Grounding an Appliance

However........ It would seem in my very limited knowledge of all things antennas that a directional antenna would give me the greatest amount of gain.......... Just how directional is a directional antenna?

A very precise direction with an unmeasurable degree of error?
A very close direction with a narrow angle of directional accuracy?
A wider more tolerable degree of adjustment?

A Yagi, is the most directional type of antenna in common use. Yagi type is the same type commonly used on chimneys for terrestrial TV reception and produce figures of around 20:1 gain. That's a 20 to 1 better signal strength when pointing directly at the transmitter, that when not pointing at the transmitter. The more elements to the antenna, the greater the gain figure, the narrower the reception angle.

In the early days of wifi, a relative living a little over half a mile away and almost LOS, needed Internet access, but with lots of other wifi in between. To provide that access, I built a pair of home-made 7 element Yagi antennas - 5x directors, 1x active, 1x reflector at the back. These plugged into adapted wifi routers. To limit coax losses, I co-located the routers in water tight boxes on the masts. Both radio amateurs and wifi is an amateur band, so permitted for us. It was mostly experimental, I had ideas to set up a national high speed packet data network at the time, but it worked very well indeed for several years.

Licence free, limits how directional and the gain of an antenna the public can use - it doesn't prevent suppliers making wild claims about the gains of their antennas. I think you are suggesting you have reasonable reception of local masts outside your home, that alone suggests that almost any antenna will work, if mounted outdoors, at a reasonably high spot - but keep in mind that losses in coax cables are large, connecting router to antenna, so the 'high place' needs to be not to far from your router. It might be possible to improve the directivity and gain of such an antenna slightly, by adding a suitably sized sheet of alloy to the back of such a ready made, as a reflector element.
 
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Thank you Davelx and Harry,

Dave, a very interesting read partly understood.

Harry, i'm getting the impression that antennas / aerials etc can't damage what is going to be an expensive buy?

I haven't exchanged contracts on the house i'm buying and moving into later in the year yet (It needs a Kitchen and bathroom amongst other things before i move in) but when i've visited i've made a note of just how strong my mobile signal is in each room and outside. Outside my phone suggests i have a full signal. Indoors everywhere that i can determine there is no signal at all whatsoever.

I'm thinking that i may have to just go for something antenna wise and try it, if i'm not happy then accept that i may have to buy something else until i find an antenna that works well. Struggling to decide whether to go for a omni or a directional antenna though.

I'm guessing that i'll try an omni directional to get started because of it's simplistic setup / installation along with it's flexibility. If i'm unhappy then try something directional.
 
I'm guessing there is no logical way of deciding what antenna is best to buy and i'll just have to go for it and hope for the best knowing that i may have to try again.

I will endeavour to return and post here what happens and let readers know how well or badly i get on. But this will be in several weeks or even a month or two.
 
Hoping someone can offer a little advice.

I'm going to be buying a pro mobile router (Teltonika RUTX11 router with a Poynting OMNI-402 Antenna) shortly, and it's primary use is a mobile one such as in a vehicle such as a coach, bus, tram, boat or train etc.

It has a metal casing with a grounding screw. This'll be for earthing the case in a mobile vehicle.

There will be a serious external high gain antenna plugged into it sited high on a gable end wall in a rural location. The power will be provided by a 240V 3 pin plug transformer that will provide an output of 12v DC to the router.

Used in a domestic home will this grounding screw require earthing either to ground or into the mains service wiring.

NO - do not connect the case earth to the mains earth as it will then cause the mains earth to be part of the radiating system. It needs a separate earth - including it's own earth spike, connected by a multi-stranded cable.

As for the antenna - 'Gain' is only achieved by a 'trade-off' elsewhere, in the case of antenna's by narrowing the 'aperture' - in this case the 'effective' height of the signal. The 'gain' figure quoted for your named antenna is 6.2dB so the effective vertical height of the signal is around 20degrees centered on right angles to the antenna's vertical plane. Outside of that beam aperture the signal is much reduced.
Sales blurb referring to 'Ommi-directional' on a gain antenna means gain is only in the horizontal plane with a loss in the vertical plane.
 
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Thank you wgt52,

so i'm guessing from what you're saying is that the omni antenna picks up a signal from anywhere in a 360 degree radius in the horizontal plane and 10 degrees either side of plumb level in the vertical plane. At a distance of 2 to 4 miles that's a great deal of scope.

Do you know just how directional a directional antenna is? Presumably such an antenna's aperture is very much reduced in the horizontal plane and the vertical plane. The 3 masts i have to choose from are spread out over roughly a 60-degree angle. Two of them are within roughly 10 degrees of each other, but one is 2.1 miles away and the other is 4 miles away? The third is to one side a good 50 degrees at roughly 3 miles.

