The above are typical portable tabletop antennas. Being broadband they are quite suitable for Digital or Analogue TV reception. To save you reading more on this page my recommendation is to buy a tabletop portable version that looks similar to either of the above. Don’t pay more than £10.00 dated December 2007.
A common TV loop antenna, can be ok for a good signal area.
The above antenna is a complicated variant of a log periodic antenna. Log Periodic antennas are quite useful tools in the armoury of TV antenna installers, however this one may not have been seen yet,, The log periodic Yagi is still the best option for your truck or caravan. I have seen small double boom tabletop log periodic antennas, so you can assume that many antenna designs can be theoretically available as tabletop designs.
The above antenna was available from Maplins in 2007 and is quite suitable from the point of view of reception. Cost was near £10.00. You may see others saying they are for DIGITAL SIGNALS, BEWARE BECAUSE THERE IS NO SUCH THING AS A DIGITAL OR ANALOGUE TV ANTENNA/AERIAL. ITS JUST THE FREQUENCY RANGE THE AERIAL COVERS THATS DIFFERENT. This one will do for some years yet, dont worry. Beware of others that look similar this is model L23BB from Maplins, for £9.99 you can get it with an amplifier for £20.00 but personally I would not bother, any advantage would be rare, and depending on how the amplifier circuit is connected it can be a disadvantage, I choose my words carefully.
This article looks at an Antenna or Aerial (they are the same thing) for the travelling person but reading it you will see enough to guide you regards your home digital TV aerial Antenna situation where you may need an antenna with a larger frequency range, however don’t panic because the rule is wait and see. You will still get most channels if not all of them without an Aerial/Antenna change. If you are in digital range today don’t be concerned if you cant receive the signal well enough for a picture because they are just about all on quite low power until the switch over for that area, this is to prevent interference on the present Analogue channels.
The advice on this page will help you to make an educated choice. The writer has a class one Ham Radio licence and has made Aerials Antennas for a varied range of frequencies to propagate locally and globally.
The first point I am going to make is don’t think that a higher cost for a portable (or fixed mobile) antenna means a good reception, in fact sensibly speaking the opposite is essentially the truth.
Some Caravan owners have an antenna that looks like a herringbone and is called a log periodic Yagi type antenna which often has 5 or 8 (even more) elements on the length of the boom, these are excellent and are often fitted on a small mast and turned to point in the direction of a signal source.
A small version of this is the table top antenna in condensed form,, the best antenna for limited space, both these antennas are what is known as broadband antennas in that they cover ALL transmitter frequencies in the UK (and possibly EU) … Doing this all over coverage they are essentially not the best for receiving any specific one of the transmitters,, but they are pretty good and unless you carry around quite a number of different antennas, each of slightly different dimensions, there is not another solution, so we will not labour that point any more. When it comes to digital transmissions you may find the odd area you stay in where a few channels are not too good,, technically an even more broadband antenna is called for,, but fear not,, you may never need to watch TV in an area where this might just be the case,, but you can research this as time goes by. My advice is stick with what you have unless it is not providing you with a decent signal as and when it is required.
Now to other types of commercial antenna available,,, you will see enclosed antennas in fancy covers,,, with fancy names,, some with amplifiers to boost the signal,, these may be different aerial types,, but unless the covered enclosed antenna is a Yagi type (very rare if they exist, I have not seen one)(see top or bottom left images) which is allowed to rotate,, and should not be expensive, or at least it has no technical reason to be expensive,, I would suggest that you leave it alone. Different manufacturers may produce this yagi type in variants of shape, which is fine.
Many of these circular flat looking antennas are a simple loop antenna,, some with pre-amplifier pretending to be grand,, and have an relatively expensive price tag (£50.00 to £100.00). If you have one of these fitted to your mobile home, caravan, or whatever,, buy a table top portable antenna of the Yagi type mentioned and try this, positioned often by a window pointing at the transmitter or any big local buildings where reflections can occur, even sides of hills/mountains can produce a result,, the point is a table top portable yagi antenna (aerial) can be adjusted in an infinite number of ways, which includes moving the horizontal elements into vertical positions and any number of degrees in-between,, even walking around the mobile home can produce problems if the signal is weak so putting the aerial itself outside can be an answer, but read the following with care.
