CABL Forum - Re:Return path Problem w/ Modems

i think whats going on here is the surfboard has a diagnostic page you can pull up to check the transmit power back to the HE. what he is doing is checking the power then taking out the splitter then checking it again.i have seen the same thing happen, you check the power then pull splitters or rearrange them to get the power where you want it and the power level on the diagostic page wont change.not always but once in a while.i think its just a glich not allowing the info to update with the changes.but back to the original problem about the 4 and 8 ways not working, you got two freq to consider, the return which at 45 db should be good but also your forward modem freq (ours is 117mhz) has to be in a certain range also. hope this helps (-REDACTED-)

>How are you checking the 19 mhz? If you are looking at it at the headend, the modem will self adjust to compensate for whatever loss you have up to 60db. So if you checked the return to see what you are getting back at the headend, and it was 45. Then when you put in a splitter and check it again, the signal you recieve back at the headend would be close to 45. The modem will adjust to compensate for the loss created by the splitter. So it really depends on where you are checking for the loss. (-REDACTED-)
>
>>I disagree;
>>I beleive that it would take someone more than a day in our industry to learn about the dynamics of attenuation
>>People are getting on this forum asking for our help. This forum is for the friendship and helping of one another. Join in, it feels good to help others
>>
>>>OBVIOUSLY AT LOWER FREQUENCIES THE LOSS WILL BE LESS THAN AT HIGHER. DEPENDING ON BRAND AND MODEL OF A 4 WAY SPLITTER, THE LOSS IS ABOUT 7. SO LETS SAY 6 AT 19MHZ UPSTREAM AND POSSIBLY 8DB ON THE DOWNSTREAM. BUT ANYONE WHO HAS BEEN IN CABLE FOR MORE THAN 1 DAY KNOW THAT YOU CAN NOT HAVE 45DB GOING INTO A 4 WAY AND 45 COMING OUT. A BARREL POSSIBLY.
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>>>>I dont think any questions are stupid. Anyone that comes to this forum and asks questions is a brother or a sister in cable and will likely be successful. On the other hand, folks that judge and insult come from a different place, who knows where they will end up.
>>>>Saying a four way splitter has a 7 db loss is to broad of a statement. At what frequency are you speaking of? Do you know the loss of 19mhz?
>>>>Lets be kind
>>>>J
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>>>>>YOU CAN NOT GET 45 IN AND 45 OUT OF A 4 WAY. 4 WAY HAS 7DB LOSS...ITS NOT THE BRAND OF THE SPLITTER, ITS HOW MANY PORTS. YOU ARE LOSING TOO MUCH SIGNAL DOWNSTREAM AND UPSTREAM ON AN 8 WAY. ITS PECKIN AT YOU BECAUSE YOUA RE STUPID
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>>>>>>I install a lot of cable modems. Have installed several kinds but the ones I'm havinf trouble with is the GI Surfboards. The cable modem is external and connects to an ethernet card.etc,etc,etc,
>>>>>>the problem is that when it is hooked to a four way splitter or eight way the modem becomes unstable or works intermittingly. I use primarily Regal Gold 120db EMI or Tru Spec 120dB EMI. The modem would work fine thru a 2way or three way but 4's and 8's would kill it. The RF being sent back was 19MHz and it measured 45db before the 4 ways and 45 dB out of the four way input. This was very strange and have no explanation for it.Has anyone come across this before or know why this happens. It is easily gone around to get it going again but the WHY is peckin at me. help if ya can. Thanks
>>>>>> (-REDACTED-)
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Re:Return path Problem w/ Modems