Archive for the ‘Radio Frequency’ Category:

2021-09-11 The Notorious Russian Woodpecker

For years the HF bands were filled with RF interference that would appear at a frequency for a minute and then jump to another frequency. The direction the pulses were coming from was the Soviet Union. There was no way to stop the interference; the Soviets were ignoring complaints. This YouTube video tells about it

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2021-06-14 Electric Vehicles Are In Stealth Mode

I have a PIR (passive infrared) motion sensing light on my porch for more than a year, and I’ve noticed that it can sense some of the cars that go by. If the car has been running, like coming home it will usually trigger the light. But when a neighbor starts the cold car and

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2021-04-30 Circuit Won’t Oscillate At UHFs

From FB post Apr 29 Joshua E. Hrouda I trained on Radar repair in the Army, and since then I’ve known that circuits with ‘lumped constants’ have problems with parasitic capacitance and inductance above a few hundred MHz. But I experimented with this circuit anyway. I think Colin should say, instead of ‘tight’, that the

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2021-04-28 Colpitts Oscillator For FM BCB

This is a low power oscillator using an air core coil and silver mica capacitors for stability. Parts values are subject to the frequency needed. There is no modulation. For FM the 10 pF capacitor would be lower and include a reverse biased diode as a varicap in parallel. The audio should be across this

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2021-03-24 The New 5G Is Safe

This should not be necessary to continually debunk a myth that should be dead. https://www.sciencealert.com/major-review-still-finds-5g-technology-to-be-completely-safe

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2020-08-03 Wireless Power Transmission In NZ

2020-08-03 article says it uses the industrial, scientific, medical frequencies. Tesla Redux! << NZ to trial world-first commercial long-range, wireless power transmission >> https://newatlas.com/energy/long-range-wireless-power-transmission-new-zealand-emrod/

2020-06-18 Michael Pupin & Patents

From the list of his patents in his wiki. Armstrong co-authored some patents. https://www.google.com/patents/US1416061

2020-06-08 Military Intelligence Is A Joke

From FB comment Jun 8 Gayle McGowen Nobbs 🙄🙄 “Military intelligence is an oxymoron.” I was stationed in the Army nike site in Minneapolis. We had to keep the buttons with the secret words for the Radar’s switches in a locked safe. The very same buttons with Lin-Log, Integrator, Dicke Fix, etc. were on the

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2020-05-28 Solid State Shortwave RF Preselector

Comment left 2020 May 29 on YouTube video in the title. This video covers MOSFET, dual gate MOSFET, JFET and BJT tuned preamps (preselectors) for his shortwave crystal radio. “The talk about using 18 volts for the cascode got me thinking about tube designs. When the plates need 100+V, and when the heater to cathode

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2020-05-22 PIM Passive InterModulation Explained

Good article on passive intermodulation, AKA the Rusty Bolt Effect. https://www.electronics-notes.com/articles/radio/passive-intermodulation-pim/what-is-pim-basics-primer.php

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