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Cable, Connectors and Leads  (Also see Online Sales / Mail Order Sales)

Subjects on this page are listed in the following order :  

The Importance Of The Cable And The Routing Of It  (including Surface Plates ,

                       Cable Through Your Window Frame and Clipping Cable To The Roof Slates)

The Three Main Types Of TV Aerial Cable

"Low Loss" Co Ax

RG6 Type Satellite Cable

H109 / CT100 Type Satellite Cable

Joining Two Cables Together

SCART Leads And Phono Leads

SCART Switch Boxes

TV Leads / Fly Leads

Co-Ax Plugs And F Connectors

We are more than willing to give advice to those actually purchasing from us.  

Could those only seeking information please just ring an aerial installer local to them or try calling reception advice on 08700 100 123 (BBC) or 0844 881 4150 (ITV).

The Importance Of The Cable And The Routing Of It

A fair proportion of our call outs for "poor picture" are not caused by the aerial at all, but by the cable. Usually it is perished or cracked or just bodged in the first place, e.g. a kinked cable or joined together with insulation tape etc etc. If it is a fringe area and there is a long cable run it could even be due to the use of "budget Lo-Loss co-ax" cable. The cable is just as important as the antenna (and any amp or splitter, if fitted) in providing a decent signal

on your set. The cable should be changed as a matter of course if any work is undertaken on the aerial, unless you are sure it is sound and of good quality. Whilst on the subject of cable / connectors, we do not recommend the use of surface plates in the wall particularly if a PSU (for a mast head amp) is used in the system. Apart from providing an extra join in the downlead, the cable is often "kinked" (at the point where it is attached to

the PCB at the rear of the plate) and this is bad practice from the RF point of view. We advise utilising the cable direct from the aerial straight into your TV or Digital/Freeview box.

If you have one of the latter the cable should always go into that first. Placing a "hole tidy" (sometimes called a cable tidy or grommet) around the cable just where it enters the house provides a neat job (see picture) and it`s quicker / cheaper than a wall socket. We have had customers complaining of poor signal who have gained significant improvements by simply dispensing with the surface plate. Unscrew it from the wall and check if you have a bit of slack in the Co-Ax leading to the rear of the plate, don`t pull it too hard though ! If you have enough spare cable, detach it and then unscrew the PCB from the back of the surface plate. Now throw it in the bin. Gently pull some of the downlead out and push it through the hole which you have just exposed in the plate. Replace the plate on the wall and attach a Co-Ax plug to the stub of cable, then join an extension to this.

“ Hole Tidy” (installed in a sheet of Perspex)              “Blow Out” cover

If you plan to recable your aerial yourself, a typical cable run from the chimney is about

15 m. One should always buy a little more than is required as few things are more

frustrating than completing the job only to discover you`re short of cable !

If your downlead is cut through, best practice is to replace the lot. It may be budget Co-Ax and cable does degrade over time anyway. If you must join a new length of cable outside, we recommend using the method shown below. The use of Co-Ax plugs covered in insulation tape is very bad practice.....

After the cable exits the aerial`s junction box introduce a slight downward gradient to it help prevent the ingress of water. Now (on a cradle mounted aerial) comes the big question !

Do I route the cable forward (and then down the pole) ? Or do I route it back round the reflector and then onto the pole (which is what aerial manufacturers recommend these

days) ? Well we did a series of tests and found no measurable difference, I`m not saying there isn`t any difference, I`m just saying we couldn`t measure it !

It certainly looks worse sending it back round the reflector though.....

Next use decent quality insulation tape to secure the tape to the outside of the pole, preferably on the North side so as to minimise exposure to the sun. The use of cable ties

is not recommended as they degrade in the sunlight and when they fail you don`t want to have to go back up to replace them ! Running the cable down the inside of the mast can also be problematic due to the possibility of chaffing on the cut end of the pole and any

wind movement can cause the downlead to bang against the inside of the tube in a most annoying fashion.

