Courtesy of Allard, -- PE1NWL and the DXRobot - Gouda - The Netherlands
Written 2003, revised 2004. Please advise of any needed revisions.


Home Page of the DX Robot -

There are two North American lists.
One list is "eskip-na". This will alert you only when the sporadic E MUF has actually reached 144 MHz.
A second list, eskip-na-early, will alert you when the MUF is building but has not necessarily reached two meters.
You can subscribe to either list.
(And there are other interesting lists - see the GoodDX Home Page for more).

The "early warning" list will produce more false alerts, but may not alert you until after the typical short North American Es opening has already died out.
Therefore, it is suggested that you try the "early warning" list first. If this generates too many alerts where the MUF does not quite reach two meters, unsubscribe from it and subscribe instead to the "tighter" list.
See under This is still experimental, below, for more details on the two types of alerts.

You can subscribe/unsubscribe/change your subscription at
Enter your E-mail address in the box indicated, check Browse All the Lists and click "GO", and check the "eskipna" or "eskip-na-early" box (plus any others you're interested in. You might want to also subscribe to the daily European Es summary - it's fascinating to see what they have worked!).

When a report is uploaded that contains a "key word" concerning sporadic E, the DXRobot will send out an E-mail alert to those who have subscribed.

Remember, though, that most people do not yet know how to properly post their reports. Also, this is new and is still being fine-tuned. Thus there will be bugs and false alerts at times. Please be patient.

If you log on to, you can get a listing of the loggings that were harvested by the NA DXRobot. Each of them would have caused the DXRobot to generate an Es alert. This North American summary is not sent out automatically each day - you must manually go on the Web and read it, so you may wish to bookmark this page.


Please remember that the alerting system works only if YOU report your Es observations. These reports must be made to the 144 MHz Propagation Page! (Bookmark this page!) When you report, you must use Es, Eskip, or e-skip in the post, along with the location of each end of the propagation and call (if known), and your call.

WARNING - when entering an Es report on 144 MHz Prop page, use the text box at the top of the page, and include your call and grid on that line! Do not use the box at the bottom for your call, because the DXRobot strips this off.

Do not abuse this service! (The DXRobot can be set to disregard anyone who continually misuses the service).
However, remember that the 144 Prop page is for reporting all types of propagation. Simply specify what you are reporting. The DXRobot ignores any posts that do not include one of the sporadic E "key words" and it also ignores posts that include any of a large number of "inhibiting" words.

How well it works will depend upon the reports available to the DXRobot on the 144 MHz Propagation Web page.

HOW IT WORKS, as explained by PE1NWL

Every 5 minutes the Robot checks the reports on the 144 MHz Propagation page at The Robot then filters the newly received reports based on certain criteria (i.e., one of the "Es key words"). If the criteria for Es are met, then the Robot will send alerting messages out to its mail list.
Once an alert has been sent, the Robot then "locks out" for a period of time (currently set at one hour) and does not send any more alerts until that time period has elapsed and another post is made. This is to keep from flooding your mailbox if a number of additional reports quickly follow the initial report.
It is set so that "European," "No", "Nil," etc.will cause it to bypass that message; otherwise, comments on a huge European opening or on our lack of sporadic E would trigger it, causing false alarms. (There are a number of other words that will also inhibit an alert. Therefore, when making a report, make it short, simple, but complete. But nothing extra. If you need to put in further information, put it on a separate posting [separate line] on the Prop Page).
The DXRobot has its own mailserver so that all of the E-mails can be sent out rapidly.
The DXRobot does not make forecasts, and the alerts are not generated based on any prediction or forecast. It simply 'detects' that there could be an opening based on the band or SWL activity, as reported on the 144 MHz Propagation Web page.

PE1NWL has also added an E-skip status flag specifically for NA at the propagation monitor page. Other people can easily add this real time flag to their own websites (see and look at the bottom of the page for instructions how to add the monitor to your own webpage). See the Hot News Page for examples.

Remember, all you will get via E-mail is a single alert. This will not really tell you anything except that you need to start checking.
1. Go immediately to the 144 MHz Prop page and read any other postings. Then check that page occasionally after that.
2. Turn on your 2-meter rig, point your antenna in the most likely direction, as indicated by the loggings.
3. Turn on your 6-meter rig, TV or FM BC receiver or whatever you have to check the lower frequencies.
4. You may want to download the simple Es MUF Calculator by G7RAU. (Put in the grids at each end of the path, along with your grid and the reported frequency, and it gives you some general idea of the MUF, a possible direction to head, etc). Go to, download RAUMUF.ZIP at the bottom of the page.
(Note - the Live MUF program has been modified to be usable in North America. See the other column for information on it.
5. If there is no usable sporadic E in your area, continue to check occasionally. It can build to a high MUF in only a few minutes!
6. If you do hear something of interest, report it on the 144 MHz Prop page.
7. Later, get a summary of all the loggings from the DXRobot.
8. Remember that this North American Alerting Service is still new and false alerts must be accepted. There have already been several changes, and there will continue to be changes as it is fine-tuned to meet our needs. Check this page and the Hot News page occasionally for updates.
9. Some other important points from Allard:
- The DXRobot is a FREE and strictly NON-COMMERCIAL service to the VHF ham radio community.
- Your email address will NEVER be given away to anybody.
- The DXRobot will NEVER send any spam.

