Topband: Flooded CATV cables for TX, Summary

[Lennart M]

CATV cables are widely used products with prices that compete well with 
normal coax cables like RG213/U. The question was wether it can stand up to 
normal amateur power levels.
The flooded type can be buried and is protected against at least minor 
scratches.
Many hams confirm that this cable can be used for legal power level at 1.8 
and 3.5 MHz. Some fellows report problems with the F-type connectors over 
time.
At least one brand uses copper Clad steel as innerconductor, see the notes 
from Jim K9YC below.

K9YC:
"
> 2) Look at the resistance (at RF) of the two conductors, and
> compare it with coax that IS commonly used for transmission. The
> drop cable I see here in the US has copper clad steel (CCS) as a
> center conductor and aluminum foil with braid for shield.
>
> 3) To get a handle on resistance, look at DC resistance, AND look
> at graphs of attenuation versus frequency. If you can't find those
> data for the cable you have, look at that data for cables of
> similar construction. CCS is used in some Belden RG59s, and their
> data shows that skin effect hasn't really kicked in much below 5
> MHz, so much of the current at 1.8 MHz will be in the steel. "

The Italian manufacturer CAVEL says:   "Our 11/50FC is tested during 
jacketing at 8 kV and 500 Hz. 8A max
current means DC current as used to supply distant devices like rotors,
amplifiers and so on. I have no measure at 1 MHz but an extimated  loss
value will be around 0,7/0,8 dB for 100 meters of cable" (At 5 MHz the loss 
is 1.5 dB/100 m)

The innerconductor of that cable is plain copper (not Copper Clad steel)
Loop resistance for a length of 100 m is 3.15 ohm

ED KG4W came up with this calculator which might be helpful
http://www.timesmicrowave.com/cgi-bin/calculate.pl

Many thanks for all good advice which supports the idea of using this fairly 
inexpensive cable for transmission as well.
73
Len/SM7BIC