Recently, I have been bedeviled by unstable Internet service from
COMCAST (Xfinity) in the Boston area. The following story is not
limited to COMCAST, and it could have been any Cable-TV Internet
Service Provider.

Starting in late July 2021 and ending in early August 2021, for about
one month total, my Internet service became very unstable. (Cable TV
service was unaffected, so it was not that the physical cable path was
interrupted.) Internet service had been rock solid since about 2016,
when I purchased and installed the current cable modem, an ARRIS
SB6183. My service tier is 200 Mbit/sec download, which is well
within the capabilities of the SB6183, 686 Mbits/sec.

The main external symptoms were that browser access would randomly
slow and hang, sometimes recovering, something not. Likewise email
(POP account). Rebooting the modem (by cycling power) often but not
always restored Internet service. As the month progressed, things got
progressively worse, although it was always relapsing-remitting - it
should spend all night trying to connect, failing, trying again, and
so on.

Called COMCAST tech support, which forced me to deal with a robot lady
that could only follow a script, the main point of which was to get me
to power-cycle the modem. This power cycle often did work, probably
because she was probably also sending a modem reset signal at the same
time, but she never made that clear. (The robot lady here is in fact
a machine, not just an unimaginative human, a droid.)

Got a human later, after calling back and answering that the problem
was not fixed. The human came to the conclusion that my cable modem
was too old and likely broken, and insisted that I call ARRIS and have
them diagnose the modem, and only if ARRIS declared that the modem was
not broken would COMCAST do anything like send a truck without
charging an arm and a leg.

Called ARRIS. Cost US $50 (out of warrantee). Got a real human, in
Chennai, India, who did seem expert in the modem internals, with
perfect English and a very good telephone line, and was very patient.

COMCAST had claimed that ARRIS could do technical (ie, electrical)
tests remotely, but this turned out not to be true. Anyway, I had
collected lots of status data from the modem, which we discussed, and
he concluded that the modem was not broken and did not need to be
replaced

Now one mystery had always nagged me: While the Internet was up, the
modem would report received signal powers (over 16 parallel RX
channels) of +5 dBmV (decibels over one millivolt in a 75-ohm system),
and a SNR of about 40 dB, and yet errors (both corrected and
uncorrected) kept accumulating.

When the link was down, the received signal level would drop by 20 dB
to -15 dBmV (which is in the DOCSIS 3.0 Spec Range) , and the SNR
would still be 35 dB (also in spec range).

How does that work? With 35 to 40 dB SNR, there should be no errors.
Neither COMCAST nor ARRIS were able to interpret that oddity.

Called COMCAST back. Went through the robot lady yet again, but on
the third call, got another real human.

He really had no idea what went on inside modems et al, and insisted
that if the associated firewall/router was not also rebooted when the
modem was reset or rebooted, the ensuing chaos would cause the modem
to be unable to measure incoming RF power (at around 500 MHz)
correctly on a coax, the claim being that both Ethernet and Cable TV
were both "electrical", so they could heavily affect one another Hmm.
I'll have to think about that. For a very long time.

He was also of the opinion that Ethernet wires wear out and need
periodic replacement. I declined to disassemble the house to get at
the CAT5e cable that runs from basement (at the modem) to the 2nd
floor (where the WiFi base station lives).

He worried greatly about cables and connectors in general, saying that
they were very often the cause of such problems as I was seeing. After
one hour discussing the issue, while his theories of causation were
nonsense, this was his direct experience, and thus was my main
takeaway.

Usually, connectors are the main cause of problems with "cables", and
it had to be a coax cable, so I found an 11mm (7/16") open-end
ignition wrench, and went around loosening and re-tightening all CATV
RF connectors (Type F, for the record). The loosen-then-tighten drill
is to physically disrupt any corrosion at contact points.

All connections were tight save one, the one where the coax from the
modem connects to the RF feed coming from the nearby boiler room. The
loose connector is in the wall plate under the table upon which the
modem sits, along with my desktop computer, and that connector had
managed over the years since 2016 to unscrew itself almost to the
point of falling apart. That cable does move a bit when things are
added or removed, and so on. Tightened the connector. Bingo!

And now the cause of the oddity became clear. The SNR is measured
over time, to yield a stable value. But the connection was chattering
between normal power (+5 dBmV) and open (-15 dBmV) fast enough that
the SNR calculation didn't notice. This was also too fast for AGC et
al to react, so symbols sent during the open period were lost. Some
could be recreated by forward error correction, and some could not,
and these errors accumulated steadily over time despite the stellar
SNR.

