Coax Cable
- Thread starter Blkops
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n4yek
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At 6 feet, it won't matter to much about the coax.
LMR 400 is good for higher freqs because of it's low loss factors, but at 6 feet pretty much any 50 ohm cable will do.
Coax loss is rated at 100 feet lengths.
Example: (in theory of coarse)(also depends on the frequency the loss is calculated for)
coax loss at 100 feet = 6db
at 50 feet it would be 3db
at 25 feet it would be 1.5db
at 12 feet it would be 0.75 db
at 6 feet it would be 0.375db
see what I mean?
LMR 400 is good for higher freqs because of it's low loss factors, but at 6 feet pretty much any 50 ohm cable will do.
Coax loss is rated at 100 feet lengths.
Example: (in theory of coarse)(also depends on the frequency the loss is calculated for)
coax loss at 100 feet = 6db
at 50 feet it would be 3db
at 25 feet it would be 1.5db
at 12 feet it would be 0.75 db
at 6 feet it would be 0.375db
see what I mean?
Last edited:
Danny, your math is a bit off. The decibel scale is logarithmic, not linear.
kb2vxa said:
No, his math is correct. The db scale is logarithmic in terms of power ratios. But a 6 db cable cut in half would have 3 db loss per each half.
Here. Go play with this:
http://www.ocarc.ca/coax.htm
For convenience sake, use LMR400, at 2004.5 MHz. It works out to be 6 db loss for 100 feet. See for yourself.
K4DHR
Member
I just use mini 8 for my short runs, since it is usually better shielded than RG-58. It is just slightly larger, only a few cents more a foot and is just as flexible.
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