Here is the trace-out of my E-312 crossovers. Component values that could not be read from the component itself where measured with my Fluke BK Precision model 886 LCR meter.
I recorded above the average of the 2 readings taken from both crossovers.
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I visually traced out the circuit layed out on the circuit board and then measured with Fluke BK Precision model 886 LCR meter.
Continue reading Cerwin Vega AT-15 Xover Schematic
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Out here in beautiful rural East Texas, the noise levels on the HF bands are not too awful bad – IF you have a decent noise limiter or blanker.
We have some nasty short spike shortwave noise at a 33 mSec rep rate. It may be electric fences? our cable system?, but I have not tracked it down yet since I did not even know it existed due to modern receiver’s good noise blankers. (This explains the picket-fence spectrum of certain frequency ranges on the IF waterfall display).
Continue reading ANL Add-On for Hallicrafters SX-16
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Having a few nice vintage shortwave radios around, I decided it would be nice to actually USE the dang things once in a while 🙂 And given the almost unusably noisy performance of indoor short wire antennas, I made some loop antennas to cover approx 3 – 18 MHz to see if performance could be enhanced.
Continue reading Dual-Band X-Frame Shortwave RX Loop
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I really like the classics, the glow of tubes and smell 🙂 of transformers And having a short window of free time decided to pick up a poor ugly semi-rusted Hallicrafters S-53 for cheap. I was interested in it’s somewhat unusual 2.075 MHz IF frequency (used to enhance image rejection). I decided to try out a weird idea in regard to not really restoring, but rather quickly resurrecting an old not-so-valuable boat anchor.
Continue reading Hallicrafters S-53 Ressurection
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First cut at an Excel spread sheet to analyze a small RX loop’s noise and frequency response performance.
Continue reading Small RX Loop Analysis – An Excel Sheet – Fields, Voltages, Noise Levels…
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You may have wondered why some of us keep yammering on regarding “Common Mode Current” on the coax, and why common-mode prone designs (like end-feds and JPoles) are so problematic. Here’s an example of a 915 MHz antenna for a wideband comm system prototype I am designing. I decided on a wide-band vertical dipole.
In the pix below, we see the dipole front, and the dipole rear in it’s final form (sans heat shrink) – with a single loop binocular type 61 core performing the 1:1 current BalUn / choke function (they are the same thing):
Continue reading Why We Don’t Like Unintended Common-Mode Current Flow On Our Transmission Lines
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Apparently there are lot’s of differing opinions on antennas – now there’s a shocker Hopefully, we can put some rough numbers on things to help folks to figure out where opinion ends and basic principle begins.
Continue reading Low Gain Ground Mounted Antennas for LEO Satellites
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The 40 Meter Pixie (available at the time of writing for about $7 assembled on eBay) is an interesting minimalist transceiver design – crystal controlled, 2 transistors and an audio amplifier chip. And you are on the air with a unit that you can make QSO’s with! Naturally, there is much room for improvement, and it can in fact be done for only a few dollars more. Below I describe a set of additions that I think really enhances the Pixie’s usefulness.
Continue reading Project LOAP (Lipstick On A Pig) – Pixie XCVR Mods with Outboard CW Filter and Audio Amp
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