The modulation type is QAM256, and the symbol rate on each QAM256
channel is 5120 Ksymbols per second. There are 16 downlink and 4
uplink channels. The AM component of the QAM symbols will have a
fundamental at 5 MHz or so, far above the spectrum due to a rattling
connector.

..<https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation>

A spectrum analyzer would not have found this problem either. I
suppose if one envelope demodulated the received RF, the chattering
would have been quite obvious - big AM noise peak in the 10 to 1000 Hz
range, or the like. I would think that it would be useful for the
modem to do this - loose connectors are pretty common I'd hazard.

Anyway, it all works now, the key symptom being that there are no new
errors accumulating now.

And the takeaway is that if SNR exceeds 30 dB and yet errors
accumulate, start re-tightening RF connectors. If that doesn't work,
look for a cracked wire or connector, or a loose shield.

Joe

In article <gppfhgh3t6tnnsm751nplf7qda73v525m1@4ax.com>,
joegwinn@comcast.net says...
> spectrum analyzer would not have found this problem either. I
> suppose if one envelope demodulated the received RF, the chattering
> would have been quite obvious - big AM noise peak in the 10 to 1000 Hz
> range, or the like. I would think that it would be useful for the
> modem to do this - loose connectors are pretty common I'd hazard.
>
> Anyway, it all works now, the key symptom being that there are no new
> errors accumulating now.
>
> And the takeaway is that if SNR exceeds 30 dB and yet errors
> accumulate, start re-tightening RF connectors. If that doesn't work,
> look for a cracked wire or connector, or a loose shield.
>
>
>

I guess that the internet over the cable line could be effected and not
the TV signals.

Many years ago I had problems on 3 or 4 out of many of the TV signals
on the cable. The repair man came out and started replacing the
connectors outside the house and on the pole. I though he was waisting
his time,but when he finished all the chanels worked.

On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

>Recently, I have been bedeviled by unstable Internet service from
>COMCAST (Xfinity) in the Boston area. The following story is not
>limited to COMCAST, and it could have been any Cable-TV Internet
>Service Provider.

Which model Comcast modem/gateway?

Have you seen this?
<https://approvedmodemlist.com/intel-puma-6-modem-list-chipset-defects/>
The usual failure mode is decreasing speeds, high error rate, and
hangs, which can be temporarily fixed by power cycling the
modem/gateway.

Like all crowd sourced lists, the above defective modem list seems (to
me) to be problematic. For example, I've had no problems with Arris
SB6183 modems, which I assume are v1 version. For example, the list
shows SB6183v2 as defective, but I've never seen a v2 modem.
<https://www.newegg.com/p/pl?d=Arris+sb6183>
There are other lists on the web. I suggest you compare entries
before assuming a particular modem is bad. Incidentally, I've seen a
high failure rate with the Arris supplied 12VDC 1.5/2.0A power
supplies after about 3 years. Bulging caps from overheating is the
usual culprit. I suggest you buy a spare.

As for juggling the levels, I've found that the data sheet -15dBmV to
+15dBmV input range to be questionable. I uses a 75ohm switchable
attenuator to determine the optimum signal level for the modem. In
most cases, optimum is no external attenuator. I usually see high
levels in buildings with distribution amplifiers. I can usually find
an acceptable attenuator value by watching the SNR and upstream power
levels.
<https://arris.secure.force.com/consumers/articles/General_FAQs/SB6183-Cable-Signal-Levels>
The catch is that the optimum level can vary over time if the unused
ports on distribution amplifier. If adjusting the input level doesn't
help, I look for junk inside cable, bad crimps, junk connectors. If
that doesn't work, I drag out the test equipment and look for tilt,
ingress and other signal anomalies.

As for connectors, I've seen a few broken F connectors. The problem
is that such devices are not designed to survive a crash to the floor.
If the modem lands on the stiff RG-6a/u cable or F connector, it will
break the solder connection(s) to the PCB. I can usually solder those
back together of the modem is out of warranty. For a time, I was
constantly getting replacement modems from Comcast with broken
connectors. It seems their "refurbishing" operation doesn't check for
broken F connectors and puts the "tested" modems back in stock.