Whilst routing downleads do not introduce sharp bends or kinks to them and if you are splitting it always use an amp or splitter (as required), never just bodge it together with insulation tape. It is often neater and more convenient to split the cable outside and this

can be achieved by utilising a weatherproof splitter box (or amplifier).

It may be easier to drill a hole through the window frame but it is bad practice to route the lead this way. It will encourage rot and if you replace your window(s) the cable will then need to go through the wall anyway. Incidentally if you ever have replacement windows

fitted, do not allow the installers to "wedge" the cable under the frame. Apart from the fact

it looks awful and the crushing of the cable should be avoided, when you eventually have

the downlead replaced (cable does degrade over time) the old cut off stub will be left in situ for evermore !

If you accidentally damage the brickwork, whilst drilling the hole through the wall, we sell “blow out covers” in brown or white. Incidentally these are just to cover up any “blown out” brick work, they aren`t used to prevent water ingress, you should silicone the hole and use

a “drip loop” just before the cable enters the wall to achieve that.

When a cable is routed across a roof it should be clipped to the roof slates at regular intervals (use a short length of a few strands of galvanised lashing wire bent into a “U”) to prevent it moving in the wind and being worn away by the slates, see picture. The resulting holes let in rain water which seeps down the cable and ruins your TV tuner, or whatever

else it`s plugged into. If you have had an aerial installed, always check to see if the installer has clipped the cable to the roof slates and unless he`s got a cast iron excuse *, I would insist that he does so. Any cable over a roof should run perpendicularly straight down it. Apart from the fact that a diagonal run looks terrible this will also stop any snow build up (remember that ?) from putting strain on the downlead. If the cable was run diagonally by your aerial installer, you chose the wrong one to do the job *.

* severe access problems would be mitigating circumstances.

The piece of cable in the above picture was run

over a roof without utilising clips to secure it and

the action of the wind has worn it away on the slates.

Water then seeps into the hole and this can have a

deleterious effect on the signal. Worse still is what

can happen when the water reaches whatever the

cable is plugged into.........

The picture on the left is of a “slate clip” which is

simply a few strands of galvanised lashing wire

(as found in the lashing kits we sell) cut to around

six inches, then bent into a “U” and wedged under

the slates to secure the cable.

The Three Main Types Of Co-Ax Cable

All TV downlead should be 75 ohm in order to maintain an "impedance matched system"

but there are 3 main types of cable and they are listed below.

"Low Loss" Co-Ax

Traditionally everyone used "Low Loss Co-Ax" for virtually all TV (and FM radio) aerial cable and years ago much of  the Co-Ax on the market was of pretty reasonable quality with high percentage screening cover. The vast majority of "low loss Co-Ax" sold these days is absolute rubbish. This is an objective fact and can be proved by just looking at the exposed screening in the picture of the three main cable types. There`s probably only 40% screening coverage on the 42 strand "budget low loss Co-Ax". How much additional interference could that let through ? Don`t get me wrong, if you live in a reasonable signal area and/or the downlead isn`t too long, it should still work reasonably. But with particular reference to the

"Digital cliff edge" it`s just not worth skimping on the cable to save a few of pounds ?

How much did your TV cost ? The vast majority of brown (or sometimes white) downlead is of the budget Co-Ax variety, though (just to make things even more complicated....) in 2007 we finally began stocking copper/copper satellite cable in brown as well as black & white !

A more positive check can be made by taking off the plug and closely examining for the presence of an additional screening sheath. If it has all been trimmed off, the latter may not be visible under the outer insulation so removing a small section of this may be necessary. Most new build houses use ultra cheap Co-Ax to wire up the pre-installed TV points. If you have any input into the build of your house, I would insist on the use of decent cable. Quite apart from the superior performance of satellite cable at TV/UHF frequencies, you never know whether you (or someone who buys your house) may need to utilise existing wiring to transmit signals at satellite frequency, see Diplexers.

I`m sure electricians know more than us about "ring mains", but with respect, we know

more than they do about RF. So take our advice and don`t let them fob you off.

