Coax Question

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fireems3

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Mar 28, 2010
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Wondering if 50' is too long a run for RG58 coax to a 2m rig (max of about 25 watts) in the house?

Would be used mostly for monitoring and occasional brief transmitting. Planning to build just a Quarter-wave 2m vertical antenna with an SO239 and copper wire.

Thanks.
 

popnokick

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You could do much better than RG58 by using LMR400 Ultraflex or similar. RG58 is going to result in almost a 3dB loss over that 50 feet at 146 mHz, vs. LMR400 only about 1 dB. Following the maxim that each 3dB equates to doubling (or halving, in this case) your power.... you'll be giving up almost 50% of your transmitted and received signals. Getting better coax than RG58 will make a major difference, especially in a quarter-wave ground plane antenna that exhibits no gain. There are many calculators to figure coax cable loss for various types of cable... search here or Internet in general.
 

fireems3

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Thank you for the response. Exactly the info I was looking for. Thanks again!!!
 

dksac2

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No need to use the "Ultra Flex" LMR 400, the standard LMR 400 is much less expensive and gives up next to nothing in signal loss over the ultra flex. I use the ultra flex if it going to a beam with a rotator or for jumpers. Buy the standard LMR 400 and then get the super flex for the short portion from your lightning protector to the radio if necessary. With a feed through board in my window, I use LMR 400 for the entire feed to the outside of the feed through board. Ultra flex is only needed if you need to make tighter bends.

73's John
 
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