RG6 Max Lengths

[chefwong]

Is 150' the office cutoff for max length runs of RG6 with DTV. Moreso, is that # from dish to the splitter/switch ?

Or is it total run including from the switch all the way back to the tv/video receiver.

[HDTVsportsfan]

Actually the rule of thumb is 125'. However, many here certainly have longer runs than 125'. If you use good cable and good connectors (compression fittings) you'll probably be OK.

I'm pretty sure that's total length.

You can use some Sonora products if you have any problems.

[davring]

I believe it is the total, but I have read where people have runs of 250 ft, or more, with no issues. I'm certain they are using very good cable/connectors.

[EXTREMUM]

If the dish is peaked correctly, it gives off a dB rating of 13.5 - 14.5dB straight off a well-conditioned LNB/multiswitch. This is good for 200'+ on a good run of RG6, without any issues.

[west99999]

I believe it is the total, but I have read where people have runs of 250 ft, or more, with no issues. I'm certain they are using very good cable/connectors.

what are you trying to hook up if it is standard non hd i have seen installs with 300ft total from dish to ird work perfectly fine if it is hd i ran one 250 and it pixelated so i cut all the slack of each end which was about 10 ft it still pixelated so i ran the cable in the basement in more of a straight line which took about 25 more out and it worked so i would say hd w/o booster can go no more than 210 and also rain fade is a big problem on that install to this day on hd channels if the tech was to run one that far it would be custom charges that you would have to pay

[AntAltMike]

One key to getting the maximum length off a dish is to minimixe the current draw load of the LNB, because the siignal level can be sustained over about 400 feet of RG-6 without amplification.

If you find that you can't select even-numbered transponders over a long length coax that you can't avoid, you might try "powering" your AU9 LNB by connecting a dedicated, 18 or more volt power source to one of the ports, if you have any vacant ones. I haven't tried this, but if I were desperate, that's what I'd do.

[aim2pls]

1) 225 feet of rg-6 with no kinks and well prepared connectors (compression OR crimp <done right is a better connection>) is considered a maximum cable run to a powered mutli-switch (unpowered is 200 <insertion loss>) .... dont have a good answer on max to the receiver from the multi-switch (old age setting in lol) that would depend on the amplification characteristics of the multi-switch

2) power is typically not the issue ...... signal loss is

[AntAltMike]

1) 225 feet of rg-6 with no kinks and well prepared connectors (compression OR crimp <done right is a better connection>) is considered a maximum cable run to a powered mutli-switch (unpowered is 200 <insertion loss>) .... dont have a good answer on max to the receiver from the multi-switch (old age setting in lol) that would depend on the amplification characteristics of the multi-switch

2) power is typically not the issue ...... signal loss is

Where do these figures come from?

Back when we used round, 18" dishes and the DBS transmitters were at 120 watts per transponder, I would typicaly measure a signal strength of about -30dBm per transponder. Most CONUS beams are now twice that strong, which gets you another 3dB, and the dishes are much larger and therefore have more gain. I haven't measured the actual signal levels of Ku coming off an AU9 switch, but I would expect them to be in the neighborhood of -20dBm.

In another thread, someone with a digital FSM was posting Ka signal strength readings in the neighborhood of -15dBm, but I can't do any hard calculations with that until I find out more about his measurement technique, since there are bandwith correction factors that complicate DBS signal strength measurement, but anyway...

Off the top of my head, typical coax signal loss per 100 feet of RG6 are around 8dB and at 2 GHz, maybe around 10 dB. DBS receiver manufacturer's specs insist that they work for Ku down to an input level of -60dBm, and Sonora Design tested a bunch of old Sony boxes and they didn't show any signal reception problems until it dropped below -66dBm. I haven't seen manufacturer's published specs for Ka signal levels, but they have to be in the same ballpark, unless they are 8PSK instead of QPSK, in which case the receiver input threshold might be a few dB higher.

You can put a powered multiswitch nearly 400 feet from any dish as long as you have inline amps at the input ports. Those of us who service hotels that have headends on the ground floor do this all the time. We are stuck with RF distribution systems that were optimized for cable TV and go from the bottom up, so our multiswitch inputs go from the dish on the roof, over the side of the bulding, down to garage level, across the garage to the point at which we bring them up into the headend room. 300 feet? No sweat! And because the Ku DBS signals only need to be 8dB above the thermal noise floor, we can even rescue them through amplification if they have dropped down to around -70 something dBm. The threshold S/N ratio may be a few dB higher for Ka if it is 8PSK, but I don't know whether 8PSK is for DirecTV Ka or not.

Multiswitches generally have enough amplification in them to keep them close to neutral. There are some cheap 3x4 unpowered switches that might have as much as 4dB of net loss, and I think the strongest outputs I have ever seen published were just one or two dB of gain, so the difference in multiswitch signal output power doesn't vary by enough for me to even bother to precisely pin it down when I am installing such a product.

