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aedwa2
New Contributor III
1,232 Views

Can I modify an Edison with an internal antenna to get better performance with an external one?

I have several Edison modules with onboard antennas being used in metal boxes with external antennas. Don't let anyone say that doesn't work because it does. But would it work better if I were to remove the infamous zero ohm resistor? Is that really the correct change to make an Edison with internal antenna the same as one intended for an external antenna? How much better would it work? These units are out of warranty so that is not an issue. When I purchased them I did not realize I needed a metal box but the environment the box is in requires it. The online guidance is all over the place from just remove the black resistor to I broke my Edison removing the zero ohm resistor (Youtube). Anyone done this?

14 Replies
idata
Community Manager
143 Views

Hi allene,

 

 

Thank you for contacting us.

 

 

We want to start by saying that Intel doesn't recommend making any hardware modifications to the Edison, such as removing resistors. The Edison module hardware guide states that "Do not connect an external antenna to a board with an internal antenna." Unfortunately, there are no tests with comparisons that show how the external antenna would work versus using the on-board antenna. I did check online to see if I could find information about an external antenna being successfully connected to the Edison and I believe I found the same links you found-some saying removing the resistor works and some saying it would damage the board.

 

 

Unfortunately, we don't have information about connecting an external antenna and we recommend against it but, let us know your results of your tests and modifications.

 

 

Regards,

 

-Sergio A

 

aedwa2
New Contributor III
143 Views

I just compared two Edisons. One is in a metal box with an external antenna. The other is in a plastic box with just the antenna on the module. Both Edisons are the kind with the built in antenna. Both Edisons are set as Access Points so I can use WiFi Analyzer on my phone to measure the signal strength. The Edison with the external antenna has the stronger signal. So based on that test, it is better to use an external antenna even on the units with the internal antenna.

What I want to know is what is the difference between the Edisons with internal and external antennas. For example, I asked this same question about an Xbee I am using. I was told that the difference was not just the antenna but that the micro code in the unit was different and that I could not therefore modify a unit with a wire antenna and put an SMA connector on it even though the pads were there and the physical modification was obvious.

Is there a difference in the Edison module other than the external parts? If I want to modify my Edison to eliminate the internal antenna, will it then be the same as one without the internal antenna. I don't want to know if this modification is recommended or not, I know it is not. I am prepared to take responsibility for the modifications but just want to know what they are.

idata
Community Manager
143 Views

Hi allene,

 

 

Those are interesting results. You can share your results here so other community users can benefit as well. There are different Edison versions, take a look below:
  • EDI2.LPOF.AL.S is Low Power Off-Board Antenna Module
  • EDI2.LPON.AL.S is Low Power On-Board Antenna Module
  • EDI2.SPOF.AL.S is Standard Power Off-Board Antenna Module
  • EDI2.SPON.AL.S is Standard Power On-Board Antenna Module
We've done some tests to make a comparison between the Low Power and the Standard Power versions, which can be seen in this link http://www.intel.com/content/www/us/en/support/boards-and-kits/intel-edison-compute-modules/00002365... .

 

 

Besides from that guide, we also found these community threads where users shared their results.

 

You can see them here:

 

https://communities.intel.com/message/421581# 421581 https://communities.intel.com/message/421581# 421581

 

https://communities.intel.com/message/396442# 396442 https://communities.intel.com/message/396442# 396442

 

 

Let us know if you found this useful.

 

 

-Sergio A

 

idata
Community Manager
143 Views

Hi allene,

 

 

Do you still need assistance with this case? We'll be waiting for your response.

 

 

Regards,

 

-Sergio A

 

aedwa2
New Contributor III
143 Views

I would still like to know what the difference is between the internal and external versions of the Edison are. Specifically, 1) are there any differences in the code of the Edison that might be there to match the antenna pin to the internal circuits and 2) what is the schematic difference between the two models.

Of course, the real question is what differences, if any, would someone see between the external antenna version and the internal antenna version assuming both are actually using external antennas in a metal box.

idata
Community Manager
143 Views

We'll investigate further about your questions. We'll post our response as soon as we have more information. Thank you for your patience.

