You are here : Installing CB Into 4x4's / Fitting the Aerial & Mount / Fitting a Gutter Mount
| A "Standard" gutter mount - this is the one you get if you choose a guttermount in our packages. It also fits the majority of the aerials we sell |
There are various versions of gutter mount - the usual one is the one pictured here - the Standard 3/8" one which is suitable for most of the aerials we sell. We also do guttermounts that are made by Sirio which are a bit stronger and are available for 3/8" aerials and for PL/SO239 aerials like the Sirio Hi-Power... the method of fitting all guttermounts is identical. Most of the photos below show the standard 3/8" version as thats the most commonly installed one but we also show the other types further down this page
Installing one of our Gutter mounts is very easy...
What you need to do to install a Gutter Mount :
Fix the bracket to your gutter - making sure that the tips of the allen-keyed pins make a metal-to-metal connection with the inside of the gutter itself.
(There is a way of getting an earth connection without making metal-to-metal connection at the mount - see the "Installing without metal-to-metal connection" section below)
You will need an SWR meter (a basic and easy to use test meter) to make sure you have a good earth between the mount itself and whatever you have fitted it to. If you don't have a good earth, you will have a very high SWR, and this can damage the CB, so to be sure you should check it with an SWR meter.
Most of our aerials (Springers etc) are about the right length to give a good SWR reading if all other factors are ok (some suppliers call this "Pre-SWR'd" which is rather misleading as a good SWR depends on a number of factors, not just the aerials length), but using the meter to check, and fine tune (usually by adjusting the aerials length) if necessary, as well as check that you have a good earth/ground plane, is essential.
Read our SWR meter guide.
Metal-to-metal earth :
The points of the pins that tighten down into the bottom of the gutter channel are only a few square millimetres, but you will need to get a clean metal-to-metal earth connection here so be prepared to scrape away a bit of the paint with the end of a screwdriver or small file etc.
| Here you can see the pins that go down into the gutter channel - these need to make bare metal-to-metal contact with the metal of the gutter | Here's a guttermount fitted to a Classic Mini - where a plastic cover goes over the gutter - this will need to be drilled so that the pins pass through to make the metal-to-metal contact |
IMPORTANT : On alluminium bodied vehicles (Land Rover Defenders & Series Land Rovers etc) the exposed metal will oxidise which over time will break down the earth connection you've just made.
There are two solutions to this which should be done immediately after you've installed the mount : - 1/ Paint over the area where the mount and panel meet with a zinc based paint - "sealing" them together, and preventing oxygen from getting to the exposed metal. (Rust inhibiting paints like Red Lead and many primers are zinc based).
- 2/ Do the same basic thing as above (sealing the contact point against air) but use an aerosol plastic seal spray which is much easier, but might need recoating occasionally. This tends to be a better way of doing it for guttermounts as it means theres no unsightly red paint showing
The cable connection on the guttermount :
On the guttermount itself there is a low profile cable connector which has a multi-pointed part to it, the points of which are designed to make a good metal-to-metal connection with the underside of the gutterbracket - it's often worth rotating this a bit so that these points scrape through any paint and make good connection.
Most of the standard guttermounts have a rubber weather protector that then goes around the cable connection underneath the aerial fixing - in rotating the connector to get a good connection, you can also get it so that the "closed" side of this rubber boot is facing forwards and the cable coming out towards the back - this will minimise water getting in.
| Here is the cable connector which is on the underside of the top part of the gutter bracket, showing the points that make connection to the bracket itself, and also shown with the rubber weather protector in place. |
4m cable length :
While talking about the cable, it's worth noting that the Standard Guttermount comes with 4m of cable... this is fine for mounting towards the front of any vehicle but if you wish to fix it towards the rear or on the back of your vehicle, you'll need a 2m aerial extension lead to make the cable long enough
Installing without metal-to-metal connection :
If you cannot make a metal-to-metal connection at the mount, there is a way you can still get this mount to work correctly for you :
- You can run an earth wire from to a convenient earthing point
If you choose to use an earth wire to make the ground contact then the wire should be as short and thick as possible to get the best connection, and should be attached to the mount (not the aerial) - a good earthing point for guttermounts is the top seatbelt fixing bolt.
This method of obtaining an earth connection will work ok, but you will get slightly less range than if you had made the earth connection at the actual mount because the further the aerial is away from it's earth, the higher the angle of radiation will be - so you'll be sending signal up at something like 45 degrees, instead of a much lower angle, along the ground.
Gutter mounting :
The usual place to mount a guttermount is on the drivers side, so that it's less likely to get hit by overhanging bushes and branches etc when driving down tarmac roads.
It's worth making a "drip loop" where the cable comes in through your door seal or wherever, so that water drips off the bottom of the loop, instead of coming down the cable into the vehicle.
