Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old February 11th 12, 04:02 PM posted to sci.electronics.repair,rec.radio.amateur.antenna,sci.electronics.design
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 625
Default Increasing Cable TV signal strength

On Feb 10, 11:38*am, Jeff Liebermann wrote:
On Fri, 10 Feb 2012 06:17:03 -0800 (PST), JIMMIE

wrote:
Jeff, I installed TVRO systems for several years and used a lot of F
connectors. Suprisingly the ones I found that worked best were the
ultra cheap ones that only took a pair of pliers to fasten *These were
the ones with the separate crimp rings. Used with some good quality
heat shrink tubing this eliminated most of the problems you mention. I
dont know why these connectors went away, my only guess is *that
someone wasn't making enough money on them.


Jimmie


Yech...

Please try this test. *Insert such a crimp type F connector and cable
into some useless piece of equipment with a type F jack. *Pull on the
cable hard. *In my experience, it doesn't take much to make the cable
and connector part ways. *Repeat with a screw on connector. *Now,
repeat the experiment using a properly assembled compression type F
connector and cable. *It takes considerably more brute force to break
the connection. *I think the official minimum pull test is 55 lbs, but
I'm too lazy to Google for it now.

Hiding the workmanship under shrink tube is not very functional. *It
will have little effect on the pull test.

Most of the cable leakage problems I've seen (and found) were due to
crimp type F connectors coming apart or badly crimped. *That includes
both the hex shaped crimp, and ones held together with a crimped ring.

Bad:
http://www.fconnector.org/wp-content/uploads/2011/12/F-Connector2.jpg

Worse:
http://www.showmecables.com/images/catalog/product/F-connector-RG59.j...

Good:
http://images.lowes.com/product/converted/783250/783250926510lg.jpg

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-255


Sorry Jeff but I never used my connectors to support my cables. You
may be right but completely irrelevant to me. To me F connector and
good connection shouldn't even be used in the same sentence. They are
what that are, cheap connectors at best that uses the center conductor
of the cable for a contact. Now that is Yech. Heat shrink has nothing
to do with the pull test or hiding poor workmanship but it does help
keep corrosion down which is the biggest problem with F connectors.
Ive never seen one pull apart except in the shoddiest of
installations. One of the best things I have found to insure you
maintain a good connection is to apply something like DeOxit to the
connectors when you assemble them. Best done while all the parts are
new.

Jimmie
  #2   Report Post  
Old February 11th 12, 05:34 PM posted to sci.electronics.repair,rec.radio.amateur.antenna,sci.electronics.design
external usenet poster
 
First recorded activity by RadioBanter: Nov 2007
Posts: 568
Default Increasing Cable TV signal strength

In message
,
JIMMIE writes
On Feb 10, 11:38*am, Jeff Liebermann wrote:
On Fri, 10 Feb 2012 06:17:03 -0800 (PST), JIMMIE

wrote:
Jeff, I installed TVRO systems for several years and used a lot of F
connectors. Suprisingly the ones I found that worked best were the
ultra cheap ones that only took a pair of pliers to fasten *These were
the ones with the separate crimp rings. Used with some good quality
heat shrink tubing this eliminated most of the problems you mention. I
dont know why these connectors went away, my only guess is *that
someone wasn't making enough money on them.


Jimmie


Yech...

Please try this test. *Insert such a crimp type F connector and cable
into some useless piece of equipment with a type F jack. *Pull on the
cable hard. *In my experience, it doesn't take much to make the cable
and connector part ways. *Repeat with a screw on connector. *Now,
repeat the experiment using a properly assembled compression type F
connector and cable. *It takes considerably more brute force to break
the connection. *I think the official minimum pull test is 55 lbs, but
I'm too lazy to Google for it now.

Hiding the workmanship under shrink tube is not very functional. *It
will have little effect on the pull test.

Most of the cable leakage problems I've seen (and found) were due to
crimp type F connectors coming apart or badly crimped. *That includes
both the hex shaped crimp, and ones held together with a crimped ring.

Bad:
http://www.fconnector.org/wp-content/uploads/2011/12/F-Connector2.jpg

Worse:
http://www.showmecables.com/images/catalog/product/F-connector-RG59.j...

Good:
http://images.lowes.com/product/converted/783250/783250926510lg.jpg

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-255


Sorry Jeff but I never used my connectors to support my cables. You
may be right but completely irrelevant to me. To me F connector and
good connection shouldn't even be used in the same sentence. They are
what that are, cheap connectors at best that uses the center conductor
of the cable for a contact. Now that is Yech. Heat shrink has nothing
to do with the pull test or hiding poor workmanship but it does help
keep corrosion down which is the biggest problem with F connectors.
Ive never seen one pull apart except in the shoddiest of
installations. One of the best things I have found to insure you
maintain a good connection is to apply something like DeOxit to the
connectors when you assemble them. Best done while all the parts are
new.

