History (Part 1) of HF propagation models by Ray Rosich, 1978


[This document is part of the help files integrated into the ITS HFBC software package.]

This information was extracted from an ancient informal letter from Ray Rosich dated June 8, 1978. It has been included here as an item of historical significance. Remember, any reference to "latest" means as of June 1978.

Lenora, June 8, 1978

     For your future information and use, the history of the HF Ionospheric
Radio Propagation Models developed at ITS is as follows:

 * late 1930's and during World War II, a lot of research on propagation
         and the characteristics of the ionosphere was done.

 * 1945: the Radio Propagation Unit of the U.S.Army Signal Corps published
         a report (Kelley, L., Tech. Report No.6, 1945) which summed
         up their knowledge to that point.

 * 1948: CRPL published a treatise on ionospheric radio propagation
         (NBS Circular 462) which outlined the current state of the art
         in HF propagation and prediction (manual) methods.

 * 1950: Laitinen and Haydon (Tech. Report 9, U.S. Army Signal Radio
         Propagation Agency) presented a quite complete manual method based
         upon theoretical and empirical techniques.
 *       The above techniques and other to this time were very laborious and
         time consuming, and to alleviate this problem various workers began
         to think of computerizing the techniques that existed.

 * 1957: Stanford Research Institute (Special Report 1) offered such a program.

 * 1961: Lucas and Haydon (NBS Report 6789) presented the first of a number of
         techniques (computerized) developed by them.  This one was based upon
         computerization of the manual methods used up to that time.
 *       (MUFFOT): Techniques developed to make use of the full power of
         the computer (as opposed to manual techniques) were to come later.
         These techniques were made possible by the numerical maps of the
         ionospheric characteristics (computerized) developed by Roger Gallet,
         Bill Jones, Margo Leftin/Pokempner, Frank Stewart, Ron Graham, and
         others in CRPL at that time.

 * 1962: (MUFLUF): Lucas and Haydon (NBS Report 7619) utilized the most
         recent of the computerized maps and techniques available to develop
         a computer program to estimate the performance of HF communication
         (ionospheric) systems.

 * 1966: (ITSA1): Lucas and Haydon (ESSA Tech. Report IER 1-ITSA 1) developed
         the first truly complete computerizated HF ionospheric propagation
         prediction program.  This is the model that is referred to as the
         ITSA1 program, but actually it existed in a number of versions with
         different names, such as, SEPARTI, GEELOB, ALLMODES, etc.

 *(RADARC): When Lucas left ITSA in late-1966/early-1967, the model
         first being worked on by him from then on for a while was called
         CHIEFY.  Later verious Radar versions were developed by Lucas, Lloyd,
         Headrick, Thomason, and others (NRL Memo Report 2500, 1972), and
         called RADARC, RAMHF, and other such names.  These developments all
         culminate in various Radar versions of their propagation model which
         provide the core of ideas behind the IONCAP model described below.
 *(ITS78): Following a separate path than Lucas, et. al., starting from the
         ITSA-1 model, Barghausen and his group at ITSA developed a
         communication (point-to-point rather than radar) model (ESSA Tech.
         Report ERL 110-ITS 78) known as the ITS78 model.  There were several
         models and computer programs chronologically as the model and
         program were improved.  Each program was given a slightly different
         name and was also color coded (Red Deck, Blue Deck, Yellow Deck, etc.)
         according to the color of the cards on which it was sent out.  The
         color coding was done in an effort to make it simple to determine
         which version that a given person or organization had when they called
         on the phone to ask questions.  This did not always work, however, as
         they would often keep the deck that we sent as a "master deck" not to
         be touched.  They would duplicate the deck on their own cards and then
         work on this secondary deck - and in the process loose the color code!
         Later (with HFMUFES 3 - the Yellow Deck) we began to have the program
         print out at the top of every page the program name and the version
         number and the date of that version.  In this fashion we could find
         out which version the person had, as all he had to do was look at his
         computer printout.

