Major Magellan Problem
Magellan/Thales corporation does not care about their customers. They falsely advertise ALL their products as WAAS capable, that is a lie. When the FAA and NASA changed PRN#122 to PRN#135 in July 2007 everyone with a Magellan receiver is screwed, some immediately, some only long afterwards after a master reset of thier unit. It will be a lie when some other WAAS/EGNOS/MSAS satellite changes in the future.

With great accolades from the community, I have solved this problem, check Magellan WAAS fix to regain the capabilities that you actually paid for in your Magellan.
Sure, if you can get firmware dated somewhat after July 2007 you "might" be OK, for now until some other WAAS system change occurs. But not so for anyone with what Magellan calls Legacy Products. No new firmware is being created. Even new products like the Explorest 500 are affected and a firmware upgrade would be necessary to fix this problem, a painful process but in this case I have heard that it does work.

I am working on my own way to help everyone. I have 5 ideas:
1. Writing a firmware patch myself that fixes the issue.
2. Creating instructions so anyone can change their own firmware using a HEX editor. Possibly prone to errors so I am holding off on this for now.
3. Writing a program that uses Magellan propriatary NMEA commands to update their WAAS satellite almanac. Not yet sure if their command can be sent to a GPSr from a computer, I know the other direction works so you can see what is stored in the GPSr. At least for the 32 standard GPS satellites, but the WAAS satellites appear to be encoded differently and do not show up in any command I send to the GPSr. This program would be similar to the Garmin Almanac capability of the program G7ToWin by Ron Henderson.
4. Spoofing the satellite signals in my own lab using very expensive microwave equipment. This would only benefit me and anyone who might send me their GPSr so I am also holding off on this. Plus I am not sure if it can even be done. I am sure the government would not like people to be able to do this, since doing this is akin to spoofing or jambing the GPS signals.
5. Shoot down PRN#120 or #PRN#136, then NASA and the FAA WILL have to rebroadcast that signal again. The government would have even more dislike of this, but hey, China just demonstrated a space war weapon a few months ago. I have no idea why our Government, NASA, FAA or USCG do not broadcast that message say for 10 minutes a week at midnight on Sunday. Well I do know a little, they say that Magellan did not buy FAA certified WAAS (TSO-145/146) certification for any of their recerivers so we are screwed. Do not Fly with a Magellan, do not Survey with a Magellan, do not do precision GIS data collection with a Magellan, just don't Magellan at all if you can help it. I know when my Magellan Gold dies I will go with a Garmin or Delorme, but till then I will still work on this problem for myself and all others.

Details of the problem can be read in the folowing forums, you will have to join them if you want to add your own 2 cents:
1. The geocaching forums at forums.groundspeak.com under GPS Related Topics in the GPS Units and Software section. In particular My very first mention of this issue .
2. The www.gpsinformation.net forums in the GPS Hardware Questions under the Magellan section, in particular http://gpsinformation.biz/phpBB2/viewtopic.php?t=5548 .
3. The Southern New England Geocachers Association forums in their Geocaching Hardware section in particular initiation and current information and just for laughs . As this is my home base, this will be most up to date information on the topic.
4. The Yahoo Magellan_Meridian users group, in particular one root message and another root and yet more info and even more again and finally the initiation of all this. You have to join this group before you can even read their messages. This is a fantastic group to join so go ahead and join. There are a couple other Yahoo groups that have interesting and useful information, see below. There are some very smart people who use this forum so there is lots of great information on this and other topics here. But the tree structure of answers to posts is madening, you should read all answers to be sure to have all the correct information.


Satellite almanacs can be obtained from
http://www.navcen.uscg.gov/gps/almanacs.htm and
http://www.celestrak.com and possibly
http://earth-info.nga.mil/GandG/sathtml/index.html .
But they are not in a format that can be immediately used in anything I create to fix this problem for us.
The following document, icd200cw1234.pdf describes much of the mystery of the GPS system. It was also described as holding details the almanac data, but apparently not the hexadecimal translated version that one can read from a GPSr
 

Other Yahoo user groups of interest are:
Meridian_Europe
MapSend
MapSend Format
MobileMapper2
Explorist
I am sure that there are some Garmin related ones but I have not looked yet and have had no need as of yet.

Some other resources of note that may impart great knowledge to this project are
The TuxGPS Open SourceGNU project, a way to write programs for the processor used inside Magellan products.
Magellan's own Mobile Mapper Professional GPS along with their Mobilemapper2 program.
And a very old program, or group of programs along the line of Alm2TLE.
Plus some useful information can be found at the web site of Bev Howard .
The following site has hardware that might aid in option 4 above but it is so darn expensive http://www.navsys.com/Products/aghs.htm I have much equipment of a similar nature to some of this already.
This page also has some cost effective hardware that might help OpenSourceGPS .
Use google to search through yahoo's groups for information and links to these.


I may be reached through my profile as the geocacher TrainLove at www.geocaching.com but please do not contact me directly, if you have any information pertinent to this issue please share it with everyone by posting it in one of the 4 forums mentioned above. Preferably the SNEG one.