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160 Meter Radio Propagation Prediction Table 
for 
Middle and High Latitude Northern Hemisphere Circuits
Alska w.can c.can e.can w.us c.us e.us sw.us sc.us se.us Mex. U.K. Spain Frnce c.eur se.eur Mos. Israel Jap.
Alska Good Poor Poor Poor Poor Poor Poor Poor Poor Poor Poor Alska Poor Poor Poor Poor Poor Poor Poor Poor
w.can Poor Good Good Poor Good Good Poor Good Good Good Good w.can Poor Poor Poor Poor Poor Poor Poor Poor
c.can Poor Good Good Poor Good Good Good Good Good Good Good c.can Poor Poor Poor Poor Poor Poor Poor Poor
e.can Poor Poor Poor Good Poor Good Good Good Good Good Good e.can Poor Poor Poor Poor Poor Poor Poor Poor
w.us Poor Good Good Poor Good Good Good Good Good Good Good w.us Poor Poor Poor Poor Poor Poor Poor Good
c.us Poor Good Good Good Good Good Good Good Good Good Good c.us Poor Poor Poor Poor Poor Poor Poor Poor
e.us Poor Poor Good Good Good Good Good Good Good Good Good e.us Fair Good Fair Fair Fair Poor Fair Poor
sw.us Poor Good Good Good Good Good Good Good Good Good Good sw.us Poor Good Poor Poor Poor Poor Poor Good
sc.us Poor Good Good Good Good Good Good Good Good Good Good sc.us Poor Good Poor Poor Poor Poor Poor Good
se.us Poor Good Good Good Good Good Good Good Good Good Good se.us Fair Good Good Fair Fair Poor Fair Poor
Mex. Poor Good Good Good Good Good Good Good Good Good Good Mex. Fair Good Good Fair Fair Poor Fair Good
Alska w.can c.can e.can w.us c.us e.us sw.us sc.us se.us Mex. U.K. Spain Frnce c.eur se.eur Mos. Israel Jap.
U.K. Poor Poor Poor Poor Poor Poor Fair Poor Poor Fair Fair U.K. Good Good Good Good Good Poor Good Poor
Spain Poor Poor Poor Poor Poor Poor Good Good Good Good Good Spain Good Good Good Good Good Good Good Good
Frnce Poor Poor Poor Poor Poor Poor Fair Poor Poor Good Good Frnce Good Good Good Good Good Good Good Good
c.eur Poor Poor Poor Poor Poor Poor Fair Poor Poor Fair Fair c.eur Good Good Good Good Good Good Good Good
se.eur Poor Poor Poor Poor Poor Poor Fair Poor Poor Fair Fair se.eur Good Good Good Good Good Good Good Good
Mos. Poor Poor Poor Poor Poor Poor Poor Poor Poor Poor Poor Mos. Poor Good Good Good Good Good Good Good
Israel Poor Poor Poor Poor Poor Poor Fair Poor Poor Fair Fair Israel Good Good Good Good Good Good Good Good
Jap. Poor Poor Poor Poor Good Poor Poor Good Good Poor Good Jap. Poor Good Good Good Good Good Good Good
 

Estimated Global Topband Conditions: FAIR TO GOOD



Understanding and Using the Table:

The table above represents a rough approximation of radio propagation conditions on 160 meters (affectionately known as Topband). It is to be used as a guide only and is not a definitive forecast. It is based upon selected high-latitude magnetic observatory data which is used to estimate the influence of the auroral oval on 160 meter path propagation (refer to the March and April 1998 issues of CQ Magazine for details: "160 Meters: An Enigma Shrouded in Mystery", by Cary Oler and Ted Cohen).

Use this map just as you would use a computed distance table. For example, to find the predicted 160 meter propagation conditions between the central United States and Spain, find the central U.S. along the top of the table (it is labelled "c.us", and then find Spain along the left-hand side of the table. Then follow the column and row for the central U.S. and Spain until they converge together in the table. The color you observe in that square dictates whether propagation might be possible between the U.S. and Spain or Spain and the U.S..

A GREY box means that propagation is generally not influenced by the current level of auroral activity. Propagation should therefore be observed more often than not. However, keep in mind that there are almost certainly a myriad of factors that might affect propagation on 160 meters. This table only considers the role geomagnetic and auroral activity might play. Grey boxes should therefore imply that geomagnetic and auroral activity should not affect propagation and that a contact might be possible regardless of the state of the geomagnetic field. Some level of sensibility must be applied, though. For instance, during a severe geomagnetic storm, attempting to contact certain locations identified by a grey box might be an exercise in futility.

