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bob G

GSM mobile phone reach North sea coast Belgium

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some years ago KPN boasted they were enabling 4 g on the North Sea with a reach of 20 km and more does any one have any information on the currenct situation. In particular what is the distance from the Zeebrugge Belgium coast  one can reasonably expect to get a usable signal.

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Isn't cellphone service essentially line-of-sight?  How high are their towers?  And if you want to talk, then we'd have to know how powerful the transmitter in your phone is. You may be able to receive data, but not transmit. Sounds like a boast good enough pull in some business.  Has their stock taken off since then?

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20km? It's possible but won't be a slam dunk. The frequencies are all line of sight. (800MHz to 3GHz) and the visible horizon is 6 miles (9-10 km) out standing on the shore. Higher towers will extend that distance somewhat.

http://www.ringbell.co.uk/info/hdist.htm

With the above you can take a 100 foot tower and hit 12.3 miles out, which is 19-20 km. A weak signal however may have issues, but cell phones have some impressive dynamic range with the capability to take signals successfully with over 100dB of dynamic range. (really weak to very strong if you ditch the geek speak)

 

YMMV

 

 

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5 hours ago, jerryj2me said:

20km? It's possible but won't be a slam dunk. The frequencies are all line of sight. (800MHz to 3GHz) and the visible horizon is 6 miles (9-10 km) out standing on the shore. Higher towers will extend that distance somewhat.

With the above you can take a 100 foot tower and hit 12.3 miles out, which is 19-20 km. A weak signal however may have issues, but cell phones have some impressive dynamic range with the capability to take signals successfully with over 100dB of dynamic range. (really weak to very strong if you ditch the geek speak)

This thread is somewhat confused: the subject is said to be GSM but all posts is about later generations. And then there is talk about frequencies, LoS, dynamic range of mobile phones ...

GSM in its original shape was had a very robust modulation, gmsk, was based on time slots and frequency separated up- and downlinks, ie TDMA/FDMA/FDD, with an associated bandwidth of 200 kHz. Very robust al of it. The time division slots resulted in a maximum of 34 km between mobile and base; the original mobiles had a max output power of 6 W (car mounted).
The standard has been upgraded in many steps, GPRS and EDGE has been introduced to increase data rate as well as using double adjacent time slots to increase radio range - with that it is possible to reach up 200 km. If the base and mobile power amplifiers are strong enough this is certainly possible . However, there is little or no market demand for these radio ranges, and a modern smart phone output power is < 1 W.
The traditional fequency band for GSM is 900 MHz, in the early 1990 also the 1800 MHz band were added. Higher frequencies generally gives shorter radio range, which also higher modulation, as used in EDGE does.

Moving on to 3G, CDMA technology (in Europe the WCDMA with 5 MHz bandwidth), the users are separated by code and not so much by frequency and time. 3G  was motivated by data rate, and certainly not radio range - in almost all cases 3G radio range is shorter than GSM.
For 3G there is the same story about improving standard, introducing HSDPA and similar ideas which boosted data rate but also was a priority put on the users close to the base - we got cell breathing resulting in lower data rates at the cell edge and lower prio for users with a lousy link budget.

4G, LTE, is OFDMA based. To some extent going back to the basic principles of GSM. Again, the driver is data rate, LTE is now capable of delivering up to 1 Gbit/s user data rate - close to the base station (LTE advanced). As in the first approx data rate is proportional to output power (Shannon) then radio range has to be limited, combined with the fact that modern smart phones spend a considerable power to feed the display so from battery budget point of view there is not much left to use for the rf output power. In real life - be happy if you get more than some few km radio range. Specialized solutions are possible to get better range.

Spectrum (in Europe) is now mainly said to be technology neutral, resulting in LTE using frequency bands from 700 MHz (from the digital dividend) to 3.5 GHz. In some countries LTE has inherited the 450 MHZ from 1G (typically NMT), narrow band but gives good coverage.

Finally, no there is not any cell phone which can handles recieve signals with a dynamic range of 100 dB. Ability to handle dynamic range in any signal is given by the (rf) A/D converter, which typically has 6-8 bits resolution in the best recievers. The reciever sensitivity of mobile phones has improved very much over the years, somwwhat hampered by the increased  bandwidth. To set up a call / connection some signalling in both downlink and uplink must take place, thus it is not sufficient for the mobile phone to recieve signals it must also transmitt and these signals to be recieved by the base.

You just wanted a short answer? OK, unlikely you will be able to set up a connection from the North Sea outside Belgium to land over a distance of many km. Most of the radio based antennas are directed towards land where the mobile traffic is. 
Use VHF or satellite.

