Author Topic: Taoglas FXP-14 U.FL antennas  (Read 11199 times)

Plantje

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Taoglas FXP-14 U.FL antennas
« on: January 11, 2011, 10:31:36 PM »
I just received my two Taoglas FXP-14 U.FL antennas. I will probably build them into my laptop and connect them to my Huawei EM770W card tomorrow.

But I still have some questions:
-Is it okay to bend the antennas? (without breaking loose the connection of course)
-They should act as diversity antennas, what would be the best: put them close to one another or as separate as possible?
-I understood the back cover of my laptop is of rubber plated metal; will that cause reception problems? And if so: to what extend?
-Are there more hints, tips and tricks to be given?

Thanks!

Hengist

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Re: Taoglas FXP-14 U.FL antennas
« Reply #1 on: January 12, 2011, 10:13:19 AM »
-Is it okay to bend the antennas? (without breaking loose the connection of course)
Yes, it is. This is what these kind of antennas are been meant for. Be aware that the more you bend the antenna, the more you modify the antenna characteristics and probably, according my direct experience, quite quickly after a certain extent.

-They should act as diversity antennas, what would be the best: put them close to one another or as separate as possible?
I Managed to find some documentation:
page: http://maxon.com.au/menu_modules.php
module: http://www.maxon.com.au/udocuments/EM770W_HW_SPECV1.12.pdf
kit: http://www.maxon.com.au/udocuments/EM770W_DEMO_BOARD_GUIDE_1.02.pdf
I would never put them closer than the distance D between the two antenna connectors. I would start with a distance between 1xD and 2xD. For further references, I recommend you to have a look at antenna diversity theory and practices. I think, it strongly depends on mobility statistics of the transceivers with regard to the environment.

-I understood the back cover of my laptop is of rubber plated metal; will that cause reception problems? And if so: to what extend?
Insulators ("rubber") slightly modify electromagnetic fields.
Conductors ("metal") heavily modify electromagnetic fields.
Try to maximize
- open view
- distance
of the antenna(s) with regard to all/most metal parts.

-Are there more hints, tips and tricks to be given?
:)
If you need a professional-grade solution, consult a radio frequency agency.
If you need a personal-grade solution, just try many reasonable combinations while measuring absolute/relative performance. Wireless modules normally provide AT commands or application software to measure absolute/relative radio-frequency performance (RX/TS decibel, bit error rate, ...).
« Last Edit: January 12, 2011, 10:19:14 AM by Horsa »

Plantje

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Re: Taoglas FXP-14 U.FL antennas
« Reply #2 on: January 12, 2011, 10:48:40 AM »
Yes, it is. This is what these kind of antennas are been meant for. Be aware that the more you bend the antenna, the more you modify the antenna characteristics and probably, according my direct experience, quite quickly after a certain extent.
You mean they will not pick up the correct frequencies?
I Managed to find some documentation:
page: http://maxon.com.au/menu_modules.php
module: http://www.maxon.com.au/udocuments/EM770W_HW_SPECV1.12.pdf
kit: http://www.maxon.com.au/udocuments/EM770W_DEMO_BOARD_GUIDE_1.02.pdf
I would never put them closer than the distance D between the two antenna connectors. I would start with a distance between 1xD and 2xD. For further references, I recommend you to have a look at antenna diversity theory and practices. I think, it strongly depends on mobility statistics of the transceivers with regard to the environment.
Insulators ("rubber") slightly modify electromagnetic fields.
Conductors ("metal") heavily modify electromagnetic fields.
Try to maximize
- open view
- distance
of the antenna(s) with regard to all/most metal parts.
:)
Thanks! Documents like these can be very helpful! I don't see GPS mentioned, but if I take a look in my device manager I do see the Huawei supporting GPS. I'm thinking of inserting the new antennas in a similar way as I have the current antennas. (And currently they're bend around the battery) I know they pick up 3G signal when installed in that area, so I hope it will work the same for these antennas. And perhaps I will try the antennas first while the device is open.
If you need a professional-grade solution, consult a radio frequency agency.
If you need a personal-grade solution, just try many reasonable combinations while measuring absolute/relative performance. Wireless modules normally provide AT commands or application software to measure absolute/relative radio-frequency performance (RX/TS decibel, bit error rate, ...).
I found it very hard to find radio frequency specialists here in the Netherlands.

Anyway: I hope to start working on it tonigh. Thanks for your help so far!

