Radio frequencies for the London Undergound

[thenorthern]

This may seem a strange question but what frequency bands does the London Underground radio's use and do they have a mixture of them.

I am only wondering if they have an Ultra Low Frequency system in place as its the type thats used in mine communications for emergencies given that the trains are below ground.

 

[Nym]

As I'm sure you appreciate, this information isn't in the public domain (or is exceedingly hard to find) for quite good reason.

 

[HMS Ark Royal]

This may seem a strange question but what frequency bands does the London Underground radio's use and do they have a mixture of them.

I am only wondering if they have an Ultra Low Frequency system in place as its the type thats used in mine communications for emergencies given that the trains are below ground.

LPFM and UHF if I remember rightly

 

[DaleCooper]

This may seem a strange question but what frequency bands does the London Underground radio's use and do they have a mixture of them.

I am only wondering if they have an Ultra Low Frequency system in place as its the type thats used in mine communications for emergencies given that the trains are below ground.

Ask London Underground, if they won't tell you then you're not supposed to know.

 

[OneOffDave]

London Underground use two digital systems based on the TETRA architecture. Reception underground is assisted by repeaters and so-called 'leaky' feeds.

This is public domain information from the Comms provider's website

 

[John Webb]

I believe 'leaky feeders' were being trialled some years ago so that normal cell-phones and particularly the emergency services 'Airwave' units could be used underground without the need for any specialist equipment. These phones use 'packet switching' whereby their digital signal switches frequencies at very short intervals, thus giving extra security besides any digital encryption that might also be in use.

 

[thenorthern]

According to TFL the communications they use is called Connect.

 

[rebmcr]

I believe 'leaky feeders' were being trialled some years ago so that normal cell-phones and particularly the emergency services 'Airwave' units could be used underground without the need for any specialist equipment. These phones use 'packet switching' whereby their digital signal switches frequencies at very short intervals, thus giving extra security besides any digital encryption that might also be in use.

That's called frequency hopping. Packet switching is used to route traffic, strictly at the stages where it's in cables.