Tweet
Originally posted by big_tiger
View Post
So what exactly does that mean?
-
mine has a lot of shit like that and has been dropping only during the heat of the day.....
So what exactly does that mean?"No free man shall ever be debarred the use of arms. The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government"
-- Thomas Jefferson, 1 Thomas Jefferson Papers, 334 -
If could be that the coaxial cables are old and wearing out. Coaxial cable is designed to have a per unit length impedance of 75 ohms. This impedance matched to the transmitter's output and the input of the receiver will allow maximum power transfer. When the impedance is different from transmitter to cable or cable to receiver or both, it creates reflected waves. The reflected wave is energy not transferred and creates interference and changes signal amplitude. The impedance of the coaxial cable will change with temperature as will the loss of the cable. The amount of loss can get worse with age.Originally posted by FATHERFORD View Post
The loss of the cable is also related to frequency. Higher frequencies have more loss. The loss is also different for types of cable, RG59 vs RG6, per 100 foot length.
............................RG59...........RG6
Loss @ 100 MHz ... 3.4 dB ...... 1.92 dB
Loss @ 400 MHz ..... 7 dB ....... 3.73 dB
Loss @ 900 MHz .. 11.1 dB ...... 5.79 dB
RG6 has less loss than RG59. My cable modem down stream is in the 600Mhz range. TV channels go up to just under 900Mhz. The loss in dB is from a log function. 3 dB is 50% loss and 10 dB means 90% loss. RG59 loss @ 100Mhz of 3.4 dB means that over half the energy is lost during the transmission. At 900Mhz only 7.7% of the power get through and more than 92% is lost. Remember this loss is over 100 foot unit length.
The only way to know for sure would be to use a network analyzer on the cable and measure it characteristics. If you change out your coaxial cables, I would suggest RG6 which allows for higher bandwidth to benefit the ATSC frequencies. Cables should be run with the shortest lengths. Bends in the cable should be kept above a minimum radius to prevent damaging the center dialectic insolator and changing the impedance at that point. Rule of thumb is ten times OD, that is 10 x 0.300" = 3" minimum bend radius.
For optimizing the system, if you have spare lines or wall jacks that are not being used, I would also suggest the ends should be terminated with 75 ohm loads to prevent reflections in to the system at the open termination, like pictured for $0.59
Last edited by TexasDevilDog; 07-13-2014, 11:36 AM.class joke
{
private:
char Forrest, Jenny, Momma, LtDan;
double Peas, Carrots;
string MommaAlwaysSaid(const bool AddAnyTime = True)
};Comment
-
Well all my cables and ends were changed out about a year ago, even the line from the pole to the house. Still worth looking into.Originally posted by TexasDevilDog View PostIf could be that the coaxial cables are old and wearing out. Coaxial cable is designed to have a per unit length impedance of 75 ohms. This impedance matched to the transmitter's output and the input of the receiver will allow maximum power transfer. When the impedance is different from transmitter to cable or cable to receiver or both, it creates reflected waves. The reflected wave is energy not transferred and creates interference and changes signal amplitude. The impedance of the coaxial cable will change with temperature as will the loss of the cable. The amount of loss can get worse with age.
The loss of the cable is also related to frequency. Higher frequencies have more loss. The loss is also different for types of cable, RG59 vs RG6, per 100 foot length.
............................RG59...........RG6
Loss @ 100 MHz ... 3.4 dB ...... 1.92 dB
Loss @ 400 MHz ..... 7 dB ....... 3.73 dB
Loss @ 900 MHz .. 11.1 dB ...... 5.79 dB
RG6 has less loss than RG59. My cable modem down stream is in the 600Mhz range. TV channels go up to just under 900Mhz. The loss in dB is from a log function. 3 dB is 50% loss and 10 dB means 90% loss. RG59 loss @ 100Mhz of 3.4 dB means that over half the energy is lost during the transmission. At 900Mhz only 7.7% of the power get through and more than 92% is lost. Remember this loss is over 100 foot unit length.
The only way to know for sure would be to use a network analyzer on the cable and measure it characteristics. If you change out your coaxial cables, I would suggest RG6 which allows for higher bandwidth to benefit the ATSC frequencies. Cables should be run with the shortest lengths. Bends in the cable should be kept above a minimum radius to prevent damaging the center dialectic insolator and changing the impedance at that point. Rule of thumb is ten times OD, that is 10 x 0.300" = 3" minimum bend radius.
