Antenna for a GPS module

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Aranha
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Posted by Aranha: Sun. Feb 22, 2015 - 11:40 PM
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Hello everybody!

 

Some time ago I decided to play a bit with a GPS module so I bought one, this one: http://www.tme.eu/en/details/gts... . The problem is I was too excited about my idea and didn't actually think it all through. Of course I checked the basic information in the datasheet and I decided it will be enough but after I got that module I realized I don't have any antenna for it.

The problem is that I'm not any electronic engineer and I actually have no idea whether my GPS module would work without an antenna. Of course the first thing I did was looking on the Internet for similar problems but I guess people buying these GPS modules are already smart while ordering them, not like me.

My question is - can I buy for example this antenna: http://www.tme.eu/en/details/rfe... and it will work? If yes, how should I put it on a PCB? I'm a software engineer so I really don't have much idea about analog circuits (although I enjoy studying it but it doesn't come easy to me). I'm pretty sure I need an antenna so please, if you have any definite suggestions, I will gladly listen to them!

Just please don't tell me it will be too hard and it's better to buy a new GPS module with antenna. I'm not impatient and I wanna learn so I'm looking forward to your opinions!

 

Greetings,

Daniel

Tags:

Learning and Information, General Electronics, GPS antenna
Last Edited: Sun. Feb 22, 2015 - 11:42 PM
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valusoft
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Posted by valusoft: Sun. Feb 22, 2015 - 11:52 PM
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Hi Daniel.

 

My quick examination of the datasheet(s) available via Google would seem to indicate that your unit already has an internal antenna and that you do not need another.

 

Have you tried to turn it on yet?

 

Cheers,

 

Ross

 

Ross McKenzie ValuSoft Melbourne Australia

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Aranha
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Posted by Aranha: Mon. Feb 23, 2015 - 12:35 AM
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Yes, I saw that 'internal antenna', too but I wanted to be sure about it - I didn't want to break it somehow or solder it and then be told that I forgot about antenna. So NO, I did not try to turn it on. Do you think adding this SMD antenna would be worth trying or module's sensitivity is good enough for some outdoor projects? Before I make schematics and board layout, I just want to get as much information as I can. I really tried to find something useful on the Internet but I couldn't.

 

Thank you for your reply :)

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valusoft
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Posted by valusoft: Mon. Feb 23, 2015 - 01:20 AM
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Daniel,

 

I am confident that you cannot "break it". Simply connect a 3.3 volts power supply to pin 23 and ground to pin 24, a pullup resistor between pin 17 and pin 23. After the unit has acquired enough satellite signals, you should be able to see a 1 per second pulse on pin 3 with your multimeter, oscilloscope or an LED with series resistor. Then you can examine the NMEA serial output messages.

 

Cheers,

 

Ross

 

Ross McKenzie ValuSoft Melbourne Australia

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DocJC
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Posted by DocJC: Mon. Feb 23, 2015 - 01:47 AM
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I guess Ross and I were looking at different data sheets.

 

I don't see a built in antenna mentioned in the data sheet.

I do see discussion about the connections for a passive antenna, an active antenna powered by the GPS module, and an active antenna powered externally.

 

I'm looking at a data sheet for the GTS-4E-60.

 

One of the reasons this GPS module is rather inexpensive is because it doesn't have a built in patch antenna.

 

If I was just starting off with some GPS work I would get a GPS module with a built in antenna.

It removes many potential problems from your initial designs.

 

JC

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valusoft
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Posted by valusoft: Mon. Feb 23, 2015 - 01:59 AM
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Jay & Daniel.

 

You may well be correct. Too many options/datasheets. But I cannot see anything on the seller's website where he says that an antenna needs to be purchased. Do you?

 

Cheers,

 

Ross

 

extra: Here is a datasheet (including pcb layout details) for this specific module. Yes an external antenna is needed. http://wenku.baidu.com/view/5d7f...

 

Ross McKenzie ValuSoft Melbourne Australia

Last Edited: Mon. Feb 23, 2015 - 02:11 AM
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Aranha
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Posted by Aranha: Mon. Feb 23, 2015 - 02:17 AM
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Oh, I checked it again and you're right. Sorry for the mess... I must have been looking at another GPS module datasheet while writing previous post. So basically that's what I've been told by someone from where I study - to buy a new module, already equipped with antenna.

 

I'm aware of the fact that antenna is a bit complicated thing and one does not build it just like that. Would you tell me if I could actually use that little smd antenna? If I not, why? I'm a curious guy :). I guess building a circuit that will contain an antenna and provide some kind of filtering will be quite complicated for a beginner (I actually started learning on my own about analog filters a few days ago) so I'm not going to try any of those. I would really appreciate if you just wrote something about what would circuit between antenna and GPS module do or look like - just for me to learn analysing it.

Maybe there is an antenna I could actually buy and attach to my GPS module?

 

Thank you for your help!

 

edit: Oh, I attached the link to page from where I bought that GPS module because you can find the datasheet there.

Last Edited: Mon. Feb 23, 2015 - 02:19 AM
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ford2go
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Posted by ford2go: Mon. Feb 23, 2015 - 06:03 AM
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I looked at the datasheet on the vendor's link, and it looks like an antenna is indeed required. Page 19 details the connections for an active or passive antenna. It says nothing about what sort of physical layout you might need.

 

The antenna that you referenced does have a somewhat vague description of how it should be hooked up -- vague to me at least. Possibly if you're in the industry, it would make more sense. It does look as if it should be mounted on a circuit board with a solid ground plane and  connected via a specified length of 50 ohm line (some spec'd to work at that frequency).

 

Possibly someplace like sparkfun has a breakout board that you can use to hook up this module. I think that they have the most GPS related products. If they do, it should have either an internal antenna or a hookup for an external one. (There's also adafruit, but I don't think that they do GPS-- I could be wrong).

 

Will you damage the module without an antenna -- almost certainly not -- it's  a receiver. However, it probably won't work due to little or no signal being received without an antenna. 

 

You might try googling something like "antenna for the GTS-4E-60".

 

Good Luck,

 

hj

 

 

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meslomp
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Posted by meslomp: Mon. Feb 23, 2015 - 07:23 AM
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You do need an external antenna, this is only the GPS receiver part.

I have bought some helical antennas a long time ago from sparkfun. you might check if they sell any, then you should have them in not to long a time.

If you have an open field to test in you could just attach a piece of wire with 1/4 wavelength length to the signal line(leave the other end open) and one 1/4 wavelength length to the ground connection(also leave end open

 

 

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DocJC
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Posted by DocJC: Tue. Feb 24, 2015 - 03:55 AM
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that little smd antenna

Have a look at Spark Fun Electronics, as mentioned above.

 

They have a chip SMD GPS antenna, and used it on several ( ? ) PCBs.

 

RF is 1/2 science, 1/2 Black Magic.

 

The test equipment, especially in the GHz range, is very expensive.

 

One can tweak impedance matching circuits only so much before one has to just do another PCB, and another PCB, and another PCB... to optimize the design, (or sometimes just to even get a functional design).

 

Start with the normal, Non-RF, electronics, then move to the RF stuff as you gain a little more experience.

 

Note, also, that the SMD antenna is a passive antenna, i.e. not low noise, impedance matched, RF amplifier connected to the antenna.

Many GPS antennas are "active", meaning they have a small RF amplifier built in to the antenna, and get power from the GPS module.

 

JC 

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samfeng
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Posted by samfeng: Tue. Aug 18, 2015 - 03:03 AM
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Daniel.

 

I sent a private message about some of gps module idea for that... 

 

Hope can help u.

Sam

Sam San Sam

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