T'is The Season of Blinky Lights

I like to play with old fashioned neon tubes. They make a soft and friendly mystical glow and are especially good for a night light, so you don't fall down the stairs.

Seven of Nine

More here: Olde Skool Blinken Lights

...and for really, really slow blinky lights, see the VASCO project at https://vasconsite.wordpress.com

Have fun!

Herman

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Parasitic Quadrifilar Helical Antenna

This article was reprinted in OSCAR News, March 2018: http://www.amsat-uk.org If you want to receive Satellite Weather Pictures , then you need a decent antenna, otherwise you will receive more noise than picture. For polar orbit satellites, one needs an antenna with a mushroom shaped radiation pattern . It needs to have strong gain towards the horizon where the satellites are distant, less gain upwards where they are close and as little as possible downwards, which would be wasted and a source of noise. Most satellites are spin stabilized and therefore the antenna also needs circular polarization, otherwise the received signal will flutter as the antennas rotate through nulls. The helical antenna, first proposed by Kraus in 1948, is the natural solution to circular polarized satellite communications. It is a simple twisted wire - there seems to be nothing to it. Various papers have been published on helix antennas, so the operation is pretty well understood. Therefore,

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The older free Numerical Electromagnetic Code version 2 (NEC2) from Lawrence Livermore Lab assumes an air dielectric. This makes it hard (but not impossible) for a radio amateur to experiment with Printed Circuit Board Patch antennas and micro strip lines. Air Spaced Patch Antenna Radiation Pattern You could use the free ASAP simulation program , which handles thin dielectrics, you could shell out a few hundred Dollars for a copy of NEC4 , You could buy GEMACS if you live in the USA, or you could add distributed capacitors to a NEC2 model with LD cards (hook up one capacitor in the middle of each element.), but that is far too much money/trouble for most. More information on driving an array antenna can be found here: https://www.aeronetworks.ca/2019/03/driving-quad-patch-array-antenna.htm l Air Dielectric Patch The obvious lazy solution is to accept the limitation and make an air dielectric patch antenna. An advantage of using air dielectric, is that the antenn

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