But keeping the 18 volt switching voltage above the approximately 15.5 volt odds/evens cutoff point is more difficult. The coax and LNB form a voltage divider, with part of the voltage being dropped over the coax. The old fashioned dual LNBs used to draw around 200 or so milliamps, and the coax resistance per foot varies greatly depending on the composition of the inner conductor, as well as the density of the braiding, but figuring out how much voltage drop will occur over a given length cable is a simple matter of applying Ohm's Law to the manufacturer's resistance specs. And not only will a system drop its 18 volts below 15.5 in just about any real world situation before the signal level drops below the receiver's input threshold spec, there is no cheap and easy way around the voltage drop problem, whereas you can often put an amplifier at the midpoint of a downlead to sustain the signal levels almost indefinitely. I have sent DBS signals through nearly 1000 feet of RG6 using inline amplifiers along the way, but I wouldn't recommend the practice to anyone who does not have an FSM and knows how to make sure that none of the inline amps are being overdriven.

[P Smith]

I'll show Dish standard values without posting measures from my own experience - just official numbers:
- signal after LNBF: -33 dB
- signal at IRD input: -63 dB ( min)
- attenuation of each F connector: -2 dB.

[texasbrit]

Where do these figures come from?

Back when we used round, 18" dishes and the DBS transmitters were at 120 watts per transponder, I would typicaly measure a signal strength of about -30dBm per transponder. Most CONUS beams are now twice that strong, which gets you another 3dB, and the dishes are much larger and therefore have more gain. I haven't measured the actual signal levels of Ku coming off an AU9 switch, but I would expect them to be in the neighborhood of -20dBm.

In another thread, someone with a digital FSM was posting Ka signal strength readings in the neighborhood of -15dBm, but I can't do any hard calculations with that until I find out more about his measurement technique, since there are bandwith correction factors that complicate DBS signal strength measurement, but anyway...

Off the top of my head, typical coax signal loss per 100 feet of RG6 are around 8dB and at 2 GHz, maybe around 10 dB. DBS receiver manufacturer's specs insist that they work for Ku down to an input level of -60dBm, and Sonora Design tested a bunch of old Sony boxes and they didn't show any signal reception problems until it dropped below -66dBm. I haven't seen manufacturer's published specs for Ka signal levels, but they have to be in the same ballpark, unless they are 8PSK instead of QPSK, in which case the receiver input threshold might be a few dB higher.

You can put a powered multiswitch nearly 400 feet from any dish as long as you have inline amps at the input ports. Those of us who service hotels that have headends on the ground floor do this all the time. We are stuck with RF distribution systems that were optimized for cable TV and go from the bottom up, so our multiswitch inputs go from the dish on the roof, over the side of the bulding, down to garage level, across the garage to the point at which we bring them up into the headend room. 300 feet? No sweat! And because the Ku DBS signals only need to be 8dB above the thermal noise floor, we can even rescue them through amplification if they have dropped down to around -70 something dBm. The threshold S/N ratio may be a few dB higher for Ka if it is 8PSK, but I don't know whether 8PSK is for DirecTV Ka or not.

Multiswitches generally have enough amplification in them to keep them close to neutral. There are some cheap 3x4 unpowered switches that might have as much as 4dB of net loss, and I think the strongest outputs I have ever seen published were just one or two dB of gain, so the difference in multiswitch signal output power doesn't vary by enough for me to even bother to precisely pin it down when I am installing such a product.

But keeping the 18 volt switching voltage above the approximately 15.5 volt odds/evens cutoff point is more difficult. The coax and LNB form a voltage divider, with part of the voltage being dropped over the coax. The old fashioned dual LNBs used to draw around 200 or so milliamps, and the coax resistance per foot varies greatly depending on the composition of the inner conductor, as well as the density of the braiding, but figuring out how much voltage drop will occur over a given length cable is a simple matter of applying Ohm's Law to the manufacturer's resistance specs. And not only will a system drop its 18 volts below 15.5 in just about any real world situation before the signal level drops below the receiver's input threshold spec, there is no cheap and easy way around the voltage drop problem, whereas you can often put an amplifier at the midpoint of a downlead to sustain the signal levels almost indefinitely. I have sent DBS signals through nearly 1000 feet of RG6 using inline amplifiers along the way, but I wouldn't recommend the practice to anyone who does not have an FSM and knows how to make sure that none of the inline amps are being overdriven.


You obviously have a lot more experience that I do in these installs, but my experience helping people sort out issues with their existing installations coincides with yours. Installations fail due to voltage drop on the signalling voltage at much shorter cable lengths than they ever do due to signal strength issues. That's why using the WB68 which is an unpowered multiswitch is so "iffy" for many people. Adding a "power locker" to an existing unreliable installation solves almost all of these issues, the signal strengths are fine.