Hengist

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Re: Taoglas FXP-14 U.FL antennas
« Reply #3 on: January 12, 2011, 12:54:16 PM »
Yes, it is normal that everything changes everything in the antenna characteristics: directionality, sensitivity, ... Commercial antennas are typically designed to minimize this variability to the maximum extent possible.

Plantje

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Re: Taoglas FXP-14 U.FL antennas
« Reply #4 on: January 13, 2011, 08:38:22 AM »
Yesterday I connected these new antennas. First I tried them while the device was still open and I didn't have the antennas stowed in some part of the device. Unfortunately no GPS sattelites where received.
At some point I will try the device outside as wel, but I think my Huawei EM770W just doesn't receive GPS :(

Horsa

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Re: Taoglas FXP-14 U.FL antennas
« Reply #5 on: January 13, 2011, 11:38:42 AM »
GPS signal reception has to be dealt with extreme care. Not to tell about indoor GPS reception.
As per my reply to your very first inquiry to your topic, the first think to consider when choosing a GPS antenna is whether the GPS receiver needs an active antenna or not. FXP-14 is obviously not.
  • manual > GPS antenna specifications > active or passive?
  • manual > GPS antenna specifications > if gain > 1 or dBic > 0 (typically > 10), then you need an active antenna
  • manual > is a GPS input amplifier documented? then you probably need a passive antenna
If no info is given, everything is possible: try and measure with patience.

Plantje

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Re: Taoglas FXP-14 U.FL antennas
« Reply #6 on: January 13, 2011, 12:29:19 PM »
The only thing I can find on the antenna subject in the documentation is on page 17 of the documentation under this link: http://www.maxon.com.au/udocuments/EM770W_HW_SPECV1.12.pdf

There it does state: "It is recommended that the antenna whose gain value is greater than 1dBi be used."
So, this means I should have ordered an active antenna?

How is it possible that 3G does work?

To be honest: I am not a radio specialist. I am able to open my device, insert a mini pci-e card and connect antennas. But it is really frustrating to see that nobody can just sell me a mini pci-e card that supports 3G and GPS and works with the antennas that come with the card!

Horsa

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Re: Taoglas FXP-14 U.FL antennas
« Reply #7 on: January 13, 2011, 12:59:45 PM »
So, this means I should have ordered an active antenna?
This means, you should have ordered an antenna with at least active GPS part. Documentation tells something like this:
- main antenna connector: U.FL antenna with passive cellular part + active GPS part
- aux antenna connector: ideally the same
I do not know of any of such antennas.

Alternatively, you could try like this:
- main antenna connector: passive cellular antenna (U.FL)
- aux antenna connector: active GPS antenna (U.FL)
and hope the diversity engine does a good job. Still, I do not know of any of such GPS antennas, but there could be some.

How is it possible that 3G does work?
Because of the passive cellular part of FXP-14.

... But it is really frustrating to see that nobody can just sell me a mini pci-e card that supports 3G and GPS and works with the antennas that come with the card!
You are not the first we are supporting with the same or worse problem...

PS: try to contact Maxon ...

Plantje

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Re: Taoglas FXP-14 U.FL antennas
« Reply #8 on: January 13, 2011, 08:40:33 PM »
Have you ever heard of these antennas?
http://www.taoglas.com/antennas/GPS_Antennas/Internal_GPS_-_SMT_Loop_Antennas/

Perhaps that will work.

Yes, I think I should try to contact Maxon.

Horsa

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Re: Taoglas FXP-14 U.FL antennas
« Reply #9 on: January 14, 2011, 09:23:29 AM »
Have you ever heard of these antennas?
http://www.taoglas.com/antennas/GPS_Antennas/Internal_GPS_-_SMT_Loop_Antennas/
Perhaps that will work.
I have seen them before. But it is NOT a step forward toward your solution. Short GPS specifications are very similar. For example, the GPS Gain:
  • FXP14: 2.2 dBi
  • GLA.01: 2.5 dBi
But the GLA series needs a support PCB whit at least the following requirements:
  • much more complex design (e.g. impedance-matched lines)
  • much bigger ground-plane
than FXP. By the way, I am really not sure that a gain of dBi > 1 (UMTS module documentation) is enough. Active antennas start with an overall gain (antenna intrinsic gain + amplifier gain - cable loss) of at least 10 dBi.

Do not forget that most active antenna are DC supplied through the same receiver connector. Probably it is nowhere documented that your UMTS module support that. So, you should start assuming that it is not supported.

Should you get qualified support from other sources, please do not forget to share back here.