My first home brew 2.2GHz 3G Yagi aerial with the home made plug shown boxed
Construction details are lower down this page
Welcome to what are the most popular pages on this
entire web site! So it seems that people all over the world need to boost
their 3G broadband signals and don't see why they should pay much for the
privilege. That's what these pages are here for!
We are here to discuss ways to improve mobile
broadband reception for those of us who are in "not-spots" or more likely
"virtual not-spots". These are areas where the 3G broadband signals range
from well nigh useless to perhaps more like ours - very unreliable. This
site is NOT for people who don't like getting their hands dirty with
soldering, or perhaps spending a day making something before throwing it
away as a failure only later delving into the dustbin to retrieve your
design, changing a part and then trying again. Maybe after trying the
dustbin lid as a reflector on the way! In other words it's for those of us
who like experimenting.
To make their work worthwhile experimenters need to
know why they are doing something, so I will try to explain in as simple
terms as possible the reason why we need to do some of the things that I am
about to suggest. It's no good just saying "do this", bend this, "do that"
as you can easily go wrong and not know why. In this way experimenters can
do what I did, learn as I went. Oh I did get a Ph.D. at university but still
love to experiment!
I have tried various ways to improve our 3G signal
levels and have reached the point where despite being on the white part of
the coverage map - which supposedly means no coverage - we can connect
reliably with three and often four bars on the signal display. In all the
cost can range from nothing to a few tens of pounds at most.
If you have tried a mobile broadband dongle in the
past and given up then I recommend that you dust it off and try again. You
don't need to pay any money to test the signal level as all dongles will
connect to their home web site whether activated or not but to do this they
must have a card inside. In the UK Three have actually done what they say in
their adverts and have recently improved their signals in many parts of the
country. I now get 4 bars on my display using a home made cardboard aerial
booster when last year for most of the time I could not even connect!
Because of this I have just renewed my Three Broadband contract - they gave
me a 50% reduction to keep me for 12 months more! Some other mobile
broadband suppliers have also improved their coverage so never give up and
Let's get one thing out of the way at the start. The
dashboards from the various dongle manufacturers like Huawei mostly have 5
bars but whilst these are a guide they do NOT represent signal level at all.
Instead they show the amount of corruption that is affecting your signal
while it is in the "ether" (an old fashioned term for the atmosphere)
between their transmitters and your home. Your dongle checks the integrity
of every data packet that it receives and when there is a lot of corruption
that it cannot sort out the dongle has to keep asking the base station for
the last packet of data to be repeated which obviously slows the whole
process down. The less corruption of the signal, the less time is wasted.
It's rather like being on a noisy phone call when you are deaf and saying
"Pardon, can you say that again please? over and over again. (I have
tinnitus so I am not disrespecting the deaf.) This can mean that to get
faster reception you frequently do NOT need to increase your signals at all,
but instead need to reduce the interference that is getting in the way. In
this way you get your complete data faster! Much, much more on this
interesting problem later as interference is something that the home
experimenter can attack using just simple things like bent metal and tin
foil. Oh where would we be without soup cans, Sainsbury's or the Pound Shop?
IMPORTANT UPDATE FOR THREE UK USERS
If you are reading
this site in the UK then I need to warn you about a new technique
that Three are apparently using. Basically they are adjusting
their cell power levels dynamically - this means the transmitter
power can go up and down in less then one second. In the past when
a cell was set up it tended to continue to transmit at the
original power all the time whether it was lightly or heavily
loaded. This meant that users tended to get used to being able to
connect when they pointed their aerial in a certain direction.
So why should this
If you are nearby this
won't affect you, but if you have a good signal you won't be
reading this site anyway! If you are connecting with a large
aerial then it may appear to the cell that you are nearby so it
"turns down the wick" and as a result you can lose your
The reason seems to be
to enable them to prioritise connections that are more powerful
and push away the more distant calls. I am sure there is also an
element of electricity cost saving in the scheme.
I can't see a solution
to this (in the short term anyway) as if you use a smaller aerial
you appear to be less powerful and lose your connection as well!
This message is just
to warn you that you may not be able to rely on using a single
cell as you have been in the past. I am trying to work out a way
around this, but don't hold your breath. Please don't shoot the
made 3G Broadband passive reflectors
You can skip the next few paragraphs if you like and
go on to the next page, but some background is as I said above very helpful
as it helps you see what you are trying to do. In a previous life I worked
in broadcast technology and we quite literally played around with reflectors
when designing the early satellite dishes - that's was with the IBA at
Crawley Court in Hampshire, when Sky was just a twinkle in the eye of Rupert
Murdoch. Our boss said that direct PAL television reception from a satellite
to a small "coffee table" size dish was impossible and we would have to use
a different and far more complicated system for transmission - he was wrong,
totally wrong! Sky Television using a 60cm dish was the result, and Sky
Television worked just fine. It now uses a tiny 30cm dish that I helped
So with this behind me I have already designed a
passive "device" that is excellent at not only boosting received 3G
broadband signals but more importantly at blocking unwanted interference. I
visited a lady on the South coast recently who was too far from her
telephone exchange for a.d.s.l. broadband and she could get virtually no 3G
reception because she was also 5 miles from the nearest Three base station.
