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
4G LTE modem MikroTik LHG LTE6 kit white
38 Review
Boost Mobile Signal with 4G LTE Antenna TS9 - Dual πΆ Mimo WiFi Amplifier for Huawei Hotspot - Long Range High Gain Antenna
9 Review
Gadgets World FBA_ALFA ARSN19M OMNI Directional High Gain
9 Review
π StarTech.com NETRS2321P: 1-Port RS232 to Ethernet IP Converter, Serial over IP Device Server - Black
5 Review
π CERRXIAN RS232 to Ethernet Serial Device Server - TCP/IP Converter with 1Port DB9 RS232 Serial to Ethernet Connectivity
3 Review
HB-UMLS Sabrent USB 2.0 Hub with 4 Ports and LED Power Switches for Each Port
12 Review
π Juiced Systems Silver BizHUB USB-C Multiport Gigabit HDMI Hub with 3 USB 3.0 Ports, Gigabit Ethernet, 4K HDMI, SD/Micro SD, and USB-C Power Delivery
11 Review