What is a good signal to noise ratio number?
brian-i
Newbie

Can I please get some kind of reference to the numbering of the SNR entry in "About Jetpack<>Diagnostics"   I just received one of the Wilson Sleek booster cradles and see an improvement of the signal strength from about -112dbm without the cradle, up to about -84dbm when in the cradle. That part I understand.  But the SNR number, I don't.  I'm generally seeing a number of "6" (positive, not negative or a minus sign leading the number).  I don't know how to interpret that number or put it in any frame of reference.

Thanks,

Brian

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7e18n1
Specialist - Level 3

Sorry if I didn’t get the meaning of your post. SNR should be greater than 0.  6 is fine, 7 is better.  Mine is -87dbm SNR 19.  If I recall correctly, SNR will lower with weaker signals and raise with stronger signals. Receive pre-amps amplify everything at the target frequency meaning SNR would be unchanged with or without the cradle. There is rule of thumb that every 3db doubles power or divides it by two. If SNR is measured in decibels (it is not specifically stated so) then SNR 6 is 4 times as strong as the background noise.

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7e18n1
Specialist - Level 3

SNR is the ratio of wanted signal to the unwanted (background) noise.

http://en.wikipedia.org/wiki/Signal-to-noise_ratio

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brian-i
Newbie

Well, Mr. (or Ms.) 7e18n1,  the answer doesn't match the question... at all.  I know what SNR stands for (obviously, by my subject line).  But thanks for your time, anyway.

I'm going to presume that "6" is not a BAD number, as the thing is working quite well.  I was just curious.

Brian

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7e18n1
Specialist - Level 3

Sorry if I didn’t get the meaning of your post. SNR should be greater than 0.  6 is fine, 7 is better.  Mine is -87dbm SNR 19.  If I recall correctly, SNR will lower with weaker signals and raise with stronger signals. Receive pre-amps amplify everything at the target frequency meaning SNR would be unchanged with or without the cradle. There is rule of thumb that every 3db doubles power or divides it by two. If SNR is measured in decibels (it is not specifically stated so) then SNR 6 is 4 times as strong as the background noise.

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brian-i
Newbie

Alrighty then... thank you so much for that detailed explanation. I really appreciate it.  And as always, John, thank you for ALL of your helpful answers and comments!!

Brian

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John_Getzke
Champion - Level 1

6 is a good number.

From the Wikipedia article:

"A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise."

Therefore we can assume your signal is 6x as powerful as the noise in that environment.  In other words the greater the SNR the better.  A SNR of 6 combined with a signal strength of -84 (lower is better here, are you 4G or 3G though?) should provide you with a nice connection to the towers.  Granted that is not everything when it comes to the overall user experience while connected, but its a good start.

I do not have access to a Jetpack that can display a SNR for me at the moment.  If I can get my hands on one that does I'll post my SNR for you as a comparison.

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lookinforanswer
Contributor - Level 2

Also, the diagnostics-field test does reference whether it is a RSSI (3G) or a RSRP (LTE) signal type.  RSSILTE rsrp=-92 dBm, sinr=7 dB.

Here is something in addition to John Getze's explanation from the VZW site which I do not agree with the LTE signal reference as it's actually RSRP instead which means you should show a signal of -112dbm being equivalent to -92dbm as the difference in RSSI and RSRP is about 20dbm.

  • Signal - LTE:
    • The LTE should be greater than -58 dBm (e.g. -32 dBm). A value of -96 dBm indicates no signal. If the signal is between -82 dBm and -96 dBm, move the device to an alternate location (an outdoor location is preferable).
  • SINR - LTE:
    • The SINR LTE should be greater than 12.5. The connection may drop to a 3G network with an SINR value of -6, resulting in slow speeds.

The MHS291 shows mine as:

4G LTE Network

Network Operator  Verizon Wireless
RSRP  -102 dBm
SNR     66 dB

The signal is with 3 of the 5 bars available, speed test with a 32ms ping, 13.32 ↓ and 7.87 ↑ so I suppose it would be for you to decide about the signal strength.

4G LTE Network

  • Status Connected
  • Network Operator Verizon
  • RSSI   -92 dBm
  • SINR   8 dB
The above is the 4620 and shows 4 out of 5 bars with 55% at that signal strength. 

Speedtest shows 59ms ping, 15.55 ↓ and 5.65↑ so at this point who really knows how they reference the signal.