| Q. |
Can I use the Jupiter 32/30 with a passive antenna and what type of antenna would Navman recommend? |
| A. |
Navman recommends an RCP passive patch antenna with a minimum gain of 0 dBi and ideally greater than 2 dBi. When choosing a patch antenna, the patch should not be smaller than 15 x 15 mm for good performance and should be on a minimum of 40 x 40 mm ground plane. Linear polarised antenna need 3 dB more gain to be equivalent to a 0 dBi RHCP antenna. The passive antenna must be no more than 10 cm from the GPS input for optimal performance, especially with very low gain passive elements. The antenna and input trace must be matched to the 50 ohm input impedance required. Poor RF return loss will result in significantly weaker performance. If the application requires absolute highest sensitivity such as an indoor or covert application an active antenna is recommended to achieve peak performance. |
| Q. |
Can I use the J32/30 in extreme temperatures? |
| A. |
Yes, Navman tests the device from -40 degrees C to +85 degrees C. However the ramp in temperature must be kept to a minimum by insulating the GPS from rapidly varying sources of temperature. Navman qualifies the J30 at a maximum of 2 degrees C per minute variation in temperature. Temperature ramps outside of this might have a negative effect on Time-To-First-Fix and Low power mode operation. Navman recommends a minimum operational voltage of 3.3Volts in applications that will operate in -40 to +85 degrees C conditions. Applications that will operate above 0 and below +55 degrees Celsius can operate at a minimum voltage of 3.1 volts. The voltage can drop once operational to 3.0 volts but the Brown –out detector will trigger at a voltage lower than 3.0 volts. |
| Q. |
Can the J32 be reworked? |
| A. |
No. The J32 can only be removed from a PCB in order for it to be scrapped and replaced with a new unit. A small solder stencil will be required to re-apply the correct thickness of solder paste again before re-soldering the new J32 in place. |
| Q. |
What is the typical Solder Stencil thickness required for the J32? |
| A. |
O.133mm |
| Q. |
How do I control the Wake-Up line on the J32/30? |
| A. |
Ensure that this line is always low while the GPS is operational. Any high or pulsing of this line can cause the GPS to move into an indeterminate state. This line must ONLY be triggered once the GPS has been commanded into Push to Fix mode and the GPS has actually dropped into the SLEEP mode. Only then can the Wake-Up line be triggered to wake the GPS. |
| Q. |
Must I ensure a stable voltage is always applied to the J32/30? |
| A. |
Yes, even though the J32/30 have their own on-board regulation there are sense lines that are used to ensure start up of the GPS. If the voltage is applied in a rapid ON/OFF/ON fashion such as seen with cigarette lighter attachments and when a power plug is pushed into a socket the GPS can be forced into an incorrect state that requires the power to be removed including Vbat before it recovers. This is due to corrupted data. Good design principles such as having the host micro turn the GPS voltage supply on once the entire system has stabilised will prevent this occurring. |
| Q. |
What voltage should I run the J32 at? |
| A. |
Typically 3.3 Volts for most applications experiencing extreme temperatures. Applications requiring lower power consumption at normal operational temperatures should use a minimum of 3.1 Volts. |