Hennepin Outdoor Sirens

[fwfdengine2]

Does any one know how the tornado/outdoor sirens are activated in Hennepin county? Is this done by HCSO, MECC? Do the southwest (Eden prairie, Edina/richfield, Bloomington, SLP) do this independently than the rest of the county?

Is this typically done on VHF with quick call or DTMF tones? If so, what frequencies? Or is this done via fiber/IP?

There is a frequency listed in the database for Civil Defense but I’ve not heard anything on it.

 

[nd5y]

Post a picture of one or locations that we can look at on google street view so we can determine what type of antenna they have, if they have antennas.

"Typically done" will vary depending on the siren manufacturer, how old the system is, whether or not they reused existing infrastructure when the system was installed, which government agency owns and controls it and many other factors.

 

[lenk911]

Does any one know how the tornado/outdoor sirens are activated in Hennepin county?

It used to be on TR 155.0550 MHZ prior to ARMER. Not sure if it has changed. System was two way SCADA (Healy-Ruff) system. After a siren activation it was some time while the activated sirens reported back to system control their status.

 

[Robdobb]

Does any one know how the tornado/outdoor sirens are activated in Hennepin county? Is this done by HCSO, MECC? Do the southwest (Eden prairie, Edina/richfield, Bloomington, SLP) do this independently than the rest of the county?

Is this typically done on VHF with quick call or DTMF tones? If so, what frequencies? Or is this done via fiber/IP?

There is a frequency listed in the database for Civil Defense but I’ve not heard anything on it.

The District highway patrol dispatch does it

 

[fwfdengine2]

Post a picture of one or locations that we can look at on google street view so we can determine what type of antenna they have, if they have antennas.

"Typically done" will vary depending on the siren manufacturer, how old the system is, whether or not they reused existing infrastructure when the system was installed, which government agency owns and controls it and many other factors.

I don’t see any type of antenna- here is a photo for reference.

 

[fwfdengine2]

This news story shows the screen where they active them. Since it is not a Motorola console I’m guessing its software/non radio based.

 

[nd5y]

I don’t see any type of antenna- here is a photo for reference.

The antenna will be on the box on the pole not the siren.

 

[nd5y]

Since it is not a Motorola console I’m guessing its software/non radio based.

It doesn't have to be Motorola.

 

[fwfdengine2]

Here’s the only other boxes/equipment on the pole

 

[nd5y]

The picture isn't clear enought to see if there are any mobile type antennas on the box or regular antennas higher up on the pole.

 

[ofd8001]

A while back our community had a pulse activation system on a VHF frequency. Someone got clever and figured out how to activate them, creating a big nuisance. So they switched to some kind of offset frequency and were very closed-mouth on activation means.

They were activated by the fire alarm office for fire calls or upon direction of the NWS for weather. Been many, many years since they were used for fire alerting purposes.

 

[stmills]

Currently it is still on vhf 155.055 as Lenk911 described- you can hear the data traffic when they activate. The sirens are maintained by Hennepin County Emergency Management and are activated by Hennepin Dispatch.
Hennepin County is working on upgrading this from VHF to ARMER.

 

[fwfdengine2]

Thanks for the responses everyone. Ill check out 155.055 on the next 1st Wednesday of the month test.

 

[KA0XR]

You'll hear a bunch of shrill nails-on-a-chalkboard like tones on 155.055 during the monthly siren activations. I regularly tune to that frequency during the monthly tests to verify they are still using VHF, and heard them last Wednesday.