Wireless Signal Strength

[bwhite]

Just curious, it seems like the signal strength to my cell phone will vary widely and wildly from say 2 bars down to none when the thing is just sitting in the same place. I find it hard to believe that the signal strength can vary that much over a minute or two of time. I could understand if I was moving (even a little), we all know the jokes about standing on one leg facing NE, etc to get a signal. Anyone have similar observations and/or know why the variability?

 

[N_Jay]

Lots of reasons.

The bars are not always a true measure of signal strength.
They can be signal strength, C/I, or decode quality, or even some combination of all three.

They can also be averaged over time or updated immediately depending on other signal or other parameters.

In addition, the signal from a site can vary due to multipath and slight movements of either the phone antenna, the site antenna, or significant reflecting objects in the path.

Also, since the measurement may be associated with signal quality in addition to signal level, all these parameters can be related to the "interfering" signal.

In addition, even when not moving and not in a call you can be transferred between channels or sites both of which can have signal strength and signal quality impacts.

 

[SAR923]

Yes, I've seen the same thing happen. I don't really know the reason but I suspect the amount of network traffic affects signal strength. There are people here who will let me know if I'm wrong though.

 

[UFEMTFF]

I've found that it has a bit of a delay, and isn't as accurate as the monitor on your scanner, for instance. Sometimes I'll get in the elevator, and it'll be 2-3 seconds before I loose signal. Then, once I get out of the elevator, it'll be another few seconds before it goes back up again.

Now if your phone is sitting on a table and not moving for a few minutes and is still fluctuating, I'd bring it back to the shop and get a replacement. That doesn't sound right to me.

 

[N_Jay]

. . . That doesn't sound right to me.

Did you read my posting?

Do you have experience or information that is different? (if so please share)

 

[UFEMTFF]

Did you read my posting?

No, actually I didn't. There were no replies when I began typing my response.

Do you have experience or information that is different? (if so please share)

Yes, I have. I've never had a cell phone that the "bars" constantly changed when the phone wasn't physcally moving (excluding severe weather, etc.) So, I stand by what I said, "That doesn't seem right to me." I'd at least bring my phone back to where I got it and have them check it out.

EDIT: I have very slow fingers and was in the middle a few different tasks before I finally hit sumbit, hence the time gap.

 

[SCPD]

MY pro 97 signal strength on the local control channel jumps around also while just sitting here on my desk

 

[bwhite]

I'm beginning to believe it is more a measure of "available" network (signal strength and availability on the tower).
Even in a good wind with my phone stationary (and the objects around it) I can't believe the 18" or so that the top of the tower would sway would make that dramatic of a change in outright signal strength. I can believe that the resources available from that tower would/could vary like this.

 

[N_Jay]

I'm beginning to believe it is more a measure of "available" network (signal strength and availability on the tower).
Even in a good wind with my phone stationary (and the objects around it) I can't believe the 18" or so that the top of the tower would sway would make that dramatic of a change in outright signal strength. I can believe that the resources available from that tower would/could vary like this.

"believe" what you want.

Yes they are a measure of availability, but not typically in capacity, but of signal level and quality (in TDMA based systems. GSM, USDC, and iDEN). There is a loading effect in CDMA due to the sharing of the channel.

You do realize that at 800 MHZ a wave length is about 14 inches, hence a 18 inch sway is running through several 1/2 wave nulls!

Don't forget the software that runs the "bars" is different between brands, models, software loads, and even between carriers if they request it from the manufacturer!

 

[Don_Burke]

It could be something closer desenses your phone. Other wireless phone users and wireless LAN would be my first suspects. 800MHz radio systems would follow somewhat closely, with other radio systems following that.

Do other people on the same provider have the same problem in the same places? If you can find someone with the same model phone and the same provider it would be even better.

If it is not affecting the functioning of the phone, it may just be a display with mood swings.

Just curious, it seems like the signal strength to my cell phone will vary widely and wildly from say 2 bars down to none when the thing is just sitting in the same place. I find it hard to believe that the signal strength can vary that much over a minute or two of time. I could understand if I was moving (even a little), we all know the jokes about standing on one leg facing NE, etc to get a signal. Anyone have similar observations and/or know why the variability?

 

[N_Jay]

It could be something closer desenses your phone. Other wireless phone users and wireless LAN would be my first suspects. 800MHz radio systems would follow somewhat closely, with other radio systems following that.

Do other people on the same provider have the same problem in the same places? If you can find someone with the same model phone and the same provider it would be even better.

If it is not affecting the functioning of the phone, it may just be a display with mood swings.

Sort of what I said.

Remember the interference can be other cells in the network assigned to the same frequency.

EDIT:
Now I know why Don basically repeated what I said.
Seems he has me on ignore.
Guess some people believe ignorance is bliss!

 

[bwhite]

Actually, I live in a rural area, not a whole lot of other RF type distractions. Other users with other phones see the vascilation so our curiosity piqued. Thanx

 

[slicerwizard]

I find it hard to believe that the signal strength can vary that much over a minute or two of time.

Fluctuating bars are caused by changes in signal strength and/or BER (bit error rate). BER can be influenced by interference from nearby strong signals. When using a handset in an elevated location (e.g. office or apartment building), interference caused by a distant site reusing local site frequencies can also raise the BER.

Changes in signal strength or BER can lead to handoffs to neighbour sites, which will affect the bars display. As conditions change, a handset may repeatedly bounce between several sites, which would produce the described symptoms.

If you really want an answer, you need to either use the handset's diagnostic modes or run diagnostic software on your PC (e.g. iFTA for iDEN handsets, etc.)

 

[n2mdk]

I think the real key to this is the fact the signal is marginal to begin with, "only 2 bars" when you have a low signal it really takes very little to make the meter fluctuate.

 

[N_Jay]

Actually, I live in a rural area, not a whole lot of other RF type distractions. Other users with other phones see the vascilation so our curiosity piqued. Thanx

You might be somewhat surprised at the amount of RF around you, and the amount of RF around the site (that could also affect your displayed signal strength indication).

 

[bwhite]

Good info, I learned a lot.

 

[JohnnyGalaga]

If you really want an answer, you need to either use the handset's diagnostic modes or run diagnostic software on your PC (e.g. iFTA for iDEN handsets, etc.)

Where do you get software like that and how do you hook it up to the fone?

How do you learn what all those numbers and codes mean on the screan and software?

 

[N_Jay]

Where do you get software like that and how do you hook it up to the fone?

How do you learn what all those numbers and codes mean on the screen and software?

To take the class on network optimisation, then you practice what you have learned.

Lots of guys who do drive testing also think they know what it means also.

 

[JohnnyGalaga]

To take the class on network optimisation, then you practice what you have learned.

Is that a college class?

 

[N_Jay]

Is that a college class?

Most of the best classes are from the system suppliers.

I think there are some that are more generic taught by industry consultants, but they are probably not as detailed.

I have not taken any since the mid 90's.