SIGNAL SERVER CHANGELOG 

2.61 - 27 Oct 2015
BUGFIX - FSPL model floor reduced from 150MHz to 20MHz.

2.6 - 9 June 2015
Multithreading support added by Michael Ramnarine
PlotPropagation() and PlotLOSMap() use four threads by default
Feature can be disabled with -nothreads flag
Static and global variables have been made threadsafe

2.5 - 27 May 2015
Code refactored by Andrew Clayton / ac000 with header files
New Makefile with c / c++ multi mode compilation
Single executable now with run time switch for HD mode 
Models separated into directory

2.44 - 25 Mar 2015
Improved PPA text report to list other prop models
Added HD mode to build script

2.43 - 06 Mar 2015
Improved model error handling
Tweaked params for Ericsson model and inverted environment variables to match rest

v2.41 - 27 February 2015
Simpler PPA output for scripting
Enabled new models for PPA (previously just ITM)
#Define to enable HD mem options/build at build time (-DHD)
Optimised build command (-Ofast) to improve speed by 14%
Improved test script

2.4 - January 2015
Added SUI, ECC33, Ericsson models in new 'models' module
Added model validation
Retired individual model files as some models only 1 or 2 lines of code

2.31 - October 2014
ERP up to 5MW for Mexican TV(!)

2.3 - 29 September 2014
Replaced itm.cpp with itwom3.0.cpp and added ITWOM model as result

2.23 - 14 August 2014
Improved diffraction model to work only for dips deeper than 20m and not to exaggerate result by an arbitrary figure (3)
Fixed false 'frequency too low' error message for FSPL model which was intended for Hata models only.

2.22 - 
Fixed LOS not outputting bounds

2.2 - 
Made .dot output opt in to save some disk space
Changed version number to line 1 of main.cpp instead of buried in code in two places.

v2.1 - 
Added experimental dual core support with -haf
Requires double the RAM

1.3.8 - 16 Jan 2014
Added Free Space Path Loss model (with optional diffraction)

1.3.7 - 30 Dec 2013
Added propagation model option (-pm)
Added HATA urban/suburban/open models (150-1500MHz) 
Added COST231-Hata (urban) model (1500-2000MHz) 
Added custom Knife Edge Diffraction option (-ked) to enhance new models
Removed unused variables 

1.3.6 - 12 Aug 2013
Added LOS model for up to 100GHz 
Added 1 arc second (3600 pixels/degree) support (-res 3600)

1.3.5 - 07 Jul 2013
Reduced maxpages to 9
Added memset() to clear DEM before use

1.3.4 - 16 May 2013
High resolution SRTM1 1-arc second DEM support added.
Use -res 3600 and ensure .sdf files are produced with srtm2sdf-hd

1.3.3 - 04 Nov 2012
Air planning:
Increased maximum Tx height to 60,000 (m/f)
Increased maximum Rx height to 60,000 (m/f)

1.3.2 - 04 Oct 2012
Re-instated grey scale option to allow for terrain background.
Off by default. Enable with switch -t

1.3 - 03 Jan 2012
Added user defined clutter layers from SPLAT! (-udt switch)

1.2 - 31 Dec 2011
Max colours increased from 32 to 128
Radius value fixed at metric
Metric / Imperial conversion bug fixed

1.1 - 08 Dec 2011
Max Tx altitude increased to 20,000(m) for high altitude aircraft. "Can you 'ere me now?"
Added 2 new options -tercon, -terdic for *custom* dielectric values and ground conductivity. -te terrain option remains. Use with care!
New Earth Dielectric range (Permittivity): 80 to 0.1
New Conductivity range (Siemens/m): 0.01 to 0.000001

1.0 - 19 November 2011
SS released.