Congrats on solving your problem and good luck.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

>Recently, I have been bedeviled by unstable Internet service from
>COMCAST (Xfinity) in the Boston area. The following story is not
>limited to COMCAST, and it could have been any Cable-TV Internet
>Service Provider.
>
>Starting in late July 2021 and ending in early August 2021, for about
>one month total, my Internet service became very unstable. (Cable TV
>service was unaffected, so it was not that the physical cable path was
>interrupted.) Internet service had been rock solid since about 2016,
>when I purchased and installed the current cable modem, an ARRIS
>SB6183. My service tier is 200 Mbit/sec download, which is well
>within the capabilities of the SB6183, 686 Mbits/sec.
>
>The main external symptoms were that browser access would randomly
>slow and hang, sometimes recovering, something not. Likewise email
>(POP account). Rebooting the modem (by cycling power) often but not
>always restored Internet service. As the month progressed, things got
>progressively worse, although it was always relapsing-remitting - it
>should spend all night trying to connect, failing, trying again, and
>so on.
>
>Called COMCAST tech support, which forced me to deal with a robot lady
>that could only follow a script, the main point of which was to get me
>to power-cycle the modem. This power cycle often did work, probably
>because she was probably also sending a modem reset signal at the same
>time, but she never made that clear. (The robot lady here is in fact
>a machine, not just an unimaginative human, a droid.)
>
>Got a human later, after calling back and answering that the problem
>was not fixed. The human came to the conclusion that my cable modem
>was too old and likely broken, and insisted that I call ARRIS and have
>them diagnose the modem, and only if ARRIS declared that the modem was
>not broken would COMCAST do anything like send a truck without
>charging an arm and a leg.
>
>Called ARRIS. Cost US $50 (out of warrantee). Got a real human, in
>Chennai, India, who did seem expert in the modem internals, with
>perfect English and a very good telephone line, and was very patient.
>
>COMCAST had claimed that ARRIS could do technical (ie, electrical)
>tests remotely, but this turned out not to be true. Anyway, I had
>collected lots of status data from the modem, which we discussed, and
>he concluded that the modem was not broken and did not need to be
>replaced
>
>Now one mystery had always nagged me: While the Internet was up, the
>modem would report received signal powers (over 16 parallel RX
>channels) of +5 dBmV (decibels over one millivolt in a 75-ohm system),
>and a SNR of about 40 dB, and yet errors (both corrected and
>uncorrected) kept accumulating.
>
>When the link was down, the received signal level would drop by 20 dB
>to -15 dBmV (which is in the DOCSIS 3.0 Spec Range) , and the SNR
>would still be 35 dB (also in spec range).
>
>How does that work? With 35 to 40 dB SNR, there should be no errors.
>Neither COMCAST nor ARRIS were able to interpret that oddity.
>
>Called COMCAST back. Went through the robot lady yet again, but on
>the third call, got another real human.
>
>He really had no idea what went on inside modems et al, and insisted
>that if the associated firewall/router was not also rebooted when the
>modem was reset or rebooted, the ensuing chaos would cause the modem
>to be unable to measure incoming RF power (at around 500 MHz)
>correctly on a coax, the claim being that both Ethernet and Cable TV
>were both "electrical", so they could heavily affect one another Hmm.
>I'll have to think about that. For a very long time.
>
>He was also of the opinion that Ethernet wires wear out and need
>periodic replacement. I declined to disassemble the house to get at
>the CAT5e cable that runs from basement (at the modem) to the 2nd
>floor (where the WiFi base station lives).
>
>He worried greatly about cables and connectors in general, saying that
>they were very often the cause of such problems as I was seeing. After
>one hour discussing the issue, while his theories of causation were
>nonsense, this was his direct experience, and thus was my main
>takeaway.
>
>Usually, connectors are the main cause of problems with "cables", and
>it had to be a coax cable, so I found an 11mm (7/16") open-end
>ignition wrench, and went around loosening and re-tightening all CATV
>RF connectors (Type F, for the record). The loosen-then-tighten drill
>is to physically disrupt any corrosion at contact points.
>
>All connections were tight save one, the one where the coax from the
>modem connects to the RF feed coming from the nearby boiler room. The
>loose connector is in the wall plate under the table upon which the
>modem sits, along with my desktop computer, and that connector had
>managed over the years since 2016 to unscrew itself almost to the
>point of falling apart. That cable does move a bit when things are
>added or removed, and so on. Tightened the connector. Bingo!
>
>And now the cause of the oddity became clear. The SNR is measured
>over time, to yield a stable value. But the connection was chattering
>between normal power (+5 dBmV) and open (-15 dBmV) fast enough that
>the SNR calculation didn't notice. This was also too fast for AGC et
>al to react, so symbols sent during the open period were lost. Some
>could be recreated by forward error correction, and some could not,
>and these errors accumulated steadily over time despite the stellar
>SNR.
>
>The modulation type is QAM256, and the symbol rate on each QAM256
>channel is 5120 Ksymbols per second. There are 16 downlink and 4
>uplink channels. The AM component of the QAM symbols will have a
>fundamental at 5 MHz or so, far above the spectrum due to a rattling
>connector.
>
>.<https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation>
>
>A spectrum analyzer would not have found this problem either. I
>suppose if one envelope demodulated the received RF, the chattering
>would have been quite obvious - big AM noise peak in the 10 to 1000 Hz
>range, or the like. I would think that it would be useful for the
>modem to do this - loose connectors are pretty common I'd hazard.
>
>Anyway, it all works now, the key symptom being that there are no new
>errors accumulating now.
>
>And the takeaway is that if SNR exceeds 30 dB and yet errors
>accumulate, start re-tightening RF connectors. If that doesn't work,
>look for a cracked wire or connector, or a loose shield.
>
>Joe

