MMCX Aerial. Where and how to site it?

ChrisJones · Occasional Visitor Joined: Oct 04, 2003 Posts: 28

Hi all. I have been using an Ipaq 2210 with Haicom MMF 303 for about a year, VERY successfully. The combination with TomTom 3 is fantastic. Recently, I have been using hire cars for work and have found a large number of them produce weaker signals (I guess cos of the coated windscreens). The other day, my ultimate nightmare happened. I lost signal completely and couldnt regain, also, had no idea how to get to my destination (I have come to rely soely on my trusty GPS)! So, very next day, purchased a Haicom MMCX antenna.

This arrived this morning but now I have the dilemma of how and where to site it. No instructions came with the antenna and I cant find any references to the procedure. My initial thoughts were to attach to the roof via mag base and have the wire coming into the car via the door. Im now wondering if this will slice the wire in two on the first closure of the door! Im hoping I dont need to do my 5 hour one way journeys with the winodw open 8O . Can someone assist me please?

Sorry for posting such a dumb question but I just dont know the correct answer. Many thanks all.

Regards, Chris.

Dave · Posted: Sun Sep 26, 2004 8:05 am Post subject:

You may not need an MCX patch antenna. How many sats do you get with your PPC in-car ? And if you move it outside the car without doing anything to it, do the sats increase by 3 or 4 ? If the answer is YES, then you need a patch antenna because you may have an athermic (UV coated windscreen).

Sometimes though you can be receiving 7-9 sats in-car and freak of nature as it is, you lose a sat fix, the GPS gets confused and goes into a factory fix. This can happen some times, so try not to confuse this with needing an antenna.

The patch antennas are best positioned either on the roof or on the bonnet of the car. Providing your car doors have a rubber seal then shutting the cable between the rubber seal and door won't cut the wire, the rubber seal will act like a sponge in cushioning the wire and forming around it.

ChrisJones · Occasional Visitor Joined: Oct 04, 2003 Posts: 28

Many thanks for reply Dave. In cars with normal screens, I reguarly get that magical 10 sats displayed. I have even seen 11 on my 303!! (thought that was impossible). On the day in question, if I was lucky enough to pickup any sats it was between 1 and 2. TomTom was snapping to roads near to my actual destination. Taking the device out of the car boosted to 6 and 7 sats.

Thanks for the answer on the closing the door question. That was the key for me. I am happy to use the additional antenna if required but just didnt want constant wind noise from the window being opened. Also didnt want to spend my 20 quid and find the cable neatly sliced in two on the close of the first door!

Thanks again Dave. Appreciate your wealth of knowledge.

Regards, Chris.

Dave · Posted: Sun Sep 26, 2004 4:36 pm Post subject:

I'm glad it helped. If you are still concerned about trapping the wire what you can do to counteract this is to wrap some black electrical tape around the cable as this will give it a little bit more insulation.

Darren · Posted: Sun Sep 26, 2004 4:36 pm Post subject:

I have a magnetic antenna installed on my roof and have secured the cable under the glass seal and through the door. The door seal ensures that the cable is not trapped or cut when the door is closed.

You may also find that with the external antenna you can locate it inside but near the bottom left or right corner of the screen where the coating that blocks the satellite signal is not present or alternatively behind the rear view mirror where agaian there is no coating to allow toll tags such as the Dart Tag used for the Dartford Crossing to be sited.
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Darren Griffin

ChrisJones · Occasional Visitor Joined: Oct 04, 2003 Posts: 28

Thanks Dave and Darren. I have now tried siting the areial in my latest hire car (Ford Focus). Looks like this doesnt have a coated screen as I get 6 sats sitting on my drive. Adding the MMCX antenna does still manage to bring in an extra satellite though. One thing that did shock me was the connector on the antenna. I pushed this fully home into my mmf 303 to test. Gentle pressure to remove the connector resulted in it falling apart! Looks like only very minor crimping was used. I have pushed it back together and found that only slight connection is enough for it to function so need to push fully home.

Darren makes a good point about the window seal and indeed I would consider this if I wasnt moving from car to car on a daily basis.

I am now strating to see the virtues of bluetooth GPS's where I assume I could simply locate on the rear parcel shelf. Having said that , the beauty of my current setup is ease of powering. The 303 takes the power from my Ipaq so only a single power cable required.

Thanks again guys. Any suggestions on making a better job of the connector on the end of my antenna?

Regards, Chris.

Darren · Posted: Sun Sep 26, 2004 5:14 pm Post subject:

I would send it back for replacement, normally the connectors on these antennas are well secured.

On mine it requires quite some force to remove the external antenna from the socket (although your should be holding the connector and not the wire when removing) and it has survived my ham fisted attempts to destroy it to date. However, given the frequencies involved etc the fact that it has come undone will already have degraded it.
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Darren Griffin

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