View Single Post
  #22   Report Post  
Posted to sci.electronics.repair
Jeff Liebermann Jeff Liebermann is offline
external usenet poster
 
Posts: 4,045
Default Which is it, RG59 or RG6?

On Sun, 06 Dec 2009 23:11:22 -0500, "Michael A. Terrell"
wrote:

Ingression is external signals getting into the CATV plant. You are
describing radiation' where the signal is lost to being radiated from
the outer conductor, due to poor connections. It is monitored on a
continuous basis on most cable systems using 'Sniffer' or other brands
of monitoring equipment. While the signal is on the video carrier
frequency, it is FM modulated with annoying audio to make it easy to
identify.


Well, the leak or ingress goes both ways. While ingress from ham,
commercial, and broadcast radio xmitters are irritating, the
regulatory requirement is to prevent cable leakage from interfering
with public safety, aircraft, and of course, OTA broadcast. Lots of
nice toys to measure this leakage:
http://www.trilithic.com/Broadband%20Instruments

Personally, I prefer visual inspection, a TDR (time domain
reflectometer), signal level measurements, or just a pre-emptive
replacement.


Those are OK if you can shut a system down for repairs. Poor
connections in the trunkline can be detected by reading the voltage drop
between the coax and the amplifier housing, splice block or any other
splice in any powered cable. 60 volts modified sine wave AC @ 30 amps
from a CVT doesn't tolerate much resistance without causing hum
modulation or burning up a connector.


Ummm... the OP is trying to troubleshoot his home installation, not
the trunk line (or cable drop). I think it's a safe bet that he can
unplug his spaghetti without difficulties.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558