Don’t apply pressure to the wall of the coax cable as many are air spaced and ovulating the shape will reduce its efficiency,,, make sure that a drip or water loop is made in the cable to cause all rain/water that might run down the cable to drip or drop off and NOT NOT NOT be allowed to follow the cable down to the appliance,, The indoor table top antenna should be plastic bagged (perhaps doubled) to prevent ANY water ingress. .
The above is a solution that can be used if desperate and I mention it only to show what can be achieved if in that situation where you are otherwise proverbially stuffed. It’s the sort of thing a radio ham might do,, or technician,,, if it works don’t knock it.
I have only crossed the T’s & dotted the I’s of safety here,, and have excluded vapour ingress if outside, however specialist sealant can be used to vapour seal connections. I wont go into this as it should not be generally needed, if only used outside occasionally and is protected.
So to sum up,, with one antenna only, a Yagi (log periodic) antenna is best (for your moving home situation) with its ability to move from its horizontal alignment to vertical as is required by circumstances. I apply this comment only to none domestic situations as fixed situations can be complex but because they are fixed different solutions can be sought and often applied.
A normal outdoor element is decent of course,, all such antennas for broadband use will have a BLACK bung in the antenna boom end,, all other colours are designed for specific transmitters and may be very poor with others,,, so BLACK boom bungs only if you are into caravanning and like a proper antenna, good luck!
To the left are a number of different antenna (aerial) types; it can be considered they are not for practical reasons, used for domestic receiving purposes for the situation/s I am concerned with for this article. It should be noted that the odd transmitter might be vertically polarised,, meaning your yagi antenna needs to have its elements in the vertical position. As a matter of interest there is a massive amount of different configurations for antennas/aerials, and there is no point in mentioning them in this article, as they would be quite unsuitable,, many are for fixed situations,, and point to point communications.
Getting a few cheap suction cups from a hardware store and using a combination of plastic sticks (or thin very dry wood) and polypropylene type string (which gardeners use) can assist you in placing your antenna in an odd position in your truck cab or caravan if you find yourself in a borderline TV signal situation. The string or thin plastic will not essentially affect your antenna.
Horizontal Omni Antennas are low gain and fine for areas where signal strength is very good. Omni directional Antennas (for these purposes) are for good signal strength areas only.
Cross Yagi antennas which can be electrically made to produce circular polarisation as a helical, (rotating magnetic field) but to any single degree either clockwise or anticlockwise. There is a small price to pay which is a little loss in effeciency.
An Isotropic (the name is a reference point) antenna is an hypothetical antenna in free space.
Dipole antenna (is a sensible reference point) is a half wave antenna more often used as a benchmark (reference point), it is about 2.2db better than an isotropic antenna. To help you further, an antenna/aerial that gives its gain in dbi as say 5dbi is about the same as an antenna that says its gain is about 2 or 3dbd, given I would trust a rating from those who quote gain in dbd more than those who quote dbi, and then hide the dbi figure in small print if its there at all! we can argue that point but thats my opinion. If you cant discover the reference point for the gain,,, DONT BUY IT!
dbi (the name is a reference point) gain means how much better this antenna is than an Isotropic.
dbd (is a reference point) gain means how much better this antenna is than an dipole which is a real antenna.
To help you appreciate more how an aerial works,, the word gain has been used,, I will apply the same to a cars headlights,, if you remove the reflectors from a cars headlights,, then try and drive at night, you will fail,, you won't be able to see a thing,, all the light produced (and the power has not changed) goes all over the place, not where you want it,, all the reflectors do is direct all the light produced forward in a controlled cone shape, the result is quite remarkable I am sure you agree,, yet we did not change the power of the lamps/bulbs,, we call this Gain,, an antenna is the same, we stop it listening (mainly) in all directions and direct it where we require it to listen (or transmit as is the case), the difference is we are dealing with magnetic waves of different lengths so we need to understand that subject,, and that can be complex.
db gain means the seller or manufacturer does not want you to know what the gain is reference to, but assume its dbi 100% and remove MORE than 2db from its figure against a antenna giving dbd. Also consider that if the claim is db for gain, which can only be designed to get some advantage which could be considered dishonest,, should we then consider them suitable to receive our money in return for goods they have possibly sort to misrepresent.