I'll go tighten them all now!

A lot of people complain about Comcast, but it's been excellent here.
The install/service folks have been great. They keep upping my speed
for free, probably to compete with Sonic (fiber) and MonkeyBrains
(short-hop microwave links).

We do have to reboot the modem now and then, once a month maybe, when
it quits working.

Their cable TV boxes hang up occasionally too. The wall plug has to be
pulled to do a real reboot, and then they reload their code for a
while.

We have Suddenlink at the cabin, the only choice, and they're not so
good.

--

Father Brown's figure remained quite dark and still;
but in that instant he had lost his head. His head was
always most valuable when he had lost it.

On 8/14/2021 8:55 AM, Joe Gwinn wrote:
> All connections were tight save one, the one where the coax from the
> modem connects to the RF feed coming from the nearby boiler room. The
> loose connector is in the wall plate under the table upon which the
> modem sits, along with my desktop computer, and that connector had
> managed over the years since 2016 to unscrew itself almost to the
> point of falling apart. That cable does move a bit when things are
> added or removed, and so on. Tightened the connector. Bingo!

We've seen that with video, here. It'w annoying as, often, the
cables "loosen themselves" just as a side-effect of being
physically moved (back and forth).

POTS, OTOH, would frequently suffer from line imbalance or
partial shorts to ground. Esp after heavy rains.

Amusingly (annoyingly?) OTA TV now suffers similarly.

On a sunny day (Sat, 14 Aug 2021 11:55:38 -0400) it happened Joe Gwinn
<joegwinn@comcast.net> wrote in <gppfhgh3t6tnnsm751nplf7qda73v525m1@4ax.com>:

>Recently, I have been bedeviled by unstable Internet service from
>COMCAST (Xfinity) in the Boston area. The following story is not
>limited to COMCAST, and it could have been any Cable-TV Internet
>Service Provider.

I am in the Netheelands, Europe, and had cable plus internet from Ziggo
One day Ziggo merged with Vodafone and from that day on _everything_ had problems.

So I canceled the cable and are now using KPN 4G, modem is a simple USB stick you can put in the PC
or laptop (sits in an old raspberry here that now works as router).
Uses a fraction of the power the cable modem did, I pay less and have over 900 TV channels
via my movable satellite dish.
And I can take the laptop with the 4G USB modem stick anywhere and have fast internet.
When disaster strikes all that wired stuff will be dead.
Man from Ziggo a the door some month ago tried to sell me fiber...
I pointed out the sat dish and asked how many TV channels he had,
I have fee choice there, political, I can even see Cuba TV via satellite :-)
Or Russia, almost anything.

On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

>All connections were tight save one, the one where the coax from the
>modem connects to the RF feed coming from the nearby boiler room. The
>loose connector is in the wall plate under the table upon which the
>modem sits, along with my desktop computer, and that connector had
>managed over the years since 2016 to unscrew itself almost to the
>point of falling apart. That cable does move a bit when things are
>added or removed, and so on. Tightened the connector. Bingo!

"The consequences of coaxial connector problems"
<https://www.ppc-online.com/blog/the-consequences-of-coaxial-connector-problems>
Note that this is from Belden, who blames the F connector and would
never suggest that the coax cable might also be a problem.

