I installed them on my AT&T LTE modem and they haven't changed. The signal level is still around 1-2 bars (-110-115 dBm). This model may not support an external antenna, but there are definitely ports for it. So it's not clear if the problem is with the modem or with this product.
πΆ Proxicast Ultra Low Profile MIMO 3G / 4G / LTE Omni-Directional Screw-Mount Antenna for Verizon, AT&T, Sprint (and Others) Modems & Routers with SMA External Antenna Ports
9 Review
π‘ MikroTik LHG 5: High-Gain Dual Polarization Grid Antenna, Enhanced 5 GHz Performance (US Version)
9 Review
Asus RP-N12 N300 WLAN Repeater π 802.11 B/G/N - Boost Your Wireless Range!
10 Review
Bingfu Dual Band WiFi Antenna (2-Pack) for Ultimate Wireless Performance
11 Review
HB-UMLS Sabrent USB 2.0 Hub with 4 Ports and LED Power Switches for Each Port
12 Review
π StarTech.com NETRS232 Serial to IP Ethernet Device Server - DIN Rail Mountable - Serial Device Server - Serial Over IP Device Server (Black)
4 Review
π CERRXIAN RS232 to Ethernet Serial Device Server - TCP/IP Converter with 1Port DB9 RS232 Serial to Ethernet Connectivity
3 Review
UGREEN USB 3.0 Ethernet Adapter Hub with RJ45: Fast Gigabit Ethernet Converter, 3 Ports USB 3.0 Hub Compatible for MacBook, iMac, Surface Pro, Chromebook, Laptop, PC
11 Review