USB Modem failing?

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SargeW

SargeW

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I have a Novatel USB720 modem that I have had for about 4-5 years. Lately it seems that it is dropping signal a lot. It happens using different routers, one brand new. It also happens in a variety of locations.

The question is, can the modem be tested in some fashion to determine if it is in fact dropping out?  I do not want to upgrade to a 4G modem as I would lose my unlimited 3G plan (corporate). If I switch it out for another 3G modem I can just have Verizon switch the ESN# on the account.

Any idea how to test a modem?
 
I have been having problems with Verizon 4g and 3g signals dropping the connection for the last few months both in Arizona and California. I have reinstalled Windows a few times during that period and so it is not a Windows problem. Just two days ago I downloaded the latest version of Verizon's Access Manager 7.7.1.0 and the latest firmware for my modem, VL600 but it still drops, so I think the problem is in Verizon's 4g system. I don't think they have all the bugs out.
 
Any chance you could test your modem in a different service area (different towers) or is this happening in everywhere you go?  I have found various towers have various levels of maintenance as well as different levels of traffic.  Afterall, some techs know what they're doing, some don't.
 
SargeW said:
Yeah, I was in San Diego area last week, and in Big Bear Lake this week. Still the same. I don't know, do Modems go bad?
Click to expand...
Theoretically any electrical component can go bad. The modem is probably just a chip meaning it would usually be a pass/fail type of situation.
 
I wonder if it's really "dropping" or just disconnecting during extended idle time? I have the PCMCIA version of that modem plugged into a router and notice that it won't stay connected all the time either (used to). This may be intentional at the cell site to keep from continually  polling idle modems.
 
My 4G MiFi connects and disconnects several times a day/hour sometimes.  I am running 3G service here.  I think that it is just Verizon's service.

Last month I was having problems ever connecting.  It was to one particular ip address.  In working with the Verizon tech, they sent me a new MiFi.  Nothing really changed so I don't think the modem had anything to do with the problem.  If you think that it's the modem, I have an old spare USB720 around here.
 
SCVJeff said:
I wonder if it's really "dropping" or just disconnecting during extended idle time? I have the PCMCIA version of that modem plugged into a router and notice that it won't stay connected all the time either (used to). This may be intentional at the cell site to keep from continually  polling idle modems.
Click to expand...
In my case it is the modem dropping. It happens right in the middle of me doing something. When I am not using my computer I turn it off, so there is no real idle time.
 
SargeW,

If it does fail I will send you my Verizon Novatel USB 760 modem for $25 because I am currently using 3G/4G modems and phones.  I will pay the priority mail postage.

JerryF
 
For all who are having disconnect problems with your 3G connection may I suggest the following.  I have found this even helps with 4G connections.

Get a Wilson #301103 rooftop mag mount antenna.  Get a 9 inch galv sheet metal disk and use silicone to glue it to the roof.  Put the mag mount antenna on the disk and bring the 10 foot lead down into where the modem is located.  This means placing the antenna over the area where the modem is located because of the 10 foot limitation.  BTW, the connectors are such the the cradle will connect to the incoming antenna lead.

Get a pigtail so you can connect the antenna directly to the modem.  If your modem or whatever does not have an antenna port get a Wilson #301146 Cell Phone Cradle into which you will place your modem or whatever.

The 3G store has the best prices but do Google Wilson Electronics to see their spec sheets.

Mine works great with both 3G and 4G.  Yes, the antenna does help a little bit with 4G even though it is not built for the 700 MH frequencies.

We will be in Catalina at Christmas if anyone wants to see this set up.

I have tested this, have been on 3 or 4 other forums, and the biggest part of your disconnect problems is "Verizon's Signal" so an external antenna is VERY helpful especially in a MH.

JerryF
 
The antenna won't help me at all. It is not a problem of a weak signal. I am getting three or four bars. It is a problem with Verizon's software dropping me.
 
I'll vote for this being a Verizon problem as well. We suffer slow down/drop out periodically and its not in just one location. I think Verizon is expending most or all of their effort in building up 4G and, as a result, 3G is getting more and more crowded.
We've seen this issue everywhere we've been this year to some degree (we're 3G only) including Louisville, Albuquerque, Dallas, Foley AL, etc, etc.
I'd also note that our phones on AT&T do not have similar problems. We've not had dropouts or lacked coverage anywhere we expected to have it (no joy in S. Riggins).
JM2C,
Ernie
 
Hi Jerry, I will take you up on your offer, you have a PM. 

I should have gave a bit more info. I am using an external Wilson RV shorty ground plane antenna with a Wilson Amp. The set up works very well, most of the time.  I very well could be experiencing issues with the Verizon cell towers causing the issue. I too was wondering if the modems are a "either it works or it don't" kind of situation. 

Either way it's not awful, just a little irritating as it does seem to drop right when you are in the middle of something. 
 
I am glad to know I am not the only one with drop out problems. It is an early adapter thing I would imagine.
 
I believe you're right, Tom.  When we first got 4G in our area, it was really dicey and Jerry changed back to 3G.  About a month or two later, Verizon got their act together and we're now back on 4G and very happy with it.  Imagine what it must be like to change an entire country the size of the USA from a 3G system to a 4G system!  The details must be mindboggling and it takes time to get all the bugs ironed out.  Anyway, I think it will all even out eventually.

ArdraF
 
You are right, Ardra, changing the entire country over from 3G to 4g is a mind boggling feat. It is a mind blowing feat just driving across this great country  of ours. Then factor in the fact that the cell phone manufacturers sold over 1 billion new cell phones last year...
 
I'm not sure about Verizon "changing over from 3G to 4G". From the discussions I've had with VZ tech reps about the reception quality of 3G vs 4G and their impact on one another, 4G is a separate system, in effect duplicating the 3G network physically. So as the 4G network expands, the 3G network remains unchanged.
 
ALL,

Besides the number of bars, I can see my signal strength in % or in SINR.  Having 2, 3, or 4 bars is only half of the story.  A person needs to see the signal strength taking into account the noise factor in the signal they are receiving.

My Cradlepoint MBR 1000 router shows Signal Strength (SS) as a %.  The % signal strength indicator is a number based on the combined signal strength (-dBm) and the noise ratio.  When I am getting 20% with a - 67 dBm it is not as stable as 40% and -67 dBm.  BTW, in both cases in the previous sentence I only was getting 2 bars.  SS above 30% is usually enough to get a stable signal but less than 20% is not.  Also, noise can even be introduced by the number of users connected to the network so expect more noise during high usage times.  More noise more drops.

OTOH, with the modem connected directly to my PC (no router) I can see the SINR measurement (signal to noise measurement) which is similar to Cradlepoint's SS %.  SINR is more important than the -dBm or the number of bars.  A great SINR is 12.  If it's below 6 you may start getting drops.

When folks are getting drops, the SS in % being low or the SINR being low is why 4 bars with a low SINR or a low 15% SS is NOT good.  It tends to fool us because we see 4 bars and it still drops.

Obviously there are other causes of drops but I just wanted to cover noise here.

JerryF
 
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