| Author |
Message |
    
ggoad
| | Posted on Wednesday, August 21, 2002 - 1:12 pm: | 
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I want to put up a Smoking Gun 2 beam on a tower, but it's going to be 225 feet from end to end of coax.I was planning on using RG-213. There is no way to get tower any closer to the shack i wish i could.My question is " Is this to long to run coax for a setup. I know there will be some loss but how much ???
Thanx for any input you have "Fencepost" in the BLUE RIDGE Mountains |
Alsworld
| | Posted on Wednesday, August 21, 2002 - 5:39 pm: |
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ggoad,
the amount of loss depends on how much money you are willing to spend. 225 ft is a long run, but you still have varying choices depending which type you use. Here is what I mean:
Hardline: You won't lose hardly anything, nothing noticeable but it's the most expensive per foot.
Heliax: You still won't notice loss but there will be a very minor amount. Cheaper than hardline but still more expensive than ordinary coax.
Coax: This is where it is decision making time. There are many manufactures such as LMR, Belden, DavisRF (plus others) that have low loss coax that could work for your situation. Yes you would see some loss but not near as bad, DEPENDING on what you choose. Example, if you were to go with plain old RG-58 your losses would be incredible at that length. Better choice would be RG-213 or better. Here are some links that let you look at the charts and see for yourself the loss and attenuation factors of varying coaxes.
You can make that length work. I highly recommend running one single length from antenna to your shack as each connector will have it's own loss factor. Good luck.
Alsworld
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Moderator558
| | Posted on Wednesday, August 21, 2002 - 5:56 pm: |
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Try this
http://www.timesmicrowave.com/cgi-bin/calculate |
Scrapiron63
| | Posted on Wednesday, August 21, 2002 - 5:41 pm: |
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Fencepost, my tower is next to my shop, I have 100 ft of coax from my beam into the shop, it goes thur a wattmeter, than to a switch box. From the switch box, I have another 150 feet of coax into my house, and thur another wattmeter, then the radio. People that I talk to can't tell any difference if I'm in the house or in the shop, and i've tested it on low watts, the extra 150 feet just doesn't make much difference. I use Belden RG8-8214, its a little better than 213, it has a bigger center conductor, and is shielded a little better, probably couldn't tell that much difference in side by side testing. In any installation, you would need close to 100 feet of coax, so your just adding another 100 feet or so. If it has a 10% loss per hundred feet, that means your five watts is just 4, or your 500 watts is just 400 watts at the antenna. You guys over there in the Blue Ridge mountains are too loud in Arkansas anyway, a little loss in coax want hurt anything. hehe, Scrapiron |
ggoad
| | Posted on Wednesday, August 21, 2002 - 10:23 pm: |
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Thank you guys very much for the information, I have been out of the base setup for about 25 years. I want to get this thing right if i can, when i put it back. Things have changed so much.I have so many questions but with your help, I will get it right. |
ggoad
| | Posted on Wednesday, August 21, 2002 - 10:28 pm: |
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Scrapiron63 I hope to have a unit you can hear in Arkansas before long, thanx for the info
Have a good day Fencepost |
Scrapiron63
| | Posted on Wednesday, August 21, 2002 - 11:37 pm: |
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Fencepost, I'll be listening for you, I think I have a direct line to the Blue Ridge mountains. I've talked to a lot of good stations there.
Scrapiron |
Hoosier Cardinal
| | Posted on Thursday, August 22, 2002 - 2:50 am: |
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I have 2 125' sections of the 9913 to my moonrakers and shoot, i have not noticed any adverse affects whatsoever. I say get the best coax you can afford and use only the shortest most direct route you can get by with to get from point A to point B and forget about it!:-) |
Deadly Eyes
| | Posted on Thursday, August 22, 2002 - 8:28 am: |
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RE GG
Als is correct on the types of coax. The amount of loss you will experience depends on the frequency and the type of coax used.
At 27 mhz or near it the use of the expensive heliax and hardline is cost prohibitive. Most of the time they are used only when a very low loss transmission line is manditory. Such as in VHF and UHF applications were coax is of little use.
General Rule One...
For long runs such as yours the smaller the diameter of the coax the larger the losses will be. Mini 8 for example would have more loss at those lengths than the RG 8 regular size.
General Rule Two...
Support the coax very well. Running coax over long lengths without external support will weaken the coax and it will eventually break. I would run a nylon rope of at least quarter inch from the antenna to the shack. Use some of those plastic zip strips and support the coax on the rope.
Before I leave, one more thing. If the loss due to the long length of coax is 3db then you will lose half of your signal to coax losses. So do use the lowest loss coax you can afford and still be practical.
DE |
BIG FOOT
| | Posted on Thursday, August 22, 2002 - 10:13 am: |
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...correct, but allow at least TEN feet extra INSIDE for moving station to different areas of the same room...PRAISE the LORD...BIG FOOT |
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