One of the factors that contribute to getting a good SWR is that the aerial shouldn't have too much metal close to it, so it's no good putting a guttermount right next to a roofrack where the aerial has the metal rack very close to it.
On quite a few locations on many vehicles, you might end up with the aerial not quite upright so you can use an Angle Adaptor to get the aerial vertical.
| Guttermount fitted to a Land Rover Defender | Guttermount fitted to a Land Rover Discovery - note the 'drip loop' to prevent water coming down the cable into the vehicle |
| Guttermount fitted to the back of a Land Rover Defender... | The same vehicle, with an Angle Adaptor to get the aerial upright |
Guttermount on the back of a Mitsubishi Shogun/Pajero - to fit a guttermount here, you'll need our 2m aerial extension lead | Guttermount fitted to the front gutter of a Split Screen VW Camper/Transporter |
Other places you can use a gutter mount :
There are other places you can use a guttermount, apart from on a gutter...
| Heres a guttermount fixed to the under windscreen ledge on a series Land Rover | Here's a guttermount fixed onto a roofrack - we'd recommend you use one of our roofrack/bar mounts instead |
Quick release aerial adaptors :
We sell various aerial adaptors that you can fit to make removing and refitting the aerial quicker, however, we DO NOT recommend them for use on guttermounts because the quick release adaptors have a spring inside and you have to push down on them (with considerable force) before you can remove the aerial... guttermounts are strengthend against sideways forces like hitting a branch, but not against downward forces so they can be broken when used with a quick release adaptor. Best to just unscrew the aerial when you want to remove it... it only takes a couple of seconds more than if you used a quick release.
The other guttermounts that we sell :
As mentioned at the top of this page, there are various other guttermounts available other than the standard one.
The standard one is pretty strong but it has it's limitations. When it's fitted with an aerial like a Springer, because the spring at the bottom of the aerial absorbs prettymuch all of the force of impacts, you'd normally only break the guttermount if it suffers an impact on the mount itself.
However, if you are going to be using a springer but do some pretty heavy offroading where impacts are more likely or if you already have another more rigid aerial, it might be a good idea to invest in a stronger gutter mount.
There's a gutter bracket made by Sirio which is a much stronger item, and we do two versions of it with cable for 3/8" aerials like the Springer, plus we sell just the bracket on it's own, if you need to replace a broken one.
Our best 3/8" Guttermount :
Our best guttermount for 3/8" aerials like Springers comprises a Sirio gutter bracket, a Sirio Dome 3/8 and a 5m heavy duty cable.
Advantages :- The Sirio gutter bracket is the strongest cast bracket available
- The Dome 3/8 eliminates a possible weak point by providing a very strong screw-in connection for the aerial
- The cable is Mini RG8 instead of the standard RG58 used in ALL other guttermounts... it's much stronger, lower loss, fits the plugs more securely and is only slightly thicker than the RG58 and just as flexible. It's also 5m long instead of the usual 4m supplied with other guttermounts
(As this guttermount includes the dome mount, it might be an idea for you to have a read of the
installation advice for this too, as you'll need to make a metal-to-metal connection between this mount and the underside of the Sirio gutter bracket.)
If you are purchasing one of our packages and are choosing a guttermount, you can upgrade the guttermount to our best Sirio one by adding this item to the basket : Upgrade my guttermount to the best quality Sirio one
| Here's our best quality Guttermount, featuring a 5m heavy duty cable and a Sirio Dome mount | Here's our best quality Guttermount, featuring a 5m heavy duty cable and a Sirio Dome mount |
The Sirio KF 3/8" Guttermount : This is Sirios' normal 3/8" guttermount... it has the same type of aerial connector as the other standard guttermount but uses the Sirio gutterbracket so that portion of it is stronger than the usual standard one, and it comes with the same 4m cable.
| The Sirio KF Guttermount | The Sirio KF Guttermount |
The Sirio PL Guttermount :
This is Sirios' guttermount for PL/SO239 aerials like the Sirio Hipower 3000 and 4000 it has an aerial connection to suit these aerials, and has a 4m cable.
| The Sirio PL Guttermount | The Sirio KF Guttermount shown here with a Hipower 4000 aerial |
Product links:
Standard 3/8" Guttermount
Our Best Guttermount - Sirio Gutter bracket, Dome 3/8" & 5m low loss cable
Sirio KF 3/8" Guttermount
Sirio PL Guttermount
Sirio Gutter bracket only without cable
4x4 CB Radio Package Deals (all of which have the option of choosing the standard 3/8" gutter mount)
More photos of the Standard Gutter Mount
You are here : Installing CB Into 4x4's / Fitting the Aerial & Mount / Fitting a Gutter Mount
