That kind of doubt should always be the first consideration in data transmission.
Some 9 years ago I had a request for a project that never materialized, because the "client" wanted to transmit several raw, uncompressed data base files to a central office, subtituting a "floppy mail" transfer, at the end of the month. They did not accept compressing it (it was too complex for their PC operators...LOL) nor doing daily, small incremental updates. Redundancy in DBF or CSV files is usually very high. Stubborness won on that case. Sending some 20 1 MB files simultaneously on a VHF FM packet channel was simply too much for the closing day. Of course, nowadays it would be a cinch with a WLAN. If I were to send those CSV files (which after all are history, data accumulated up to a given past moment), I would compress it first. Of course, it creates a binary file out of text, but again, there are many methods (some of them partially forgotten) to create pseudotext (btoa, uuencode, etc) to solve it. Nowadays mailers do it transparently...I had to learn about it the hard way, doing it manually. 73 de Jose, CO2JA --- list email filter <[EMAIL PROTECTED]> wrote: > Walt, > > I don't doubt that the source data is 20K/Minute or > greater, what I > question is whether or not sending the 'source' is > necessary? It seems > to me that you are asking us to find ways to solve a > problem, it often > helps to step back and look at the problem and ask > questions. I make my > living as a consulting engineer, and I know I > exasperate many of my > clients on the first day I walk into a project > because, rather than > following their predetermined thought processes, I > make it a point to > question their thought processes. Basically, I > define and solve > problems, and help implement solutions for a living. > It is not unusual > for the solutions I engineer to differ greatly from > my clients > preconceived notions of what they initially thought > they needed, but I > do solve their problems. > > What I question is whether or not we shouldn't look > at technology > solutions that for instance don't require > transmission of 20K/Minute of > text, but still solve the problem. Especially for a > weather system > (I've lived through hurricanes, and spent a fair > amount of time in > tornado alley as well, so I do understand the > importance of this > information to public safety), it seems that what we > are monitoring is a > changing system, we might be able to come up with a > data model of it > that may be a little more granular, be represented > by a lot less data, > and still get the job done. We often have more > sensors and more > precision available to us than we need to make > decisions, sometimes we > need to trim the data. When normal comms are > functioning 100% sending > the full data with the greatest precision possible > is great, when the > normal comms fail, we are left in a fall back > position. If we allow our > 'fall back data channel' to choke because we are > trying to provide a > 100% solution, haven't we failed our mission? What > if we could condense > or abbreviate our data stream significantly, > wouldn't it be a worthwhile > effort to pursue? > > Engineering is a discipline of making the > appropriate economic trade > offs, we live in an era of the information age where > data memory, > storage, and processing capacity are extremely > cheap. Usually bandwidth > is cheap as well, so we have a certain mindset about > not spending effort > or money to maximize its efficient use. In this > case though, bandwidth > isn't cheap, one could argue that from a public > safety point of view, it > may be the most precious of resources, which leads > me back to my > point... is it not possible to spend money and > processing power on > finding a way to greatly reduce the size of a data > frame, thereby > reducing the bandwidth requirements of the system? > Isn't it possible > that effort in this direction might yield the > greatest overall system > performance. > > 73, > > Erik > KI4HMS > > > DuBose Walt Civ AETC CONS/LGCA wrote: > > Erik, > > > > Send me your E-Mail address and I will send you an > 40K sample file of NWS data in csv (delimited text > format) that represents 2 minutes of WX radar data. > > > > I would never want to send this to the entire net. > > > > Walt/K5YFW > > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com Need a Digital mode QSO? 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