View Single Post
  #2   Report Post  
Old March 11th 08, 12:38 AM posted to rec.radio.amateur.antenna
Jim Lux Jim Lux is offline
external usenet poster
 
First recorded activity by RadioBanter: Mar 2007
Posts: 801
Default Attenuation Questions

Robert11 wrote:
Hello,

Would you expect to see, in a practical sense, and meaningful difference
between RG6 with a copper plated steel center conductor vs an all copper
one, going from the antenna to a receiving scanner (50 foot run; 1 GHz max).

Tried to find some attenuation tables for this in Google, but had no luck:
Plenty for the coax cables themselves, but might you know of any chart links
that show attenuation for the different types of connectors ?


No.

Connector loss is negligible (0.1dB) for all reasonable connectors.
The ohmic losses would be a tiny fraction of the ohmic loss in the cable
itself (i.e. the connector interface is a few mm long, compared to
meters of cable).

Skin depth at 1 GHz in copper is 2 microns (0.08 mil). 6.5 microns (.26
mil) at 100 MHz. Your copper clad steel is probably just as good as
solid copper (check the data sheet and see what the clad thickness is..
if it's 4-5 times the skin depth, it's the same as solid.

Also check the shield material (there's more of it, but if it's
aluminum, it's lower conductivity)

At higher frequencies, dielectric loss will be a goodly fraction of the
total cable loss. Again, the connector is very short, so its dielectric
loss is a tiny fraction of the overall cable loss.