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Joined: Mar 2002
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Ryan,
What is to say that the coaxial isn't a 725 installation instead of 820?
725.3(A) refers to 300.17 which can be interpreted to require Table 1 Chapter 9 fill requirements.
Ron
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Joined: Jul 2002
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Mustang, Is RG59 not an outdated cable? It seems that all I ever hear about anymore is RG6..Is RG6 more digital friendly? RG6 is a better type of cable and it has a lower loss level at the higher frequencies than RG59. Over here, RG6 is the only coaxial cable that is approved to be used on Satellite installations. As a note, RG59 has an Attenuation factor of 23.3dB @ 400MHz per 300ft, whereas RG6 has an Att. factor of 13.1dB @400MHz per 300ft. These losses get larger as the frequencies of the signal travelling through the cable. get hiher [This message has been edited by Trumpy (edited 10-11-2004).]
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Joined: Feb 2004
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Hi,
Thanks for that great link. I appreciate all the responses.
Just goes to show there is more to Coax Cable than one might have thought.
I will use this information as a reference.
Thanks
Mustang
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Joined: Mar 2002
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Generally RG59 is more flexible than RG6. On a CCTV project, I specify RG59 for circuitry within an equipment rack or group of racks for ease of interconnection. Coax going out of the room (or into the room) is RG6. RG6 is better for long runs.
Ron
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Joined: Aug 2003
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Good call on the 725 Ron!
If it is a 1/4" OD, I am coming up with:
27 in a 2" EMT
26 in a 2" schedule 40.
If it is a 7/16" OD, I am coming up with:
8 in a 2" EMT
8 in a 2" schedule 40.
Its amazing the difference that 3/16" of an inch makes!!!
1/4"=0.25
Pi R(sqaured)=(.125*.125)*3.14159=
.049" area.
7/16"=0.4375
Pi R(sqaured)=(.21875*.21875)*3.14159=
.150" area.
40% of 2" EMT = 1.342"
1.342"/.049"= 27.38 cables
1.342"/.150"= 8.9467 cables
40% of 2" Schedule 40=1.316"
1.316"/.049"= 26.857 cables
1.316"/.150"= 8.7733 cables
Ryan Jackson,
Salt Lake City
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Joined: Oct 2004
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I can not imagine using RG-59 for anything other than CCTV Camera work "the copper clad type" I feel it is very outdated for any kind of CATV / SAT intallation, commercial or residential other than perhaps for interconnect / patch cable assemblies. Many are starting to feel that using RG-6 60% shield is "shorting the customer" as Quad Shield is all that is recognized by Structured Wiring manufacuters like On-Q, Leviton, Channel Plus...
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These losses get larger as the frequencies of the signal travelling through the cable. get hiher Indeed. Even at mid-VHF frequencies the losses add up rather quickly on long runs. The taxi place I've been developing the software for are running about 300 ft. of tatty old RG58 on their base radio at the moment (high-band PMR, around 150MHz) and the signal and range are terrible. I've been trying to convince them to have the antenna moved closer and to replace the cable with something more suitable.
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Joined: Feb 2004
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Hi,
I appreciate the calculation. Your right it is VERY amazing that there would be such a reduction for a mere 3/16"!
Can you MIX RG59 and RG6?
Do these cables connect to a interface at the JB from the cameras or do they continue on back to the main board?
I am interested to know how they connect as well. This is for a closed circuit tv installed for observation at large refueling stations across the country.
Thanks again for the great replies, this has been a LOT of help!
-regards
Mustang
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