Category — Sunspots

The 4D Ionosphere is something that will give you hours of fun:

Today, NASA-funded researchers released to the general public a new "4D" live model of Earth’s ionosphere. Without leaving home, anyone can fly through the layer of ionized gas that encircles Earth at the edge of space itself. All that’s required is a connection to the Internet.

"This is an exciting development," says solar physicist Lika Guhathakurta of NASA headquarters in Washington, DC. "The ionosphere is important to pilots, ham radio operators, earth scientists and even soldiers. Using this new 4D tool, they can monitor and study the ionosphere as if they’re actually inside it."

When I first read this, I checked to make sure it wasn’t April 1st and some foolery. But, it’s real. Here’s a screen shot:

The key is that this information is updated every 10 minutes:

"Colors represent electron content," Tobiska explains. "Bright red is high density; that’s where radio communications are restricted to few or no frequencies. Blue denotes low density; no problem there."

Using the intuitive Google Earth interface, users can fly above, around and through these regions getting a true 3D view of the situation. Make that 4D. "The fourth dimension is time. This is a real-time system updated every 10 minutes," he says.

Undoubtedly, this technology will be banned from CW contesting as well…

Scot, K9JY

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It’s been so long since I’ve paid any attention to the sunspot and solar flux numbers, I’ve forgotten what they all mean. Pulling out some the references in the drawer revealed some simple applications of the numbers.

Sunspot measurement

Sunspot numbers are shown as a "tens" number relating to the number of "regions" on the site and a "singles" number relating to the number of sunspots associated with a "region."

So if there are no sunspots, the number is understandably zero. But, a single sunspot on the sun would translate into a sunspot number of 11. The tens spot for having one region and the singles number for one sunspot in the region.

Solar Flux measurement

Solar Flux is the 10.7 cm measurement from the daily 1700Z value recorded at Ottawa, Ontario. The solar flux varies from 66 — the lowest number associated with zero sunspots — to several hundred. It is a more "linear" view of sunspot numbers.

A very small change in the solar flux can have a big change in propagation. For example, here at the low of the sunspot cycle, a solar flux moving from 66 to 72 could mean longer openings on 20-meters until after sunset or even some 15-meter openings during the day.

An 80 reading will mean that 15-meters should open.

A 90 reading will mean that 10-meters should be open.

The A index

The A index is the measure of the geomagnetic activity or radio absorption of the ionosphere. The higher the A index, the more absorption and the weaker the radio signals. The A index range is near zero to several hundred.

As "rules of thumb," readings below 10-15 usually signify good band conditions. Readings over 30 usually mean bad band conditions.

The K index

The K index also measures radio absorption like the A index, but it is reported every 3-hours instead of every 24. Consequently, the K index more accurately reflects current band conditions than the daily A index.

The K index varies from 0 to 9, with 0-2 suggesting reasonably good conditions. The higher the number, the more absorption from disturbed conditions will exist.

Solar flux and A-K indexes work together

You always want low absorption on the bands, regardless of the solar sunspots.

The reason is that 160 and 80 meters perform very well with low sunspot numbers and low absorption, but aren’t very good with high absorption.

Yet 10 meters can be fabulous with a solar flux of 110 and low absorption and terrible if the K index and the associated absorption is 9.

So you always want low absorption, regardless of the sunspot number.

Propagation is not an exact science. There are weird anomalies all over the place all the time (which is one of the reasons ham radio is so much fun). These numbers should provide some good guidelines, however, to get you used to looking at those solar numbers again now that the new solar cycle 24 has started.

Scot, K9JY

Since we’re starting to move out into the new Solar Cycle, I’m starting to pay a lot more attention to the fundamentals about how sunspots are measured and finding some sites about it.

A cool site I was directed to was VE3EN’s Solar Cycle 24 site with all things consolidated down to a single page. Here’s  snippet of the thumbprint pics on the site:

Or some more:

The site updates every 2-minutes and has been around now for about a year.

Any other great sites out there?

Scot, K9JY