FAQ
TL;DR: Expect ~9–11 dBi real antenna gain (≈5 dBi after 10 m cable); “this router cannot force a specific LTE band.” For a D-Link DWR‑921 ~5.5 km from a site, prioritize a router upgrade or band‑locked setup over generic broadband antennas. [Elektroda, matek451, post #16733359]
Why it matters: This FAQ helps T‑Mobile users pick hardware and settings that stabilize LTE at ~5–7 km while avoiding hype gear.
Quick Facts
- D-Link DWR‑921 lacks LTE band locking; pairing it with a broadband antenna often underperforms. [Elektroda, matek451, post #16733359]
- Realistic log‑periodic gains are ~9–11 dBi, dropping to ~5 dBi after 10 m of H155‑class cable. [Elektroda, matek451, post #16733359]
- At ~7 km with LTE800 enabled, users reported ~20/10 Mbps vs ~20/0.8 Mbps on 1800‑only. [Elektroda, nomek, post #16733010]
- Recommended upgrade path: Huawei B525/B529 with band selection and LTE‑A aggregation control. [Elektroda, matek451, post #16745130]
- Avoid E5180 for long links; many units lack external antenna connectors. [Elektroda, matek451, post #16741415]
What’s the best external antenna for a D-Link DWR‑921 at ~5.5 km on T‑Mobile?
First fix the router, then the antenna. The DWR‑921 can’t lock bands, so it may jump between LTE800 and LTE1800, wasting antenna gains. Use gear that lets you pick the band, then match a directional antenna to the chosen band. “Choosing a broadband antenna for it is a bad joke.” [Elektroda, matek451, post #16733359]
Why do many “20 dBi” LTE antennas disappoint?
Marketing. Typical log‑periodic sets deliver ~9–11 dBi, and a 10 m H155‑type cable can cut that to about 5 dBi at the modem. Oversold gain claims mask cable and connector losses, which matter most at multi‑kilometer links. [Elektroda, matek451, post #16733359]
Can the DWR‑921 force LTE800 or LTE1800?
No. The DWR‑921 cannot force a specific LTE band. Without band locking, it may hunt between LTE800 and LTE1800 under load, causing unstable speeds and signal. Router choice, not antenna choice, is the main bottleneck here. [Elektroda, matek451, post #16733359]
Is the DUAL X‑CROSS 3G/4G/LTE antenna a good match here?
Not with the DWR‑921. A broadband log‑periodic plus a router that can’t lock bands leads to erratic results. Pick equipment that supports band selection first; then choose a directional antenna tuned for the band that tests best at your location. [Elektroda, matek451, post #16733359]
What router upgrade stabilizes speeds and allows band control?
Huawei B525 (or B529) enables LTE‑A and band selection using management apps. Lock LTE800, LTE1800, or specific aggregations based on testing. This approach consistently beats trying to “fix” a band‑hopping router with a bigger antenna. [Elektroda, matek451, post #16745130]
Are Huawei B593 or E5180 safe budget choices?
Avoid them. B593 variants are old, often lack easy band selection, and require firmware tweaks. E5180 units from some carriers omit external antenna ports, which cripples performance at long distances. Choose hardware with band lock and antenna connectors. [Elektroda, matek451, post #16741415]
What real‑world speeds can LTE800 deliver around 5–7 km?
Users reported about 20 Mbps down and 10 Mbps up on LTE800 at 7 km through trees, versus 20/0.8 Mbps on 1800‑only. This shows why band choice and locking matter more than raw antenna marketing numbers. [Elektroda, nomek, post #16733010]
How do I test which LTE band is best before buying antennas?
Use a T‑Mobile SIM in an LTE phone. Install Network Cell Info to read the serving band and signal. Run speed tests indoors near the router and outdoors facing the tower. Then pick the band with faster, steadier results and lock it. [Elektroda, matek451, post #16733227]
Quick 3‑step: lock, aim, and verify
- Use a router that supports band locking; select LTE800 or LTE1800 per your tests.
- Mount a matching directional antenna; keep cables short to minimize loss.
- Re‑run signal and speed tests; fine‑tune azimuth for peak RSRP/RSRQ/SINR. [Elektroda, matek451, post #16745130]
Does a broadband antenna help if I can’t change the router?
Only somewhat, and often less than expected. Without band lock, the DWR‑921 can negate directional gains by switching bands. If you must keep it, use the shortest possible cable and accept limited improvement until you upgrade. [Elektroda, matek451, post #16733359]
What apps or tools work with recommended Huawei routers?
With Huawei B525, use Huawei Manager to force bands or specific LTE‑A combos. This ensures the router stays on the tested‑best band, improving stability and throughput across the day. “You will force specific LTE bands or LTE‑A aggregations on it.” [Elektroda, matek451, post #16745130]
Any edge cases where even a good setup fails?
Yes. If your unit lacks external antenna ports (e.g., certain E5180 versions), long‑range links degrade severely. Also, heavy cable runs erase much of the antenna’s gain, limiting real improvement no matter the advertised dBi. [Elektroda, matek451, post #16741415]
Why does T‑Mobile show “full LTE” but my speedtests lag?
Coverage maps don’t reflect band congestion, router limits, or antenna losses. A band‑locking router with a tuned directional antenna beats a band‑hopping setup, even where the map claims full LTE. Test both bands and then lock the better one. [Elektroda, matek451, post #16733227]
