1. An electronic device comprising:
- an electronic device housing for the electronic device;
- a break-away antenna that couples to the electronic device housing;
- a radio-frequency transceiver in the electronic device housing;
- a communications path;
- at least one sensor that generates position signals on the communications path that indicate the position of the extendable break-away antenna relative to the electronic device housing; and
- control circuitry that receives the position signals over the communications path, wherein the control circuitry disables the radio-frequency transceiver when the position signals indicate that the break-away antenna is not coupled to the electronic device housing.
2. The electronic device defined in claim 1 wherein the break-away antenna comprises an extendable break-away antenna that retracts by rotating about an axis from an extended position away from the electronic device housing to a retracted position adjacent to the electronic device housing, wherein the at least one sensor comprises a sensor that determines when the extendable break-away antenna is coupled to the electronic device housing and that determines the position of the extendable break-away antenna relative to the electronic device housing, and wherein the control circuitry disables the radio-frequency transceiver when the position signals indicate that the extendable break-away antenna is in the retracted position.
3. The electronic device defined in claim 1 wherein the break-away antenna comprises an extendable break-away antenna that retracts by rotating about a rotational axis from an extended position to a retracted position, wherein the at least one sensor comprises a first sensor that determines when the extendable break-away antenna is coupled to the electronic device housing and a second sensor that determines the position of the extendable break-away antenna about the rotational axis, and wherein the control circuitry is configured to disable the radio-frequency transceiver when the position signals indicate that the extendable break-away antenna is in the retracted position.
4. The electronic device defined in claim 1, wherein the break-away antenna comprises an extendable break-away antenna that reciprocates along its length between an extended and a retracted position, wherein the at least one sensor comprises a first sensor that senses when the extendable break-away antenna is coupled to the electronic device housing and a second sensor that senses when the extendable break-away antenna is in the retracted position, and wherein the control circuitry is configured to disable the radio-frequency transceiver when the position signals indicate that the extendable break-away antenna is coupled to the electronic device housing and in the retracted position.
5. The electronic device defined in claim 1 wherein the break-away antenna comprises a magnet and wherein the at least one sensor comprises a Hall effect sensor that senses the magnet in the break-away antenna.
6. The electronic device defined in claim 1 wherein the at least one sensor comprises a mechanical switch and wherein the break-away antenna presses against the mechanical switch when the break-away antenna is coupled to the electronic device housing.
7. Apparatus comprising:
- an electronic device having an antenna receptacle;
- a resilient antenna that elastically flexes into a stowed position in the antenna receptacle, wherein:
- the resilient antenna has a natural unbiased position;
- when the resilient antenna is in the stowed position, the resilient antenna is elastically bent out of the natural unbiased position; and
- when the resilient antenna is in the stowed position, the antenna receptacle exerts a force on the resilient antenna that maintains the resilient antenna elastically flexed in the stowed position and that prevents the resilient antenna from elastically returning to the natural unbiased position;
- a radio-frequency transceiver that transmits radio-frequency signals using the resilient antenna;
- a sensor that determines the position of the resilient antenna, wherein the sensor generates position signals that indicate when the resilient antenna is in the stowed position;
- a communications path; and
- control circuitry that receives the position signals over the communications path from the sensor, wherein the control circuitry disables the radio-frequency transceiver when the signals indicate that the resilient antenna is in the stowed position.
8. The apparatus defined in claim 7 wherein the resilient antenna comprises an elastically flexible wire.
9. The apparatus defined in claim 8 wherein the resilient antenna comprises a magnet and wherein the sensor comprises a Hall effect sensor that senses the presence of the magnet when the resilient antenna is in the stowed position.
10. A method of using an electronic device that has at least one antenna sensor, a break-away antenna that couples to the electronic device, and a radio-frequency transceiver that is electrically coupled to the break-away antenna, the method comprising:
- determining whether the break-away antenna is coupled to the electronic device by generating position signals with the antenna sensor that indicate whether the break-away antenna is coupled to the electronic device; and
- in response to determining that the break-away antenna is not coupled to the electronic device, operating the electronic device with the radio-frequency transceiver disabled.
11. The method defined in claim 10 further comprising:
- in response to determining that the break-away antenna is not coupled to the electronic device, displaying an alert for a user of the electronic device that indicates that the break-away antenna is not coupled to the electronic device.
12. The method defined in claim 10 further comprising:
- in response to determining that the break-away antenna is coupled to the electronic device, operating the electronic device with the radio-frequency transceiver enabled.
13. The method defined in claim 10 further comprising:
- extending and retracting the break-away antenna relative to the electronic device;
- determining whether the extendable break-away antenna is in the extended or retracted position by generating position signals with the antenna sensor;
- disabling the radio-frequency transceiver when it is determined that the extendable break-away antenna is in the retracted position.
14. The method defined in claim 13 further comprising:
- when it is determined that the extendable break-away antenna is in the retracted position, displaying an alert for a user of the electronic device that indicates that the extendable break-away antenna is in the retracted position.
15. The method defined in claim 13 further comprising:
- disabling the radio-frequency transceiver when the position signals indicate that the antenna is in a partially extended position between the extended position and the retracted position.
16. The method defined in claim 15 further comprising:
- when it is determined that the extendable break-away antenna is in the extended position, displaying an alert for a user of the electronic device that indicates that the extendable break-away antenna is in a fully extended position.
17. The method defined in claim 13 further comprising:
- determining from the position signals that the extendable break-away antenna is in a partially extended position between the extended position and the retracted position and disabling the radio-frequency transceiver in response.
18. The method defined in claim 13 further comprising:
- determining from the position signals that the extendable break-away antenna is in a partially extended position between the extended position and the retracted position and placing the radio-frequency transceiver in a low-power mode in response; and
- when it is determined from the position signals that the extendable break-away antenna is in the extended position, operating the electronic device with the radio-frequency transceiver in a full-power mode.
19. The method defined in claim 18 further comprising:
- when it is determined that the extendable break-away antenna is in the partially extended position, displaying an alert for a user of the electronic device that indicates that the electronic device is operating with the radio-frequency transceiver in the low-power mode.
20. The method defined in claim 13 further comprising:
- determining from the position signals that the extendable break-away antenna is in a partially extended position between the extended position and the retracted position and placing the radio-frequency transceiver in a single-band mode in response; and
- when it is determined from the position signals that the extendable break-away antenna is in the extended position, operating the electronic device with the radio-frequency transceiver in a dual-band mode.
21. The method defined in claim 20 further comprising when it is determined that the extendable break-away antenna is in the extended position, displaying an alert for a user of the electronic device that indicates that the electronic device is operating with the radio-frequency transceiver in the dual-band mode.