I haven't come across discussion of a top loaded antenna. Have I missed something?
The antenna used on our TIS station is nearly what I would consider top loaded. The overall lenght is about 10 feet. The loading coil is long, about 3 feet and the tuning stub above that is only about 1 foot.
Works fairly well.
I built a center loaded antenna that did OK.
Sorry.....what's "TIS"?
There has been a great deal of discussion over the years on this forum. Use the Part15.us search box at the top of the page. Type in "top hat".
TIS stations are used for highway information, weather alerts, tourist info, etc. They are low power AM stations (up to 10 watts) licensed to Government agencies. This service is not available to individuals or groups, but only to governmental entities and park districts.
Our city has one used in conjunction with an outdoor siren warning system.
http://www.fcc.gov/encyclopedia/travelers-information-stations-search for info about TIS.