Detecting signals

1. A receiver device comprising:

a frequency hopping radio receiver for operation according to a frequency hopping radio protocol using multiple channels and arranged to detect the presence of a predetermined other radio protocol as interference with respect to said frequency hopping radio protocol, wherein said other radio protocol represents a wireless network protocol; and

a user-alerting unit responsive to the receiver;

the receiver being configurable to actuate the user-alerting unit for alerting a user of the presence of a wireless network to which the user may desire to connect, in response to the detection of the other radio protocol;

wherein the receiver is capable of identifying interference as being characteristic of the other radio protocol;

the receiver being configurable to log detected interference while performing frequency hopping according to the protocol in which the receiver operates.

2. A receiver device as claimed in claim 1 , wherein the receiver device comprises a user actuable control whereby the user can configure the device to actuate the user-alerting unit in response to the detection of interference characteristic of the other radio protocol.

3. A receiver device as claimed in claim 2 , wherein the user-alerting unit is an audio device operation of which generates an audible signal for a user.

4. A receiver device as claimed in claim 2 , wherein the user-alerting unit is a video device operation of which generates a visual signal for a user.

5. A receiver device as claimed in claim 1 , wherein the user-alerting device is an audio device operation of which generates an audible signal for a user.

6. A receiver device as claimed in claim 1 , wherein the user-alerting device is a video device operation of which generates a visual signal for a user.

7. A receiver device as claimed in claim 1 , wherein the receiver is arranged to identify the presence of interference characteristic of the other radio protocol by identifying interference on one or more channels of the frequency hopping system that remains over a predetermined period of time.

8. A receiver device as claimed in claim 1 , wherein the receiver is arranged to identify the presence of interference characteristic of the other radio protocol by identifying interference on a predetermined number of adjacent channels of the frequency hopping system.

9. A receiver device as claimed in claim 8 , wherein the receiver is arranged to identify the presence of interference characteristic of the other radio protocol by identifying interference on a predetermined number of adjacent channels of the frequency hopping system that with frequency rises to a peak and then diminishes over that set of channels.

10. A receiver device as claimed in claim 9 , wherein the receiver is arranged to identify the presence of interference characteristic of the other radio protocol by identifying interference on a predetermined number of adjacent channels of the frequency hopping system that with frequency rises to a peak substantially at the centre frequency of a channel of the other radio protocol and then diminishes over that predetermined number of channels.

11. A receiver as claimed in claim 1 , wherein the frequency hopping radio protocol is Bluetooth.

12. A receiver as claimed in claim 1 , wherein the other radio protocol is a wireless LAN protocol.

13. A receiver as claimed in claim 1 , wherein the other radio protocol is an IEEE 802.11 protocol.

14. A method of alerting a user to the presence of a wireless network of a first radio protocol, to which the user may desire to connect, the method comprising:

detecting, by means of a frequency hopping radio receiver for operation according to a frequency hopping radio protocol using multiple channels, the presence of the first radio protocol as interference with respect to said frequency hopping radio protocol;

alerting a user by means of a user-alerting unit in response to the detection of the first radio protocol; and

identifying detected interference as being characteristic of the first radio protocol;

wherein the step of detecting the presence of interference comprises logging detected interference while performing frequency hopping according to the protocol in which the receiver operates.

15. A method as claimed in claim 14 , wherein the frequency hopping radio protocol is Bluetooth.

16. A method as claimed in claim 14 , wherein the first radio protocol is a wireless LAN protocol.

17. A method as claimed in claim 14 , wherein the first radio protocol is an IEEE 802.11 protocol.