Typical loss (per 10m at 800MHz) of "low loss" Co-Ax is approx 2.7 dB,  i.e. a typical 15m run would lose just over 4 dB                (a 6dB loss is half )

RG6 Type Satellite Cable

This is the lower quality grade of satellite cable, but even the cheapest is far better than "budget low loss" Co-Ax. The major difference between satellite cable and "low loss" Co-Ax

is the addition of a layer of foil screening just under the braiding, i.e. (for simplification) it`s "double screened". The latter can have a big effect in helping to minimise interference and minimise loss. With RG6 type cable that foil is usually aluminium or some similar material, although the cheaper brands seem to use a plastic film covered in a metallic substance.

To be quite honest it`s perfectly suitable for virtually all TV/Radio (i.e. UHF/VHF)

applications and this is particularly true if it is a branded product, e.g. Webro.

Although Sky don`t recommend this grade of cable, I would say that it`s adequate for

most satellite use provided the down lead is not of excessive length.

Typical loss (per 10m at 800MHz) of RG6 type cable is about 1.9 dB, i.e. a typical 15m

run would lose just under 3 dB

H109 / CT100 Type Satellite Cable

The third type of cable also has "double screening", but this time the additional foil is copper (see picture above). This grade of cable is the best of the generally available types, though when I say generally available it`s not usually sold at DIY shops.

To be frank, it`s overkill for TV/DAB/FM (i.e. UHF/VHF) but being a perfectionist I like that. The price difference on a typical 15m run is only a few pounds, so why not fit the best ?

It is also suitable for all satellite installations and it is CAI / Sky approved.

Our cable is normally of the foam filled type as opposed to air spaced (subject to

availability) though quality wise it`s “six of one and half a dozen of the other” really.

H109/CT100 is the only type of cable we sell. Sold in Black, White or Brown at 55p per m

or by the 100m drum for £45.    In addition we stock 50m reels (in Black only) at £25.

Note if you require white or brown cable please specifically request it,

because if not we would normally send black !     

Typical loss (per 10m at 800MHz) for this type of cable is 1.8 dB, i.e. a typical 15m run would lose just over 2.5 dB

Joining Two Cables Together

Obviously it is preferable to have a continuous cable run with no joins in it. Unfortunately

this is not always possible and if the following method is used, a join which we would be happy with (the ultimate recommendation ! ), is perfectly acceptable.

Screw an F connector onto each end and then utilise a “Back to Back” to join these two ends together, see picture. If the joint is outside then self amalgamating tape must be used to waterproof the joint, not ordinary insulation tape ! Cut off about one foot (we sell it by the 10m reel and also by the foot) and remove the backing layer. Start wrapping the tape round the joint about 1 to 2 inches above the join (stretching it to about half it`s width whilst you do so) and finish the same distance the other side. If possible try to install the joint so that the cable runs downwards either side of it (so water will run away from the joint) and better still place where it is sheltered, e.g. under the eaves. No cable should be installed where it is under strain but obviously this is even more important where it is joined.

Provided the above is executed correctly this gives a reliable and waterproof joint.

(We sell 2 x F-conns, an F-conn B to B and one foot of self amalgamating tape for £3.25)

We also stock weatherproof joint boxes but “spare” cable is needed to route into/out of the enclosure at the bottom and in addition to this they aren`t screened. If joining cables of different diameter they can be useful however.

Note, we now stock a superior type of F Conn at 75p (or 50p ea for 5+).

SCART Leads And Phono Leads

SCART leads were introduced by Philips (as "Peritel") and are used to connect your

TV/ Video/Digital box etc etc.

They bypass the tuner(s)/modulator(s) on the units(s) and supply the signal in it`s component parts of Video + Audio (left) + Audio (right). In addition a switching voltage is sent over the SCART lead which automatically switches the TV connected to it to the

"AV" (or "EXT") channel. I must confess I do not like this function as it can be confusing  when setting up the system and also when in use. Furthermore if you have two devices

connected to your TV by SCARTs things can get even more "interesting". Speaking as a TV engineer I dislike any "auto function" system (including "auto tuning") and also "user friendly" menus, which in my experience are anything but. The switching voltage can be disconnected by carefully pushing pin 8 (of the SCART) back into the plug head or by cutting the wire to it. Other signals and voltages can also be sent/received but these are beyond the scope of this article.

