Q for Nokia CDMA owners regarding antenna patch cables and couplers

Submitted: Thursday, Jun 09, 2005 at 00:35
ThreadID: 23705 Views:2449 Replies:7 FollowUps:11
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Firstly, sorry about my handful of questions on this topic lately. This forum is the only place I've been able to get useful responses (and that includes Nokia customer service).

So, Nokia keeps telling me that their antenna couplers aren't compatible with CDMA phones. I own a 3205, there's a coupler that fits the 3200 (which is GSM but otherwise exactly the same as the 3205) but they tell me I can't use it. I've read past threads on this forum and people have said that they use these couplers with ther Nokia CDMAs (I believe Robert R said he was using one with his 6225 earlier this year). But if you have a look at the nokia page for that model (http://www.nokia.com.au/nokia/0,,58334,00.html) or for any other CDMA model it states that "External antenna connection is not supported by current Nokia CDMA products." And Nokia have told me the same thing directly. So, to the people using these couplers with their CDMA phones, do they actually improve your reception? Are you sure? Can anyone think of a reason as to why Nokia is saying that they aren't compatible if they do actually work? Could they damage the phone somehow?

I've been looking at the AXF-15S coupler (it fits the 3200 GSM). It seems logical that since GSM antennas are at a different frequency to CDMA antennas, the couplers would also be at different frequencies. Or would the coupler just transfer whatever frequency the antenna recieves?

Secondly, patch cables - the type that plug into the bottom of the phone. I've read (I think in another past thread on this forum) that patch cables are basically useless with Nokia CDMA phones (and possibly Nokia GSM phones too) because there is no physical, electrical connection between the phone's aerial and the plug on the bottom that the patch cable plugs into. Can anyone confirm or deny this? Does anyone use a patch cable with a Nokia CDMA phone and if so does it actually improve your reception? Are you sure?

If anyone's got any info on this it'd be greatly appreciated. Just wondering what the best option is, if any, before I part with the $.

thanks

matt
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Reply By: Grungle - Thursday, Jun 09, 2005 at 07:48

Thursday, Jun 09, 2005 at 07:48
Hi mattlobie,

Antenna couplers are an 'tuned' inductive plate connected to an external antenna of some sort and the phones internal antenna radiates through this plate (which in itself is an antenna) to the external antenna. There is some componentry such as inductors and capacitors connected to the plate to tune it to certain frequencies therefore they are suited to particular applications only. A GSM antenna coupler will work to some (small) degree with a CDMA phone but it would be like using VHF antenna with a HF radio so there is a mismatch, poor performance and increased power consumption. There is around 100Mhz difference between the GSM and CDMA bands so it will be far from optimal.

There are many sites on the web that describe how to build inductive antenna setups. I have looked at a few for GPS units and they look relatively easy to make.

Regarding patch cables, there is usually an external direct connection of some sort on the phone to enable frequency testing of the handset when in for service. Very few manufacturers utilise inductive coupling for the purpose of testing or tuning a handset due to the amount of interference you get from outside signals (even using screened boxes is not 100% effective). However these connections are quite small and fragile and can break quite easily hence the manufacturers warnings against using them and losing your warranty.

One has to understand that phones are designed in countries where carkits and external antennas are very rarely used due to the population density and mobile coverage that they have. This is completely different in Australia due to our vast land mass and small population. The manufacturers are always trying to cut costs and the only way to do this is by making a handset that sells well but doesn't fail. Unfortunately things such as connectors (external antenna and system) are high failure items due to contaminants and breakages so a manufacturer will get rid of this feature to save money.

Regards
David
AnswerID: 115004

Follow Up By: mattlobie - Thursday, Jun 09, 2005 at 10:32

Thursday, Jun 09, 2005 at 10:32
Thanks for the info David, very useful. The differences in the GSM and CDMA couplers were as I suspected. So, with the patch cables, you're saying there's probably an external aerial connection somewhere on the phone, it's just a matter of finding it. What you said about testing etc would make sense, but if that is the case, why would the only type of aerial that Nokia sell be the inductive type? You'd think if there is an aerial connection of some sort there, that they would utilise it. Do you think it could be possible that the connection could be somewhere inside the phone, where it's not accessable until you pull the phone apart?

