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I came across these promotional items the other day:   http://components.arrow.com/part/detail ... 91464N1044   Try not to be to greedy, and shipping isnt so cheap!   they are difficult to work

Hello Kenemon, I'm willing to sponsor a batch of 10PCBs from Seeed, otherwise what good are the adverts. Currently Hyland Savior is also trying to make one here which will also be getting sponsored.

I took a closer look at the antenna and I think it should be pretty easy to use the built-in one. It appears that the only part missing is a little piece of shorting chip (judging by the picture of th

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Module does have PCB antenna.

 

Does it? I was under the impression that the bottom pads were for *attaching* it to a PCB, but there wasn't necessarily a built-in antenna.

 

I think that you are right. I held the module up to the light and can see a thick trace at the top of the module that appears to be an antenna. It's the gold strip on page 28 of the datasheet.

 

It's also why they have the keep-out space on page 27 (which I see that you incorporated into your PCB). I like that you've kept that antenna above the shield PCB. Do you anticipate any problems with it being placed over the top of the emulator space?

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The antenna is there, but it is not active. Some of the components are missing, and some in the matching network are the wrong value for the PCB antenna.

Are you talking about F antenna's soldering point right above RF socket?

Also, the following part description suggests that you are right, that we got modules with external antenna (modules on a dev kit pictures do not have u.fi sockets.)

Part Number Description

450-0012 ProFLEX w/ u.fl Connector

450-0011 ProFLEX w/ PCB (inverted F) Antenna

 

Oh well, I was planning on getting an antenna anyway and hanks for pointing that out, saved me from "duh" moment.

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The antenna is there, but it is not active. Some of the components are missing, and some in the matching network are the wrong value for the PCB antenna.

Are you talking about F antenna's soldering point right above RF socket?

Also, the following part description suggests that you are right, that we got modules with external antenna (modules on a dev kit pictures do not have u.fi sockets.)

Part Number Description

450-0012 ProFLEX w/ u.fl Connector

450-0011 ProFLEX w/ PCB (inverted F) Antenna

 

Oh well, I was planning on getting an antenna anyway and hanks for pointing that out, saved me from "duh" moment.

 

Since parts are missing and it's not connected, a PCB antenna is probably out of the question, but is it worth exploring the possibility of placing a hole in the bottom of the PCB (under the circular pads)? I am assuming that those pads are points for soldering the module to a PCB in a scenario where it's fabricated in a factory, but maybe I am wrong. I've seen a lot of wireless cards that don't have a u.fl connector and the antenna breaks out to an rp-sma or similar.

 

I'm not a big fan of u.fl and I can see modules braking easily when removing these things. U.fl isn't really intended to be disconnected.

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I took a closer look at the antenna and I think it should be pretty easy to use the built-in one. It appears that the only part missing is a little piece of shorting chip (judging by the picture of the model w/o u.fl connector.) PCB antenna is very close to other F type antenna designs I have seen. When it comes to wrong values in the matching network, not sure how this can be verified without the schematic and without values on parts. It actually doesn't make sense that they would use different values for those 2 models, I think it would be easier to make PCB antenna that matches u.fi connector's impedance. I am waiting to hear back from LS to confirm that.

 

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When it comes to wrong values in the matching network, not sure how this can be verified without the schematic and without values on parts.

 

The source of my information.

 

No you cannot just solder a u.fl connector to the ProFLEX01 set up as an F-antenna. There are matching components that change between the two configurations.
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Yeah, then later he could not give a straight answer about that, he offered another kit.

I am just not buying it because it does not make sense. CC2520 optimal impedance is 50ohm, u.fl is 50ohm, so unless they have some "creative" engineers, I am expecting that PCB antenna was designed to also be 50ohm (since they are both fed from the same point.)

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Yeah, then later he could not give a straight answer about that, he offered another kit.

I am just not buying it because it does not make sense. CC2520 optimal impedance is 50ohm, u.fl is 50ohm, so unless they have some "creative" engineers, I am expecting that PCB antenna was designed to also be 50ohm (since they are both fed from the same point.)

 

I think that the real issue is about warranty and FCC certification. It's doubtful that they would recommend that anyone use the modules in a different manner than they were designed. They appear to be intended to function as a platform that works out-of the-box.

 

That said; I think that we have enough of them for next to nothing, so it's fair to say that we can break a few during our experimentation. There should be nothing here that is any different than any other CC2520 board.

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He gave a very straight, to the point, and clear answer:


  • [*:18pt2ndo]The matching network is different
    [*:18pt2ndo]We do not support modifying the module
    [*:18pt2ndo]We will not specify the changed component values

 

Ask an experienced RF engineer about the many differences between a whip antenna at the end of a short piece of coax and a F antenna on a PCB. They can explain it much better than I can - and with more authority.

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