The Siren Board

I have a few questions regarding the 500AT.

-When did production start and end?

-About how far away (miles wise) can it be heard?

-What all different port ratios did they have?

There is 2 versions of the 500 the 500T before 1960 and the 500AT after
500t has 8, 12, 9/12 the 500AT was 9/12 and 10/12. The 550AT 8/8 12/12 8/12 9/12?? 10/12?? on the 550 this is single tone each side was there dual tone each side??

In the case of production, the 500AT & 550AT were made from the mid-1950's, and discontinued in the early 1980's.

As with coverage, they produced 120-125 dB, and covered around 1/2 to 3/4 miles.

Finally, the port ratios were 8 & 12 for single tone, and 8/12, 9/12, & 10/12.

Archon wrote:There is 2 versions of the 500 the 500T before 1960 and the 500AT after
500t has 8, 12, 9/12 the 500AT was 9/12 and 10/12. The 550AT 8/8 12/12 8/12 9/12?? 10/12?? on the 550 this is single tone each side was there dual tone each side??

On the 550AT, there is one tone per side. One side has the high and the other has the low tone.
http://www.youtube.com/watch?v=ByERSRa2Ops
In this video, you can hear each side as it comes towards/goes away from the camera.

Thunderbolt 612 wrote:In the case of production, the 500AT & 550AT were made from the mid-1950's, and discontinued in the early 1980's.

As with coverage, they produced 120-125 dB, and covered around 1/2 to 3/4 miles.

Finally, the port ratios were 8 & 12 for single tone, and 8/12, 9/12, & 10/12.

According to Art Johannes and Dan Bierovic and Federal Signal, when I talked with them 18 years ago, they both said the Model 500 series came out in 1949, but became more popular in the 1950s. Likewise, there was a smaller version of the siren, but it lasted as long as the Model 550AT did, which was not very long.

The Federal Signal brochures I've seen from the late 1970's and the 1980's didn't even list the 500AT as a model at all. So, I'm thinking the 500AT was just made in the 1950's, maybe early 1960's.

Same with the SD-10. Only the brochures I've seen from the 1950's had this model listed.

I have two Federal Catalog 200s from the early and late 1970s and they both list and illustrate the Model 500AT. Likewise, so does Federal Catalog 36, which is strictly for Civil Defense & Disaster Warning Sirens and that was printed in the late 1970s as well. Therefore, the 500AT was still in production at that time, up until 1981-82.

What is interesting is that the Model 500A was available is a single-tone version when Catalog 200 was produced in the summer of 1973. However, it was been supplanted by the 500AT in 1977-78. I just wish the Model 500 would have been a better seller for Federal, but many fire departments preferred omni-directional sirens for their needs.

Thunderbolt 612 wrote:In the case of production, the 500AT & 550AT were made from the mid-1950's, and discontinued in the early 1980's.

As with coverage, they produced 120-125 dB, and covered around 1/2 to 3/4 miles.

Finally, the port ratios were 8 & 12 for single tone, and 8/12, 9/12, & 10/12.

I never knew that Federal made any 8/12 sirens. Does anyone know if Federal made any other sirens with 8/12 5th harmonies?