Collinear Antenna,, this could be ok but still a waste of effort as it needs to be quite long,, and then it looks (hears) in all directions at right angles essentially, so its not a practical contender for this job. A 5 to 8 element house type (size) yagi (caravaners with storage space) is great for those who want practically to have a good chance of TV in most places, but not all. This coupled with a cheap omni or table top is fine.
Truck Drivers or WVM (white van man) would as my preference have a table top portable yagi, log periodic.
Number of elements does not mean more gain as spacing between the elements is the most serious factor with antennas, however,,, in the practical world we have to compromise.
Antennas are rather complicated and are a specialist subject, experience can be a great benefit for TV house antenna installers,, but a very deep electrical knowledge is required to dig into the concepts of its design. Electromagnetic field distribution knowledge along/around the antenna and feed points is essential for design. I have written another page on this site for CB Radio (citizens band Radio) users if you have an interest in antennas for CB Radio.
OK! After all this stuff most of which you didn’t want to know,, you are thinking ok,,, but what would you do, well the answer is not a surprise,, I would use a table top antenna bought from say Maplins for less than £10.00 it would be a yagi 4/5 elements or more, don’t worry about the fancy shapes some of the elements have on these antennas,, its ok,, just look for what seems robust enough to be sensible for you,,, just the one antenna for all occasions,, if that doesn’t work,, then any other aerial apart from an external one wont succeed either. Don’t forget you can orientate this antenna in a multitude of different ways in a poor location,, where signals are bouncing all over the place and all of them quite weak, I wont explain the reason for this, please just accept it,,, in some cases its quite common to point the antenna away from the transmitter to collect a sum of reflections and direct signals,, but, beware of moving around in your accommodation if this is the case as the signal can vary if you move.
Don’t be fooled into buying an expensive flashy looking antenna generally covered in beautifully shaped plastic with pretty symbols on it claiming to answer all problems and costing well over £50.00 and often near to £100.00. These antennas may have applications in good or decent signal strength areas but outside that they are useless,, they often boast a internal amplifier,,,,,, but note this,, when a signal is weak it will also have noise (unwanted content) included in the signal,, an amplifier will simply amplify everything, including the unwanted noise,,, and then add to that its own inherent noise level,, to a fine point its fair to say you can improve matters with such amplifiers, but beware the result can also be rubbish!
You may see antennas/aerials saying they are for DIGITAL SIGNALS, BEWARE BECAUSE TECHNICALLY THERE IS NO NO SUCH THING AS A DIGITAL or ANALOGUE TV ANTENNA/AERIAL. THE SIGNALS MAY BE TRANSMITTED ON A DIFFERENT FREQUENCY OR RANGE OF FREQUENCIES which may require a different antenna, but NOT because its digital, it would be simply because they have chosen to transmit the digital signals on a different frequency or frequency range.
Portable TV antennas are broadband for the range of TV transmissions offered at this time; fixed external antennas/aerials that have a black bung in the end are also broadband antennas and may not need changing. Indeed your present antenna may be suitable. DONT get another unless you find difficulty with some channels, which will be because the NEW frequency range or frequencies for some stations are outside the remit of the antenna,, but it will not be because its digital,, per se, it will be because the signal for a certain channel has moved too far away in frequency for this antenna. The proof of the antenna is simple, are you receiving ok.
Digital Broadcasting has many benefits including much better coverage from a given antenna transmission point, and at lower power giving green savings. Because much lower strength and quality signals can be made into a perfect (well near enough) image/sound your present antenna may be more than able to supply the signal for your receiver,, because the digi box can make good sense from a much weaker signal. NO you don’t need a new TV, just a conversion box like the present free view one,,, cheap as chips,,, Sky satellite viewers often don’t even bother to receive signals from ground stations, they get everything via satellite,, for them nothing has changed!
