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Tips and questions relating to the GPS modules from SFE
By fgcity
Hi everyone.

I have an Active antenna on a GE 863 module.

Works fine.

But i want to make the reception a bit more powerful.

If i put an LNA between the antenna and the module will the reception be stronger?

Please help out.
User avatar
By leon_heller
An active antenna already has an LNA.

By fgcity
yeah, i know. but if i put another one will that make a difference?

Are there any other tricks i could use to make the signal a couple bars more?
User avatar
By leon_heller
It'll probably overload with another amplifier, or you'll just introduce more noise. You could try a higher gain active antenna, or shorten the lead if the length is excessive.

By fgcity
it's actually not a normal active antenna. It's this:

It has 24db+

There are others which are a bit bigger with 14 and 15db+

Those would get better reception you think ?
User avatar
By leon_heller
I think I've got a couple of those, you probably won't find anything better. You need about 25 dB gain for most GPS modules.

By scalegps

Adding an extra LNA would help somewhat, but it's not that easy to do. You have to make accomodations for a bias-T for the new LNA, and also pass voltage through to the LNA in the antenna. Doable, but more trouble than it is worth. What kind of C/No values are you getting now? If most of them are in the high 30's to low 40's you should be fine.

An EASY way to add 3-4dB to the C/No's on these small patch element antennas is to add a groundplane behind the antenna itself. Without the groundplane the side lobes are substantial, and you are giving up a lot of sensitivity in the direction you want. The plane can be as simple as a piece of aluminum foil behind the LNA can on the antenna. 1" to 2" in diameter will help quite a bit. As you get up to 4-5" or so you won't see much more improvement, but that first 1-2" is REALLY important.
By signal
Most Active Antenna LNA Gain is 24 - 27 dB,

I've tested Active Antenna with 55dB Gain LNA,

here's several results

GPS Module without LNA + 55dB Active Antenna = Best

GPS Module with LNA (27dB well designed automatic gain ) + 55 dB Active Antenna = superior than the regular one

GPS Module with LNA (27dB poor designed) + 55 dB Active Antenna
= worst among 3 <- because LNA-LNA saturation.

MTK3318 module without LNA from GTOP was best one with

55dB Active Antenna from

I have nothing to do with fis4her

best regards
By no first name supplied
You'd be better off choosing a GPS module with better sensitivity than the GM-863. The SiRF III modules (EM-406 etc) are great, and the 5th gen u-bloc are even better. Of course you would lose the GSM integration.