Try this experiment... Unscrew the F connector nut on your modem
about 3/4th of the way out. Nice and loose. Watch the numbers on the
modem status page. This works for most Comcast modems:
<http://192.168.100.1/RgConnect.asp>
I'm watching a random YouTube video at 720p. No loss of bandwidth, no
intermittents, no loss of carrier, no stops, and no hangs. SNR and
upstream power are unchanged. I wiggled the cable/connector around
trying to make it fail for about 5 mins. No change. In my never
humble opinion a loose connect isn't going to cause a problem.

For fun, I monitored the modem status page, and unplugged the coax
cable from my modem. Modem power was left on at all times. I kept
hitting the browser refresh button waiting for the modem status page
to change. That took about 100 seconds. After plugging the coax
cable back into the modem, it took about 200 seconds for my modem and
the Xfinity CMTS to shake hands and agree to reconnect. In other
words, a carrier loss of less than 100 seconds might not be noticed. I
should try this again while streaming or running a benchmark program,
but I'm short on time today.

In some cases, where the complaint was allegedly a "loose connector",
it turned out to be a corroded center wire, or insufficient exposed
center wire from the F connector. The connector may have been loose,
but what caused the failure was the center wire being retracted from
the F receptacle. The standard field test is to put your finger over
the male F connector. If you feel the center wire, it's ok. If it
drill a hole in your finger, or you can't feel the center wire, it's
time for a new connector.

You might want to revisit the connector you tightened and see if you
have a center pin problem. My guess(tm) is that there's something
else wrong besides a loose F connector.

Some of my CATV tools:
<http://802.11junk.com/jeffl/antennas/Misc/slides/CATV-tools.html>
Favorite F compression connector (Belden SNS1P6U red):
<https://www.ebay.com/sch/i.html?_nkw=SNS1P6U>

I can also rant endlessly about crappy coax, crimpers, strippers,
connectors, and tools, but I'm short on time today.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 14 Aug 2021 19:02:28 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

>So I canceled the cable and are now using KPN 4G, modem is a simple USB stick you can put in the PC
>or laptop (sits in an old raspberry here that now works as router).
>Uses a fraction of the power the cable modem did, I pay less and have over 900 TV channels
>via my movable satellite dish.

FTA (Free to Air)?
<https://www.youtube.com/watch?v=kOpadmYJoeY>
<http://www.americandigitalsatellite.com/all_free_to_air_satellite_channels.html>
--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 14 Aug 2021 11:09:43 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joegwinn@comcast.net>
>wrote:
>
>>Recently, I have been bedeviled by unstable Internet service from
>>COMCAST (Xfinity) in the Boston area. The following story is not
>>limited to COMCAST, and it could have been any Cable-TV Internet
>>Service Provider.
>
>Which model Comcast modem/gateway?

SB6183, bought in 2016. Don't think it's v2 at all. No mention of
Intel.

>Have you seen this?
><https://approvedmodemlist.com/intel-puma-6-modem-list-chipset-defects/>
>The usual failure mode is decreasing speeds, high error rate, and
>hangs, which can be temporarily fixed by power cycling the
>modem/gateway.

Yes, but my SB6183 has no Intel markings. Nor was I having gradual
degradation.

>Like all crowd sourced lists, the above defective modem list seems (to
>me) to be problematic. For example, I've had no problems with Arris
>SB6183 modems, which I assume are v1 version. For example, the list
>shows SB6183v2 as defective, but I've never seen a v2 modem.
><https://www.newegg.com/p/pl?d=Arris+sb6183>

ARRIS may have pulled it, and had some very frank discussions with
Intel.

>There are other lists on the web. I suggest you compare entries
>before assuming a particular modem is bad. Incidentally, I've seen a
>high failure rate with the Arris supplied 12VDC 1.5/2.0A power
>supplies after about 3 years. Bulging caps from overheating is the
>usual culprit. I suggest you buy a spare.

While COMCAST first concluded that the modem was likely bad, mainly
due to age, I did not come to that conclusion, instead calling ARRIS.

>As for juggling the levels, I've found that the data sheet -15dBmV to
>+15dBmV input range to be questionable. I uses a 75ohm switchable
>attenuator to determine the optimum signal level for the modem. In
>most cases, optimum is no external attenuator. I usually see high
>levels in buildings with distribution amplifiers. I can usually find
>an acceptable attenuator value by watching the SNR and upstream power
>levels.
><https://arris.secure.force.com/consumers/articles/General_FAQs/SB6183-Cable-Signal-Levels>
>The catch is that the optimum level can vary over time if the unused
>ports on distribution amplifier. If adjusting the input level doesn't
>help, I look for junk inside cable, bad crimps, junk connectors. If
>that doesn't work, I drag out the test equipment and look for tilt,
>ingress and other signal anomalies.

