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
Would loose "hand tight" be sufficent?
|> I'm in the UK. I have the usual F-series connector on the coax|> entering my cable modem.
|> 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?
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
On 16 Sep 2008 03:50:43 GMT, email@example.com wrote:
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.
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 fashioned with the
It is a snap-on six point (important) 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 incorporated into some system
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.
In Peter Wright's book Spycatcher, he describes a technique for
remotely bugging the phones of the day - 1950s - by using an RF
carrier to bridge the hookswitch by means of its innate capacitance
and therefore activate the microphone. A dim memory suggests it used a
frequency somewhere around Medium Wave - about the same as ADSL.
On Tue, 16 Sep 2008 07:41:45 +0100, Burton Bradstock
It barely worked on SOME susceptible phones at the time, and for a time
after that, but none of the modern ISDN switched phones do, and the
construction is different now as well.
Then, all hook switches were exposed, just like the old pinball
machines. Most are sealed switches these days. Still, there are far
more and better ways of surveilling someone's activities.
But sure... that was one "genius'" "discovery". Again, it required a
specific set of circumstances to work. The main one likely being a
Another field you don't know anything about, Phil. I worked as the
engineer for a major MSO years ago. I was responsible for all the
electronics in CATV systems scattered all over the US. You are a ham
radio operator, and should be familiar with CFR 47. There are a lot of
regulations in there concerning CATV equipment & installations. CATV
systems share some frequencies with airports and commercial airliners.
It is required by the FCC. The cable company is responsible for any
RF radiation from their system, from their antennas, to every TV they
provide their service to. Most commercial grade 'F' connectors had a
specification of 1/8 to 1/6 turn after finger tight to meet the
radiation & ingression specification. If they detect leakage they have
to find the source. If it is from inside your house and you either
aren't home or won't let them in, they are required to disconnect your
service until all repairs are made.
aioe.org, Goggle Groups, and Web TV users must request to be white
Yep, for what you have in mind.
You can also, IIUC, get adapters to go on the end of the F plug and turn
it into "push on". Which will probably give a more reliable result as
"loose hand tight" could very easily turn into "fallen off -lying on the
Sorry, Sue, it won't be more reliable, just very convenient if you are
continually removing/replacing F connectors into various pieces of
equipment......... By your reasoning, then both will fall off :) The push on
F connector adapter is very prone to falling out of the back of whatever
it's connected to....... but boy, is it handy :)
Grease should only be used when making a weather tight seal. i.e. outdoors.
Typically a silicon sealer on 'N' connectors.
Grease is not commonly used on F connector threads. Some weather tight
models exude a sealer when crimped... but not on the threads.
Hand tight is insufficient in this case because one of tech support's first
questions is invariably "is your cable firmly attached" (I think it's on the
Likewise any modification or adaptor you add will bear the brunt of blame in
any "discussion" with tech support or field service.
Constant plugging and unplugging of a F connector is not recommended because
the jack is likely to wear out making the center conductor connection
Not true. There are several cities where the cable contractors followed
the CORRECT methodology of SEALING their fittings with an
This has NOTHING to do with U/G coax cabling, which has a liquid
sealant layer between the sheath (jacket) and the first braid or foil
That's the threads, AND the "stinger". From a man hour POV, it is
easier to simply plop a wad of it in the fitting, then the center
conductor as well as the threads get the application. The media does not
damage the connector or ANY fitting it gets mated with.
Cable companies are SUPPOSED to cut back their fittings every ten years
and place a new, properly treated fitting.
THAT is what the original plan called for, and is also what SHOULD BE
practiced. A ten year old uncoated fitting will have far more losses (can
have) than one which has had anti-oxidant treatment after a ten year
So, in a PROPERLY implemented cable system, treatment IS the common
practice and teaching.
Where did I learn this? Cincinnati's Time Warner (formerly CUBE) cable
system. Way back in the early 80's. That was a DUAL system, so every
run was twice the number of fittings. Every hard line run was twice the
number. Dual taps at every node. All sealed from moisture.
You have a choice between conductive gunk which will tend to short out the
connection or non-conductive gunk which will tend to block the flow of
electrons where you would like them to flow. Take your pick. I pick neither.
Time Warner in new York picks neither also, as least as far as far as indoor
Given the OP's constant unplugging of the cable I doubt oxidization will
ever be a problem for him.
You obviously have very little grasp of RF terminations.
First off, NOBODY EVER uses a conductive medium to dress a cable
If they do, then they must be as dumb as any idiot that thinks they do.
T/W in NY is what? Queens? No, I do not give the folks in NY ANY
credence on their capacity to know what the industry does or recommends
gets done (more like their capacity to FOLLOW the method).
They are the epitome of slam it, cram it, ram it, and jam it mentality,
and no, they would not ever do anything that takes up extra time,
regardless of whether it is the way one is supposed to do it, NOR would
they ever CONSIDER the customer when doing it.
They epitomize the term CABLE TRASH inasmuch as they cut a fitting and
move on. Since it works, they could give a shit that it starts dropping
dBs within a few months of termination without preparation.
The wiper does not scrape the stinger in the same spot each time, and
relying on an insertion move to "clean" one's connection is just plain
It is far easier to replace the female "barrel connector" that most
cable runs end up termination into. That way, all the insertions in the
world can be made "brand new" by putting a new barrel fitting in the
line. Still, the cream/paste/gel whatever is still going to be the best
defense against oxidation.
ANY freshly scraped wipers or stingers, etc. are going to actually be
vulnerable to oxidation even quicker due to the bare metals, and
dissimilar metals in the connection. The anti-oxidant keeps said
oxidation from happening, and NO, it does NOT EVER "inhibit electron
flow" as you have declared.,
Hearing that from you makes one wonder if you know ANY electronics at
Seeing your posts here in the past, I know that is not true, therefore,
you must have latched on to some lame urban myth. What you should have
relied on is your common sense.
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