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#1
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75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the
dielectric is reduced in diameter to accomodate the extra shielding. How does this affect the performance? I'm looking at 1 GHz (HDTV use). Thanks. |
#2
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On 3/14/2014 6:51 PM, Bob E. wrote:
75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the dielectric is reduced in diameter to accomodate the extra shielding. How does this affect the performance? I'm looking at 1 GHz (HDTV use). Thanks. How are you going to use it for HDTV? HDTV is a TV signal protocol, not a communications method. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
#3
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How are you going to use it for HDTV? HDTV is a TV signal protocol, not
a communications method. Not to be rude, but it's a simple question asked. The answer doesn't involve the use to which it will be put. Just trying to keep replies on-topic... |
#4
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75 ohm cable with a loss of ~6db/30m at 1GHz
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#5
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Bob E wrote:
How are you going to use it for HDTV? HDTV is a TV signal protocol, not a communications method. Not to be rude, but it's a simple question asked. The answer doesn't involve the use to which it will be put. But sure that does matter. Especially the signal frequency at which you will use it, and the tolerable losses in the run of cable. "HDTV" by itself does not tell enough. It could be terristrial broadcast, cable TV, satellite TV. Each of them has different characteristics w.r.t. frequencies in use and losses that are tolerable. |
#6
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In message ,
Bob E. writes 75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the dielectric is reduced in diameter to accomodate the extra shielding. How does this affect the performance? I'm looking at 1 GHz (HDTV use). Thanks. I note that there have been a some replies, but none seem to make much attempt at answering your question. RG6Q is used extensively in the UK cable TV industry as 'drop' cable - ie from the taps in the street cabinet to the home. It is used to provide a high degree of immunity from ingress of interfering signals - especially those at the lower frequencies (in the reverse path part of the spectrum - typically between 5 and 65MHz). RG6 is not a particularly low-loss cable, and for long drop runs, RG11 is sometimes used. As for the attenuation differences between RG6 and RG6Q, I've done a bit of Googling, and I can't see anything which is immediately pointed out. Even on this site http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html all it says is that "RG-6 and RG-6Q share nearly the exact same outer dimensions and have similar flexibility. RG-6Q is slightly stiffer due to the increased amount of inner shielding". I suspect that even if the diameter of the RG6Q dielectric is slightly less (something which I've never really noticed) - requiring a slightly thinner inner conductor in order to preserve the Zo - the increase of attenuation won't be very much. However, I'm sure that a bit more intensive Googling on RG6 physical and electrical specs will reveal the true answer! -- Ian --- news://freenews.netfront.net/ - complaints: --- |
#7
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On 3/15/2014 1:29 AM, Bob E. wrote:
How are you going to use it for HDTV? HDTV is a TV signal protocol, not a communications method. Not to be rude, but it's a simple question asked. The answer doesn't involve the use to which it will be put. Just trying to keep replies on-topic... Yes, it does. The question was completely on topic. How you use it will determine if RG6-quad is usable of your needs or not. -- ================== Remove the "x" from my email address Jerry Stuckle ================== |
#8
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On 3/15/2014 9:18 AM, Ian Jackson wrote:
In message , Bob E. writes 75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the dielectric is reduced in diameter to accomodate the extra shielding. How does this affect the performance? I'm looking at 1 GHz (HDTV use). Thanks. I note that there have been a some replies, but none seem to make much attempt at answering your question. RG6Q is used extensively in the UK cable TV industry as 'drop' cable - ie from the taps in the street cabinet to the home. It is used to provide a high degree of immunity from ingress of interfering signals - especially those at the lower frequencies (in the reverse path part of the spectrum - typically between 5 and 65MHz). RG6 is not a particularly low-loss cable, and for long drop runs, RG11 is sometimes used. As for the attenuation differences between RG6 and RG6Q, I've done a bit of Googling, and I can't see anything which is immediately pointed out. Even on this site http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html all it says is that "RG-6 and RG-6Q share nearly the exact same outer dimensions and have similar flexibility. RG-6Q is slightly stiffer due to the increased amount of inner shielding". I suspect that even if the diameter of the RG6Q dielectric is slightly less (something which I've never really noticed) - requiring a slightly thinner inner conductor in order to preserve the Zo - the increase of attenuation won't be very much. However, I'm sure that a bit more intensive Googling on RG6 physical and electrical specs will reveal the true answer! No one has answered his question because the information is insufficient. FYI - my company (a home automation company) installs thousands of feet of coax every year (even more twisted pair). But we never specify what to use until we know how it is being used. Additionally, it depends if he needs to send send power over the coax also, and if so, how much. For instance, the new specs for HDTV (Ultra-hi-def, 3D at 240 frames/sec) require bandwidths of up to 18Ghz. It's something we have to take into consideration on ANY installation. Just saying it's going to be used for HDTV is not sufficient. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
