GPS Golf device measures the distance of 'C' is shorter the 'B' of laser equipment

No. Sonocaddie provides all the information you need on the golf course (distance to greens, obstacles, hazards, driving distances, etc.) as well as a Scorecard function to calculate your scores. So, there's no need to change any your tactics.

Please check the GPS reception on the GPS Status screen at the time to be sure you have at least 6 stable satellite signals. Also check the Settings menu (Wrench icon) to be sure the distance units (yard or meter) are correct.
In addition, the distance in GPS device is nothing related with the locations of tee boxes-The distance is calculated based on the difference between your position (the “apparent” position) and the known position. The apparent position is the moveable location of the GPS device which receives the signal.
The known position is fixed and is the coordinates, such as bunker and green, downloaded from the database of website. Therefore when you stand by the tee box (apparent position of GPS device you carry), the unit will calculate the distance between you and the green (known position).

All the data you store in your Sonocaddie will never be lost unless you edit or erase the data on purpose.

The internet connection environment could cause this problem. Have you ever installed any additional firewall, computer security program and IP router? These programs could cause the data transmission between our server and your computer. Therefore, if yes, please try to disable them.  Besides, the internet connection at your work/office environment might cuase this issue too. Therefore, we suggest that you can install the V300a software on the other computer and in different internet environment, for example at your home place.

You are more than welcome to request your home course data to www.sonocaddie.com to see if we need your help by sending us the most up to date course scorecard with course layout information on it. To request new courses, amend course data, and add scorecard or course name on our website, please click mappingV500@sonocaddie.com to request the courses information. There is no subscription fee of requesting course data. Requesting steps as below:
1. Email us the course information you want to play, including course name/address/website/scorecard/layout (if available)
2. Once receiving the information, we will check if the satellite images and course layout of the courses required are available in the database, and will email you the results.
Most of the time, we are able to map the course except when course change layout recently (thus our Satellite photo is not yet up to date) or our Satellite photo data is deem to old thus the data is not accurate enough (we feel the data needs to be within 5yd to be acceptable). Sometimes we need more information such as course layout from users to complete the mapping procedure. We will let you know if necessary. Of course, it would be great and efficient if you can provide us this information from the beginning. You could also map the course yourself by referring Sonocaddie user guide.

*Shipping & handling, taxes will be shown during checkout before you place your final order.

United State/ Canada
* US$ 15 / per unit (Not refundable)
* Business shipping day does not include weekends and holidays and take approximately 7 working days depends on the area.

International
* US$ 50 / per unit (Not refundable)
* Business shipping day does not include weekends and holidays and take approximately 7 working days depends on the area.
* Sonocaddie products are shipped via DHL Express / mailing service or other methods Sonostar assigned.