            The deck names, color codes, and significant characteristics of
         the programs are as follows:

         Program Name  Color   Significant Characteristics
         ------------  ------  -------------------------------------------------
         HFMUFES       Red     The program as originally listed in Appendix A
                               (pages 160-224) of the ESSA Tech. Report
                               ERL 110-ITS 78.
                               HF = High Frequency
                               MUF= Maximum Useable Frequency
                               ES = Sporadic E
                               First and original version of the ITS 78 program.

         HFMUFES2      Blue    This version had a number of bugs fixed over
                               HFMUFES, and a number of improvements added.  In
                               particular the "2" in the program name indicates
                               that the continuous (on month and SSN) maps of
                               foF2 were added.  The atmospheric noise maps and
                               ground conductivity/dielectric constant maps were
                               also revised per reports OT/ITSRR 2 & OT/TRER 31.
                               Multiple antennas at the transmitter and receiver
                               (up to 3 each) were allowed.  Revised virtual
                               height maps for the bottom of the F-layer and the
                               E-layer critical frequency (foE) were included.
                               A number of other changes were also made - all
                               described in the "form" cover letter to the
                               Blue Deck (part of the Errata and Addenda).

         HFMUFES3      Yellow  A number of bugs were found in HFMUFES2 & fixed.
                               In addition the program was modified to allow
                               antenna patterns to be read in, an error in
                               subroutine RELBIL was fixed, the "curtain"
                               antenna was modified to allow in-phase and
                               anti-phase configurations.  The foEs deciles and
                               median were checked to insure correctness,
                               subroutine WOMAP was fixed, the ground reflection
                               point calculation & loss calculation were fixed.

                               AND EXTENSIVE COMMENT CARDS WERE ADDED TO THE
                               PROGRAM to explain what the program was doing
                               and to provide references to the reports and
                               books where the equations, etc. were obtained.
                               Also a revised version was installed on the
                               Univac 1108 in Washington,D.C. for use by
                               OT/IRAC.  This is documented in an unpublished
                               report by R.K. Rosich, R.G. Peterson,
                               L.L. Proctor, The OT/ITS-IRAC HF Ionospheric
                               Propagation Prediction Program.

         HFMUFES4      None.   This is the current latest version of the program
                     sent on   as sent out by Vaughn Agy.  A number of fixes &
                    magnetic   improvements were made by myself, Margo Leftin/
                      tape     Pokempner, and Vaughn Agy.  The program is
                               documented (like HFMUFES3) in terms of report
                               ITS 78 and copious comment cards in the program,
                               but also in OT Report 76-102 by Haydon, Leftin,
                               and Rosich.  This version runs on CDC-6600
                               computer, whereas the others ran on the CDC-3800
                               computer.  It is written entirely in FORTRAN and
                               occupies roughly 500K to 600K bytes of memory,
                               and the data base occupies roughly 2.4MBytes
                               on either disc or magnetic tape.

         IONCAP        None.   This is the latest version of the program being
                               developed by John L. Lloyd and Larry R. Teters.
                               It is highly modularized, written entirely in
                               ANSI FORTRAN, and occupies about the same number
                               of bytes of memory and data base.  It is expected
                               to be released soon to replace HFMUFES4 and will
                               come with 4 volumes of documentation:
                                Vol 1: Mathematics & Physics of the Model
                                Vol 2: Internal Structure of the Program
                                Vol 3: User's Manual giving details of the
                                       mechanics of the user of the program
                                Vol 4: An annotated listing of the program.

                               As noted earlier, this program is based upon the
                               good points of both HFMUFES4 and upon the
                               modeling developments of RADARC.

I hope that this helps once and for all to completely spell out the history and existence of
the various HF Ionospheric Propagation Models that have been developed by ITS personnel.
It should also serve to identify which computer programs and reports are associated with each
of these modeling efforts.  If there are any further questions, please do not hesitate to ask them.

                                             Ray Rosich