A GREEN box means that propagation on the specific path might be possible and that levels of geomagnetic and auroral activity might permit the signal to pass through the high-latitude regions unscathed. It might be worth a try. The four 'mights' in this paragraph are intentional: don't expect this table to provide you with magnificent openings to areas that have green boxes. A green box should be interpreted as a higher potential for DX between the specific paths represented by the green box. Whether your signal actually makes it through to the destination will depend on the location of the auroral oval, the thickness of it, the position of the mid-latitude trough, the effects of the trough and the auroral oval on your signals' behaviour (refraction, absorption, etc), and many other circumstances. But a green box generally implies that the auroral oval is in a good state of inactivity for potentially establishing DX. It indeed may be worth a try.

A YELLOW box implies that your chances of establishing a successful DX contact between the two specific locations is only marginal. It still might be possible, but probably will be difficult and/or short-lived.

A RED box should be interpreted to mean that your odds of making contact between the specific locations is poor to very poor. This does not mean that making contact is impossible. Anyone who works Topband should know how erratic this band can be. But a red box is generally much worse than a yellow or a green box.

The prediction table is designed for the NIGHT-SECTORS ONLY! Absorption in the D-region on daylit circuits is far too high to allow 160-meter contacts. If any part of your signal path crosses into daylight, these tables will be invalid (and so should your signal!).

The prediction table is also most useful during the northern hemisphere winter times, when the Sun does not affect high-latitude propagation paths.

Only northern hemisphere locations were selected for this table, for three primary reasons: 1) Propagation through the northern polar hemisphere is more common, and 2) There aren't enough realtime magnetic observatories around the southern polar auroral ionosphere to make such a table even marginally reliable (blame the ocean), and 3) Transequatorial propagation of 160 meter signals are affected by other mechanisms other than geomagnetic and auroral activity and would not be well represented in this table.

Each of the locations identified along the left of the table can be clicked. Clicking on the location will bring up an oblique azimuthal equidistant map projection centered on that location. These are maps where great-circle paths follow straight azimuthal lines. For example, the map for the central U.S. contains azimuthal lines radiating from the center of the United States. If you are located in or near the central U.S. and transmit a signal at an azimuth of 30 degrees, you can determine the path that your signal will take by following the straight 30-degree azimuthal line from the center of the United States to any other region of the world along that line. In this case, the 30-degree azimuthal line is the great-circle path. The maps are distorted so that great-circle paths from the center of the map (where the azimuth lines converge) follow straight lines. Distortion is greatest along the edges of the circular map where the azimuthal lines converge on the antipodal region.

These predictions do not require that your location be exactly at the specified areas. The predictions are valid over a fairly wide region near the specified areas. For example, if you are located at Cyprus (near Israel), or if your desired DX contact is in Cyprus, you can use the table entries for Israel as well as the oblique azimuthal equidistant map projection for Israel to determine propagation conditions.

Each of these maps were produced using our Proplab-Pro HF Radio Propagation Laboratory software. If you are unable to find a map centered near your particular location, you might want to consider obtaining this software to plot an oblique azimuthal equidistant map projection centered on your precise geographical coordinates.

Determined and serious radio communicators would also do well to invest in our SWARM PROPAK software, which gives radio communicators a significant edge in determining future radio propagation conditions by monitoring solar and space-environment conditions in realtime. It can even reliably predict the arrival of interplanetary disturbances up to 60 minutes before they actually impact the Earth - enough time to perhaps get prepared for the pre-storm enhancements that very frequently occur. It has been said that this software is as valuable as a good rig on a mountain top. It is, in fact, the only software in the world for PC's capable of plotting almost every conceivable parameter relevant to radio communications.

If you'd like to learn more about radio propagation conditions and how the Sun affects ionospheric radio propagation conditions, you would do well to enroll in our Internet Space Weather and Radio Propagation Forecasting Course, which will open your mind and teach you how to interpret solar and ionospheric conditions and apply them properly.

For a complete menu of radio propagation, solar, and auroral activity, please visit our home page by clicking here. We have been a major supplier of reliable solar and geophysical services and software to prestigious research institutions around the world for almost a decade.