# Information Needed During this guide, you'll need the following information at hand: * The altitude (above sea level) of your antenna. To find this, you can either use a GPS, or use something like to zoom in on the exact spot of your antenna, and then add the distance above ground level your antenna is located. * The latitude and longitude of your antenna (to at least five decimal places). To find this, you can use the output from the elevation finder above, or you can use a GPS, or use maps.google.com to zoom in on the exact spot of your antenna, and click to get the latitude and longitude. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://sdr-enthusiasts.gitbook.io/ads-b/intro/information-needed.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.