I would rather use zip, rar or gzip. Maybe, bz2 for an extra squeeze.
.doc format is VERY redundant and has a minimum size around 20 K,
even if you type a pair of characters.
Possibly .odt is a good move. Even then, I would compress it.
Even using plain text, compression and uuencoding did gain a few bits.
It does not matter on a 28 K modem, it did on 1200 baud packet.
Possibly, .pdf is adding some more redundancy or a minimum payload size,
as .doc does. I have not verified this.
Jose, CO2JA
KV9U wrote:
> I ran a few tests to see just how long it really takes for sending a
> document via a digital data program such as WinDRM. If you had a
> good path and probably at least a 10 db S/N ratio, the transmission
> time for my test document of 29 K was only about two minutes. The
> test file is a two page document with an inserted table listing the
> Emission Classifications and then some additional notes. Fonts are
> large so a close spaced two page doc might be large in size. However,
> 20 to 30 K is very doable on digital SSTV so docs should be no
> different.
>
> Now if you convert this .doc file into a moderately compressed (90%)
> pdf file, it grows to 67 K, so that is probably not a good direction.
>
> A possible answer might be to move toward the coming standardized
> file structure already available in FOSS software such as Open Office
> that uses the Open Document formats such as Open Document Text
> (.odt). These files are almost always half or less of a MS .doc file
> and yet it seems to have quite adequate formatting and Rich Text
> equivalency.
>
> The identical ODT file was transmitted in about one minute.
>
> Needless to say, this is really pretty neat since the program can ask
> for any fills if there are damaged blocks, a crude form of delayed
> ARQ. And in between you can be chatting back and forth on voice too.
> This has major applications for emergency type communications,
> especially with the need to send ICS Form 213 and that type of
> document. For really bad conditions, you could not use voice all that
> easily anyway and would want to revert to the Data/RTTY part of the
> band to send it as text perhaps, but that is not that easy to do with
> tabular information.
>
> Perhaps we should be carving out a frequency for playing with this
> digital stuff in the HF bands? At one time wasn't image only
> available to Advanced and Extra Class here in the U.S. and that was
> what lead to the choice of frequencies? If I understand it correctly,
> General Class Operators can use image anyplace on their voice
> privelege areas under the current rules. Perhaps we could use 5 KHz
> above the bottom of the General Class voice frequencies. That way if
> you did use LSB you would not be accidentally out of your subband if
> you were a General.
>
> Since 7175 will be the new lower end of the band for 40 meters, maybe
> we could use 7180. Then on 80 meters for "local" work, we could use
> 3810. And on 20 meters, which won't change, we could use 14220. If
> there are existing nets we would have to work around that of course.
>
> 73,
>
> Rick, KV9U
>
>
>
> John B. Stephensen wrote:
>
> > The FCC rules provide the following definitions for fax:
> >
> > Image. Facsimile and television emissions having designators with
> > A, C, D, F, G, H, J or R as the first symbol; 1, 2 or 3 as the
> > second symbol; C or F as the third symbol; and emissions having B
> > as the first symbol; 7, 8 or 9 as the second symbol; W as the third
> > symbol.
> >
> > Facsimile. A form of telegraphy for the transmission of fixed
> > images, with or without half-tones, with a view to their
> > reproduction in a permanent form. (RR)
> >
> > Telegraphy. A form of telecommunication in which the transmitted
> > information is intended to be recorded on arrival as a graphic
> > document; the transmitted information may sometimes be presented in
> > an alternative form or may be stored for subsequent use. (CS)
> >
> > Since it can be transmitted in either analog or digital form with
> > almost any kind of modulation and there are no encoding
> > restrictions, a fax seems to be any printable document -- even if
> > it isn't printed immediately.
> >
> > 73,
> >
> > John KD6OZH
> >
--
MSc.Jose Angel Amador Fundora
Departamento de Telecomunicaciones
Facultad de Ingenieria Electrica, CUJAE
Calle 114 #11901 e/ 119 y 127
Marianao 19390, Ciudad de la Habana, Cuba
Tel:(53 7) 266-3352
Email: [EMAIL PROTECTED]
__________________________________________
XIII Convención Científica de Ingeniería y Arquitectura
28/noviembre al 1/diciembre de 2006
Cujae, Ciudad de la Habana, Cuba
http://www.cujae.edu.cu/eventos/convencion
