulator/controller for use with LiFePO4...
I was recently retrofitting my brother's RV's electrical system with LiFePO4 batteries (Rel3ion RB-100's) are considered to be very safe (e.g. they don't tend to burst into flame when abused or...
View ArticleTeasing out the differences between the "AC" and "DC" versions of the Tesla...
Interested in such things, I've been following the announcements and information about the Tesla PowerWall 2 - the follow-on product of the (rarely seen - in the U.S., at least)"original"...
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Adding a useful signal strength indication to an old, inexpensive...
A field strength meter is a very handy tool for locating a transmitter. A sensitive field strength meter by itself has some limitations, however: It will respond to practically any RF signal that...
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Odd differences between two (nearly) identical PV systems
I've had my 18-panel (two groups of 9) PV (solar) electric system in service for about a year and recently I decided to expand it a bit after realizing that I could do so, myself, for roughly $1/watt,...
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A 173 mile (278km) all-electronics, FSO (Free Space Optical) contact: Part 1...
Nearly 10 years ago - in October, 2007, to be precise - we (exactly "who" to be mentioned later) successfully managed a 173 mile, Earth-based all-electronic two-way contact between two remote mountain...
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Analyzing "fake" solar eclipse viewing glasses - how good/bad are they?
Note: Please read and heed the warnings in this article.About a month and a half ago I ordered some "Eclipse Viewing Glasses" from Amazon - these being those cardboard things with plastic filters....
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Monitoring the "CT" MedFER beacon from "Eclipse land"
Figure 1:The MedFER beacon, on the metal roof of my house,attached to an evaporative ("swamp") cooler. I must admit that I was "part of the problem" - that is, one of the hoardes of people that went...
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Using an inexpensive MPPT controller in a portable solar charging system
As I'm wont to do, I occasionally go backpacking, carrying (a bit too much!) gear with me - some of it being electronic such as a camera, GPS receiver and ham radio(s). Because I'm usually out for a...
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