//J

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hit or miss.

I had some luck with getting an 3G signal 4nm out of the coast, but my friends had no signal at all. Same provider (Vodaphone/proximus) same Phone (iphone 6).

But  during the Ostend-Ramsgate, I had all the way minimum 'edge' or higher. In between the separation zone, I had 4G. Crazy, but nice to send some pictures around.

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On 4/13/2018 at 11:22 PM, Jaramaz said:

This thread is somewhat confused: where the mobile traffic is.

((edited out all the inane babble about modulation types))

//J

God I hate it when somebody asserts themselves as an authority :o and doesn't know WTF they are talking about. :wub: :angry:

The original GSM systems (the old ones) have a dynamic range of 91 dB

http://www.analog.com/en/analog-dialogue/articles/wideband-radios-need-wide-dynamic-range-converters.html

Read the above if you don't believe me. 

Also if you read the below, you will see illustrated that on a good day you can get to 115 dB of dynamic range:

http://www.radio-electronics.com/info/receivers/dynamic_range/dynamic_range.php

Which is why in my prior post I sort of handwaved and called it  over a 100dB. Depending on which cellular standard we are talking about they range from 91 to IIRC 106dB. 

As well, if  you think that you are just connecting up an 6-8 bit ADC to the damned antenna, you have obviously never designed a cell phone receiver in your life. Considering my last 2 boats were largely paid for from contracts working for Motorola, Broadcom and Qualcomm I got a different story to tell.

Rant off...

:)

 

 

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On 2018-04-19 at 1:55 AM, jerryj2me said:

God I hate it when somebody asserts themselves as an authority :o and doesn't know WTF they are talking about. :wub: :angry:

Jerry, don't be so hard on yourself.  You are so agressive - why?

 

We have to clear some things here:

Dynamic range of a mobile phone is not really the most important factor wrt its radio range. Instead reciever sensitivity in downlink and output power and PA linearity in uplink are the important factors.

Coming to the first link you offered, the one from ADI, that was about radio base stations. The paper discusses necessary dynamic range for the reciever in a base station,  not the GSM System dynamic range (system dynamic range is not the same as receiver DR). The paper use a 12 ADC as an example - that was what was used in base stations at that time with the architecture used. A 12 bit ADC gives about 75 dB dynamic range (probably drops some 4-6 dB as enob is likely to be ~11 ), to improve reciever DR further one adds AGC and in the paper it is suggested to go for oversampling to supress noise which further improves DR. In 1995 that was what one could do, nearly state of the art.

A mobile phone does not have the same requirements; a base station is a multi user system whereas a mobile is a single user. Radio and baseband architecture is quite different for base stations and mobiles: A base station must be able to handle many simultanous mobiles near and far, to handle blockers, interference etc whereas the mobile will be assigned a frequency which isn't full of interferers. A mobile simply doesn't demand such high DR, and to in 1995 put a 12 bit ADC in a mobile - no, that would be too powerhungry, too large footprint and too expensive. 

The paper of the second link you offered is very general. Doesn't say anything about application it is just about how it is possible to design a high performance reciever - figures are reasonable and generally ok, even if the architecture it is based on is somewhat dated. Of course it is possible to achive very high DR - if you can afford it in terms of power consumption, cost and size. Which you can't in a mobile.

Lately it has been discussed to use real low resolution ADC in eg 5G due to the high isolation in those systems. As 3-4 bits ... something for you to consider :) . Myself, I am not so sure this will be the case in products, but you can easily find both papers and patents on this.

The argument " my last 2 boats were largely paid for from contracts working for Motorola, Broadcom and Qualcomm I got a different story to tell. " is a rather weak one. You are not saying anything about what you really did in this work; very few, if any, is designing a complete mobile by themselves. There use to be different teams - rf, baseband, audio and so on.

//J

 

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On 4/21/2018 at 7:57 AM, Jaramaz said:

We have to clear some things here:

Well, this conversation is down to two people and one of them seems to want to lecture me. 

Have a nice day. 

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Dont know the answer,  in southern europe...mountainous  coastline...i get 8 or so miles reception from the shore ant 

you might talk  to an electronics pro in the area.    

Also Some mobile phone brands have poor reception .

an external antenna on the mast is very common.

my old mast mounted ant...now kaput from lightnight strike ...would pick up the signal 12 or more miles offshore and was very valuable .

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They're regularly putting antennas on offshore wind farms now, there's loads off the Belgian coast, but not sure if they've got antennas or not. 

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