Summertime and the listening is easy!

It's the middle of summer, and while outdoor temperatures are set on "bake," some of the radio communication bands are sizzling as well.

These are rewarding days in the radio hobby, with intense rounds of skip reception on frequencies that typically come alive during June, July and August. Technically, this is known as "Sporadic-E," where ionized particles in the atmosphere's E layer reflect signals from about 20 MHz up to the FM broadcast band and higher.

For ham operators, this means enjoying the higher shortwave bands like 10 meters (28 MHz) and also the VHF six meter band (50 MHz) which spends most of its time in the doldrums, but occasionally springs to life in spectacular fashion and earns its nickname, "The Magic Band."

Last month's VHF contest saw an incredible six meter band opening here in Connecticut on Saturday evening, when signals suddenly emerged from the Canadian Maritime provinces and the Carolinas, lasting until the wee hours of Sunday morning.

How can you spot Sporadic-E? Signals appear suddenly, can be very strong but fade rapidly, and the operators often have regional accents and call signs that are from the south or the mid-west. The range for Sporadic-E skip communications is about a thousand miles or less, but on occasion, multi-hop skip can provide communications double or triple the usual range.

Here's last evening's six meter propagation map for North America, showing radio paths from the western states to the Great Lakes area. This a screen shots taken from the real-time propagation website, dxmaps.com.

For radio hobbyists who monitor police and fire departments, summertime also has a lot to offer, in an "old school" sort of way.

Some state highway patrols still use VHF low band because of the wide ground wave coverage, and one of the most active is Missouri on the 42 MHz band.

Posted below is a short video I recorded of transmissions from Missouri Highway Patrol as copied at my station. Note how strong the signal is and how fast it fades.
                 



Another type of  summer radio propagation is tropospheric ducting. Weather systems and temperature inversions cause VHF and UHF signals to travel much farther than normal, especially during nighttime and early morning hours. (This is great for hobbyists who stay up really late, but I'm not one of them.)

Tropo ducting lets me listen to NYPD in the 470 MHz band, while normally the Big Apple is too far for UHF reception at a distance of more than 90 miles. Fortunately, NYPD is still using analog FM and has not switched to digital.

I will explore tropo listening and how it plays havoc with FM radio stations in a future edition of The Squelch Tale - coming soon to a computer near you. Meanwhile, check out William Hepburn's real-time tropo forecast map and learn more about this amazing natural phenomenon.