SA8300HD signal strength

Shelton77

My system is about a month old and has been working excellent until Sunday night when about half of my HD stations went blank. I called Adelphia and they could not fix it over the phone but will send tech later in the week. Since then I checked the signal strength screen and noticed that there were two reading that were changing in the Tunner 1 block. A number in Yellow varied between -11db and -20db as I changed stations with the -20 db singal on the stations that were blank. The second number of interest was below the yellow number and was -10db on almost every channel. (this was the number the cable installer was interested in when he installed my unit) I went up stream and removed a splitter from the line feeding the converter and the -10db signal strength improved to -7db. This also gave me back all but two of the blank channels (HBOHD and ESPN2HD were still blank or pixelating). The yellow value is still -20db for these stations but was improved to -14db for the other stations that came back. My incomming signal is split 5 times in the attic but these connections were done by the installer. Do I need a booster where the signal is split? Any suggestions?

amf1932

A 5x split would generally need a signal amp since every splitter used creates signal loses. Sometimes they could boost your signal strength a bit at the cable companies end, but that probably wouldn't help, especially in your case. I would have the installer come back to your house and do the job right.

Alan

theCableGuy

-20 is out of operating range, hence the colors it's a warning that the signal is too low. Yes an amp will correct the problems, but I would be interested in why you're so low with just a 5 split? You either have a really long cable from the main plant to your house or there are some signal issues that need addressed before hand. If you amp a bad signal you only get higher levels with the same problems (pixilation or no picture), once the QAM is corrupt you can't fix it after the fact. Get them back out to your house and get the signals as close to zero at the back of your STB as they can. Digital channels work really good at -10, but analog channels would look like crap. Fix the problem at the source first, then weigh the options of amping your signal based on what's left signal wise.

Shelton77

My cable run is about 150 feet from the pole to connection on house and another 150 feet to STB through attic. the splitters are 50 feet from STB. Where should the Amp be located?

treker

You should install a whole house booster(add it where your main feed orginates)I have 2 units(in case one goes out as it did this year because of a near by lighting strike ie;the static in the air after the strike blew it)

http://broadband.motorola.com/consum...ignal_booster/


this is the one that works better than what the cable company gave me.One thing to note if you have cable internet(HSI)it is not good to boost the signal going to the modem it has ill affects,put a splitter on the main feed and send the modem a seperate signal(un-boosted)

cousin eddie

Do you mean that you have a the signal split to 5 different locations or that you have 5 splitters in different locations? I would probably suggest a house amp but remember you need to amplify at the input,(before any splitters) for it to do any good. That is sometimes not easy, but I am sure it would fix your problem.

If you do have just one splitter, that would suggest an 8-way in the attic, the loss, depending on the splitter would probably be around 10 db give or take. Depending on cable lengths, (drop and outlets), you could easily begin to get into the negative territory. If you have analog channels you will start getting fuzzy/grainy pictures when you move down that low as well.

Call them back out, plant gets worked on all the time. It is just as possible something changed with the outside plant as it is inside your house. Good luck!

theCableGuy

Any amplification should always be done at the first entry point into your house...unless you have a cable modem, which you should isolate from the main cable feeds for your televisions. Amping it at it's strongest point ensures best quality. 200 feet total distance from tap to TV's would lose -12 dBmV on your high end so play the math game with me.

• Cable Strength at tap (using minimal levels) +13 (high end) +9 (low end)

• 150 feet to house you would have +4 (high end)+ 7 (low end) run it through a 5-way splitter (-10) gives you -6 (high end) and -3 (low end) at the output to your splitter

• Total signal at back of TV after subtracting 50 feet of cable would net you about -9 (high end) -4 (low end)

• Add a single port amplifier +15 dBmV at entry point of house (remember +4 (high end) +7 (low end) + 15= +19 (high end) +22 (low end/+22 is a little strong signal wise)

• Subtract -10 dBmV for your 5-way splitter you should have +9 (high end) +12(low end)
  
  
• Subtract the 50 feet from splitter to TV net signal at back of TV would be +6 (high end) and +11(low end)

*high end/low end are refrences for your analog signal, your digital channels usually are around -6 to -8 dB down from your analog high/low. If you're at the last levels listed, you should be sitting pretty without any problems.

As you can see your total signal strength has improved to a positive number and was done at the first location it can be done so. You can not, or should not amplify any line that is connected to a cable modem (not that it can't be done, it's not recommended) Your total net gain from not having an amp to having an amp should equal +7 dBmV overall gain in signal. Keeping in mind this was done with minimal standard levels we use in our system. Be nosey...walk with the tech and have him tell you your signal strength at the tap (write it down) then have him tell you the signal levels at the first connection point at your house (should be a ground block). For sake of ease you can round off the signal loss by using -6 per 100 feet on the high end, and -1 on the low end (there's actually decimal points, but we're trying to keep this simple). Start with your tap levels and subtract your house levels to see if the numbers are consistent with equal amount of footage being lost. If you're losing more then 5 dB of signal on your low end for a 150 foot line on your low end there's a problem with a connector somewhere. If you're losing more then 12 dB on your high end, have them replace the cable. If your signal levels are negative when they get in the house, don't amp them, have them fix the low levels outside before you do so. Settle for nothing less the perfect, expect nothing more what physics allow. Don't make the mistake of over amplifying. Any questions?
Class dismissed

Shelton77

Thanks Cable Guy. The tech is coming tomorrow. I did an experiment last night and bypassed the splitters in the attic.(there are 2 three ways giving me the 5 drops with the HD set coming off the first splitter) The signal at the set was better but still not up the spec. I still had a -20db on HBOHD. the low end improved to -3db. It looks like the incomming signal is weak.

Shelton77

Oh boy aren't cable companies wonderful. The service tech from Adelphia showed up yesterday and did nothing. All my HD channels were working and even though I showed him the low signal strengths -20db on HBOHD and ESPN2HD he just gave me a lot of BS. Quote: "the orange color of the reading means it is good" "those readings are not what we go by" I asked if he could install an Amp and his reply was we don't carry them on the truck I would need approval from my supervisor. I pay over a $100 a month and they won't put in a $25 dollar device.I decieded there was no sence arguing with this guy, I will have to try again and hope for a different tech or put in my own amp. I tried calling Adelphia to complain but the service center is in Orlando and they will not connect you with a local tech supervisor here in CT.

amf1932

I'd like a penny for all the times that a cable guy told me "I don't have one in my truck". The biggest problem is that most cable companies use contractors to do their service calls, so in actuality you're not dealing with the cable company directly. This is extremely frustrating, so as you said, you could call up to make a service appointment and hopefully you'll get a different service guy that can fix your problem. Otherwise, I would go to an electronic supplier like Radio Shack and buy a bi-directional cable amplifier and install it myself. The great thing about that is, if it doesn't work satisfactorily you can return it and get your money back.

Alan