How to fit ‘F’ Connectors to coaxial cable

  for UK Sky and Freesat and Virgin cable and US TV

  How to undo

  How to fit plugs

  Use Grease

  More Grease

  How Tight?

  Gold ‘F’ Plugs

  Extension cables

  Joint Kits

  Protect unused ports

  Self-Amalgamating Tape

  Watch movie

  Push-on adapter

  Right-angle adapter

  Rubber boot

  Best Cable?

  Crimp Connectors

  Signal Distribution Plate

  Twist-on ‘F’ plug fitting – Buy F Plug


  Many so-called “LNB faults” are caused by a simple bad connection. The bare copper wire corrodes. Before spending your hard-earned cash on a new LNB, you might like to cut back the cable a couple of inches and refit the plug. Coat the copper wires with silicone grease to prevent corrosion in the future. (We’d love to sell you a new LNB but we believe in honesty and we’ll help you to save money whenever possible.)

  What’s the difference between…?

  Twist-on plugs can be screwed on by hand.

  Crimp plugs have to be crimped with a special crimping tool that matches plug and cable. We do not sell these.

  Compression plugs have to be fitted with a special compression tool. We DO sell these. Some people think they look nicer than twist-on plugs. Some people think they perform better but, as with all such connections, it depends on the cable preparation. It’s just as possible to make a horrible mess of fitting a compression plug as it is with a twist-on plug.

  We strongly recommend the use of silicone grease with ALL plugs.

  We can supply cables with plugs already fitted.

  ultra thin coaxial cable

  The method shown below is also used for “shotgun” or ultra-thin 4.5mm coaxial cable but you must use our “Special” ‘F’ plugs.

  How do I undo the ‘F’ plug attached to my equipment?


  Unscrew the nut, which rotates while remaining attached to the knurled section of plug. If it is tight, a spanner with 11mm opening will usually fit. Be sure to rotate the nut anticlockwise.

  TIP: DO NOT work on a “live” cable. (i.e. one that is connected to a satellite TV receiver, which is still connected to mains power). The satellite TV receiver supplies up to 18 volts to the LNB cable and up to 9 volts to the RF2 cable, so short-circuiting it will do it no good.

  How do I Remove the ‘F’ plug attached to my cable?


  If the plug is a twist-on type, unscrew it from the cable. Pliers might be required. (If pliers are not required then the plug might be the incorrect size for the cable.)

  F plugF connectorF plug coax

  First ensure that you have the correct plug to suit your cable. There are several sizes and they all look the same! Read our info Click HERE.

  (All ‘F’ plug nuts are the same 11mm AF. Only the cable entry size is different.)

  Note: we select our ‘F’ plugs to fit the cable that we sell. We can’t comment on other plugs or cable that we don’t sell.

  cut WF100 coaxial cable

  About 25 mm from the end, use a knife to cut around the outer plastic covering. Be careful not to cut the braided copper wires inside!

  strip WF100 coaxial cable

  Pull off the plastic cover. Separate the braided copper wires then push them back over the black insulation.

  copper foil

  Cut off the exposed metal foil shield.

  prepare WF100 coaxial cable

  Cut off the white plastic insulation to expose the inner wire core, leaving about 3 mm of white plastic insulation. This reduces the risk of the braided copper wires touching the inner wire core which must never happen!

  Now for the previously unpublished trade secret!

  silicone grease

  Apply silicone grease to all the exposed copper at the end of the cable, including the central copper wire. Alternatively, push the cable end into a jar of petroleum jelly so it soaks into the copper braid. This will help weatherproof it and make screwing the plug on much easier. (Silicone grease is better as it doesn’t oxidise and go brown).

  The grease coats the inner copper wire and the outer copper braid, preventing moisture and oxygen from causing corrosion. The electrical connection is unaffected because there’s more than enough pressure for the contact metal to bite through to the copper.

  (Our twist-on ‘F’ plugs are chosen to be a tight fit and may be very difficult or even impossible to screw onto the cable if you don’t use grease.)

