Cat Cdma System

[ThaiLife]

and maybe it is parallax error but are both the yagis in you photo pointing in the same direction ?

whoops - actually enlarged the photo and saw one was dtac

can you look in the setting of the modem and see what the SnR is ?

Hi , can you tell me how to check the SnR , I am running the MC727 on an iMac

Thanks

[phallang]

The Antenna was supplied by CAT, it does not look that well made, and I do think that there is room for improvment

may be with changing the cable from 75 Ω to 50 Ω ,any chance of describing your home made set up ? Thanks

Do you still have the packaging (as shown on your pic) and could do a closeup? It looks as if the table (in red) on the right side would contain some technical details, but your picture is too blurry...

My DIY antenna is rather ugly, big and heavy, but as i said, works great (with 15 meters of "Aircom Plus" low-loss cable). You would need some steel L-profiles, a lot of brass (or copper) sheets (aluminum would do as well, but is not easily welded) and some thick solid wire (or small brass / copper tube). And of course you need a massive pole 'cause it's heavy, but i mounted on thick bamboo and it worked ;-)

If you're interested i can look for my calculations and give you the measurements...

(Btw. the reason why i went with the "cube" (a.k.a "3 D Corner Reflector) design is, that it has a wideband characteristic and is thus very well suited for the CDMA spectrum.)

Edited February 2, 2009 by phallang

[ThaiLife]

Thanks again for the info and photo's , I will have another look at the antenna packing box, and post back, If you could dig out your calculations and the measurements that would be great as I would love to give it a try .

[phallang]

Thanks again for the info and photo's , I will have another look at the antenna packing box, and post back, If you could dig out your calculations and the measurements that would be great as I would love to give it a try .

Unfortunately the link to the version i've built seems to be broken.

However i found a slightly modified version (which as a triangle instead of a square as the "lower" sheet). [start reading from page 20 if you're confused...]

This description is basically all i used, you just need to , as mentioned in the last paragraph of the document, need to "scale" all measurements for CDMA use:

For CAT-CDMA use i chose the frequency to be 859 MHz ( the middle of 894 and 824 Mhz ) and thus the wavelength (lambda) will be 34.7 cm. Use this for the measurement calculations on the last page and give it a try!

[kleik]

so, if someone has a weblink or something... would be good thank you

http://www.bezte.com/

Try these guys. Explain your problem and see if they have anything that can help you. I bought something from them many years ago, and found them basically knowledgeable and willing to overlook some less than reasonable regulations.

No experience with them for several years though, so no guarantees. In my case, they were able to special order something for me that wasn't locally available, and would have required some finesse to get through customs.

That's about the best I can offer you, other than the knowledge that there are ways to improve your situation, but it will probably requiring some experimenting on your part.

ok thank you for the link and info about your experience with this company

i have look myself a little more and fund this page interesting for manny kind of antenna http://www.siammastershop.com

bye

[kleik]

However i found a slightly modified version (which as a triangle instead of a square as the "lower" sheet). [start reading from page 20 if you're confused...]

This description is basically all i used, you just need to , as mentioned in the last paragraph of the document, need to "scale" all measurements for CDMA use:

For CAT-CDMA use i chose the frequency to be 859 MHz ( the middle of 894 and 824 Mhz ) and thus the wavelength (lambda) will be 34.7 cm. Use this for the measurement calculations on the last page and give it a try!

hi phallang,

thank's for share your knowledge about antenna, it's usefull for me.

nice antenna you have build yourself, do you think it's working with a standard tv dish off course with the adaptation for such reception? ( i have few im not using so...)

thank you

[loong]

All of this about antennas really goes over my head.

Not understanding all this, so maybe this question is stupid.

If you lose a lot of the advantage of an antenna due to the length of cable, is it possible to have the set up near the antenna with a wireless router sending to the computer?

[stumonster]

All of this about antennas really goes over my head.

Not understanding all this, so maybe this question is stupid.

If you lose a lot of the advantage of an antenna due to the length of cable, is it possible to have the set up near the antenna with a wireless router sending to the computer?

keeping the cable length short to minimise losses is common. having good quality and skilled crimped connections also cuts down on losses. The problem I think with the modem in question is it is a USB device so it needs to be connected to a computer. ( there maybe some wifi routers that will accept the USB modem ).

you could either run ethernet/LAN cable from the modem device or wifi. I think the CAT CDMA modem problem is the only modem with an external aerial connection is the USB one.

[phallang]

All of this about antennas really goes over my head.

Not understanding all this, so maybe this question is stupid.

If you lose a lot of the advantage of an antenna due to the length of cable, is it possible to have the set up near the antenna with a wireless router sending to the computer?

definitely yes, good point!

