You'll loose a lot of information when you export the spread sheet as a csv file. It all depends on what's in the spread sheet and what you wan't to do with it on the other end. Exporting to csv reduces the file size but it is not a "universal" answer. Compressing the spread sheet into a zip file will reduce the size for transmission without loosing any information.
WOW, this old thread received a big bump. There are some good things to bring out;
File compression is a great point. I would do both, use a CSV (comma seperated variable) file format and some ZIP-type or on the fly compression system.
One time I had to write an EDI (electronic data interchange) application to move spreadsheet type data from a Windows application into an IBM mainframe. CSV was the format I used as it did not have any of the formatting that is embedded in an Excel-type application (fonts, spacing, field types, etc...). All I cared about was the data. I was able to move a significant amount of information across a 300 baud type telephone modem (the same baud rate we can use on HF).
Radio, and particularly HF radio is subject to all sorts of effects like fading and impulse noise that will cause data drop-outs. You want to move your data in as small of packet sizes as you can so your total errors are lower (the error rate
will be the same but because it may only be 10-20% of the larger data transaction size your errors will go down significantly).
CSV's are very easy to understand. It is just blocks of data, separated with commas. It would look similar to this; 1,1542,65,Y,N,3,54... Your application knows to put the first value in the first cell, look for the comma and put the next value in the next cell, and so on.
Using an application like ZIP will give you compression but also features like CRC (cyclic redundancy check) error detection so you will know about single bit errors and toss out a corrupted packet as invalid. If you were using something like FEC (forward error correction) that validates each packet by two way communications across the radio link you can also improve reliability.
Remember that we cannot encrypt data but I think that since ZIP is a mostly open standard that anyone can use it might be acceptable to use that (ask the legal eagles on here that question).
I ran a test, I took one of my Excel spreadsheets from work that has 437 cells (23 rows, 17 columns, some cells up to 13 characters in length, mixture of numbers and text). Here is what it looked like;
Excel format 16,384 bytes 131,072 bits 300 baud 436 seconds to send
CSV format 4,765 bytes 38,120 bits 300 baud 127 seconds to send
PDF format 114,688 bytes 917,504 bits 300 baud 3058 seconds to send
CSV and zip 1,468 bytes 11,744 bits 300 baud 39 seconds to send
I used the free program, 7-Zip and used the maximum compression (no encryption).
This does not include any sort of packetization (breaking those big transmissions into chunks) or any sort of FEC.