There little wrong with good quality F-connectors. They are generally
good enough for what they were intended for. Problems are usually down
to who installs them, and how.

For personal outdoor use, I always give any connectors a squirt of WD40
- both during and after installation. [I guess DeOxit would be similar
or better.] After cleaning off most of the WD40, I then seal with
self-amalgamating tape. Obviously, heatshrink would be better, but for
me, is usually less convenient.

Mechanically, even screw-on Fs can be hard to dislodge, provided just
the right amount of braid is trapped under the screw thread. However, I
suppose that sometimes they might not provide the ultimate in screening.

In the UK, in the large CATV networks, crimped connectors are well and
truly a thing of the past. Anyone using them (even the good ones) would
be liable to be hung, drawn and quartered, and then severely punished.

The standard connector is of the 'Snap and Seal' type (and similar). In
themselves, these are pretty well watertight, and the screening is
excellent. It should be almost impossible to pull one off the cable.

However, it is unusual for F-connections to appear naked in the open
air. The final RF distribution to the home is invariably from a street
cabinet which houses an optical node or an RF distribution / line
extender amplifier feeding a bank of taps/splitters. The 'traditional'
cascade of in-line taps has not been used for a very long time. Under
these relatively benign conditions, the F-connectors probably suffer
much less from corrosion than those used on taps hanging on aerial
messenger wires, USA-style. Nevertheless, there are various purpose-made
short 'chunky' rubber sleeves which can be installed first on the tap
ports before the cable connectors are screwed on. These seal the screw
threads. Personally, I would have liked to have seen a bit of WD40 used
but I never managed to drum up much enthusiasm for this as an approved
practice.
--
Ian
  #3   Report Post  
Old February 11th 12, 07:11 PM posted to sci.electronics.repair,rec.radio.amateur.antenna,sci.electronics.design
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 398
Default Increasing Cable TV signal strength


JIMMIE wrote:

On Feb 10, 11:38 am, Jeff Liebermann wrote:
On Fri, 10 Feb 2012 06:17:03 -0800 (PST), JIMMIE

wrote:
Jeff, I installed TVRO systems for several years and used a lot of F
connectors. Suprisingly the ones I found that worked best were the
ultra cheap ones that only took a pair of pliers to fasten These were
the ones with the separate crimp rings. Used with some good quality
heat shrink tubing this eliminated most of the problems you mention. I
dont know why these connectors went away, my only guess is that
someone wasn't making enough money on them.


Jimmie


Yech...

Please try this test. Insert such a crimp type F connector and cable
into some useless piece of equipment with a type F jack. Pull on the
cable hard. In my experience, it doesn't take much to make the cable
and connector part ways. Repeat with a screw on connector. Now,
repeat the experiment using a properly assembled compression type F
connector and cable. It takes considerably more brute force to break
the connection. I think the official minimum pull test is 55 lbs, but
I'm too lazy to Google for it now.

Hiding the workmanship under shrink tube is not very functional. It
will have little effect on the pull test.

Most of the cable leakage problems I've seen (and found) were due to
crimp type F connectors coming apart or badly crimped. That includes
both the hex shaped crimp, and ones held together with a crimped ring.

Bad:
http://www.fconnector.org/wp-content/uploads/2011/12/F-Connector2.jpg

Worse:
http://www.showmecables.com/images/catalog/product/F-connector-RG59.j...

Good:
http://images.lowes.com/product/converted/783250/783250926510lg.jpg

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-255


Sorry Jeff but I never used my connectors to support my cables. You
may be right but completely irrelevant to me. To me F connector and
good connection shouldn't even be used in the same sentence. They are
what that are, cheap connectors at best that uses the center conductor
of the cable for a contact.



Then you would hate most microwave connectors lit SMA.


Now that is Yech. Heat shrink has nothing
to do with the pull test or hiding poor workmanship but it does help
keep corrosion down which is the biggest problem with F connectors.



You didn't need heat shrink on good 'F' connectors.

Ive never seen one pull apart except in the shoddiest of
installations. One of the best things I have found to insure you
maintain a good connection is to apply something like DeOxit to the
connectors when you assemble them. Best done while all the parts are
new.



Not needed, if you use flooded outdoor cable.


--
You can't have a sense of humor, if you have no sense.
  #4   Report Post  
Old February 11th 12, 08:11 PM posted to sci.electronics.repair,rec.radio.amateur.antenna,sci.electronics.design
external usenet poster
 
First recorded activity by RadioBanter: Jun 2007
Posts: 1,336
Default Increasing Cable TV signal strength

On Sat, 11 Feb 2012 08:02:37 -0800 (PST), JIMMIE
wrote:

Sorry Jeff but I never used my connectors to support my cables. You
may be right but completely irrelevant to me.


