I've got an AT&T WF721 wireless phone base (a transceiver that converts a plain vanilla touch tone desk phone to wireless).

I bought it 2-1/2 years ago and it's been on a table next to a window in a 4 story apartment building. It's been working OK - until July of 2017. Since then, it's been giving an intermittent no signal indication (red antenna icon). However, if I take the transceiver out on the sidewalk in front of the building, it shows maximum signal strength so that tells me the problem is a severe loss of signal strength inside of the building.

Since it works OK outside, I suspect there may have been some changes in the building itself that's blocking the signal. I'm wondering if there's a way to extend the antenna to the outside of the building or a signal booster that could be placed inside my apartment?

I found this extension antenna (without an amplifier), but I need some advice before I shell out $20 for something that might not work.

http://www.maxmost.com/ztewf720mag3db-MMP.php

 

It's possible there has been no change in the building, but the RF gain of the transceiver has dropped, e.g due to a decoupling capacitor failing.

 

Here's the results of latest experiments.

I can carry the base unit out in the hallway and the signal goes from red to 3 out of 5 bars. There are also some hot spots in other parts of the building, but most interior parts are poor to red. So I can safely conclude that there's something in the building that's interfering with the signal.

I just want to eliminate all possibilities before blaming it on the base unit and having to buy a new one.

 

Something in exterior path has probably changed. Set your transceiver in a hot spot.....and run phone extension cable to it.

 

The problem is that all the hot spots in the building are outside my apartment so I can't run a phone cord from the transceiver to the phone in my place.

So I'm wondering if an extended antenna would do the trick:

https://www.alternativewireless.com/wilson-4g-trucker-cellular-antenna-304414.html

 

I wouldn't go that route. Your problem is a weak signal........adding any length of feed line will weaken what you have.

Hold transceiver up high near windows.....try both sides of windows. Build shelf there.

 

I'm wondering if someone in my building (or a building close by) has a WIFI router that could cause interference with a wireless phone.

From what I've been finding online is that WIFI operates in the 2.4 GHz. range and that frequency can interfere with some wireless phones. By the way, my wireless desk phone set suddenly started working like a champ this morning and it's still going pretty well 18 hours later. That tells me that there's something in the environment that's causing the problem.