The £130 upgrade buys you four things that matter in a large home: (1) 500 m² of coverage instead of 250 m² — enough for a five-bed detached house rather than a three-to-five-bed semi; (2) 50 simultaneous users instead of 25 — enough for a busy shop, bar or restaurant rather than a corner café; (3) flagship gain of ≥55 dB uplink / ≥60 dB downlink, 5 dB more than the GD250's 50/55 dB; and (4) a 7 dBi high-gain indoor panel antenna instead of the GD250's 5 dBi panel, which reaches further across open-plan rooms. If your home is 250 m² or smaller and you are a household rather than a business, the GD250 at £235 is the better buy. The GD500 exists for the five-bed detached home, the small office, the shop or the bar that has outgrown the GD250's 250 m² / 25-user ceiling.

The 500 m² rating is the maximum coverage area the GD500's 7 dBi indoor panel can serve from a single central placement — and a typical five-bedroom detached house in the UK is around 180–250 m² of floor area, so 500 m² comfortably covers the house plus a garage, garden office or annexe on the same plot. If your property is a six-plus-bed mansion, a converted barn, a three-storey townhouse or a 1000 m² commercial unit, a single 7 dBi panel will not reach every corner and you would need either a second indoor antenna on the same coax (not recommended — it splits the signal) or a second GD500 unit on a separate donor antenna. For the vast majority of five-bed detached homes, one centrally placed 7 dBi panel on the landing or hallway covers the whole house. Walk every room after install — if the farthest bedroom still shows weak signal, move the panel more central or upgrade the coax length.

No — the dB number is lower because one chassis is doing two jobs, not because the amplifier is weaker. A single-band G500 (Band 8 only, £300.96) or D500 (Band 3 only, £265.00) dedicates its entire RF budget to one frequency, so it can push 75 dB through one antenna path. The GD500 has to split that same power supply and amplifier budget across two bands simultaneously — Band 8 (900 MHz) and Band 3 (1800 MHz) — so the per-band gain lands at 55/60 dB. The trade-off is deliberate: you lose 15–20 dB of raw per-band gain, but you gain both voice and data in one box, one drill kit and one power supply. If your building is very large and weak and you only need Band 8 voice, the G500's 75 dB will go further; if you only need Band 3 4G, the D500's 75 dB will go further. The GD500 is the right call when you need both bands in the same building and you cannot justify two separate units.

Yes, and this is the exact use case the GD500 flagship was built for. The GD500 amplifies Band 8 (900 MHz) and Band 3 (1800 MHz) continuously — it does not switch between them. So an EE phone gets amplified 2G calls on Band 8 and amplified 4G data on Band 3 at the same time. An O2 or Vodafone phone gets amplified 2G calls and SMS on Band 8, with its 4G data left as-is (because O2/Vodafone 4G rides Band 20 800 MHz, not Band 3). A Three phone gets amplified 4G data on Band 3, with its calls left as-is (because Three has no 2G network). Up to 50 devices can be connected at once, which is plenty for a five-bedroom household with teenagers on separate SIMs. The carrier caveat is the same on the GD500 as on the GD250 — only EE customers get both voice and data from this one unit.

It depends on the layout. In a typical two-storey detached house, the Yagi on the ridge or chimney is 6–8 m above the indoor unit on the first-floor landing, and the horizontal run along the loft or skirting is another 4–6 m — so 10 m is often just enough, but tight. If your Yagi is on the gable end of a long house and the indoor panel is in the central hallway 15 m away, the 10 m standard cable will not reach and you will need the 20 m, 30 m, 40 m or 50 m upgrade. Each extra metre of low-loss N-type coax loses a small amount of signal (around 0.1–0.2 dB/m at 1800 MHz), so pair a longer cable run with the higher-gain Yagi option to compensate. Before ordering, measure the route from your proposed Yagi mount to your proposed indoor panel position along the walls and loft — if it is over 10 m, add the cable upgrade at checkout. Do not stretch or coil the 10 m cable; a tight loop creates its own interference.

