https://web.archive.org/web/19981201043600/http://www.d-shore.demon.co.uk/HQ.htm

HQ MODES NEWS UPDATE

2 March 1997

Dear Robot 1200c/SuperScan 2001 user,

The HQ mode was introduced at the end of October 1996, to provide
improved picture quality and reduced transmission times compared to
the currently popular 'Martin 1' and 'Scottie 1' modes.

At least part of this improvement in quality, is made possible by the
precision and accuracy of the crystal oscillators in the Robot 1200C
and SuperScan 2001, originally added to work with the synchronous
modes like Martin and Scottie.

The HQ mode has been specifically designed to work with these
dedicated scan converters and takes advantage of their particular
characteristics. To avoid a repetition of the Martin 1/Scottie 1
'sloping picture' phenomenon on PC based software systems, and errors
in colour registration, other SSTV software developers, have been
asked to satisfy the precise timing parameters of the HQ mode and
verify the performance of their systems with the HQ mode designer
before releasing this mode on their software.

However, despite this request, one company, G. V Associates, who
produce WinPix Pro, have secretly reverse engineered the HQ mode,
presumably from signals received from the 1200/2001, and now have HQ
mode on their system, which was released around the beginning of
February 1997.

If you use this Mode you should be aware that this implementation of
the HQ mode does not conform to the original specifications, as might
be expected from the way the parameters were obtained.

You can recognize these transmissions as they do not have the yellow
writing on blue background callsign identification which you will be
familiar with from your own transmissions. Due to timing inaccuracies
you will observe more ragged verticals from these transmissions.

There is also a problem with picture starting, as it is almost
impossible to start the Robot/Superscan on these transmissions if the
VIS start-up code is missed. This system is ruining the HQ mode and
spoiling the hobby for ALL slowscanners.

To make matters even worse there is now a 'Freeware' version of this
software called "WindowSSTV" which may be downloaded from the
Internet, so you can try it and verify the problems, I mention, for
yourself. If you have any comments or suggestions please write and
tell me:-

E-Mail -> memmer@stcssl.co.uk.