Umm... you've never tripped over a cable, had the equipment fall off
the table with the cables attached, run RG6a/u up a pole to where it
has to support its own weight, moved furniture with cables still
attached, flexed the connector when used as a test lead, pulled cable
through the wall or conduit with connectors attached, etc? These are
all very common situations which will stress the connector to cable
connection. While it might not be a problem for a fixed (stapled in
place) installation, it certainly will be a problem for the average
home user.
http://802.11junk.com/jeffl/pics/drivel/slides/mess01.html

I find it odd that outdoor CATV uses quad shielded cable to prevent RF
leakage and ingress, and having the cable swept to perfection, while
you recommend using inferior F connectors.

To me F connector and
good connection shouldn't even be used in the same sentence. They are
what that are, cheap connectors at best that uses the center conductor
of the cable for a contact. Now that is Yech.


I do have some issues with RG6a/u that uses copper plated steel core
center wire. Mostly, it's a corrosion problem for outdoor connections
where the home owner does their own wiring, and uses F connectors
without the necessary rubber o-ring needed for waterproofing. I've
swept F connectors on the bench and find them quite good and often
superior to the rare 75 ohm TNC and BNC connectors near the top end
(2GHz for satellite). Incidentally, most of the antennas (that
survived a recent storm) on my roof use RG6a/u coax. The mismatch
loss between 50 and 75 ohms is minimal. Some use F connectors, but
most use BNC's made for RG6a/u.

Heat shrink has nothing
to do with the pull test or hiding poor workmanship but it does help
keep corrosion down which is the biggest problem with F connectors.


Ahem. I worked for a marine radio company during the 1970's. I
learned a few things about waterproofing and corrosion. Heat shrink
doesn't work. Capillary action along the heat shrink to connector
boundary will suck the water into the connector.

What I use (when needed) is a layer of 1" PTFE tape (or 1/2" if that's
all I can find) over the connector. Once in place, a layer of Scotch
66 or other electrical tape to hold it in place. The PTFE will cold
flow into the irregularities on the connector surface, and there will
be zero capillary action. If I want UV resistance, I spray the tape
with clear Krlyon (acrylic) spray.

While we're on the topic, I've experimented with various allegedly
waterproof enclosures and packages. The only ones I consider
genuinely waterproof are sealed and pressurized with dry air. Anything
less will eventually leak.

Ive never seen one pull apart except in the shoddiest of
installations.


I have and all too often. I was at the neighbors trying to
troubleshoot their Comcast cable tv and modem mess. They had some
friend of theirs do the wiring. All the F connectors were crimp ring
type and were falling apart. The coax was mostly RG-59 with maybe 80%
coverage. I replaced the most disgusting and will finish the job when
I have time.

One of the best things I have found to insure you
maintain a good connection is to apply something like DeOxit to the
connectors when you assemble them. Best done while all the parts are
new.


DeOxit and Cramolin contain oleic acid, which will slightly corrode
copper. It's good for CLEANING connectors by removing the oxides, but
should not be left on the connector. If you want to make sure that
you can take the connector apart after the threads rot in place due to
galvanic action between the aluminum receptacle, and the nickel plated
crimp type F connector, some silicon or lithium grease would probably
be better.

Some notes on the contents:
http://www.antiqueradios.com/forums/viewtopic.php?t=82058&start=40&sid=71ca160c8f60768 6916a0f355e9ecc34

Jimmie


As for special tools, I love them. My various cable preparation tools
for various coax cable have saved me countless hours of fumbling with
a pocket knife and diagonal cutters. Using the various compression
tools on F connectors almost guarantee a good connection, unless I did
something dumb. Same with crimp lugs, various LMR-xxx coax cables,
and Anderson Power Pole connectors. The days of using a hammer or
vice grips to crimp a connector are over. The cost can be
substantial, but is well worth it if you work with connectors
regularly.
http://802.11junk.com/jeffl/antennas/Misc/slides/crimpers.html
About $35/ea.

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

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tecsun PL-310 Signal Strength Metering Richard Fry Shortwave 4 May 17th 10 10:58 PM
What's Your Signal Strength? Chuck Shortwave 4 October 6th 04 10:51 PM
Signal Strength Suggestions Nickolas Antenna 4 August 30th 04 04:53 PM
APRS and signal strength.. Joel Homebrew 0 January 4th 04 11:13 PM
APRS and signal strength.. Joel Homebrew 0 January 4th 04 11:13 PM


All times are GMT +1. The time now is 03:25 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017