I'll have a look for some sites on building inductive antennas, and mybe try to suss out some technical info on Nokia phones regarding the aerials.

thanks a lot.

matt
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Follow Up By: Leroy - Thursday, Jun 09, 2005 at 10:59

Thursday, Jun 09, 2005 at 10:59
Matt,

There is no external antenna connection. I recently went through all this and ended up with a GSM Nokia 6100 with the car kit (coupler etc) and GSM antenna (not a GSM/CDMA). The only Nokia phone to have the external antenna skts are basically the 6310 style gsm and 6385 cdma phones. They have a connection on the car kit cradle that directly connects the phone to the antenna.

Leroy
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Reply By: Member - Captain (WA) - Thursday, Jun 09, 2005 at 10:53

Thursday, Jun 09, 2005 at 10:53
Hi Mattlobie,

I have the Nokia 6225 CDMA with genuine full car kit and 6.5dbi external antenae. There is no physical connection between the phone and the antenae coupling, a proximity module is added on the back of the phone holder and the antenae plugs into this. When the phone is in the holder, it basically rests on the proximity module.

The car kit makes a huge difference to range. As an example, when in my garage at home (roller door down, concrete slab on top, double brick walls) I have 1 bar of signal strength. Simply placing the phone in the holder gives me full range. This was the same for my previous phone, a Kyrocera wih full car kit and proper antenae connection.

I too was skeptical of the proximity connection when changing from my Kyrocera to the Nokia but I have since found that the performance is just as good. In fact it out performs a mates older CDMA Nokia (with car kit and proper antenae connection) by a significant margin, I had signal ~70kms south from Coolgardie while he had to drive another ~20 kms before he had signal.

Cheers

Captain
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Follow Up By: mattlobie - Friday, Jun 10, 2005 at 00:15

Friday, Jun 10, 2005 at 00:15
Thanks for the info Captain. So what model coupler do you use, since Nokia claims that none of theirs are suitable for your model?

thanks

matt
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Follow Up By: Member - Captain (WA) - Friday, Jun 10, 2005 at 00:25

Friday, Jun 10, 2005 at 00:25
Good question? I just ordered the Nokia 6225 car kit thru work and the sales rep delivered it. It appears to be the "standard" coupler for the phone holder, either GSM or CDMA.

My antenae is a RFI 1795 dual band (GSM/CDMA) and I have been told the car kit works equally as well for a GSM phone (the nokia 6220 GSM fits the same cradle, possibly others too) but I have yet to try it for a GSM. It works very well for the CDMA and almost seems too good to be true to work just as well for a GSM. Overall very happy with the performance of the 6225 and car kit, exceeded my expectations.

Cheers

Captain
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Follow Up By: mattlobie - Friday, Jun 10, 2005 at 00:43

Friday, Jun 10, 2005 at 00:43
Hmmm, seems funny that Nokia won't officially endorse it yet their agents are happy to sell it...

matt
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Follow Up By: Member - RockyOne - Saturday, Jun 18, 2005 at 09:22

Saturday, Jun 18, 2005 at 09:22
Hi Captain,We are next week getting new CDMAs..Keen on Nokia 6 2 5 5 as it has "Bluetooth"..I alrerady iSync on my 3 Macs all addresses,phone no's,appointments etc..A iDisc on my Macs (incl little iBook) and the main iDisc (in USA ?) auto updates every time I connect to web.So having wireless Bluetooth is not just a gimmick as it loads while I do other things..Ok! Enough rambling..Do you think a beaut car cradle like yours will work with ext antenna..We need the good CDMA reception as we go out in the sticks to call on coal mines,often new ones just being developed,not yet set up..I also tend to go onto bush to take landscapes and old gold mining pix..Thks your great info..Rgs RockyOne!MPG:7!
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Follow Up By: Member - Captain (WA) - Saturday, Jun 18, 2005 at 11:06

Saturday, Jun 18, 2005 at 11:06
Hi RockyOne,

My 6225 has infrared, NOT bluetooth. Don't know if this has changed (now ~8 months old) but definetely not on my phone. As for the car cradle I reckon it rocks. You can leave the phone in the cradle connected to the external antenae AND connect a laptop to the phone by a cable (cable plugs into where the external power/mic/speaker connects). You do run on phone battery power for this though.

I run a ~800mm external broomstick antenae, but you can now get 2.1m versions of these. Apparently some mining comopanies are using these for range in hilly fringe areas. Supposedly the ducks nuts, but I haven't used one. I do run a 2.1m UHF antenae when I go bush, too big for daily use so haven't got a CDMA 2.1m as I am happy with my current setup.

