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Satellite Dish & TV Aerial Alignment Calculators

Von: Java Jive (java@evij.com.invalid) [Profil]
Datum: 05.06.2010 13:18
Message-ID: <h3ck061n1vhpk9mm34odh3emdngmphmfq5@4ax.com>
Newsgroup: alt.satellite.tv.europe alt.satellite.tv uk.tech.digital-tv
In the past few days I've released updated versions ...

http://www.macfh.co.uk/JavaJive/AudioVisualTV/SatelliteTV/SatelliteCalculator.html
http://www.macfh.co.uk/Test/UKTerrestrialTVTest.html

... and there's now something like an intended final version of the
Aerial Alignment Calculator in the new Terrestrial TV section of the
site (addressed munged because I don't want search engines to find it
until anyone here who chooses has had a chance to rip it to bits first
- for the same reason it's not yet linked from the rest of the site,
you can get out, but not back in) ...

h t t p : / / w w w . macfh . co . uk /
JavaJive/AudioVisualTV/TerrestrialTV/TerrestrialTV.html

Another time-consuming major revamp, and, with the major exception of
the new TV Aerial Calculator, of which more anon, again it's mainly
better old functionality rather than anything startlingly new.


The major changes are ...

All Calculators:


+	Greatly improved support for (the shortcomings of) IE8.

And a number of major efforts to improve loading speeds:

+	Changing loading orders so that the pages can appear sooner.  This
also required ...

+	Asynchronous script and data loading.  For example, settings can
be entered into each calculator before the mapping code has finished
loading  -  the buttons for creating the maps become visible once the
required code has loaded.  (You just cannot conceive how time
consuming that was to achieve).

+	Much better code crunching, by which I mean removal of layout
spacing in the code the sole purpose of which is to make it more
easily read by humans editing it.

-	Unfortunately I cannot easily implement compression, which I
wanted, without changing hosting provider, so that hasn't happened yet


Additionally ...


The Satellite Calculator:

Updated the satellites.xml file, also removing all the transponder
data which the calculator doesn't use.

Added TM-2300 rotor.


The Test TV Aerial Alignment Calculator

Updated the transmitter files with the latest information, including
HD, and also the data is crunched more efficiently.


The Terrestrial TV Aerial Alignment Calculator

Has all the functionality of the test one plus:

+	New format of transmitter file which initially loads and can look
up data more quickly.

+	Regional transmitter lists.

+	Transmitter group lists.

+	List of transmitters in distance order from the receiver out to
100km.

+	List of the likeliest strongest signals from the above  -  this
works down the distance list looking at relays until either it has
covered five or encounters a main transmitter, then works down the
rest of the list looking at main transmitters until it has covered
five or encounters the end of the list.  For each transmitter found,
it looks at the signals currently broadcasting (but perhaps it should
also include post-DSO, even where that is still some years away?
Currently it doesn't!) attenuates them for distance, and for those
that are above the approximate minimum of 54dBuV/m for analogue or
47dBuV/m for digital(*A), it goes and gets path profile information
and attenuates the signals for obstructions.  Any having transmissions
remaining above the minima are listed.

+	Options to switch the OS map between showing the signal path and
whatever of the above transmitter lists is currently selected in the
form.

+	Ability to be used with greatly reduced functionality anywhere
world-wide.


The new Terrestrial TV section has some glaring omissions which I'm
aware of:

1	General Introduction

-	Nothing about how to make a link between the output of the
official postcode checker, or equivalent such as my own calculator,
and what aerial needs to be chosen (beyond my knowledge, constructive
suggestions welcome).

2	Calculator

-	No transmitter coverage maps  -  Ofcom have said that they'll only
release them for each area some time after its DSO, by which time the
major need for them will have passed!  Also, the ones I've seen don't
actually look detailed enough to be very useful, and I don't think
could be used as a basis for calculations.

*A	Formerly I have been quoting figures in dBm/m2, which I rather
confusingly abbreviated to dBm, apologies for any confusion caused.

But that's the least of it  -  mega blush time:  Around February I
gave out some figures that were so wrong I'm surprised that someone
from the group didn't jump down my throat about them.  I'd copied a
calculation from one piece of code working in metres to another
working in km, without noticing the difference in units, so for about
two to four weeks, I'm not sure how long exactly, the prototype was
systematically out by 60!  Two people asking the group for help were
affected, one from Ayr who was wondering whether he might be able to
get HD from Black Hill, and the other had a Southampton postcode and
was walled in by high ground  -  as the *relative* ordering of the
likely transmitters I gave was not affected, I don't think the error
changed anything for them much, but mega apologies anyway.

Realisation of the above has caused me to go searching back and check
all the other results I've quoted, and allowing for differences in the
units and minor improvements in the methods of processing the terrain
profiles, they seem to be consistent with current results.
--
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