cell phone repeater - Electronic Circuits Projects Diagrams Free

Thunderchild · 7th July 2006, 07:28 PM

So I am at a dissadvantage with reception at my house on my cell phone. can I build a simple repeater like just two yagi areals connected together so I can gain a bit on the reception would this work how would I set about doing it ? do I need a specific type of wire to connect them

Hero999 · 7th July 2006, 07:37 PM

The problem is you need a big enough distance and adequate sheilding between the aerials to avoid feedback which would lead to oscillation. Pretty much the same as when you have the amp turn up too much and the microphone is too close to the speaker.

Thunderchild · 7th July 2006, 07:47 PM

hm sheilding can be arranged I can get aluminuim sheets 50 X 70 cm and really the problem is height so they would be out of each others line of sight

stevez · 7th July 2006, 07:58 PM

Cell phones work on relatively high frequencies - wavelengths less than one meter. Line losses are relatively high, antennas can be relatively small.

A remote antenna might be beneficial but the gain might be lost in the connecting line unless you get some really expensive feedline. Amplifiers can be used to offset the line losses and a control must be provided because the transmit amplifier is different than the receive amplifier (usually called a preamp).

Thunderchild · 7th July 2006, 08:04 PM

well cell phones are 1.9 GHz max what about satelite cable that takes 11 GHz or is there a matching problem. can a repeater be made/bought ? I am really in trouble where I am as my mobile is my modem

**Nigel Goodwin** · 7th July 2006, 08:32 PM

Quote:

Originally Posted by Thunderchild

what about satelite cable that takes 11 GHz or is there a matching problem.

Satellite cable ISN'T 11GHz, the LNB down converts the signal to 1-2GHz - so it's pretty good for phone.

JimB · 7th July 2006, 08:36 PM

Yes, I believe that two yagi antennas connected back to back can be made to work.
Try googling for "passive repeater".

If the antennas are separated by a large distance, you will need very good coax cable to make the connection between them, otherwise the losses in the cable will completely negate the gain of the yagi antennas.

You will not need to screen the antennas from each other, there will not be any oscillation if they "see" each other. (Unless you put an amplifier between them).

An amplifier is not a good idea, it would need to have gain in both directions at the same time which is a bit of an impossibility.

Idea, is there a "car adaptor" which can be used with your phone?
My phone has provision for an external antenna when used in a car.
OK so your car is all bent and battered, but a car adapter/antenna could be a solution to your problem.

JimB

Thunderchild · 7th July 2006, 08:44 PM

ah you remember I wrecked my car ? well unfortunately due to so called antipolution laws I had to scrap the car as well as turn in the documents, I had hoped to sell off the parts and even cut the body up and sell the metal, shitty country just to make the demolishers rich. well it is like a couple of metres one above the other to help get a better signal from higher up.
there is no socket on my phone for an externl antenna else problem solved

**Nigel Goodwin** · 8th July 2006, 09:16 AM

Quote:

Originally Posted by Thunderchild

there is no socket on my phone for an externl antenna else problem solved

Still check out car kits for your phone, often they don't appear to have an aerial connection, but it can be done through the socket on the base - where they plug in to the car kit.

8th July 2006, 09:54 AM

simply cut multiple 1/4 wave lengths of wire and leave them everywhere(vertical), I have seen commercial type versions of this back in the early days of mobiles when coverage wasn't so good.

steve83 · 8th July 2006, 09:59 AM

First off, you need to make sure that you do have a decent signal where your antennas are going to be placed. As people have mentioned, your losses from the antenna to your phone will negate any gain you recieve from your antennas. As mentioned, you would need an amplifier to give you the signal boost from the antenna through the line to your phone.

As far as pricing goes, yah you save alot of money by using a Yagi and a coax line but you probably wont see an increase in your reception. The fellow that mentioned car adapters is what you would need to connect the Coax to your phone, but these car adapters are used in conjunction with small antennas that mount on your car via magnet and their lines are pretty short (couple of meters tops).

