Re: F-plug need to be fully tightened?

On 16 Sep 2008 03:50:43 GMT, phil-news-nospam@[EMAIL PROTECTED]
 wrote:

>In alt.engineering.electrical Steve <80977969755483@[EMAIL PROTECTED]
> wrote:
>
>| "Peto" <peto@[EMAIL PROTECTED]
> wrote in message
>| news:Xns9B1A7EBD9C40B37E1A@[EMAIL PROTECTED]
>|> I'm in the UK.  I have the usual F-series connector on the coax
>|> entering my cable modem.
>|>
>|> http://www.newtechindustries.com/newtech/catalog/images/200-045.jpg
>|>
>|> --------
>|>
>|> I need to remove the connector every now and then so I lubed the
>|> threads with a smear of vaseline.
>|>
>|> At these RF frequencies (about 340 MHz) do I need to have true
>|> electrical contact between the plug and socket or is close proximity
>|> enough?
>|>
>|> Would loose "hand tight" be sufficent?
>| 
>| Hand tight is sufficient, yes.  Its rare I would tighten them up any
more
>| than hand tight for most jobs,
>
>Tell that to the cable guy.  They always tighten those things to the
extreme.
>Maybe that's a good thing outside.  But I've had to use big wrenches to
get
>them off after the cable guy leaves.  Maybe they think its a means to
keep
>me from using a pirate box?


  No.  There is an actual torque range spec for the fitting class.

  Also, a connection IS required. There is no "jumping the gap" at any
frequency. RF lines are not your car's spark plug wires.


  The torques:

  For an SMA connection, it is between 7 and 11 in//lbs.  An F fitting is
slightly more than that.

 Hand tightening can yield about 3 to 5 in/lbs on a good day.

 There is an actual tool they use. It can easily be fa****oned with the
right tools.

  It is a snap-on six point (im****tant) 7/16", deep length impact socket
that has had the neck turned down to a diameter just greater than the 6
points by about a millimeter or less.  This allows access inside the
security "bells" that are so often used to keep us out.  Then, the socket
needs to have a coax (number 6) wide slot cut into the entire length of
the socket with a dremel cut-off tool, since the socket is hardened
steel, you will not be able to use a hack saw or other steel based
cutting device without going through a few of them.

  The socket sits on the cable, and slides up onto the fitting, and
VIOLA!  One can properly torque the fitting on or off, and also can
access the security prevention devices incor****ated into some system
installations.

  Finger tight is NOT enough on a cable that gets hooked up long term as
a simple flexure of the cable can result in a loose connection.

 For a hook-up that you are going to be using over and over again, finger
tight is fine as long as you know it is tight, the connection it good.
Just remember that even the slightest cable flexure can twist it loose.

  So, if you are always "eyes on" then you should be alright because you
know it is still tight.