Mounting a satellite dish sounds dead simple until you’re up a ladder in a stiff breeze, staring at a bracket that’s already half a bubble out. The reality is that a dish installation lives or dies by a handful of details most how‑to guides gloss over. I’ve been the guy called out to fix installations that worked fine on a sunny Tuesday and fell apart the moment a real storm rolled in—water in the coax, an LNB twisted a few degrees off, or a mount that turned a 60 cm dish into a wind sock. This isn’t a copy‑paste manual. It’s the stuff I’ve learned the hard way, written for people who’d rather do it once.
1. Site Survey: Stop Guessing, Start Measuring
Before you even open the box, you need to know exactly where the satellite sits from your patch of ground. Geostationary birds stay put, but the path from your wall to that chunk of metal 36,000 km up is easily blocked by stuff that barely registers as an obstruction. A neighbour’s extension, the top third of an oak tree, a chimney you never look at—any of these can cut a Ku‑band signal down to nothing. And Ku‑band is unforgiving; the wavelength is short enough that even a few twigs scatter it like crazy.
1.1 Compass and Inclinometer—But Actually Check Them
Grab the azimuth and elevation numbers for your postcode. A phone compass gets you close, but if you don’t correct for magnetic declination you’ll be off by enough degrees to miss the satellite entirely. In the UK declination can be 2–3° and I’ve seen it catch out plenty of decent installers. For elevation, a smartphone inclinometer works if you first check it against a door frame you know is plumb. Don’t trust the sensor until you’ve done that.
1.2 Trees Have Leaves, Even in Winter
That bare sycamore in January is a solid wall of water‑filled foliage by June. Stand where the dish will go, sight along the elevation angle, and imagine the tree in full leaf. If the line even grazes the canopy, find another spot. I’ve relocated dishes in August because someone in February thought the line of sight was “mostly clear.” Mostly isn’t a thing.
2. Mounts That Stay Put
The bracket is the bit that quietly ruins everything if you cheap out. A dish isn’t heavy, but wind load turns it into a lever, and a wobbly mount turns that lever into a signal‑killing wobble.
2.1 Wall Brackets: Masonry vs. Timber
On brick or block, I use a T‑ or K‑bracket with at least four expansion bolts—10 mm diameter minimum—driven deep into solid material, not just the render. If you only catch the render, the first gale will crack it and loosen the lot. For timber frames, find the studs. Coach screws with big washers spread the load. Cladding or fascia boards are a no‑go unless you’ve reinforced behind them; I’ve pulled brackets straight out of rotted fascia with one hand.
2.2 Pole Mounts and Flat Roofs
A ground pole set in concrete is rock solid—but only if it’s absolutely plumb. A 2‑degree lean makes your carefully dialled elevation meaningless. On flat roofs, non‑penetrating mounts with ballast blocks keep the membrane intact, but you have to do the sums. An 80 cm dish in an exposed spot can drag a whole frame across the roof. I’ve found them wedged against the parapet with the ballast blocks cracked. Calculate the wind load for your zone, then add a bit more weight. Rubber matting under the frame stops the roof covering from wearing through.
3. Putting the Dish Together Properly
Offset dishes are the norm, and they’re fussier than they look. The reflector panel needs to hold its shape, and the LNB has to sit at exactly the right spot in three dimensions.
3.1 Don’t Warp the Reflector
Assemble the dish on the flat, tightening the bolts in a cross pattern a little at a time. If you crank one side down hard before the other, the panel twists. A twisted dish doesn’t focus the signal; it sprays it. Run your fingers over the rim and check for dents—shipping damage is common and a small crease can knock a few dB off your gain.
3.2 LNB Skew Isn’t a Suggestion
The skew angle compensates for the polarisation tilt of the satellite signal. It’s a calculated number for your location, not a “bit to the left.” On a monoblock LNB the feed spacing is fixed, so the whole dish has to be aimed at the central satellite. Then you tweak the LNB’s distance from the dish face—slide it in or out of the clamp while watching the signal‑to‑noise ratio. A few millimetres make a measurable difference.
4. Cabling: The Stuff That Carries the Signal
Coax is more than just wire. Get the type, the connectors, and the routing wrong, and you’re building loss and interference into the system from day one.
