SparkFun Electronics Commentsurn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f82492024-03-28T12:54:34-06:00SparkFun ElectronicsCustomer #1807486 on GPS-15247 - SparkFun GNSS Chip Antenna Evaluation BoardCustomer #1807486urn:uuid:e4e5279e-3bc1-9504-5dab-0b0e6fe72f662023-01-09T11:50:20-07:00<p>Hello,
something is really wierd for me with this module. 4 out of 6 antennas present a short circuit in the Ohmic sense. This is not strange itself since this is the case for DC current only. But! The antennas are tested in your "GNSS Chip Antenna Hookup Guide" tutorial with the ZOE-M8Q board. And in ZOE-M8Q there is permanently 3.3V on the antenna connector (designed to supply active antennas). It goes through a coil and a small resistance on the module.
So how it is possible that you tested the antennas with ZOE-M8Q, having permanently 3.3V on antennas being effectively a short circuit for DC currents?
When I performed the tests (not being aware of the problem), my ZOE-M8Q board got very hot. Now I know, this was fortunately not the chip but the coil and the resistor acting as a heater. Indeed, the current was almost 300 mA what is generally consistent with the resistor value.</p>
santaimpersonator on GPS-15247 - SparkFun GNSS Chip Antenna Evaluation Boardsantaimpersonatorurn:uuid:0d9f60ac-851f-e4cb-8a03-118e0fc6dbb62020-07-14T18:54:57-06:00<p>Hi there,
Please feel free to file an <a href="https://github.com/sparkfun/GNSS_Chip_Antenna_Evaluation_Board/issues" rel="nofollow">issue</a> in the GitHub repository, with your suggestions. Otherwise, you can also modify our <a href="https://github.com/sparkfun/GNSS_Chip_Antenna_Evaluation_Board/tree/master/Hardware" rel="nofollow">Eagle files</a> directly and submit a pull request. I would be happy pass along your feedback/suggestions for improving the performance of this product to our team.</p>
Customer #1572636 on GPS-15247 - SparkFun GNSS Chip Antenna Evaluation BoardCustomer #1572636urn:uuid:5b63a919-6a0b-ba40-c4ad-088a2178b5a12020-06-23T11:16:12-06:00<p>Do NOT make any decisions based on this board. Apparently the people who created this have never heard of matching networks. The only 2 antennas that are even <em>close</em> to being matched correctly are the 3011 (center frequency of 1.556 GHz) and TE Puck (1.612 GHz). The other antennas are so poorly matched (center frequency of > 2GHz) that you're really measuring the transmission line, not the antenna itself. That doesn't make them bad antennas; they've been placed on boards without the necessary caps and inductors needed to make them work well.<p>SparkFun – I have VNA and I can tell you the matching networks needed to fix this board. Please contact me if you're interested in fixing this!</p></p>
Nate on GPS-15247 - SparkFun GNSS Chip Antenna Evaluation BoardNateurn:uuid:5fcb37df-247b-30ac-99af-3d3f4c0f741a2019-04-07T14:27:44-06:00<p>This comment made my day. Thanks!</p>
Customer #34076 on GPS-15247 - SparkFun GNSS Chip Antenna Evaluation BoardCustomer #34076urn:uuid:a8e4f57f-1778-1fa7-faba-64bf346a57bd2019-04-06T07:24:07-06:00<p>This is a great product that shows some creative thinking. Good job!</p>