For a corner shop, a 20-desk small office, a neighbourhood café or a 30-cover restaurant, 50 concurrent users is plenty — it covers staff plus a typical number of customers on their own phones at any one time. For a busy pub with 80+ patrons at a weekend, a 100-desk open-plan office, a warehouse with staff across two floors, or a hotel with guests on Wi-Fi-calling and mobile data, 50 will be too few and you should step up to a commercial C-series unit (C1000 / C2000). The 50-user cap is a hard limit built into the RF design — it is not a soft licence you can upgrade. If you are unsure, count how many phones, tablets and mobile hotspots are actively using mobile data or making calls during your busiest hour; if that number stays under 50, the GD500 flagship is the right size. The GD500's 50-user capacity is exactly double the GD250's 25, so it is the flagship step-up for growing small premises.

Yes, 2 dBi matters more than it sounds at first. Antenna gain is logarithmic: a 2 dBi increase means the indoor panel radiates roughly 60% more effective power in its main direction. In a 500 m² open-plan home — where the indoor unit sits in a central hallway and has to reach bedrooms on both sides, a kitchen diner, a home office and possibly a garden room — that extra 60% reach is what makes the difference between a bedroom at the far end showing two bars versus four bars. The GD250's 5 dBi panel is fine for a 250 m² semi with small rooms, but for a five-bed detached house with open-plan living, the 7 dBi panel is the reason the GD500 can claim 500 m². Place the 7 dBi panel at the centre of the home, on the landing or hallway ceiling, facing downwards into the open-plan area — do not tuck it in a cupboard, or the wall will absorb the extra gain.

No, and this is the single most important caveat to understand before ordering. The GD500 boosts Band 3 (1800 MHz), which is the 4G LTE band that EE and Three use. O2 and Vodafone carry most of their UK 4G traffic on Band 20 (800 MHz) — a lower frequency that penetrates buildings better but that the GD500 does not cover at all. So an O2 or Vodafone SIM in a GD500-boosted home will show full bars for calls and SMS on Band 8 (900 MHz), but your 4G mobile data will not be amplified at all. If your pain point is slow O2 or Vodafone 4G data indoors, you need the C500 Band 20 (800 MHz) booster at £335.00, not the GD500. The GD500 is the right choice if your pain point is dropped calls and failing texts on O2/Vodafone, or if you have an EE or Three data SIM in the same building. Do not order the GD500 expecting it to speed up O2/Vodafone 4G — it will not.

Yes, the GD500 works band-by-band independently. It has two amplifier paths — one for Band 8 (900 MHz) and one for Band 3 (1800 MHz) — controlled by separate AGC loops and shown on separate LED indicators. If your Yagi picks up strong Band 8 donor signal but weak or zero Band 3 signal, the Band 8 path will amplify calls and SMS normally, and the Band 3 path will simply idle (the Band 3 LED will show low or off). Your EE/Three 4G data will not be boosted, but your O2/Vodafone/EE calls will. Conversely, if your Yagi picks up strong Band 3 but weak Band 8, your EE/Three 4G data will be boosted but calls will not. The 8 dBi Yagi is directional, so if you find one band is missing, try re-aiming the Yagi slightly — different operators' masts sometimes sit on different bearings, and a 10–20 degree adjustment can bring in the missing band. The LED indicators on the front of the GD500 tell you exactly which band is locked, so you can diagnose this in seconds.

The GD500 is designed for DIY install in 30–60 minutes with a drill, screwdriver, spanner and ladder — but the Yagi mount at 3–5 m is the one step where safety matters. If you have a sturdy extension ladder, a wall-mounted bracket at 3–4 m on a solid brick or rendered wall, and a helper to hold the ladder, most competent homeowners can do it. If your Yagi needs to go on a pitched slate or tiled roof ridge, a chimney stack above first-floor guttering, or a thatched or listed building, hire a professional aerial rigger or scaffolder — the cost is worth it for the safety margin. You do not need an electrician: the GD500 runs from a standard UK 3-pin wall socket (DC 5 V output), there is no mains wiring inside the unit, and the coax is low-voltage RF. The only electrics work is drilling a hole through an external wall for the coax and sealing it with silicone. If you are nervous about heights, the 365-day guarantee gives you the option to install the Yagi at a lower wall height (2–3 m) and accept slightly weaker donor signal before committing to the chimney mount.