  Some “professionals” will not use grease because they don’t want the connection to last beyond the guarantee period (they want you to call them out after a year) or because they simply don’t realise that it improves reliability.

  Some “professionals” simply doubt the necessity of using silicone grease. Please Click HERE to read what the American company “Channel Master” had to say about it back in 1999.

  But SatCure doesn’t do installations so we’ve got nothing to lose by telling you how to make yours survive longer.

  If you don’t believe how quickly copper oxidises, take a piece of pure copper (an old penny, for example), degrease it and leave it in vinegar for an hour. Take it out, rinse it with water and leave it exposed to the air. You’ll see the surface quickly oxidise and go brown.

  Continued, below…

  See more uses for silicone grease. CLICK HERE

  It’s handy stuff!

  Hi #SatCure,

  Reading your mention of silicone grease took me back to a radio programme I heard on the old BBC Radio London when Johnny Longdon was the engineer there and used to broadcast a technical session once a month. One broadcast dealt with rigging aerials and one of the BBC riggers recommended the plentiful use of silicone grease in all aerial connection boxes and connectors. I have followed the advice ever since, especially during my time as a licensed radio amateur, when I found a complete absence of corrosion in connections given the treatment and taken down after many years exposure to the elements. I find it especially useful these days when applied to F connectors under their boot.

  Kind regards,


  rubber boots

  This photo from “What Satellite TV” magazine shows what can happen when inferior rubber boots are used without silicone grease protection. Don’t let anyone convince you that silicone grease is unnecessary!

  ”For indoor use you don’t need to bother with grease.”

  This is incorrect for our plugs. We choose our plugs to be a tight fit so you MUST use some sort of grease, otherwise you’ll find the plugs very difficult to turn.

  ”I don’t have any grease so is it OK to use oil?”

  You don’t usually know what is in the oil. It might attack the PVC plastic. Some types of oil (e.g. WD-40) contain a degreaser, which may cause corrosion rather than prevent it. Oil won’t prevent moisture from creeping down the cable.



  Screw an ‘F’ connector as far as the inner white plastic, holding it with a piece of cloth or leather or pliers to protect your fingers.

  The copper strands must be cut off and this means that sharp ends will protrude. You can wrap these with self-amalgamating tape or heat shrink tube indoors.

  (Alternatively, another quick way of dealing with this problem is to cut the ends off just before completing the last 2 or 3 turns of the connector. That way the sharp ends disappear under the connector out of harm’s way. This tip came from Ivan Dally.)

  Cut off the exposed copper braid

  Make sure that the inner wire core can not touch the braided copper wires. Cut off the exposed copper braid.

  Use sharp cutters to cut the inner wire core

  Use sharp cutters to cut the inner wire core to leave about 3 mm exposed. Make this cut at a 45 degree angle to make a point. This makes it easier to push the wire into a connector without risk of damage or bending the wire. Be careful not to cut yourself on this sharp point!

  you can wrap self-amalgamating tape

  For indoor use, you can wrap self-amalgamating tape over the end of the plug to prevent the sharp copper wires from cutting your fingers. Alternatively, use heat shrink sleeving.

  For outdoors, use the S.A. tape to seal the plug connection completely.

  I can not stress too strongly the importance of applying a waterproof grease coating to the copper wires in the ‘F’ plug, AND partly filling the plug with grease* before screwing to the socket, especially if used outdoors. This will prevent corrosion caused by the combination of moisture, air and electricity.

  *Use grease sparingly when using self-amalgamating tape; if grease oozes out, the tape won’t stick to itself.


  Many otherwise “professional” people attack my suggestion but why take the risk? I am a qualified electronics engineer and one of my previous occupations was “Reliability Test Quality Assurance Engineer” – a job in which I subjected various equipments to rigorous environmental tests in a humidity chamber. In all cases of connections with no protective plating or poor quality plating, the connections that were carrying electric current failed very quickly, due to a build-up of corrosion that forced the metal contacts apart. The best solution I found was silicone grease.

  This is what can happen if you don’t fill the LNB ‘F’ plug with silicone grease. Not only has the LNB connection corroded – rainwater has run all the way down the cable to the receiver and caused damage to the dish input 1 socket. Water has probably gone inside and destroyed the tuner!