The big advantage of using SCARTs (rather than modulated signals at RF through the

tuner) is that the risk of co-channel interference is eliminated. In addition stereo signals can be sent between units. One major disadvantage of the SCART system is the physically weak construction of the sockets in the actual TV and indeed the plugs themselves. For

this reason I would avoid pulling the SCART plugs in and out any more than is absolutely necessary, use a SCART switch box if necessary. In fact if you lose sound or video from a device (which is connected by a SCART) the first thing I would do is check if the lead is firmly pushed home, then I would try a different lead.

I may be obsessed with quality but I wouldn`t advise buying one of those ridiculously expensive "professional" type SCART leads. The retailers make more money on the

SCART lead than the actual TV or Video they sell you. Take it from me they give no improvement over any "individually screened" SCART on which there is a screening foil over each individual wire plus over the whole bundle (see picture), also known as “U Type cable”. The latter are worth buying and they don`t cost that much more than "budget overall screened" types. These only have a screening foil around the whole bundle of wires and

can usually be identified by their smaller diameter cable.

Our suppliers inform us that U Type cable is OK for lengths up to 15m, though just to

be on the safe side we only stock up to 10m !

ATV sell individually screened SCART leads  in lenghths of 1m, 3m, 5m and 10m

Personally I think that Phono leads are superior to SCARTs as the plugs (and the

sockets in the TV) are far more robust. Phono leads tend to be used on non European market TVs/Videos but are also used on Hi Fis and some other audio visual products in

this country. We can supply Phono leads (and Phono to SCART adapters) if required.

(Also see Sales / Mail Order Sales including price information)

SCART Switch Boxes

More and more devices require connection to TVs and it is becoming common to run out of available SCART sockets on the set. This is where SCART Splitters or Switch Boxes come in. We do not recommend the former because all the SCART sockets in the system are permanently connected together. This can lead to spurious patterning or interference on the picture and sound, particularly if more than one device (e.g. your Video and your DVD or

Sky) are switched on at the same time. The Switch Box has it`s down side in that one

must manually switch over from one device to the other. Terrible, you have to get up out of your armchair ! Unfortunately it is the only way of avoiding the aforementioned signal problems. If you have two SCARTs on your set you can always utilise one of the TV switchable sockets for the most used device and the other for the switch box. Thus you don`t need to use the manual switch over as often as you would think.

ATV sell 3 way manually switchable SCART boxes.    

(Also see Online Sales / Mail Order Sales including price information)

TV Leads / Fly Leads

If you have a wall socket (which we don`t recommend) then you need a lead from there to the set. Also the same is required to connect up your Video to the TV. These leads are relatively cheap so make sure you buy a decent one. If possible it should have double screened cable and just as importantly the plug should be crimped to the end (see below), rather than just moulded on with the centre core soldered. There are few things more annoying than an intermittent connection in your fly lead and in our experience this is most often caused by the centre core breaking off (at the soldered joint) where it`s been put

under stress.

Our Fly Leads are white, use quality double shielded cable and, just as significantly,

utilise crimped on plugs, they are £2.50 for a 2m and £5 for a 4m.

To be honest these leads are probably the biggest bargain we sell and I can`t understand why we don`t sell more of them !

To quote that well known idiom “all that glitters is not a decent fly lead” (or something like that) and this picture illustrates this perfectly. The top lead looks very flashy, gold plated in fact (gimmick, unless you live in a salt mine....) and it`s “Standard Linear Bandwidth” no

less - whatever the hell that means - but it`s got a soldered on plug ! A customer bought the lead in to show us and kindly donated it to the aerialsandtv.com website. We cut it

open to show the joint and took a picture, so here it is.