 

 

Regards,

 

-Sergio A

 

aedwa2
New Contributor III
143 Views

@Sergio A

Thank you. I have several Edisons I want to modify so look forward to your further information.

idata
Community Manager
143 Views

Hi allene,

 

 

Thank you for your patience. We now have some updates for this case. For questions 1 and 2, unfortunately the information requested is not available. If you'd like to leverage the external antenna connector, we recommend you to purchase that module configuration. We have two purchase options for you to get the off-board antenna (multi-pack and single item purchase):

 

-10 pack EDI2.SPOF.AL.S 939957 - Intel* Edison Compute Module (IoT, Off-Board Antenna) Single

 

-EDI2.SPOF.AL.MP 939983 - Intel* Edison Compute Module (IoT, Off-Board Antenna)

 

 

As for the 3rd question, looking at Section 3.7 on page 13 of the Intel(R) Edison Compute Module Hardware guide http://www.intel.com/content/dam/support/us/en/documents/edison/sb/edison-module-hardware-guide.pdf , you should see an improvement but only on the external antenna version one. As for the internal antenna version, the U.FL connector is only used as a manufacturing test point, so I wouldn't think you should see an improvement. Please note it is also stated not to connect an external antenna to the board with an internal antenna. You can find this information in the following guide http://www.intel.com/content/dam/support/us/en/documents/edison/sb/edison-module_HG_331189.pdf , section 3.7 on page 13.

 

 

Regards,

 

-Sergio A

 

aedwa2
New Contributor III
143 Views

Thank you for looking into my question. It is unfortunate that Intel is unwilling to answer my question. Obviously Intel knows the difference in the schematic between these two versions as well as knowing if there are any software differences between the versions. Apparently they consider this a secret.

As to the statement that you would not see an improvement on the internal antenna version using an external antenna, that is just not true as I explained in replay # 2 above.

idata
Community Manager
143 Views

What we can recommend right now is to follow our previous suggestion to purchase the off-board antenna module configuration and restate that Intel does not support or warranty customers taking an internal antenna design to leverage the external connector.

 

 

We hope you understand our position and would like to offer our apologies for not being able to support your design goals further.

 

 

Regards,

 

-Sergio

 

aedwa2
New Contributor III
143 Views

I do not understand your position of not answering a simple question. I do understand your position of not supporting or warranting customers modifying a product. I was not asking you to warranty my out of warranty Edisons. I was asking two simple questions.

1) What is the schematic difference between two models

2) Is there any electrical difference other than the schematic (like software).

aedwa2
New Contributor III
143 Views

I made two changes to one of my Edison boxes. 1) I mounted the antenna in the center of the top of the box. 2) I removed the 0 ohm resistor. The result was about 10 dB more signal strength.

It was very difficult to remove the resistor so I see why some people ruin their Edisons trying it. I used a very small tip soldering iron with a flat tip about the width of the resistor. It also took a high magnification hood. Even then it was difficult to heat up both ends of the resistor. I had some solder splash that I had to clean up after.

Problem is I am not sure which change made how much difference. I will have to modify another one and just change one thing to see.

Allen

KMill10
Valued Contributor II
143 Views

If you make any changes at all to the Edison, or even use it other than intended (for example, by adding an external antenna to the SPON modules) then it will void its WiFi and Bluetooth certifications.

Strictly speaking it is not legal to use a device which has no certification. It certainly would be illegal to sell such a device, or use it in a commercial context.

If intel were to publish the schematics for a certified device, it could expose their IP, but it could also encourage people to make modifications which damage the performance of the Edison, and, by extension, the reputation of Intel. That is why I don't think Intel can answer your questions, even if they want to.

Although the two devices (SPON and SPOF variants) may well be identical with the exception of the placement (or not) of a few components, the official certification applies to the model number. Modifying the board doesn't get you over to the other certificate, it just nullifies your existing one. The correct approach is to buy the correct model, and to replace any modified boards or any boards with internal antennae which are now in violation of their certification by having external antennae added.

I do not work for Intel and am not in any way connected with them. The above is my understanding of the certification from my years of working in this industry.

aedwa2
New Contributor III
143 Views

I am no expert on what you are saying but it sure looks like a WiFi certification is an industry thing and not a law and not an FCC certification. WiFi operates in the unlicensed ISM band. There are laws regarding power output and antenna gain, which is why the WiFi antenna I use has a RP-SMA connector. That prevents the use of high gain antennas that would have a normal SMA connector. Basically, I do not think what you are saying is correct. I also use xBee radios that operate in an ISM band. They had no problem answering the same question I asked Intel. Intel just doesn't support answering my question. Simple. It is their choice. They asked that I share any results of experiments and I have done that.

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