Wednesday, January 25, 2017

Get Ready for the Solar Minimum. Post #1023.

Title:  Get Ready for the Solar Minimum.
Authors:  Steve Ford (WB8IMY), Joel Hallas (W1ZR), and Curt Luetzelschwab (K9LA).
Source:  "QST", February 2017, pp.48-51.

Comment:

While I was searching for low-band HF antenna ideas (160 through 40 meters) suitable for our changing propagation, I ran across this article in the February 2017 issue of "QST"-- the official membership journal of the ARRL.

Steve Ford (the "QST") editor does a good job of describing how our operating habits will change as the Sun reaches solar minimum.  According to Steve, "The solar minimum will have its greatest impact on the high- and medium-frequency bands, and we're already seeing hints of what is to come."

In most cases, higher HF bands such as 12 and 10 meters will suffer the most fluctuation.  Propagation won't be entirely dead above 24 MHz, but it will rely on "sporatic E" to send signals to distant points.  As any 6-meter enthusiast will tell you, "Sporatic E" "can set off spectacular propagation fireworks."

However, for daily nets, schedules, and dx work, 40, 80, and even 160 meters will play a growing role in daily amateur radio contacts.

In this well-written article, Steve describes three vertically polarized antennas that can keep you on the air and and deliver plenty of casual and long-distance contacts:

A 43-foot/13.109 meters vertical usable on 40, 80, and 160 meters.  The antenna, combined with a ground radial or counterpoise system and an antenna "tuner", will cover these three bands in style.  The antenna is also usable on 20 meters, where the wire serves a 5/8 wavelength antenna. You may be able to get some decent performance on 17, 15, 12, and 10 meters as well.

The Inverted "L" is also another low-band favorite, offering both vertical and horizontal radiation patterns.  If you have a 30-foot/9.146 meters fiberglass pole, you can attach another 100-feet/30.48 meters to the top of the mast and use the full length of 130-feet/39.63 meters to make a 1/4 wavelength antenna for 160 meters.  Once again, a good ground radial or counterpoise system and antenna "tuner" will round out the system.

"Short-Circuiting" Your Dipole.  You can often make an antenna made for one band  play on a lower band by shorting the center conductor of the antenna coax to the shield and then connecting the feed line to your antenna "tuner."  In this way, a 40 meter dipole antenna can be made to work on 80 meters.  In the dawn of the AM broadcast era (1920s), such antennas were known as "The T Antenna" and performed reasonably well on medium wave frequencies (550-1600 kHz). As with all vertical antennas, please install a ground radial or counterpoise system.

Steve concludes his simple tutorial with this advice:
"Put up as much wire or metal tubing as possible and load it with RF energy any way you can.  You won't be busting pileups on the other side of  the world during the solar minimum, and you won't always be the strongest signal on the air, but I guarantee that you'll make enough contacts to stay busy no matter how long the minimum may last."

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