Cheers

Captain
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Reply By: BenSpoon - Thursday, Jun 09, 2005 at 14:35

Thursday, Jun 09, 2005 at 14:35
Although the couplers do not specifically say they are used for CDMA as well as GSM, I can vouch that they work- hell, you get broadband aerials (eg one that will do CDMA and all GSM freqs all in one aerial) so I cant imagine why they would specifically tune out the CDMA freq on the coupler
AnswerID: 115072

Follow Up By: mattlobie - Friday, Jun 10, 2005 at 00:16

Friday, Jun 10, 2005 at 00:16
So any idea as to why Nokia would claim that they don't? Is there any way that their use could damage the phone or something?

matt
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Follow Up By: BenSpoon - Friday, Jun 10, 2005 at 11:00

Friday, Jun 10, 2005 at 11:00
you quoted "External antenna connection is not supported by current Nokia CDMA products" external antenna connection.... sounds to me like it is referring to an externally available socket or pins on the connectors of the phone. You will note that page mentions nothing about antenna couplers. I think what it is saying is that the car kit as is will not support the CDMA external aerial- you will need to purchase the coupler.

This shows handsets the coupler will work with on there, it states it is compatible with CDMA-only handsets, and I cant see any disclaimers stating otherwise.
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Follow Up By: mattlobie - Friday, Jun 10, 2005 at 11:49

Friday, Jun 10, 2005 at 11:49
That site has been updated since I made the original post. The 6225 site no longer says the AXF-15S is incompatile and there were 4 coupler models on the enhancement page and all specifically said that they were not compatible with CDMA hand sets. Now there's only one model, the AXF-15S, and it now lists the 6225 as being compatible and no note about incompatibility with CDMA. Interesting....

Still doesn't list my 3205 though. But at least they're not totally debunking CDMAs now. I wonder what prompted the back-flip? I wonder if I get in contact with customer service now, they'll tel me it's fine to use the AXF-15S?

matt
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Reply By: angler - Friday, Jun 10, 2005 at 21:40

Friday, Jun 10, 2005 at 21:40
When buying a nokia CDMA phone try not to get a model with the multiple connectors at the bottom. The in car kit plugs into it for charging and hands free use. The connectors are extremely unreliable and disconnect at the slightest movement. My old 8210 had the normal twin sockets and the connection was never broken even over the roughest of roads.
I am very dissapointed with my 2280 for this reason alone.
Never again.
AnswerID: 115301

Reply By: Glenno - Saturday, Jun 11, 2005 at 22:28

Saturday, Jun 11, 2005 at 22:28
I bought one of the couplers from cell link my 6225. What a piece of crud it is. If anything the signal strength drops when I connect it.

There are three options when buying these antennas for nokias

GSM 900 MHZ
GSM 1800MHZ
CDMA

So obviously buy the one for CDMA, and buy the db rated antenna for your scenario.

If anyone in Brisbane wants mine they are welcome to to it. send me an email glenno at glenno dot com

Cheers,

Glenno
AnswerID: 115388

Reply By: Member - Ray C (QLD) - Monday, Jun 13, 2005 at 15:47

Monday, Jun 13, 2005 at 15:47
Totally agree with the reply from Captain.
I purchased the Nokia 6225 from Telstra and got the full Nokia car kt for $49.95 including the proximity coupler. I live in rural Queensland and when at home without the car kit I get reasonable reception, when installed in the car I get an extra 2 bars on the signal strength meter. I also have a 6.5 dB AE. Really happy with CDMA coverage and the 6225.
AnswerID: 115547

Follow Up By: Member - RockyOne - Sunday, Jun 19, 2005 at 09:46

Sunday, Jun 19, 2005 at 09:46
Thks Captain & Ray..That's the great info that makes ExplorOz forum so important to the 4x4 fraternity.Best $50 I ever spent..Looks like,the worst I can do is to go for the tried & proven Nokia 6225 (reminds me of the great joke about Nokia mobiles.Wicked) as it does what we all require.Works!Thanks again,see you out there,somewhere.R1
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FollowupID: 371861

Reply By: Jimbo (WA) - Sunday, Jun 19, 2005 at 11:55

Sunday, Jun 19, 2005 at 11:55
Matt,

On the Nokia web page for your phone, under enhanvements, it has a link for "car" that goes to a page which says this - "Car Installation Kit CARK126 -
Provides handsfree functionality with a connection to an external antenna."

Seems to me you have several options (according to that page for car kits, but this would be the one of choice since it goes to an external antennae.)

As the others have said, an external antennae makes a huge difference!
AnswerID: 116355

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