  Note: the connection must be absolutely dry so please don’t make it in pouring rain! Any moisture inside the connection can cause the copper wire to oxidise. The oxide film may be almost invisible but it can create a bad connection in the future and cause weird symptoms such as “no signal on a warm afternoon”. (Imagine trying to ascertain the cause of that. You’ll probably end up replacing the LNB and cable without really knowing why!)


  You can easily test to see whether I’m right about copper. Take an old copper coin or copper wire and leave it in vinegar until it’s bright. Rinse it in water and dry it. Apply silicone grease to part of the coin or wire. Leave it on a shelf somewhere – the more damp the better. See what happens after a few weeks!

  How Tight?

  An ‘F’ plug nut should be “finger tight plus one flat”. Tighten it as far as you can until you feel it stop. Then use an 11mm spanner to turn it a further 1/6 of a turn. You should not then be able to loosen it with fingers. If you can loosen it, turn it another 1/6.

  (You may find instructions telling you to use a torque wrench and giving a specific figure such as 1.4 foot-pounds. However, the actual torque depends on the manufacturer’s tolerances, the plating type (nickel or gold), the plating thickness – impossible for you to measure – and whether grease is applied. Consequently, such figures can not be relied upon.

  You may also find suggestions that a broader nut makes it easier to tighten – but the tightening force is so tiny that it really doesn’t matter. The size of the thread that goes over the cable is MUCH more important.)

  Gold ‘F’ Plugs

  gold F plug

  We don’t stock them because:

  The gold is a thin “flash” and won’t last long outdoors There’s no way to gold-plate the copper braid, or wire, which forms the “pin” LNB sockets are not usually gold-plated Nickel-plated plugs are fine when used with silicone grease You’d pay more for no benefit


  Lightning Surge Protector?

  We don’t stock them. Click HERE to find out why.

  Extension Cables

  ultra-thin 4.5mm coaxial cable

  You can use ultra-thin 4.5mm coaxial cable to feed TV around the house and for SkyLink “magic eye” connections.

  join cablesTerrestrial and Satellite extension cables are available from SatCure

  If you MUST join cables please do it correctly (see below). Ready-made Terrestrial and Satellite extension cables are available from SatCure in many colours.

  Joint Kits


  Never join cables like this. It will let interference in and there will be no impedance matching. Channels will probably be missing or weak.

  screw terminal block


  This is not a good way to join cables. TV plugs are not suitable for LNB signals and not even very good for RF.

  join TV cables

  Please join cables correctly:-

  Real Joint Kits are available

  joint kits


  Always coat the copper wires with silicone grease to prevent corrosion.

  joint kit

  Protect LNB Outputs


  Blu-Tack can be used to cover unused LNB output connectors. It’s also a good (temporary) sealant for outdoor cable connections and a permanent protection for connections inside aerials.

  self amalgamating tape

  Seal joints outdoors against moisture ingress with silicone grease and self-amalgamating tape. (Don’t get grease on the tape.)


  If you don’t see a movie screen above this line, you will need to install Flash Movie Player then reload the page.


  Just wanted to congratulate your company for an easy to understand web site with lots of helpful hints. The Silicone Grease will be wonderful in this wet and windy part of the Scottish Highlands where “F” connectors often become inoperable because of water ingress despite self amalgamating tape!!!!!!!!!!!!!

  Thanks again.

  Ewen S.

  Push-on Plug

  Push-on adapters are available

  Push-on adapters are available. These screw into an ‘F’ connector plug to turn it into a push-on plug. Useful when you are using a sat finder meter and also as an LNB selector (see below). Much favoured for temporary connections to caravans and motorhomes!

  Again I recommend using plenty of silicone grease to reduce wear and to prevent, or at least reduce, corrosion outdoors. A rubber boot fitted over the connector will also help to protect it.

  NOTE: if interference is a problem, you should avoid push-on ‘F’ adapters, as they have slots and are susceptible.

