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Review of HF propagation analysis & prediction programs

58 programs at a glance

Since the release of the first Windows environment in 1985, some publishers and amateurs have created small Windows applications on-the-air oriented giving an overview of propagation conditions. Drawback of their simplicity, most show approximate predictions, and very few use the flexibility of multi-windowing. 

None of these applications use the VOACAP engine or a down-sized version of the IRI model, except some methods (e.g. E-layer) used in CCIR noise model. All these applications give thus forecasts with a 50% reliability as all them use median values and don't take into account all parameters of a communication circuit.

Most of these applications display only a couple of parameters, the MUF and LUF for either a specified circuit or at global scale. Some programs provide in addition a point-to-point prediction with a relative indication of field or signal strength or S/N ratio at the target location. Others, more user-friendly, display the global status of the ionosphere on an active map, the user clicking on any location to get the MUF over that area or the signal strength for a point-to-point circuit. The most recent programs, designed specially for Windows 32-bit platforms, are however more complete, providing for example either critical frequencies or downloading from the Internet spaceweather bulletins, alerts or images dealing with the current solar and geomagnetic activity.

Do not hesitate to give me your feedback with any additional information.

DOS Programs  -  Non-VOACAP VOACAP-based

Beacon monitors  - Web & Research oriented

DXToolBox - HFProp - AREPS - SpotPath - W6ELProp - DXProp / PropHF

ASAPS - HF-Prop - PropWiz - Propagation Predictor - IONSOUND Turbo

Black Cat Systems

License, $24.99

DX ToolBox

A special effort has been done to provide a program easy to use, fast with an attracting GUI. DX ToolBox uses online solar and geomagnetic data to calculate propagation estimations. Results are displayed in a large propagation map. Clicking anywhere on the map you can display the target location coordinates, the signal strength, and the number of hops.

All current solar and geomagnetic parameters can be displayed in four additional charts (Current conditions, Solar wind, Magnetic field and Solar data extracted from SEC and ACE websites). In addition MUF and LUF to a target location are displayed in a 24-hour chart using a rainbow indicator to predict the signal strength expressed in dB. A gray-line map permits to follow beacons in real-time, to display short paths, heading and distance to target locations. Long path are not supported yet. At last thanks to its Internet connection, it can also download and display in real-time various bulletins (WWV, Geoalert, etc) and images from any website.

Only drawbacks, it doesn't use either the VOACAP or the IRI model and shows thus some approximations (MUF, silent zone, top band, etc). Windows are also fixed excepted the one related to images and bulletins. I should have give it four stars but working without the VOACAP engine, it lacks globally of accuracy but I like much its GUI.

Now at version 4.6.3, DX TooBox is available for all Windows and Mac platforms (incl. OS/X, iPhone, and iPad). It requires an active Internet connection for get online updates. Read my review.

License, $24.99. 30-day-fully-functional free trial.




To not confuse with the old USAF bulletin of the same name and other homonyms.

Developed in 2000 by Julian Moss, the latest corrections where added in 2002. The GUI is user-friendly and displays a realistic world map showing even cities lights in the darkness (compare the left screen dump to this satellite picture).

The screen is limited to a window of 673x481 pixels. A second small window pops up when you request the MUF/LUF chart. This very simple and light propagation program (~700 KB) takes into account the solar flux or the smoothed sunspot number and planetary indices. Interesting feature, when you type the SFI, the equivalent SSN is displayed and vice versa, an option that I use regularly as a "converter" to enter one or the other index in other applications.

HFProp uses Fricker's F2-layer prediction model. Offering an original and user-friendly interface, it displays iso-contour frequency maps on a gray-line cartesian world map, predict the DX activities for each band, the F2 and E critical frequency, and MUF. In addition it displays a MUF/LUF chart and the strength of you signal to the receiver based of rough assumptions and statistical data.

The new version 1.3 released in 2004 also includes a connection to the Internet (you can type any URL, for example to NOAA's WWV messages) and an automatic updater to get current solar flux and K index. These new features are very appreciated.

While version 1.2 was a freeware, version 1.3 is a shareware. By default the two critical frequency charts are not displayed, but can be enabled (as can maps for other bands, including broadcast bands) by right-clicking the map and selecting "Set visible tabs". HFProp runs on all Windows 32-bit platforms. Read my review.

Today these versions are no more available and the time window stops end 2009 but you can download the version 1.3 installer from this site. They have been replaced by VOAProp that uses the VOACAP engine. It uses the same interface as the this version, and you can download it free of charge on G4ILO's website.




The Advanced Refractive Effects Prediction System (AREPS) program was developed in 2003 by the Space and Naval Warfare Systems Center of US NAVY at San Diego. In a military framework, AREPS computes and displays various electromagnetic system performance in order to assess tactical decisions. These systems include radar probability of detection, electronic surveillance measure (ESM) vulnerability, V/UHF communications, simultaneous radar detection and ESM vulnerability, and surfacesearch detection ranges.