Is it possible that i could point a directional antenna at the two masts that are within 10 degrees of each other in the horizontal plane and get the benefit of both?
 
Is it possible that i could point a directional antenna at the two masts that are within 10 degrees of each other in the horizontal plane and get the benefit of both?

For an omni, imagine a dinner plate laid flat, with the edge diameter of the plate being where your are transmitting and receiving from. For a direction antenna, just imagine a narrow cone, becoming wider the further it gets from your antenna. Point to note with a Yagi style antenna - it needs to be polarised horizontal or vertical, to suit the transmitter. I'm guessing for a mobile mast that will be horizontal, so your antenna's elements need to be horizontal to match.

10 degrees is well within the reception width of your directional antenna - you will find it quite difficult to even align the direction of the antenna that accurately. Does this equipment support multiple sims, so you can access different providers at the same time?
 
Think you are looking to deep into this. I see the router you are proposing is 'Dual SIM' (not that you need to have 2 networks available at a fixed location) so that means it will connect to a 'mast' out of the several it can 'see', by using directional antennas it reduces that availability and your continuous service. As the networks evolve (3G - 4G - 5G) the users device (in your case the wireless router) becomes more integrated into the total system. The 'mast' selection will depend on many factors including signal strength (both to and from the router), the load on and capacity of the present 'mast', the service provider. Mast 'selection' is entirely under the control of the network so with a directional antenna you could actually see your router directed to a mast that you have intentionally 'hidden'.

At the distances you have quoted you are just as well off using the simplest antenna you can.
 
Does this equipment support multiple sims, so you can access different providers at the same time?

It does support multiple sims but i'm not planning on utilizing this feature. The 3 masts are all used by both EE and vodafone, one of them is also used by 'three'. I am now very much tempted by a directional antenna and pointing it at the two masts that are closely aligned even though they are a sizeable distance apart.

I'm with vodafone on my mobile and i have no problem with either the service or the company, and they are currently offering an affordable MAX contract whereby you get unlimited use at the maximum speed available (no throttling). But i'm also smitten by EE's offering of "Data Sharing" whereby an allowance of 200GB month can be shared across two sims, my router and my phone, but it's unclear whether download speeds are throttled, many are.
 
The OP is suggesting all of the available masts are in one direction.
They are all in one direction insofar as the masts that are in the opposite direction are 'over the top of a sizeable hill'. To the rear, over the hill top there is a vodafone mast that's less than a mile away but i'm thinking that because of the topography of the landscape it's height above the house and out of sight it's inaccessible to me.
 
Think you are looking to deep into this
Thank you wgt52, i probably am but i am trying to get an understanding of what this is all about in the hope i can get my choice of kit right the first time.

It's clear there are advantages and disadvantages of both types of antenna. A directional one may give me the best speed, but an omnidirectional one may give me better reliability but at a reduced speed.
 
At the distances you have quoted you are just as well off using the simplest antenna you can.
Indeed. As I said to the OP very early on, since he told us that he got a good signal on his phone (which has a 'minimal' internal antenna), then the antenna he needs is also 'minimal' - i.e. virtually anything would serve his purpose.

Once one has moved to thinking about simple/cheap antennae (with not even any claims of 'high gain'), then all the protracted discussions about directionality become moot, as do the OP's concerns about the multiple masts he wants to be able to connect to.

Kind Regards, John
 
With wireless internet frequency has a greater impact on data rate than signal strength. The other benefit of higher frequencies is that once the signal strength drops to a point where it is no longer usable It's re-use is a lot easier as it will interfere less with other radio channels on the same frequency. Higher frequencies signal strength reduces quicker due to atmospheric conditions (rain, pollution, vehicle exhaust gases). Also higher frequencies are much more 'Line of Sight' and do not follow the terrain like low frequencies. Digital signals can operate at lower received signal strength levels than analogue ones so the internet speed doesn't reduce that quick until it fails completely.

Higher frequencies are attenuated more by the cable connection antenna to device than lower frequencies which is why satellite TV dishes have a first receiver stage in the LNB at the dish focus. The LNB converts the (already very low power) 12GH signal to a lower one (}a higher power{ 1.5GHz) which is much less attenuated in the antenna cable.
 
It's clear there are advantages and disadvantages of both types of antenna. A directional one may give me the best speed, but an omnidirectional one may give me better reliability but at a reduced speed.
I don't think that connection speed is an issue. Basically, the wireless connection will either 'work' or not work - and if it 'works', then you will get the full connection speed available from the network.

Connection speed would only be impacted if the signal strength were so marginal (very low) that the system had to repeatedly re-send packets because of errors, but that's very unlikley to be an issue with a fixed antenna that usually 'works'.

Kind Regards, John
 

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