  Push-on adapter

  A push-on ‘F’ adapter fitted to a standard ‘F’ plug to allow easy connection of a Satfinder signal meter.


  A push-on ‘F’ adapter fitted to a standard ‘F’ plug to allow easy connection to an LNB.

  A push-on ‘F’ adapter can also be used to connect a cable to a satellite TV receiver tuner input or any other equipment fitted with a threaded ‘F’ socket.

  Always apply grease to minimise wear.


  Right-angle adapter

  Right-angle adapters are available. These can be used where space is limited – such as behind a wall plate – or to route a cable around a sharp corner.

  F connectors outside MUST be sealed to keep water out

  Outdoor ‘F’ connectors outside MUST be sealed to keep water out, otherwise it will run through the cable, damaging the inside of the LNB and the satellite receiver. Water runs VERY quickly through coaxial cable by “capillary action”.

  Be sure to use Self Amalgamating Tape (or a rubber boot – see below). Cut off about four inches (100 mm) and peel off the plastic backing.

  Wrap the tape around the cable

  Wrap the tape around the cable, just below the ‘F’ connector, stretching it strongly as you wrap in a spiral. Overlap by at least half the width of the tape so it bonds to itself. Continue to stretch and wrap it around the cable then the ‘F’ connector all the way up to the body of the LNB.

  (We used an “Alps” LNB for the demonstration).

  spiral it back down the cable

  Now stretch the excess length and spiral it back down the cable to finish off the joint neatly.

  As you stretch the tape to twice its normal length, you create energy that makes the tape melt into itself to form a solid rubber tube. You won’t believe this stuff till you try it. There’s NO glue. Also great for repairing leaking hose on car or washing machine!

  The only way to remove it is by cutting with a very sharp blade.

  unique rubber boot for LNB

  A useful alternative to tape is our unique rubber boot. More information HERE.

  threaded F coupler

  See catalogue page 8

  >I have an easy question for you! Basically I am moving my digibox to the other side of the room and I need to extend the cable. I have already been told by sky that I need H109 or CT100 cable, but which connector do I buy?

  That cable is obsolete. Ideally you should replace the entire length, using the correct, double-screened coaxial cable. See page 8 of the catalogue.

  In practice you will get away with using two Threaded “F” plugs and an 090-3078 Threaded “F” barrel to join two lengths of cable. See our Cable Joint Kit.

  Send this page address – CLICK HERE – to a friend !

  What’s the best cable? Read the review

  no-name cable

  >I installed El-Cheapo no-name cable throughout my house before consulting you. Please tell me what ‘F’ plugs will fit?

  If this cable has no metal foil screen, I recommend you rip it all out and use the proper stuff. Otherwise it might cause problems with interference that can be difficult to diagnose. Obviously we can’t tell you what “F” plugs will fit because we don’t sell this cable. Order each of the three 7 mm sizes that we stock and try them. Or ask your cable supplier, who, unfortunately, will probably tell you (incorrectly) that “one size fits all”.

  Crimp Connectors

  > I understand that professional installers use crimped “F” connectors. Why don’t you sell them?

  We do sell WF125 crimp plugs and WF100 cable with compression ‘F’ plugs fitted. We can also supply the tool and plugs, if required.

  It takes training and practice to fit a crimp connector correctly and we haven’t found the result is nearly as good as with compression or twist-on connectors. Twist-on connectors give adequate performance in most circumstances whereas a badly fitted crimp connector will give far worse performance than a twist-on or compression. Indeed, I’ve seen such connectors actually fall off the cable after being fitted by so-called “professionals”!

  A crimp connector must be chosen to fit the cable being used (generally only foam dielectric cable is suitable). An expensive crimping tool is required and it must be fitted with a die that matches both the crimp connector and the cable.

  There are some really cheap crimping tools available (under £20). In my opinion these are unlikely to give a satisfactory result unless you are extremely lucky in your choice of cable and connector.

  (Be warned – I tried for two days to make a decent crimp connection using the proper cable, stripping tool, crimping tool and crimp connector and I failed).

  ? 2008 – 2015 SatCure

  Send this page address – CLICK HERE – to a friend !

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