In case your CDMA-modem is of USB type, you don't even need a router. Just place the modem as close to the antenna as possible using a USB extension cord. The Maximum length of USB extension is 5 meters, but if you put some active (i.e. powered) USB-hubs in between, you can easily cover 20 meters or so.

[phallang]

......, do you think it's working with a standard tv dish off course with the adaptation for such reception? ( i have few im not using so...)

thank you

basically it could work, you would need to build a special feed ( as a replacement for the LNB) though.

But the main point is: For 850 MHz, the "TV"-Dishes (usually 60 .. 80 cm diameter) are too small to get good results. You can expect gains of about 10 dB, which is easily surpassed with other designs.

[ThaiLife]

Thanks again for the info and photo's , I will have another look at the antenna packing box, and post back, If you could dig out your calculations and the measurements that would be great as I would love to give it a try .

This is on the Antenna box that came from CAT ..

[phallang]

Well, it says "FREQ RANGE 850-980 MHz". It looks, as expected, like it is an antenna *not* specifically designed for CDMA use, more likely it was designed for GSM (900MHz) use. But still it looks pretty wideband and that's the reason it kind-of worked for you, although the 824..849 Mhz (uplink) band is not explicitly covered. This means you might have trouble connecting, even if you get a nice signal from the tower, because the tower may not be able to receive your signal that well.

Anyway, before building your own antenna, as loong suggested, try making your antenna cable as short as possible and see how it works.

Edited February 3, 2009 by phallang

[ThaiLife]

Well, it says "FREQ RANGE 850-980 MHz". It looks, as expected, like it is an antenna *not* specifically designed for CDMA use, more likely it was designed for GSM (900MHz) use. But still it looks pretty wideband and that's the reason it kind-of worked for you, although the 824..849 Mhz (uplink) band is not explicitly covered. This means you might have trouble connecting, even if you get a nice signal from the tower, because the tower may not be able to receive your signal that well.

Anyway, before building your own antenna, as loong suggested, try making your antenna cable as short as possible and see how it works.

Many Thanks, Changing the cable is the first thing I will do , for those who want to try and improve the CDMA signals, but may not be able to build an antenna like your self, just looking at the antenna links shown here ..

http://www.siammastershop.com/

http://www.bangkokwireless.net/blaithaishop/

http://www.surfnshop.biz/

http://www.l-com.com/category.aspx?id=2071

is there a model of ready made antenna that you think has the best properties and best chance of offering better results than the CAT type antenna I was provided with, which I think is what most CAT users may be using . your thoughts are most welcome - thanks

[kleik]

there maybe some wifi routers that will accept the USB modem

yes there is a wifi routers that accept the usb from cat telecom the cradlepoint mbr 1000 and also the kyocera kr2

i fund a post about that in phuket.me forum yo can have a look

http://www.phuket.me/2008/07/sharing-an-ev...iple-computers/

http://www.phuket.me/2008/06/cat-evdo/

the kyocera kr2 available in thailand here http://www.surfnshop.biz/index.php?lay=sho...e&Id=348101 thank's "Thai Life" for the link

bye

Edited February 3, 2009 by kleik

[kleik]

basically it could work, you would need to build a special feed ( as a replacement for the LNB) though.

But the main point is: For 850 MHz, the "TV"-Dishes (usually 60 .. 80 cm diameter) are too small to get good results. You can expect gains of about 10 dB, which is easily surpassed with other designs.

thank's for the info i understand and the biggest i have is 80cm so go one for another design much better

[phallang]

Well, it says "FREQ RANGE 850-980 MHz". It looks, as expected, like it is an antenna *not* specifically designed for CDMA use, more likely it was designed for GSM (900MHz) use. But still it looks pretty wideband and that's the reason it kind-of worked for you, although the 824..849 Mhz (uplink) band is not explicitly covered. This means you might have trouble connecting, even if you get a nice signal from the tower, because the tower may not be able to receive your signal that well.

Anyway, before building your own antenna, as loong suggested, try making your antenna cable as short as possible and see how it works.

Many Thanks, Changing the cable is the first thing I will do , for those who want to try and improve the CDMA signals, but may not be able to build an antenna like your self, just looking at the antenna links shown here ..

http://www.siammastershop.com/

http://www.bangkokwireless.net/blaithaishop/

http://www.surfnshop.biz/

http://www.l-com.com/category.aspx?id=2071

is there a model of ready made antenna that you think has the best properties and best chance of offering better results than the CAT type antenna I was provided with, which I think is what most CAT users may be using . your thoughts are most welcome - thanks

I didn't see any suitable antenna in these shops! And i don't think you can get them in Thailand. If you want to go for import, then try google: 824+894+mhz+directional+antenna

[BlackJack]

does anyone know if a mobile phone ie NOKIA with WCDMA + CAT package would work connected to a notebook?