#9
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I note that there have been a some replies, but none seem to make much
attempt at answering your question. THANK YOU IAN!! A thousand points for noting this. RG6Q is used extensively in the UK cable TV industry as 'drop' cable - ie from the taps in the street cabinet to the home. It is used to provide a high degree of immunity from ingress of interfering signals - especially those at the lower frequencies (in the reverse path part of the spectrum - typically between 5 and 65MHz). RG6 is not a particularly low-loss cable, and for long drop runs, RG11 is sometimes used. As for the attenuation differences between RG6 and RG6Q, I've done a bit of Googling, and I can't see anything which is immediately pointed out. Even on this site http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html all it says is that "RG-6 and RG-6Q share nearly the exact same outer dimensions and have similar flexibility. RG-6Q is slightly stiffer due to the increased amount of inner shielding". And another thousand points for answering the question--which was about the cable's specs, NOT ABOUT ITS APPROPRIATENESS FOR A SPECIFIC APPLICATION. I suspect that even if the diameter of the RG6Q dielectric is slightly less (something which I've never really noticed) - requiring a slightly thinner inner conductor in order to preserve the Zo - the increase of attenuation won't be very much. However, I'm sure that a bit more intensive Googling on RG6 physical and electrical specs will reveal the true answer! Ian The question was how does RG6 compare to RG6Q, specifically whether or not the reduced diameter of the dielectric effects its specifications. Best to you. |
#10
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In message , Jerry Stuckle
writes On 3/15/2014 9:18 AM, Ian Jackson wrote: In message , Bob E. writes 75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the dielectric is reduced in diameter to accomodate the extra shielding. How does this affect the performance? I'm looking at 1 GHz (HDTV use). Thanks. I note that there have been a some replies, but none seem to make much attempt at answering your question. RG6Q is used extensively in the UK cable TV industry as 'drop' cable - ie from the taps in the street cabinet to the home. It is used to provide a high degree of immunity from ingress of interfering signals - especially those at the lower frequencies (in the reverse path part of the spectrum - typically between 5 and 65MHz). RG6 is not a particularly low-loss cable, and for long drop runs, RG11 is sometimes used. As for the attenuation differences between RG6 and RG6Q, I've done a bit of Googling, and I can't see anything which is immediately pointed out. Even on this site http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html all it says is that "RG-6 and RG-6Q share nearly the exact same outer dimensions and have similar flexibility. RG-6Q is slightly stiffer due to the increased amount of inner shielding". I suspect that even if the diameter of the RG6Q dielectric is slightly less (something which I've never really noticed) - requiring a slightly thinner inner conductor in order to preserve the Zo - the increase of attenuation won't be very much. However, I'm sure that a bit more intensive Googling on RG6 physical and electrical specs will reveal the true answer! No one has answered his question because the information is insufficient. FYI - my company (a home automation company) installs thousands of feet of coax every year (even more twisted pair). But we never specify what to use until we know how it is being used. Additionally, it depends if he needs to send send power over the coax also, and if so, how much. For instance, the new specs for HDTV (Ultra-hi-def, 3D at 240 frames/sec) require bandwidths of up to 18Ghz. It's something we have to take into consideration on ANY installation. Just saying it's going to be used for HDTV is not sufficient. My immediate lateral-thinking guess is that the OP has acquired some RG6Q, and is wondering whether he can use it as antenna drop cable for UHF TV (which, in the UK, includes HD). He has specifically said that it's for use at less than 1GHz. His main concern is probably that quad-shield might be a more lossy than RG6 (which indeed it could be as a smaller diameter dielectric would require a smaller diameter inner in order to maintain a Zo of 75 ohms, and this would increase the attenuation). Of course, he could also be concerned about some of the many other parameters - but I suspect not. If it's not attenuation that's concerning him, I'm sure he will tell us. -- Ian --- news://freenews.netfront.net/ - complaints: --- |
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