40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  PSL  Not logged in ELOG logo
Message ID: 461     Entry time: Tue Feb 1 19:26:47 2011
Author: Frank 
Type: Notes 
Category: BEAT 
Subject: loss of RF cables 

found a nice calculator here:


which has a huge amount of different cable types in it's database. Checked/compared the calculated values for some examples given in several datasheets found on the web and they are close within each other.
Here an example for our current case for the 500ft spool of RG58C/U we have in the lab. Loss is only 32dB which looks pretty good to me for that cheap cable.

Transmission Line RG-58C/U
Code RG-58C/U
Data source DSE
Frequency 160.000 MHz
Length 500.000 ft
Zo 50.00-j0.13 Ω
Velocity Factor, VF -2 0.660, 2.293
Length 44334.70 °, 123.152 λ, 152.400 m
Line Loss (matched) 32.146 dB
Loss model source data frequency range 50.000 MHz - 1000.000 MHz
Correlation coefficient (r) 0.999926
ELOG V3.1.3-