I guess I'll be the first person to say welcome to the board! In no means do I have the expertise that you may be looking for, but may bring you off to a good start.
If the area needing coverage is less than 3/4 of a mile or 1.2 kilometers, I'd suggest contacting Sentry, you can find their website at :
http://www.sentrysiren.com
They offer sirens called Omni-Directional types that do not rotate and will continually cover the given area 100% of the time until the duration of the signal stops. These Omni-Directional sirens fall into another category-Electro-Mechanical, which have a fan (rotor and stator) that continually chopps air producing sound. There are no speakers in these sirens whatsoever. Just a motor and a rotor/stator. These come with battery backup. They are based in Cañón City, CO. I'd ask them if they ship internationally as well as all the other companies.
If you are looking for coverage in between 3/4 and 1 1/4 of a mile, or 1.2 to 2 kilometers, and want a public announcement capable system, I'd contact Whelen Engineering based in Chester, CT. I am not sure if they ship internationally but you can give them a call. Their sirens are called Electronic because they have large speakers that can both speak and make a siren tone. They come in both rotational and Omni-Direcrional styles. Their number is found on their website:
http://www.whelen.com/mass/index.php
If you are looking for coverage around the same distance but don't want to deal with damaged speakers (wear and tear and weather) I'd recommend Federal Signal. They offer an extensive range of outdoor siren products both electric and electro mechanical. They come in Omni-Directional and Rotational. If you are looking for Omni-Directional sirens I'd suggest Sentry, if you are looking for rotational sirens, I'd suggest Federal Signal. They offer battery backup options too! Honsestly I'd go with their Rotational Electro Mechanical sirens. They are based in University Park, IL Their website is:
https://www.fedsig.com/control-and-activation
If you are looking for the greatest range of distance covered by a modern siren, I'd suggest getting American Signal products. They offer electronic and electro-mechanical sirens, but I'd stick with Electro-Mechanical if you buy from them. Their sirens can cover up to 2.5 miles or 4 kilometers. They can get a bit pricey though, but offer top notch sirens with battery backup. They offer sirens beyond the average siren, and are par with Federal Signal with reliability. They come in Rotational or Omni-Directional styles. They are based in Milwaukee, WI. Their website is:
https://www.americansignal.com
There is a final company called Acoustic Technologies based in Boston MA. I personally would not buy one of their sirens but if you see they fit best then go for it. The offer electronic Omni-Directional sirens that extend to about 1 mile out, or 1.6 kilometers. They have been sued for flaws in the system so I'd do your research on this company. Their website is:
https://www.atisystem.com
If you chose Sentry I'd suggest the 14V-B (127db). It has battery back up, and covers approximately 1.6 kilometers (1 mile). The alternative to that is a smaller version called the 7V8-B (121db). Same siren more or less but smaller and covers 1.2 kilometers (4000 feet)
If you chose Whelen I'd suggest the WPS-2910 (129db) because it is Omni-Directional, has battery backup, solar, and covers almost 2 kilometers.
If you chose Federal Signal I'd suggest the 2001-130 (130db) because it is a Rotational siren, has battery and solar backup and covers around 1.6 kilometers.
If you chose American Signal I'd suggest the ASC-T-135ACDC (133db). It covers up to 4 kilometers, has solar and battery backup, and rotates. It is a bit pricey though.
If you chose ATI (126db). I would personally not go with them but chose the larger HPSS-32 if you do. It covers around 1.4 kilometers.
Hope this helped,
-Whammy
Fellow enthusiasts, feel free to contradict me, everyone has their own opinions and I guarantee the poster would love to have more suggestions.
