{"id":2516,"date":"2022-10-14T16:00:00","date_gmt":"2022-10-14T14:00:00","guid":{"rendered":"https:\/\/www.nico-maas.de\/?p=2516"},"modified":"2022-10-14T07:22:00","modified_gmt":"2022-10-14T05:22:00","slug":"an-active-gnss-antenna-for-the-cam-m8q-breakout","status":"publish","type":"post","link":"https:\/\/www.nico-maas.de\/?p=2516","title":{"rendered":"An active GNSS antenna for the CAM-M8Q\u00a0breakout"},"content":{"rendered":"\n

I have been using multiple CAM-M8Q breakouts<\/a> by Watterott and really am loving these units. They are small, reasonable priced and have the advantage of an integrated chip antenna. However, this also their small shortcoming: While the antenna is good enough for most outdoor jobs, you can run into sensitivity issues when deploying it indoors - if not setup next to a window. Luckily, the module has two additional u.fl connectors for RFin and RFout, meaning you can use an external antenna.<\/p>\n\n\n\n

To accomplish this, you just need to remove the resistor R3 to position R1 - as outlined by the schematics<\/a>:<\/p>\n\n\n\n

\"\"<\/a>
Overview over the CAM-M8Q, copyright by Watterott<\/figcaption><\/figure>\n\n\n\n

With this, you could attach an passive antenna, but an active one will not work, as no power is supplied from the module. But you can add this power insert with an inductor and an capacitor.<\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

I did this with some SMD components, but did not add the insert \"behind\" the u.fl connector, but between both jumper points R1 should be using. So I can make this a part of the module.<\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

This worked perfectly and the reception is great<\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

As an antenna I am using the Navilock NL-202AA<\/a> - I have not received any Galileo signal (even though it should be possible), but other than that I am very happy with the solution.<\/p>\n\n\n\n

Thanks again to Mr. Watterott to pointing me to this StackExchange post<\/a> which contained the solution for the power insert.<\/p>\n