13 replies to this topic

[LeeS]

Since the RFM22B module supports antenna diversity, is there any chance we can get dual antenna support on the PipX?  

It would require very little in the way of additional circuitry (from what I read in the datasheet)

[dankers]

The question is what antenna connection style to use that will both fit on the board as well as be robust. Currently we use SMA, which I really don't like much as they are heavy and a crash would likely result in the damage to the board.

Open to antenna style suggestions

[K Wells]

dankers, on 14 November 2011 - 08:47 AM, said:

The question is what antenna connection style to use that will both fit on the board as well as be robust. Currently we use SMA, which I really don't like much as they are heavy and a crash would likely result in the damage to the board.

Open to antenna style suggestions

How about u.FL  This type is very common on many internal laptop wifi boards. it does not take up much real estate and would have high survival rate.






IPX is another brand name

[DrewF]

I like it, but since it's a compression fit I would be concerned with vibrations knocking it off.  Maybe I'm way off though since I know it's common in laptops and the idea is that it's light enough it shouldn't matter.

Guess worst case is a dab of hot glue to make it solid?

[peabody124]

There are U.FL. connectors on the Gumstix and they feel damn tight.  Their downside is the female end (antenna) isn't good for many reconnects but I don't think that's a big problem myself.

[peabody124]

The problem with antenna diversity is it does start adding components to the existing design - I'd rather keep it simple and elegant.

[mnuapel]

SMPM connectors could be perfect, we use them. They are much smaller than SMA, yet big enough to be robust, and mating force is high enough not to worry about vibrations. But I am not sure about price, i am afraid they are too expensive.

http://www.jst-mfg.c...talog_SMPMe.pdf
http://www.te.com/ca...69&U=&BML=&LG=1


Probably nothing can beat SMA, once price comes into consideration

[peabody124]

Man in low quantities SMA through holes are still like 6$!

[naiiawah]

DrewF, on 14 November 2011 - 11:33 PM, said:

I like it, but since it's a compression fit I would be concerned with vibrations knocking it off.  Maybe I'm way off though since I know it's common in laptops and the idea is that it's light enough it shouldn't matter.

Guess worst case is a dab of hot glue to make it solid?

Very common connector in WiFi gear as well.  On one WiFi eval demo board kit I've seen, they put a pair of 3mm holes on either side of the connector.  Goint through the holes, they had a small zip tie around the board and connector via the holes with a couple of millimeter square piece of dense foam on top of the connector and under the zip.  No way that thing was coming loose on their demo!

[dankers]

naiiawah, on 15 November 2011 - 02:26 AM, said:

Very common connector in WiFi gear as well.  On one WiFi eval demo board kit I've seen, they put a pair of 3mm holes on either side of the connector.  Goint through the holes, they had a small zip tie around the board and connector via the holes with a couple of millimeter square piece of dense foam on top of the connector and under the zip.  No way that thing was coming loose on their demo!

We did exactly the same thing on an earlier GPS board that uses an external antenna with U.FL. Works great.

[Brian]

Would it be hard to add a wire antenna option?  It would be nice for smaller "indoor" craft that don't need the range to have an option of a smaller/lighter antenna.

[Les Newell]

Most FrSky receivers use U.FL connectors and I've never had one come off, even in severe crashes. You could also then use FrSky replacement antennas instead of having them made up.

[naiiawah]

Les Newell, on 15 November 2011 - 03:17 PM, said:

Most FrSky receivers use U.FL connectors and I've never had one come off, even in severe crashes. You could also then use FrSky replacement antennas instead of having them made up.

If the frequencies are a match for the antenna, than this alone would make it worth using that connector!

[naiiawah]

Brian, on 15 November 2011 - 03:05 PM, said:

Would it be hard to add a wire antenna option?  It would be nice for smaller "indoor" craft that don't need the range to have an option of a smaller/lighter antenna.

+1  

WiFi modules commonly do this.  PCB trace "Wire" antenna by default with the U.FL connector for an off board antenna.