Divided in 10 modules, AREPS is functional for all frequencies between 2 MHz and 57 GHz. In the framework of ham activities most tools are useless. However two of them deserve your attention : the HF communication project that displays propagation conditions between two radio stations and the Ionosphere raytrace that uses the IRI model. Optionally the Troposphere raytrace project could interest the few U/SHF users.

About the HF communication module, from a reduced set of inputs like the time, the location, the environment, the sunspot number and K-index, AREPS displays several maps and charts among which the Electric Field, Received power, S/N ratio, Propagation loss, MUF, FOT and LOF. Using the mouse, you may display values not mapped (e.g. if you display the S/N ratio, with the mouse you can display the received power, propagation loss, etc).

One constraint, as explained in the manual, the regional settings must be set to English (USA) or even English (Ireland) for European in the Euro zone to prevent systematic errors with the comma in numbers, very annoying.

Now at version 3.6, AREPS is a freeware. It comes with a complete online manual, including a big PDF manual of 284 pages (3.17 MB) very well documented.

Unfortunately, for some years this program is only available to U.S. DoD military users (having a valid ".mil" e-mail address). It is no more available at Navy's Spawar and the other links are subject to malwares.

For all Windows 32-bit platforms but ME.




Richard Loftus, VK4EMM, provides an original propagation software organized around a propagation table that gives an instant picture of propagation conditions to 28 regions from your QTH. Like many non-VOACAP applications, it uses a database made from contests and DX-pedition results. SpotPath performs all path analysis during the initial program start-up using pre-compiled datas for your QTH.

After have entered the right date and solar flux FSI (between 80 and 200), the main window shows the short path conditions from your station to any entity. Expected signal strength is represented by the glow or brilliance of a cell, changing from black (highly unlikely propagation) to white (best propagation) with four different intermediate shade of blue (dark, light and cyan). You can see this way and in a glance propagation openings to a specific DX entity or to all 28 regions for all five main bands for 24 hours in one-hour or in half-hour slots.

You can zoom in the selection by clicking with the mouse in a cell, on the "zoom" button or using the command line, leading each command with a dot. For example, to display the propagation to JA, type "JA.". If your entry is not listed among the 28 predefined regions, SpotPath jumps to the nearest listed location. Indeed, its database is linked to all 75 ITU and 40 CQ Zones. You can also search on ITU and CQ zone numbers, as well as on prefixes

In addition, SpotPath includes a beacon monitor that highlights the zone in which the NCDXF/IARU beacon is currently active. You can use this tool to calibrate the propagation table in using a small tool located below left called Turbo (beam booster). Depending on your setup, you can change the propagation for all bands to reflect your real conditions.

>SpotPath comes also with a planner in which you can keep track of openings and a status map listing zone multipliers (for contests). It can be linked to a network version of CT Logging Program to keep track of zones worked in each band. In this mode SpotPath can send alert and pop up messages to operators. At last, SpotPath comes with a short manual in Word format.

SpotPath is now at version 2.01.12. Freeware for Windows 95, XP and 2003 platforms.

Unfortunately this program is no more available from Spotpath nor directly to VK4EMM.




In the line of MINIPROP PLUS, Sheldon C. Shallon created in 2001 this ionospheric propagation program that works under Windows. This point-to-point model take into account a basic communication circuit and is able to predict the status of the ionosphere on frequencies between 3 and 30 MHz. In input it uses the transmitter and target locations, and supports grid locator. Its locations are extracted from an atlas. Then the SFI (SSN in option) and K-index are take into account, as well as the QRM at target location, noise bandwidth, minimum takeoff angle, and signal level suppression threshold. W6ELProp uses a better mode-searching algorithm than MINIPROP Plus that takes into account the D-, E-, and F-layers of the ionosphere to calculate receive signal strengths. MUF calculations use Raymond Fricker's F-layer method developped in 1985 combined with the E-layer method developped by CCIR in 1983.

Results are displayed under various forms : world maps, charts and tables. The MUF can be displayed on a global ionospheric map in two resolutions (low with 57 areas or "high" with 877 areas) or in a graph (frequency vs. time). A gray line map can also be displayed. Other results related to the signal strength are displayed in tabular forms (signal strengths in dB above 0.5 mV, S/N ratio, availability, takeoff angle, etc). The program is still supported but without warranty of reliability, etc. The menuing could be improved. For example you have to close some screens (graphs) to be able to access to the main menu and maps, and you cannot display the graph without requesting a new prediction.

DOS program written with Delphi. Executable running on Windows 16 or 32 bits with 256 colors minimum. Compatible with Windows ME and XP.

Freeware. Support reduced to the strict minimum by the author.


Freeware (DXProp)

Shareware (PropHF)

DXProp / PropHF

Written by Christian Ramade, DXProp and PropHF are inspired by David L. Mills, W3HCF's application written in C language for DOS in 1995. Both applications are available with a French or English interface to select during the installation process that uses a complete windows installer from DataChris Software Inc. Both applications differ only by the screen. There are however some minors bugs in these layouts. The English interface is either inop or partly displayed in French and the user callsign is taken into account only after have closed and rerun the application.

