It looks like he took a female 1/2" pipe adapter to 1/2" PVC pipe and just glued it into the 3/4" LB, some manufactures of PVC fittings will fit into the next size up like this, and some will be to big, I have also seen a few PVC LB's with threaded bosses to which one could just use a reducing bushing, I would never have put the LB with the long side sticking out as this makes the connection to the cabinet or box weak and if it were hit it would be much easier to break off then if the short side of the LB was attached to the cabinet/box, the LB can be attached to the cabinet/box with a slip in chase fitting or more properly called a box connector but this would allow the LB to turn if not tight a threaded connection would be a more secure connection.
Personally I would like to see a metal threaded connection to the cabinet if this is in a location where it could get bumped or hit, also if your GPS antenna is lower then the cabinet some of the sats could be blocked so it might be worth while to add a little length of pipe to raise the device above any obstruction of course this depends upon how many channels this device can receive, 12 channels plus 1 for the geostationary sat (WAAS) is common but for simple time and location is not necessary as its not being used for nav use.
Welcome to the forum and as a reminder of the forum rules, since you are not directly involved as a electrician please keep any "how to do" questions limited to those that directly involve your form of work.
I find this device interesting as I do allot of outdoor lighting and do install some timers that also eliminate the use of photo cells such as ones with the astro-metric type timers, I never thought of a GPS based lighting control before as I would think it would be cost prohibited?? the ones I used the most are the Intermatic 600 series that replace a wall switch, but they are not real reliable as I have had problems with them, and most home owners would not have a clue in how to set them but most cases with the battery back up they are set and forget devices and work great, and are about $45.00 so when one works right my customers love them as they never have to mess with them after a power outage or DST changes or the season time changes of the sun setting earlier in the winter verses summer.
Knowing that a GPS has to have view of the sky, if you could design a device to have a remote GPS outdoor receiver that could send its data to a remote electronic timer maybe via a wireless means, whether wall switch mounted or it's own box, and the price is not to much it could be a hit??? as the timer would always have the correct time.
