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Long coax run using couplings

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Feb 19, 2010
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I am setting up new lmr-400 coax for my station and I wanted to know if using so-239 couplings in the feedline would be all that bad in loss for me..

Station-----<25ft>------coupl-------<100ft>-------coupl-------<25ft>-----Antenna.

The 100 feet would be in 1.5in pvc pipe underground and 2 pvc boxes at each end..

Thanks..
 

if your talking about 11 meters,................... no problem with using barrel connectors.
running coax underground could be a problem if it isn't sealed properly
 
Do not seal the underground pipe. Water will still condense inside. I had a 4 inch pipe loaded with cables completely fill with water because there was tiny point where air could get in. Best if you provide a slope to the pipe and provide a point for the water to run out. I ended up digging up the elbow at the low end and drilling a hole so waterncould run out as it accumulated. No more problems after that.
 
I have ran pvc underground many times , i never had that problem, i always terminate my pvc into pvc water tight boxes on each end. I ran my pool filter set up the same way with 1 and 1/4 and never had any water issues,, i can see if you have your ends of the pve facing up from the ground opened to the elements to seep in but this it what the pipe is desiggned to do ..stumpped on that one.,. but i was more conecerened in my db loss per barrel connection. and 6 PL-259 connectors..
 
The loss will be relativley small for this run. At 27 MHz the loss of LMR400 is about 0.0068 dB per ft., and each connector is about 0.01 dB. The six connectors are then -0.06 dB, 25 ft of LMR400 is -0.17 dB, and the 100 ft of LMR400 is -0.68 dB. This equals -0.17 + -0.68 + -0.17 + -0.06 = -1.08 dB. Starting with a legal 4 Watt (+36.0206 dBm) output from a CB you would wind-up with +36.0206 dBm + -1.08 dB = +34.9406 dBm or 3.119 Watts being fed into the antenna. Add 3 dB of antenna gain and you're above 6 Watts ERP. Peanuts, don't worry about it.
 
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I've had two 100' runs of RG-8X in a pvc pipe run about 6 inches below ground for 6 years with no problems. The pipe has standing water in it it but the coax has a vinyl cover so it doesn't leak. Just do it. You don't need to spend a ton of cash on the bury flex coax unless your just digging a ditch and dropping the coax in. The couplings are ok and will make it easier to unhook the coax outside the shack whenever lighting comes calling.
 
RatsoW8 said:
I've had two 100' runs of RG-8X in a pvc pipe run about 6 inches below ground for 6 years with no problems. The pipe has standing water in it it but the coax has a vinyl cover so it doesn't leak. Just do it. You don't need to spend a ton of cash on the bury flex coax unless your just digging a ditch and dropping the coax in. The couplings are ok and will make it easier to unhook the coax outside the shack whenever lighting comes calling.
Click to expand...


That is what my problem was as well, standing water that came from condensation. With the ends of the pipe open air would enter the pipe and water would condense out under the cooler ground. I would never run non-direct buriable cable underground without running it in a conduit run.
 
I forgot to mension this is for the Most HF 30MHZ and below and will be using a 800PEP 600 watt ameriton amp.. i was not sure of the db loss per conector. and pecentage of power loss ERP..
 
yea i saw somethig simalar to that but i wanted strainded center. that stuff is solid 10 awg cca center. i have that stuff here it bends but not well. im pulling 4 cables thru pvc at 100 or so feet with like 4 to 6 90 degree sweeps and bends so i though strainded would be better for me..
 
317 said:
yea i saw somethig simalar to that but i wanted strainded center. that stuff is solid 10 awg cca center. i have that stuff here it bends but not well. im pulling 4 cables thru pvc at 100 or so feet with like 4 to 6 90 degree sweeps and bends so i though strainded would be better for me..
Click to expand...


Try pulling 3 or 4 pieces of LDF4 half inch heliax. :headbang:censored: It's worth it in the long run but not by much. :cry: I used 45 degree elbows joined together to make 90's as it made running the cables a lot easier. I ran the cables through the straight section and then slid the elbows over the ends one at a time and then cemented them together. This the tower end as it is now,soon to change when I switch towers in the spring/summer.


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