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Tips and questions relating to the GPS modules from SFE
I've successfully used an AVR with the EM-408 GPS module and active external antenna in my project and all works well. I understand attempting to extend the 15 foot antenna cable will result in signal loss. Is there any way to extend the antenna to say 50 feet? Would it be better to separate the EM-408 from the AVR instead of extending the antenna? Any ideas will be appreciated. Thanks.
By jremington
Extending the antenna cable will result in signal loss, but satellite reception may still be acceptable. If not, simply extend the serial connection between the GPS and the AVR modules. If you use "twisted pair" cable (e.g. telephone, much cheaper than antenna cable), the latter can usually be extended to hundreds of feet .
Thanks. I found an active antenna with a 30 foot cable but I don't know if it will work with the EM-408. If I extend the serial connection, I'd have to use a separate power supply for the GPS. But I guess that also opens the door to wireless serial.
By jremington
You can send power to the GPS module in parallel with the serial connection, if you use a 4-wire cable. An ordinary 4-wire telephone extension cable will work.
Awesome. I like it. Most telephone extension cables are flat. Is twisted pair better? What about voltage drop? What gauge wire is typical phone wire?
By jremington
Try the flat cable first, as it is most readily available. Voltage drop shouldn't be a problem at the low currents required by a typical GPS module.