Remember looks aren`t everything, substance wins over style in my book, every time.

The “fly” lead below is the one we stock (in 2m and 4m lengths) and they really are good. The “double screened” cable is well worth having but what`s just as significant is the crimped on plug, no weak soldered joint here.... What was interesting is that even the suppliers couldn`t tell us if the plugs were crimped on, the only way we could tell was to cut it open ! Also note the RF chokes, normally hidden under the blue plastic covering  

Co-Ax Plugs And F Connectors

The Co-Ax plug fits on the end of the aerial downlead and pushes in to the co-ax socket on the TV or STB (see Picture).

An F connector is usually only fitted on a satellite lead (from the dish) and screws onto the STBs socket.

Push in Co-Ax connectors can be used for TV (UHF) or FM radio (VHF). F Connectors can also be used in place of Co-Ax plugs (assuming there is a corresponding F socket

obviously ! ) but it is very bad practice to use Co-Ax plugs/sockets for satellite work. Co-Ax plugs can be more convenient (as they are quicker to connect) but an F connector gives a more robust and positive connection. In addition, the fact it`s screwed on means the lead is less likely to become detached. One sign of a good quality Co-Ax plug is if the "claw insert" is brass, as opposed to one of those horrible shiny metal ones which don`t seem to grip as well. We prefer brass plugs rather than alloy ones as they are more resistant to corrosion. The alloy ones can become difficult to undo over time, particularly if the atmosphere is

damp or water has seeped down your aerial cable. It is not advisable to reuse Co-Ax plugs as the "claw insert" becomes deformed when it is screwed up onto the cable, they aren`t that expensive anyway. If you have an intermittent signal it`s always worth checking the

Co-Ax plug as a loose fitting one can cause this symptom, it may be a low quality plug or

it was not even attached correctly in the first place !  Whilst checking the plug examine it

for signs of water/dampness, this is usually caused by a damaged downlead, see

“clipping cable to the slates”. I actually think fitting Co-Ax plugs correctly is not that easy, so we supply a leaflet with ours explaining how it should be done. The same applies to F connectors. Alternatively we can attach the plugs for you at a small additional charge,

see Custom Cables. Incidentally when attaching Co-Ax plugs it is always worthwhile

slightly kinking the centre core of the cable (before you assemble the plug) so as to maximise the chances of good contact between it and the plugs centre pin.

Some people recommend soldering this connection but I`m not sure it`s really necessary or advisable, it`s probably more likely that you will just melt/deform the plastic centre spacer rather than adequately solder the centre core !

On the right we have a right angle Co-Ax plug, it IS screened by the way !

Next to it is a conventional Co-Ax plug, note the brass insert.

In the middle is a (male) F connector and a female/female (“back to back”) coupler.

2nd from the right is a male Co-Ax to female F adapter (shown both ways).

Last there is a female Co-Ax to male F adapter (shown both ways).

(Also see Online Sales / Mail Order Sales including price information)

Here we have two types of F Connector and

we used to stock the type on the left until we

discovered the type on the right. It may not

look that different but it is. It`s probably a

little stronger but what is really worthwhile

is the larger nut which make it far easier to

tighten. Yet again, something so simple......

Back to the top of aerialsandtv.com Cable & Leads

Co-Ax plug before assembly showing slight kink on centre core to maximise contact.

ATV stock brass Co-Ax plugs plus "back to back" joining barrels.

In addition we have "Right Angle" plugs & sockets for use in confined spaces.

Finally we sell decent quality F connectors ( though they are included in any amp or

splitter we sell) and F joining barrels, plus adapters to go from Co-Ax to F connector

(Male to Female and reverse).

NOTE !

Decent quality  F connectors are included with any of our

splitters, amps or diplexers which require them.

We don`t really recommend surface plates, but if you have no choice but to use one, try to ensure it`s screened (as in those above) and that the cable is not kinked. Route the cable like the one above right and not like the other one...... (see surface plates incl diplexed)