          Changes in Versions 500 and 501 of SNAPmax
          ------------------------------------------

          SNAPmax was extensively rewritten for V.500/501. Although
          it has not changed in its essential "look and feel", many
          great features have been added.  If you have used SNAPmax
          previously, it will look a little different in places but
          you will find that it's comfortably similar in use and in
          general appearance, even to much earlier versions.


         **   USING SNAP.INI FROM PREVIOUS VERSIONS of SNAPmax    **
         **  ==================================================   **
         ** As SNAPmax is now set up for free non-commercial use  **
         ** it generates a new .INI file for you automatically.   **
         ** SNAPMax is also fully compatible with any previous    **
         ** QTH files from Version 28 (2.80) onwards.             **


          Enhancements in the successive versions are:-

          Version 5.01:-
          o Field strength algorithm for top band (1.0 - 2.0 MHz)
            is new, and from 2 - 3 MHz is interpolated with HF.
          o Antenna gain vs. elevation angle was reworked to allow
            for high ray angles.
          o A noise vs. frequency presentation is now available.

          Version 5.00:-
          o A new display shows the performance of any of many modes
            (CW, PSK, RTTY, TOR, SSB, AM, broadcast AM, wideband FM)
            as Good, Median & Poor --- depending on their required
            bandwidth and inherent efficiency of coding etc.
          o Local ground-wave propagation can be displayed for a
            variety of modes, power levels & antenna polarizations.
          o Three remote sites are saved, with transmit antenna data,
            power, name, prefix, latitude and longitude. A fourth
            "site" presents your ground wave propagation data.
          o All site data may be saved independently for future use.
            The data you use for "Band Open" can now be saved too.
          o For digital modes, multipath delay is calculated, and the
            likely onset of significant signal distortion indicated.
          o Long path can be selected and displayed.
          o Noise data for VK1 thru VK8, ZL, JA, ZS, DL, F and very
            many other world wide etc. countries is now included.
          o A frequency scan from 2 - 12 MHz can now also be selected
            for better detail on lower bands, for example in NVIS use.
          o An option allows an approximate estimate of "chordal hop"
            signals, but makes no prediction of mode probability.
          o The 'analysis' graphic displays have been improved and now
            show signal-noise ratio and required levels. ["Good" etc.]
          o Day/night condition at the ends and mid-point are shown.
          o FOT is now shown on print-outs as well as on screen.
          o Presentation and operation much simplified and improved.
          o Many technical improvements described in tech. data files.

          Version 4.00 etc. This series was developmental, and moved
            to internal world-map based loss calculations.

          Versions 3.40, 3.50 etc.:-
          o  You can select your own preferred default start-up mode.
          o  The graphic 'analysis' mode has E,F mode flags, shows
              probable limits of MUF and has much path data,
              including circuit probabilities.
          o  MUF is from Fricker's equations (from the BBC).
          o  Antipodal focusing is included with optional extent.
          o  Auroral zone loss calculations are provided to Northern
              and Far Southern stations using near-polar routes.
          o  Users can use internally calculated antenna gain, their
              own gain values or zero-gain isotropic antennas.
          o  Users in USA, Canada, Australia, NZ & UK have internal
              noise maps; anywhere else, you can use your own noise
              map data, as well as an approximate internal value.
          o  All QTH records are compatible with earlier versions.

           GL & 73 DE Crawford MacKeand  WA3ZKZ, VP8CMY, ex-G4ARR
         Tyndar Press P.O.Box 236 Montchanin DE 19710 USA 19 Sep 01