For optimizing the system, if you have spare lines or wall jacks that are not being used, I would also suggest the ends should be terminated with 75 ohm loads to prevent reflections in to the system at the open termination, like pictured for $0.59
I even have an amplifier on my house."No free man shall ever be debarred the use of arms. The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government"
-- Thomas Jefferson, 1 Thomas Jefferson Papers, 334Comment
-
Tech finished up about 12:30. I got a new drop from the pole to the house. The old one was pretty chewed up. He said that the main line looked rough as well and is going to have line maintenance come and look at it. So everything from the pole to the house, including the ground block is brand new. The next order of business is a new line inti the house.Originally posted by LeahComment
-
Why are you running an amplifier? Is it only for TV signals? Cable internet is bidirectional. Is the amplifier bidirectional?Originally posted by FATHERFORD View Postclass joke
{
private:
char Forrest, Jenny, Momma, LtDan;
double Peas, Carrots;
string MommaAlwaysSaid(const bool AddAnyTime = True)
};Comment
-
Signal to Noise: this a ratio in dB, higher the better
Downstream Power Level: this is dB of milli-volts, best -8 <-> 8
Upstream power level: this is dB of milli-volts, lower the better
Here are my signal strengths for comparison on my cable modem. There are no splits from Charter's box to my cable modem. It is just outside cable connected to inside cable.
Channel ID 5 1 2 3
Frequency 627000000 Hz 603000000 Hz 609000000 Hz 615000000 Hz
Signal to Noise Ratio 37 dB 37 dB 37 dB 37 dB
Downstream Modulation QAM256 QAM256 QAM256 QAM256
Power Level
1 dBmV 1 dBmV 1 dBmV 2 dBmV
Upstream
Bonding Channel Value
Channel ID 58
Frequency 31000000 Hz
Ranging Service ID 747
Symbol Rate 5.120 Msym/sec
Power Level 48 dBmV
Upstream Modulation [3] 16QAM
[3] 64QAMclass joke
{
private:
char Forrest, Jenny, Momma, LtDan;
double Peas, Carrots;
string MommaAlwaysSaid(const bool AddAnyTime = True)
};Comment
-
It's what comcast put in. I'm running 5 cable boxes, internet modem, and telephone modem.Originally posted by TexasDevilDog View Post
I haven't had any problems today since I did a default reset on my modem. Been getting 105mb downloads and 20mb uploads on speedtest.net"No free man shall ever be debarred the use of arms. The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government"
-- Thomas Jefferson, 1 Thomas Jefferson Papers, 334Comment
-
Can you put up the cable signal report? http://192.168.100.1Originally posted by FATHERFORD View Postclass joke
{
private:
char Forrest, Jenny, Momma, LtDan;
double Peas, Carrots;
string MommaAlwaysSaid(const bool AddAnyTime = True)
};Comment
-
attached a screen shot"No free man shall ever be debarred the use of arms. The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government"
-- Thomas Jefferson, 1 Thomas Jefferson Papers, 334Comment
-
Do you have a page in there for current signal levels?Originally posted by FATHERFORD View Postclass joke
{
private:
char Forrest, Jenny, Momma, LtDan;
double Peas, Carrots;
string MommaAlwaysSaid(const bool AddAnyTime = True)
};Comment
-
just jinxed myself... the modem just lost all signal again."No free man shall ever be debarred the use of arms. The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government"
-- Thomas Jefferson, 1 Thomas Jefferson Papers, 334Comment
-
Downstream is a bit low but upstream is good.Originally posted by FATHERFORD View Post
The DS level of -8 dBmV = 395uV signal level, which is at the border optimal range or -8 to +8 dBmV.
0 dBmV = 1000uV.
The upstream is how hard your modem is pushing a signal but to the IP provider. With digital signals, they need to be in a range that is optimal. Both ends talk to each other. They say turn up or turn down the power. If you US power is low, that means a good low frequency connection. If the DS transmitter is pushing as hard as it can but you only have -8 dBmV you have high frequency loss.
I believe 0 dB is the target bull eye and give the best SNR.Last edited by TexasDevilDog; 07-13-2014, 03:02 PM.class joke
{
private:
char Forrest, Jenny, Momma, LtDan;
double Peas, Carrots;
string MommaAlwaysSaid(const bool AddAnyTime = True)
};Comment
-
You have 3 up channels.
Last edited by TexasDevilDog; 08-18-2014, 01:14 PM.class joke
{
private:
char Forrest, Jenny, Momma, LtDan;
double Peas, Carrots;
string MommaAlwaysSaid(const bool AddAnyTime = True)
};Comment
-
Well, down again. This time I think it is weatber related. It seems our signal took a shit about the same time that the rain hit. That would correlate to the tech's comment that the main line is in pretty bad shape. Should have a line tech out soon. Hell before long, I am going to be running on brand new lines...Originally posted by LeahComment
Comment