Cable is measured in decibels (db). You will not have access to the ped (pedistal) which supplies your home. The measurement coming to your home should be at least 14db higher side about 18db. Under 14db is low for the main feed and may want to involve Comcast tech as you may have an issue only they can fix. Think of cable signal as someone talking to you. If they are whispering (low db) its bad, normal talking (12-15db) is good, yelling (15-20db). !!! Keep all junctions as clean and simple as you can !!! Now when it comes to splitters and amplifiers... AMPLIFIER - Should be used on the main line in before any splitters (except a pass through splitter for any modems). You DO NOT want to amplify low signal or after several splitters. (Amplifying whispering is still hard to hear) You should aim to have 12-16db at every access point. This is all basic math and you shouldn't get virtually any loss of signal unless you are going over 100ft stretches (I believe it was .5db every 100ft). If you are getting signal loss, it is either a bad connector or bad line. Make sure you measure the signal going in and out of the splitter/amplifiers and use basic math skills to make sure your gains/losses are on point. If it falls outside of the proper range, replace the device. SPLITTERS - Use these strategically to pad any over signal issues. Keep in mind, the more junctions (amplifiers, splitters, barrell connectors) used will make it harder for the signal to report back to comcast (lag in cable boxes, slower internet response, upload internet speed) Be careful of the splitter types you use. Once again, this is just pure math. If you are starting with 20db and you use a 2 way splitter, you will get a loss of 3.5db on each split so you should expect 16.5db coming out of the splitter. These digital boxes are very finicky and should have a minimum of 12db, any less could cause service issues. Try to get a clean line (unamplified) to any cable modems. Use a passthrough splitter which will have NO LOSS (to modem) on one split and extra loss on the other(s) While amplifiers are useful, they will also amplify noise back to comcast so DO NOT USE AMPLIFIER UNLESS YOU HAVE TO. Hope this helps. Former cable/internet technician with Comcast.
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