If lack of reception is a big problem for you in your house there isnt much you can do without spending money. I would check out http://www.cellantenna.com. They sell Repeater packages of all sizes, I think they have an 80db amp which is friggin rediculous (1Billion times?). But they do have lower end packages for homes that will even allow you to operate w/o having to hook up your phone to the amp.

Hope this long post helps!

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7th July 2006, 07:28 PM	(permalink)
Thunderchild	cell phone repeater So I am at a dissadvantage with reception at my house on my cell phone. can I build a simple repeater like just two yagi areals connected together so I can gain a bit on the reception would this work how would I set about doing it ? do I need a specific type of wire to connect them __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk

7th July 2006, 07:37 PM	(permalink)
Hero999	The problem is you need a big enough distance and adequate sheilding between the aerials to avoid feedback which would lead to oscillation. Pretty much the same as when you have the amp turn up too much and the microphone is too close to the speaker. __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez And http://www.silicontronics.com, same screen name as here.

7th July 2006, 07:47 PM	(permalink)
Thunderchild	hm sheilding can be arranged I can get aluminuim sheets 50 X 70 cm and really the problem is height so they would be out of each others line of sight __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk

7th July 2006, 07:58 PM	(permalink)
stevez	Cell phones work on relatively high frequencies - wavelengths less than one meter. Line losses are relatively high, antennas can be relatively small. A remote antenna might be beneficial but the gain might be lost in the connecting line unless you get some really expensive feedline. Amplifiers can be used to offset the line losses and a control must be provided because the transmit amplifier is different than the receive amplifier (usually called a preamp). __________________ stevez

7th July 2006, 08:04 PM	(permalink)
Thunderchild	well cell phones are 1.9 GHz max what about satelite cable that takes 11 GHz or is there a matching problem. can a repeater be made/bought ? I am really in trouble where I am as my mobile is my modem __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk

7th July 2006, 08:36 PM	(permalink)
JimB	Yes, I believe that two yagi antennas connected back to back can be made to work. Try googling for "passive repeater". If the antennas are separated by a large distance, you will need very good coax cable to make the connection between them, otherwise the losses in the cable will completely negate the gain of the yagi antennas. You will not need to screen the antennas from each other, there will not be any oscillation if they "see" each other. (Unless you put an amplifier between them). An amplifier is not a good idea, it would need to have gain in both directions at the same time which is a bit of an impossibility. Idea, is there a "car adaptor" which can be used with your phone? My phone has provision for an external antenna when used in a car. OK so your car is all bent and battered, but a car adapter/antenna could be a solution to your problem. JimB __________________ Experience is directly proportional to the value of the equipment ruined.

7th July 2006, 08:44 PM	(permalink)
Thunderchild	ah you remember I wrecked my car ? well unfortunately due to so called antipolution laws I had to scrap the car as well as turn in the documents, I had hoped to sell off the parts and even cut the body up and sell the metal, shitty country just to make the demolishers rich. well it is like a couple of metres one above the other to help get a better signal from higher up. there is no socket on my phone for an externl antenna else problem solved __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk

8th July 2006, 09:54 AM	(permalink)
Paul Obrien	simply cut multiple 1/4 wave lengths of wire and leave them everywhere(vertical), I have seen commercial type versions of this back in the early days of mobiles when coverage wasn't so good.

8th July 2006, 09:59 AM	(permalink)
steve83	First off, you need to make sure that you do have a decent signal where your antennas are going to be placed. As people have mentioned, your losses from the antenna to your phone will negate any gain you recieve from your antennas. As mentioned, you would need an amplifier to give you the signal boost from the antenna through the line to your phone. As far as pricing goes, yah you save alot of money by using a Yagi and a coax line but you probably wont see an increase in your reception. The fellow that mentioned car adapters is what you would need to connect the Coax to your phone, but these car adapters are used in conjunction with small antennas that mount on your car via magnet and their lines are pretty short (couple of meters tops). If lack of reception is a big problem for you in your house there isnt much you can do without spending money. I would check out http://www.cellantenna.com. They sell Repeater packages of all sizes, I think they have an 80db amp which is friggin rediculous (1Billion times?). But they do have lower end packages for homes that will even allow you to operate w/o having to hook up your phone to the amp. Hope this long post helps!