I have had dropped calls after an hour, after an hour and a half and sometimes at the top of the hour (i.e. 1:00, 2:00...). It is very frustrating. It does this in the 78653 area code. I really need this to stop. I have a:
Moto E (2nd Generation)/ XT1528/Android Version 5.1/System Version: 23.11.17surnia_verizon.verizon.en.USvzw
Does this happen with a single individual or no matter who you are talking to? My prepaid does the same thing, completely different phone, completely different area, but mine drops between 30 minutes and 45 minutes... A call to Verizon did not resolve the issue either they said everything was fine with my servce.
This reply doesn't really answer your question but it might give some insight into what MAY be going on. I did address your concern although I left it to the near-end; it's not a cookie-cutter reply. And it was fun to type.
Your phone is given a QoS (Quality Of Service) assignment when you register to the network. Or the effective version thereof (maybe when you dial, instead of sign onto the network). If a decision has to be made between giving a postpaid and a prepaid customer the guarantee of a certain bitrate when things get rough (at the edge of a cell, or at peak times), you guessed it, the postpaid customer will always get "dibs" (source: my conjecture) on those scarce resources. The same is for MVNOs (source: fine print/conjecture) - the MVNO gets the sloppy seconds when the main provider and the MVNO user have to use that same resource simultaneously, but only one can actually use it.
I'm not sure if you're saying that a call placed at 00:55 will drop at 01:00, or if a call placed at 00:55 will drop at 01:55. I think you're saying both. This reminds me of the olden days when dialup modem ISPs would kick you off after being connected for a certain amount of time, or after being inactive for a certain amount of time. I think this scenario is what's happening.
ANYWAY, the point is, these different networks allocate resources differently. One of them is deterministic, one of them is not.
My point is, are you having trouble with a 4G network? Try switching to 3G. Are you having trouble on a 3G network? Move closer to the cell site or, switch to a 4G network. It is interesting to me if you experience the same thing on both types of networks. Since with cdmaOne/CDMA2000 systems, a call on 3G is really a 2G call, there's nothing left to try.
-- Also, I think it MAY be illegal to use non contention-based resource management on the 700MHz LTE band, as the FCC sold it to Verizon with very specific restrictions on what they can and can't do to customers that use it. This may be something to take up with someone who isn't from the internet. --
Ok, but the bright side of this, is that you won't end up wasting all your minutes buttdialing your answering machine. (Do people have those anymore?). Good luck!!
Here's some useless info thats probably 75% correct:
A 3G network can have unlimited customers connected to a single tower, from 5, to 5000 (ok, probably 200, probably related to the walsh codes in use; maybe the actual limit is 256 or 512; I have no idea). The "gotcha" is that the more users on a 3G network, the smaller the effective radius of the cell is (technical term: cell breathing). So you may have to have everyone huddling around a pole in the ground to get 5000 customers in a single tower on a 3G network.
On a 4G network, things are back to how 1G/2G/2.5G Analog/GSM networks ran, with timeslots, frequency division, and a hard limit to the number of users on a network. A 200KHz GSM base station divides a small band of frequency (25KHz? 12.5?) of that wide 200KHz into 8 timeslots, and a call takes 1 or 2 of them, I think. Do some math and you come up with a hard limit of users that can be making calls at once. LTE assigns one of many low-bandwidth "subcarriers" to a mobile phone (source: ofdm/ofdma; wifi uses ofdm), and they are dedicated to a user. If your 4G is slow, I assume the minimum is allocated to many users, and there are few extra subcarriers to allocate for speedy downloads. Eventually, the hard limit is reached and no customers can roam onto the fully loaded cell: their calls drop (unless there is another cell within range that the handoff can be completed to).