Question about Hukk cm1000

[detroittech]

I hear Brighthouse issues it's techs this meter to troubleshoot cable modem problems. I just got mine and was told to basically figure it out by the headend operator at my job. Any help with some questions below would really be appreciated.

1, what is the most important number on a BkER reading? Some people have told me the first number, others have said the exponent is what's really important. The literature I have defines BkER as the number of packets lost over total number of packets. that would make the exponent the important part I would think.

2, What is a "good" reading for BkER? I have a customer who's had his house rewired twice, his entire run swept and balanced back to the node, forward and return readings are perfect, but the Hukk reads red on the BkER 2.3E-3. The trouble is it reads that (or not good, anyway, close to that)almost everywhere in his node and he's the only one complaining (he is a gamer tho). could this be a head end issue, something with the CMTS?

3 The packet tests the meter does seem to be ongoing, how long is a good frame of time to keep the meter hooked up to get an acurate reading?

Somebody help me here! I used to get cable from here to there, that was it. I blinked and all of a sudden you have to be an electrical engineer or computer scientist to f'n do a service call.

 

[casper04]

2.3E -3 is a terrible reading...

I've never used a Hukk, I use a JDSU DSAM, I don't know why they stuck in a k into BkER... It's supposed to be just BER which is an acronym for Bit Error Ratio... we call it bit error rate, guess it just matters where u from.

The perfect BER is always 0. Alot of test equipment might not have it though, my DSAM doesn't... I think it usually says 9E -9. For digital boxes I like to stay at x.xE -7 or above. for phone and hsd it's best to have no BER at all


An error ratio is the ratio of the number of bits, elements, characters, or blocks incorrectly received to the total number of bits, elements, characters, or blocks sent during a specified time interval. The error ratio is usually expressed in scientific notation; for example, 2.5 erroneous bits out of 100,000 bits transmitted would be 2.5 out of 105 or 2.5 × 10-5. Some software may display this as "2.5e-05". The most commonly encountered ratio is the bit error ratio (BER) - also sometimes referred to as bit error rate.
this as "2.5e-05". The most commonly encountered ratio is the bit error ratio (BER) - also sometimes referred to as bit error rate.

 

[detroittech]

2.3E -3 is a terrible reading...

I've never used a Hukk, I use a JDSU DSAM, I don't know why they stuck in a k into BkER... It's supposed to be just BER which is an acronym for Bit Error Ratio... we call it bit error rate, guess it just matters where u from.

The perfect BER is always 0. Alot of test equipment might not have it though, my DSAM doesn't... I think it usually says 9E -9. For digital boxes I like to stay at x.xE -7 or above. for phone and hsd it's best to have no BER at all


An error ratio is the ratio of the number of bits, elements, characters, or blocks incorrectly received to the total number of bits, elements, characters, or blocks sent during a specified time interval. The error ratio is usually expressed in scientific notation; for example, 2.5 erroneous bits out of 100,000 bits transmitted would be 2.5 out of 105 or 2.5 × 10-5. Some software may display this as "2.5e-05". The most commonly encountered ratio is the bit error ratio (BER) - also sometimes referred to as bit error rate.
this as "2.5e-05". The most commonly encountered ratio is the bit error ratio (BER) - also sometimes referred to as bit error rate.

the small k is for block, block error ratio. thanks for the numbers

 

[jcarrera]

Is the BER a per channel test or a whole line test? Does it happen to have one channel with a really good reading and one with a really bad reading?

 

[detroittech]

The BER test is on one carrier I believe, the downstrreeam channel for the modems. The BER is ok tho, no errors at all in the downstream. The BkER (which is the meter pinging the cmts upstream) is what's off. I get E2 and 3 readings which would mean 1 error per 100 or 1000 packets, which is terrible like CAsper wrote above.

But I get these readings everywhere in the system, found them in 3 different nodes, every modem i put in today. so it has to be something in the headend ( my operator is clueless, he has been no help at all.) or something in the settings of the meter that needs to be adjusted. I can't even get someone from tech support at sunrise technologies on the phone, so I thought I
d see if anyone had any idea here.

 

[stevenl]

Each QAM (carrier/channel) has its own BER test.. Sometimes say the modem channel will have great BER's but the next channel up will fail. BER is Bit Error rate, Not ratio Just fyi, MER Is a more accurate way to measure a QAM channel which is what the more advanced type meters like the SDA5000 reads (stands for Modulation Error Ratio)

These readings usilly include both a Pre and a Post FEC test level, The pre is (Pre forward error correction) Meaning the raw signle before its been fixed by the equipment (box/modem/meter) The Post FEC is the level AFTER the meter,modem,box repaired and replaced the bad bits.

Example: Send out 100bits of data 2 are missing the box/modem/meter will take a educated guess at the 2 missing, Its pretty smart and can usally fix it perfetly so you dont notice any problems, however if your sending millions of bits and have thousands missing thats when you start getting problems with pixelation and things like that.

A Pre-FEC BER of say, anything higher then -6 is the FCC requirement at the customer equipment, BHN Standard is -8 or above, Most meters read -9 as perfect. The box will read 0 as perfect.

The Post-FEC BER will be higher then the Pre,

The MER Level on each QAM should be higher then 36, below 36 you may notice pixelation on the boxs or slow downs on the internet.

MER is almost like say CN (Carrier to noise) levels if you want to look at it that way. The higher the numbe the better.

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detroirt one thing to make sure on your meter, if your reading QAMS for their ber/mer levels make sure you have the center frequinces setup right, Make sure you also have the proper QAM selected for each channel be it QAM 64 / QAM 256 also make sure your Symbol rate is setup for a QAM 256 it would be around 5.360khz

Hope that helps

 

[detroittech]

thanks stevenl.

finally got hold of sunrise, turns out this meter is so old they can't update the firmware. sup[port people say that is most likely the cause of my erroneus readings. thanks everyone for your input, i appreciate it.

 

[jcarrera]

"...The Post-FEC BER will be higher then the Pre,.."

Hmmmm, shouldn't the error rate after correction (post-) be LOWER that the pre-correction rate?

 

[stevenl]

"...The Post-FEC BER will be higher then the Pre,.."

Hmmmm, shouldn't the error rate after correction (post-) be LOWER that the pre-correction rate?

By higher I mean the number Like Pre will be 10-5 Post would be i dunno 10-8 I guess technicly its lower but the last number is higher. Thats what I meant that whole scientific notation and powers blahblah to much math my head hurts!

 

[jcarrera]

Yeah, you are right...eight is a bigger digit than five, but (ten to the minus five) is a bigger/higher number than (ten to the minus eight).