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[image] As the 40th anniversary of the moon landing approaches, we look at key events in the history of space exploration. 4 October 1957: The Soviet Union launches Sputnik 1, the first Earth-orbiting artificial satellite, igniting the space race. Sputnik's radio signals continue for 22 days until the transmitter batteries run out. It burns up on 4 January 1958 as it…
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Brook3: Great Names of Radio History — Sir Edward Victor Appleton Sir Edward Victor Appleton was one of the key figures of the twentieth century who contributed to the knowledge of radio and the ionosphere and hence improved our knowledge of the way in which radio waves propagate in the HF portion of the spectrum. Edward Appleton received a Nobel prize in 1947 for his work, the technique for which laid the foundations for the…
Garlic: Installing new 220-foot Rohn 45G Tower — In an effort to upgrade towers I needed to replace a 195-foot Rohn 25G with a Rohn 45G tower. Rather than totally disassemble the 25G tower section-by-section and install the 45G section-by-section, we used the following method...... [image]
Goodwin: 1.9 kHz SSB Filter for Icom IC-746 — One thing I notice a lot during contests with my trusty Icom IC-746 (pre pro) is the splatter from power house stations nearby in frequency. I realize I can’t keep their splatter out if it falls within the passband of my receiver. However, I can at least try a more narrow filter to mitigate out of band energy. The IC-746 comes with a 2.4 kHz wide filters for the first 9 MHz IF and for the…
Angela679: Installing a Vertical Antenna Base with no Concrete — [image]Well I went ahead and purchased the 43 foot antenna kit from DX Engineering during that sale they were having till the end of last year. This is the story of how I constructed the ground mount for it. First a related story… The day after Christmas my son and I carefully replaced the current copper pipe 16 foot vertical with the pieces from the kit which includes a nifty…
Angela679: Priming Aluminum Antennas — If you have been reading this web site you will recall I have paid much attention to the 43 foot antenna manufactured by DX Engineering and Zero Five Antennas. After much simulation and trading the benefits against pitfalls, I purchased the DX Engineering 43 foot antenna kit with the balun. However, a shiny aluminum antenna in the back yard would attract the kind attention I just don’t…
Mari23: ANTENNA ARRAYS — An antenna array is an antenna that is composed of more than one conductor. There are two types of antenna arrays: Driven arrays – all elements in the antenna are fed RF from the transmitter Parasitic arrays – only one element is connected to the transmitter. The other elements are coupled to the driven element through the electric fields and magnetic fields that exist in the…
