[Gpsbabel-misc] Please Help!

[Ron T. <arp...@ya...>]

I had a Humminbird GPS 998C HD SI COMBO unit in a boat the I traded in. I downloaded the GPS waypoints to an SD card and when I tried to use GPS Visualizer or GPS Babel to convert the waypoints to Lowrance version 4 which I now need, there is no data there. There is only a tiny data set there which contains maybe formatting but no data points (only 77kb instead of the 2000 kb that it should be with the data file). Thinking that I may have downloaded the file incorrectly, I asked the dealer where I traded in the boat to re-download the waypoints. They sent the SD card back, thinking that they had also downloaded them correctly. Again, no data set on the card. I don't know if the data set was corrupted or lost or if there was something wrong with the unit by then.
Anyway, I do have a file with this file name on Humminbird PC on my laptop with this file name: GPSVisualizer-20170905151254-88154-data.gpx. I can't remember or re-construct how the data were downloaded onto this program on my laptop and whether they were loaded as a .gpx file directly or loaded as something else and converted.
If I click on the Waypoints tab on the Humminbird PC file, it opens a beautiful table of my 800 or so waypoints with name, latitude and longitude and date created. However I can find no way to convert this to something that I can load to my Lowrance unit version 4.
If I copy the file it shows as an Acrobat Reader icon on my desktop but can not open the file. If I use GPS Visualizer or Babel to try to convert to a Lowrance version 4 file it again gives me a file but with no data.
So can anyone please help me convert the GPSVisualizer-20170905151254-88154-data.gpx file on my Humminbird PC to a data file that I need for my Lowrance unit? I will be sincerely grateful if someone can walk me through the process. Sorry for the long dissertation but didn't know how more concisely to describe my quandary.
Ron Tay...@ya...