Both applications are based on the algorithm used by MINIMUF 3.5 and predict the MUF from the SFI, date and time, the transmitter and target locations. They offer thus the same approximations than the NOAA application. The MUF is determined by hop-testing between the home QTH and the target location until the radiation angle and the calculation stops in the vicinity of the receiver. Then, from the emitting power, frequency, and antenna gain (you have choice between an isotropic, a dipole and a beam), the ionospheric absorption is calculated, the attenuation and the delay of propagation. The signal level is fixed to a sensitivity of -123 dBm (or 0.15 mV into 50 ohms), common to all modern receivers. The S-meter is also calibrated at 6 dB per S-unit. 

Both application display all settings in the lower part of the screen and a grayline map in the lower right part but the image is a bit too dark. Results, not much, are limited for DXProp to the point-to-point MUF curve and the signal strength expressed in dBW for each frequency and time, and for PropHF to four superposed charts in text mode showing either the signal strength expressed in dBW concatenated with the number of hops to the target location, or the takeoff angle, the delay in milliseconds or the best frequency.

For all Windows 32-bit platforms.

DXProp is a freeware but PropHF is a shareware to register with a 20-day-free-trial period.



License, AUD375


This is an australian product developed by IPS. "ASAP" stands for Advanced Stand Alone Prediction System. It permits to predict propagation conditions at HF but also at low VHF frequencies (1 to 45 MHz) what is rather unusual. 

It is based on the ITU-R/CCIR noise model and is able to creates either point-to-point (field strength) or area predictions. However, if it looks like a VOACAP interface it hasn't its power and flexibility yet.

The kernel is available for Windows 32-bit, Sun, Linux and FreeBSD platforms.

License, AUD375. Much too expensive for results in the average. Demo and tutorial available for Windows 32-bit platforms.


License, $40


This is a New Zealander product written by Mike Harris in 2002, now at version 6 to not confuse with the old USAF bulletin of the same name and other homonyms.

From the home and target location, the solar flux (SFI) and K-index it predicts the MUF and LUF for the specified path, nothing else, even the SNR or power at receive is not available. 

Results are displayed in a chart. A world map shows the gray line, the short path, distance and beam heading to the remote station. In option, some capital cities can be highlighted. You can also change the QTH by double clicking anywhere on the map. A central separator permit to extend or reduce the size of both screens but you cannot get simultaneously both in full screen. Among the small bugs name for the chart the title length that exceeds the window, and for the map some paths remaining when you change of location.

License, $40. For Windows 95/98/NT/2000/ME/XP. 30-day-free trial.

Rohde & Schwarz



Propagation Wizard, or PropWiz as it is called, takes into account the date (year and month) solar and geomagnetic indices, transmitter power, transmit and receive antenna gain, takeoff angle, noise figure at receive, ground properties, and SNR. All settings and the output are displayed in the main window that does not provide multi-windowing capabilities.

Results are displayed in a chart showing the MUF and S/N margins for the specified circuit.

Freeware. For all Windows 32-bit platforms.



Propagation Predictor

Written by David Ribbins, KY1H in 1989 and updated in 1996, "MOF/LOF Contest Propagation tool" as he prefers to call his program is derived from MINIMUF for the high bands, and a VOA absorption style predictor for the low bands. The author also adjusted parameters from real contest data collected from various locations since 1990. The latest version 2.2 uses A and K indices to take into account disturbed conditions.

Predictions can be displayed in rectangular, polar or equi-distant projections at three resolutions but even the highest remains very low for Windows standards (EGA).

From a couple of dates the program generates several global propagation maps showing the MOF or LOF. Maps can be displayed with a step as short as 1 minute of interval. Of course in this case the initial calculations last some minutes to calculate all intermediate maps in the concerned time period. If the delay is too long the program provides a STOP button to interrupt the calculation and displays maps already calculated. Each map can also be overlayed with great circle paths and sun rise position. An auto-playback feature lets you replay pre-calculated predictions in real time or accelerated time. When used with the MMPRINT utility provided by the author for the CT Contest Logging software, MOF/LOF can be used to display the geographical and frequency band distribution of contacts from actual contest data. No help function is operational in this version.

Freeware. For all Windows platforms. A DOS version is also available.

Skywave Tech. Soft.

License, $5


This is the Windows 95/98 version of IONSOUND HDX. Qualified by the publisher of "very sophisticated ionospheric propagation prediction program" (sic!), he provides however no screens dumps or specification to appreciate this program. As we don't buy a cat in a bag, even cheap, I was unable to test this product that should run on all Windows 32-bit platforms.

License, $5 if sent by email.

In addition, here are some programs dedicated to V/UHF ground propagation, to name : RFPROPSPLAT!, UKW Tools, Radio Mobile Deluxe or Ground Wave Prediction System.

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