[aim2pls]

Where do these figures come from?

Back when we used round, 18" dishes and the DBS transmitters were at 120 watts per transponder, I would typicaly measure a signal strength of about -30dBm per transponder. Most CONUS beams are now twice that strong, which gets you another 3dB, and the dishes are much larger and therefore have more gain. I haven't measured the actual signal levels of Ku coming off an AU9 switch, but I would expect them to be in the neighborhood of -20dBm.

In another thread, someone with a digital FSM was posting Ka signal strength readings in the neighborhood of -15dBm, but I can't do any hard calculations with that until I find out more about his measurement technique, since there are bandwith correction factors that complicate DBS signal strength measurement, but anyway...

Off the top of my head, typical coax signal loss per 100 feet of RG6 are around 8dB and at 2 GHz, maybe around 10 dB. DBS receiver manufacturer's specs insist that they work for Ku down to an input level of -60dBm, and Sonora Design tested a bunch of old Sony boxes and they didn't show any signal reception problems until it dropped below -66dBm. I haven't seen manufacturer's published specs for Ka signal levels, but they have to be in the same ballpark, unless they are 8PSK instead of QPSK, in which case the receiver input threshold might be a few dB higher.

You can put a powered multiswitch nearly 400 feet from any dish as long as you have inline amps at the input ports. Those of us who service hotels that have headends on the ground floor do this all the time. We are stuck with RF distribution systems that were optimized for cable TV and go from the bottom up, so our multiswitch inputs go from the dish on the roof, over the side of the bulding, down to garage level, across the garage to the point at which we bring them up into the headend room. 300 feet? No sweat! And because the Ku DBS signals only need to be 8dB above the thermal noise floor, we can even rescue them through amplification if they have dropped down to around -70 something dBm. The threshold S/N ratio may be a few dB higher for Ka if it is 8PSK, but I don't know whether 8PSK is for DirecTV Ka or not.

Multiswitches generally have enough amplification in them to keep them close to neutral. There are some cheap 3x4 unpowered switches that might have as much as 4dB of net loss, and I think the strongest outputs I have ever seen published were just one or two dB of gain, so the difference in multiswitch signal output power doesn't vary by enough for me to even bother to precisely pin it down when I am installing such a product.

But keeping the 18 volt switching voltage above the approximately 15.5 volt odds/evens cutoff point is more difficult. The coax and LNB form a voltage divider, with part of the voltage being dropped over the coax. The old fashioned dual LNBs used to draw around 200 or so milliamps, and the coax resistance per foot varies greatly depending on the composition of the inner conductor, as well as the density of the braiding, but figuring out how much voltage drop will occur over a given length cable is a simple matter of applying Ohm's Law to the manufacturer's resistance specs. And not only will a system drop its 18 volts below 15.5 in just about any real world situation before the signal level drops below the receiver's input threshold spec, there is no cheap and easy way around the voltage drop problem, whereas you can often put an amplifier at the midpoint of a downlead to sustain the signal levels almost indefinitely. I have sent DBS signals through nearly 1000 feet of RG6 using inline amplifiers along the way, but I wouldn't recommend the practice to anyone who does not have an FSM and knows how to make sure that none of the inline amps are being overdriven.

I agree with everything you have said ..... as to where ..... years of experience as to what the typical lay person or installer can handle ...... there are only a handful of people that even understand what you are talking about let alone do the types of installations your talking about. It's a shame that the typical home owner can not / will not level of installation experience that they would love to get being that it is considered a low level type of labor and anyone can do it .. therefor it is "free". It is truely ashame that most technically proficent installers have left the consumer installation business because there is no money to be made.

[Ext 721]

2) power is typically not the issue ...... signal loss is

I disagree. Power loss can be an issue often enough to not dismiss it....but I see that point has been made in much stronger terms than I was going to offer, and I agree with those terms!

[bt-rtp]

Actually, it is the opposite in this case. The signal attinuation is not the problem that is caused by a long cable run, it is the loss of power needed for the 5 LNB.

For the longer cable runs, a solid copper center conductor in the coax is required to make sure enough power reaches the 5 LNB.

As others have posted, the Sonora power supply/polarity locker is a solution to this as well.

1) 225 feet of rg-6 with no kinks and well prepared connectors (compression OR crimp <done right is a better connection>) is considered a maximum cable run to a powered mutli-switch (unpowered is 200 <insertion loss>) .... dont have a good answer on max to the receiver from the multi-switch (old age setting in lol) that would depend on the amplification characteristics of the multi-switch

2) power is typically not the issue ...... signal loss is