The North American service was set up in the middle of June 2003, and a number of changes have already been made to improve its operation and better meet our particular needs (which are not exactly the same as the European needs). There will be occasional false alarms until everything is fine-tuned properly and until NA operators learn to use the system. Please be patient, and please help others learn how to use the alerting system and to post the proper messages.

From the feedback received by Allard, it appears that in NA there are basically two groups of DXRobot users:
1. Those who want to be alerted in an early stage when the MUF is high but not yet high enough for 2M DX.
2. Those who want to be alerted only when the MUF has actually reached 144 MHz.

In order to satisfy both target groups, Allard has now set up two seperate alert systems.
The original alert list named "eskip-na" will from now on be used only for alerts when it is reported that the Es MUF has actually reached 144 MHz.
A second list named "eskip-na-early" will be used for 'early warnings', e.g. FM/TV loggings, etc. as the MUF is rising and approaching two meters.

If you want to receive 'early warning alerts', subscripe to "eskip-na-early". (Note that there will be more "unnecessary alerts" with this list).
If you want to receive Es alerts only when the MUF reaches 144 MHz, subscribe to the "eskip-na" list. (However, by the time you receive an alert, the opening may be over).
(It is recommended that you first try the "early warning" alerting system. If this does not meet your needs or generates too many unnecessary alerts, simply change your preference).
If none of this suits you, or if you prefer to do all of your own monitoring, unsubscribe.

Alerts can also be sent to some pagers (depending on your pager set-up), so you might want to consider that method. (Some in North America have been able to use this service, some have not. No more details available at this time).

Remember that changes and fine-tuning will undoubtedly continue to be required. If you have problems, please let us know.
Go to for more.

What about an aurora alerting feature like the Europeans have?
Allard does not want to attempt this until we know if the Es alert generates any interest and can be used properly.
If you want a general space-weather-type (not propagation report) auroral alerting system, go to and subscribe to this service. It works quite well. And don't forget N1BUG's aurora page.


The following information is provided by Allard so that you can see how the European version of this works, which is somewhat different than our system. It might give you ideas for further enhancements of ours.

Every 5 minutes the Robot receives the DXcluster spots from the DXsummit website at (The DXsummit is just a gateway between the packet radio DXcluster and the Internet. So anything that's posted to the worldwide packet cluster will also appear on the DXsummit webpages. The Robot then filters the newly received DXspots based on certain criteria. If the criteria for Es or AU are met, then the Robot will send alert messages out to a mailinglist (currently over 1,000 users worldwide, subscribe at The DXRobot has its own mailserver so that all of the emails can be sent out rapidly. Approx. 1,000 emails and SMS messages are sent out within 4 minutes. In addition, the propagation monitor status is updated, so that other VHF websites that have links to are also updated instantaneously. Because of the many links from other websites to the monitor, I get a lot of traffic on the monitor webpage. Recent logs show that the monitor has over 12,000 hits per day.
(It also has a two-hour lock out, I believe, timed from the end of an opening. And after three years of operation, some operators still don't know the proper way to report).

If you're interested in 144 MHz (or 222 MHz) DX, try Allard's North American Es alerting service. I think you'll like it! If you don't, just unsubscribe. Be sure to bookmark the 144 MHz Propagation Page at and immediately report any Es! If you have suggestions for enhancements, let us know, since this is still experimental. Watch for notes on updates, changes, and additions to the service on the Hot News Page.

To learn more about sporadic E, here are several articles:
"Sporadic E - A Mystery Solved?", Dr. David Whitehead, QST, October and November 1997.
"144-MHz Sporadic E", Emil Pocock, W3EP, QST, July 1994.
"The World Above 50 MHz", QST, April 1998.
"The World Above 50 MHz", QST, September 1994.
N1BUG's summary page, with signals, at
A Seven-Year Study, by Pat Dyer, August 1972 CQ, at
Modeling and Maping Sporadic E with Backscatter Radar, at
Sporadic E Clouds Evolution Map, at
Dependence on Planetary Waves, at
(A primary source is Smith, E. K. Jr, and Sadami Matsushita, eds., Ionospheric Sporadic E. London, Pergamon, 1962).

Europe's sporadic E season in 2003 produced opening after opening last summer!
See an overview of the FANTASTIC European Es season at

See also Hot News page and the HSMS home page.

June 2003 - rev March 2004, May 2008