Rather importantly, and completely ignored by previous engineers who had
spend time at her home trying to help were the several dozen 70 metre high
windmills in a field not a quarter mile away off to the side of her home! As
if this wasn't enough an army firing range was behind her just down the
road, this seemed to block her signals whenever the guns were firing or the
soldiers training, which in these cash starved times was most of each day.
Using my new "device" we managed to block out much of the interference from
the side and rear and get her a quite reliable 2 bars on Three broadband!
Ah, you will say, but there is nothing in the direct path of the signals to
"get in the way" so how can the windmills and army affect reception?
Well let me try to explain and see how our attempts to
bring a broadband connection to an isolated area of the South coast worked
by the use of a couple of diagrams, and I apologise in advance for my
dreadful artistic ability.
"Before" - when we started the direct data signals were often interfered
with by the reflections from the wind farm
You have to remember that mobile transmitters send out
signals in a "circle", in other words the base does not know where you are
so it sends everybody's data out in all directions. This is the reason why
you receive such a microscopic signal as the data has to cover a lot of
ground! Some of your data gets sent direct to the house which is what you
want. However a lot gets sent in the direction of the wind farm and as this
covers a much larger area than a house even more arrives at the wind farm.
The blades are very effective reflectors of radio energy so while some of
the data gets bounced straight back where it came from a small amount
bounces off the blades in the direction of the house. Now (and this is
vitally important) the data bounced off the wind farm goes a longer way
round so takes a longer path (it goes round two sides of the triangle
instead of one). This data that arrives at the house from the direction of
the wind farm gets there "late", and can arrive when the dongle thinks that
it has received all the data for the moment and its oscillator has gone "out
of phase". Therefore the late arriving interference has the effect of
upsetting the good direct data already received. (This is an obscene over
This means that to make the dongle only work on the good
direct data "all" you have to do is "simply" block out as much as possible
of the interference data that comes from the direction of the wind farm.
Simple! Well no actually it isn't, as it is quite hard to block out signals
effectively (you can still listen to your car radio inside a short tunnel
for example) but my "device" takes care of all that whilst at the same time
slightly boosting the wanted direct data. So as you will see in the next
diagram the dongle now receives the direct data with less of the
interference which is absorbed so does not get in the way of the decoding
"After" - the direct data makes it through while the interference is
I hope this explanation will show why even though the
wind farm was not directly in the way of the wanted signals it was still
able to exhibit a dramatic effect on signal quality. Remember the
reflector may be anything instead of a wind farm such as a high building, a
hill or a motorway with lots of high sided vehicles acting as mobile
When deciding how much information to write on this page
I had to choose whether to explain why the delayed data was bad for
the dongle or just state it as a fact without explanation. It's all to do
with oscillator phases and my explanation above is truly dreadful; whilst I
could go into full details I have decided to put just enough information to
enable you know why you are doing something rather than giving a
lecture on electronics theory. I hope the above diagrams do that without
being too boring.
So you now hopefully understand that you need to remove
interference, some of which may not even be in the direct path, whilst still
letting the wanted data through and knowing that we can get down to
designing a device to do this.
As I said above we use Three as provider of choice. I
like Three, they have by far the better coverage of any of the mobile
broadband operators in this country and their contention is lower - fewer
people share each channel when on line. This is probably because Three paid
over £4 billion for an unused piece of the ether in which to operate. In
fact they have bought 50% more bandwidth than any of the other operators,
some of which they have still to set up and use. Coupled with this is their
price structure which if you are prepared to sign up for a period can give
as much as 15Gig of data each month for £15 - a bargain in anyone's
language. If you look here you will see
that in Horsted Keynes we connect at a 2.5 Meg download speed - and we are
outside their official service area! The theoretical maximum speed has
recently risen to 7.2 Meg along with the other 3G operators, although this
increase is very dependant on signal strength. A slight disadvantage is the
new faster dongles do not come with an aerial socket so are useless in our
circumstances. We have tried one of the latest "up to 7.2 Meg" dongles and
found it dreadfully insensitive! We'd rather have a good 2 meg connection
than an unreliable 5 Meg connection any day!
3G and Wi-Fi reception
I hope to be able to publish plans for making my
"device" very soon after I have received some legal advice about whether
they are patentable. If you need help with a similar connection problem or
just want a rough idea of how my "device" works do please get in touch.
Whilst I do not offer a consultancy service as such (having retired) I am
always interested to see what help I can offer those who have unusual
reception or networking problems so don't hesitate to send me an email. I
can be contacted at 3g @ the domain that you are connected to dot com. There
is also a link to a different address that is forwarded to me at the foot of
every page on this site. Sometimes messages (particularly for some reason
messages from aol ) get trapped as spam. If you don't get a reply within a
few days please try again.
By the way like the rest of this page low cost, or
shall we say "Recession Prices, are essential and it would only cost
you a few GBP to make a copy from parts available in almost any small town.
Please go to page 2 for practical designs including..
|Home made 3G aerial designs
||"Cheap 'n cheerful" CRC9 Huawei
3G dongle aerial plug (Popular!)
||Home brew 3G software
||Easy ways already tried to
boost 3G dongle signal
||Homemade 2.1GHz Yagi
this and more on Page2 !
And even more on Page 3!