4.1 Cable Spec and Connectors
RG6 or CT100 with a solid copper core and copper braid. Copper‑clad steel core cable is stiff, has higher DC resistance, and gives LNB power delivery a hard time on long runs. Compression connectors are the only choice—crimp‑on and twist‑on types let moisture in and go intermittent after a season. A decent compression tool and the right connector for your cable diameter create a gas‑tight seal that lasts.
4.2 Drip Loops and Sealing
Every cable entry needs a drip loop—a downward bend before the cable goes through the wall. Water follows the sheath, hits the loop, and drips off. Seal the hole with a grommet or silicone, but leave the bottom of the loop open. I’ve dug out enough black, water‑logged dielectric from coax to know this step isn’t optional.
5. Alignment: Slow Down and Peak It
This is the part that separates a rock‑solid signal from “it works unless it’s raining.” Rushing the alignment leaves you with margins so thin that the first weather front knocks you out.
5.1 A Meter That Shows Real Numbers
A beeping signal finder tells you you’re in the ballpark. A meter that reads MER and BER tells you how clean the signal actually is. Set the meter to the right transponder—frequency, symbol rate, polarisation—and sweep the azimuth slowly. The receiver needs a moment to lock, so don’t whip the dish around. Peak elevation, re‑check azimuth, then tweak LNB skew while staring at the MER. It’s a dance, not a checkbox.
5.2 Tightening Without Losing the Peak
Once you’ve got it dialled in, tighten the mount bolts a little at a time in a cross pattern, watching the meter. Bolts can pull the dish a fraction of a degree as they cinch down. I often over‑adjust by a hair before the final torque, or get someone to hold the dish steady while I tighten. It saves doing the whole sweep again.
6. Earthing and Surge Protection
A metal dish on the side of a house is a static collector and, in a thunderstorm, a potential path for induced surges. Earthing isn’t just good practice; in a lot of places it’s a code requirement.
6.1 Grounding the Mount and Coax Shield
Run a copper earth wire—at least 4 mm²—from the mount to the building’s main earth terminal. A ground block on the coax near the entry point bonds the shield to earth and gives surges a direct path away from your kit. And please, never clamp an earth wire to a gas pipe. I shouldn’t have to say that, but I’ve seen it.
7. Stuff That Goes Wrong Anyway
Even a careful install can throw up gremlins. These are the ones I keep seeing.
7.1 Intermittent Pixelation
Usually a marginal signal that dips below the receiver’s threshold. Water in the cable is the prime suspect—a tiny nick in the sheath and capillary action pulls moisture along the dielectric. Attenuation shoots up. If a cable run looks even slightly suspect, replace the whole section.
7.2 Cross‑Polarisation Mess
When you’re picking up channels from a neighbouring satellite on the same frequency but opposite polarisation, an LNB skew that’s a few degrees out causes interference. Re‑check the skew with a meter that shows cross‑polarisation rejection. It’s often the thing missed on a re‑visit.
8. Keeping It Running
A dish doesn’t need much, but a once‑a‑year look stops slow decay from turning into a no‑signal callout. Check the mount bolts for rust, eyeball the cable sheath for UV cracking, and sweep leaves or snow out of the dish face. Heavy wet snow sitting in the bowl detunes the signal fast—a soft brush clears it without scratching the reflector.
Frequently Asked Questions
What’s the tightest bend I can put in satellite coax?
Keep bends no tighter than about a 10 cm radius. Crank it sharper and you mess with the cable’s impedance, which causes reflections that show up as dropouts on certain frequencies.
Can I strap a dish to a chimney?
You can, but use a stainless steel lashing kit that circles the whole stack—not a couple of bricks. Check the mortar first; if it’s crumbling, the wind load will work the bricks loose. I’ve seen chimneys that needed repointing before the dish ever went up.
Why does heavy rain kill the signal?
Raindrops absorb and scatter Ku‑band signals, especially in a downpour. A bigger dish gives you more margin to ride it out. If you’re on a 60 cm dish and lose signal every time it rains hard, stepping up to an 80 cm often fixes it—the extra gain outweighs the attenuation.
Is a flat‑roof mount without penetrating the roof safe?
Yes, if you use a non‑penetrating mount with a weighted frame and rubber pads. Do the ballast calculation for your dish size and local wind speeds, and don’t let the frame sit directly on the roof membrane—rubber matting stops it from wearing a hole.