Yeah. They are supposed to put 75-ohm terminators on unused ports,
but few do I'd guess. But we can add those terminators.

The -15 dBmV to +15 dBmV range is straight from the DOCSIS 3.0 spec,
as are the allowed SNR ranges. I assume that this is the AGC range.

>As for connectors, I've seen a few broken F connectors. The problem
>is that such devices are not designed to survive a crash to the floor.
>If the modem lands on the stiff RG-6a/u cable or F connector, it will
>break the solder connection(s) to the PCB. I can usually solder those
>back together of the modem is out of warranty. For a time, I was
>constantly getting replacement modems from Comcast with broken
>connectors. It seems their "refurbishing" operation doesn't check for
>broken F connectors and puts the "tested" modems back in stock.

Yeah. This had to have been costing them money.

>Congrats on solving your problem and good luck.

Thanks. So far so good. Error counts have not budged in three days.

Joe Gwinn

On Saturday, August 14, 2021 at 4:10:32 PM UTC-4, jeff.li...@gmail.com wrote:
> On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joeg...@comcast.net>
> wrote:
> >All connections were tight save one, the one where the coax from the
> >modem connects to the RF feed coming from the nearby boiler room. The
> >loose connector is in the wall plate under the table upon which the
> >modem sits, along with my desktop computer, and that connector had
> >managed over the years since 2016 to unscrew itself almost to the
> >point of falling apart. That cable does move a bit when things are
> >added or removed, and so on. Tightened the connector. Bingo!
> "The consequences of coaxial connector problems"
> <https://www.ppc-online.com/blog/the-consequences-of-coaxial-connector-problems>
> Note that this is from Belden, who blames the F connector and would
> never suggest that the coax cable might also be a problem.
>
> Try this experiment... Unscrew the F connector nut on your modem
> about 3/4th of the way out. Nice and loose. Watch the numbers on the
> modem status page. This works for most Comcast modems:
> <http://192.168.100.1/RgConnect.asp>
> I'm watching a random YouTube video at 720p. No loss of bandwidth, no
> intermittents, no loss of carrier, no stops, and no hangs. SNR and
> upstream power are unchanged. I wiggled the cable/connector around
> trying to make it fail for about 5 mins. No change. In my never
> humble opinion a loose connect isn't going to cause a problem.
>
> For fun, I monitored the modem status page, and unplugged the coax
> cable from my modem. Modem power was left on at all times. I kept
> hitting the browser refresh button waiting for the modem status page
> to change. That took about 100 seconds. After plugging the coax
> cable back into the modem, it took about 200 seconds for my modem and
> the Xfinity CMTS to shake hands and agree to reconnect. In other
> words, a carrier loss of less than 100 seconds might not be noticed. I
> should try this again while streaming or running a benchmark program,
> but I'm short on time today.
>
> In some cases, where the complaint was allegedly a "loose connector",
> it turned out to be a corroded center wire, or insufficient exposed
> center wire from the F connector. The connector may have been loose,
> but what caused the failure was the center wire being retracted from
> the F receptacle. The standard field test is to put your finger over
> the male F connector. If you feel the center wire, it's ok. If it
> drill a hole in your finger, or you can't feel the center wire, it's
> time for a new connector.
>
> You might want to revisit the connector you tightened and see if you
> have a center pin problem. My guess(tm) is that there's something
> else wrong besides a loose F connector.
>
> Some of my CATV tools:
> <http://802.11junk.com/jeffl/antennas/Misc/slides/CATV-tools.html>
> Favorite F compression connector (Belden SNS1P6U red):
> <https://www.ebay.com/sch/i.html?_nkw=SNS1P6U>
>
> I can also rant endlessly about crappy coax, crimpers, strippers,
> connectors, and tools, but I'm short on time today.
> --
> Jeff Liebermann je...@cruzio.com
> PO Box 272 http://www.LearnByDestroying.com
> Ben Lomond CA 95005-0272
> Skype: JeffLiebermann AE6KS 831-336-2558

Actually, I'd like to have your take on 1) good F-connector crimpers and 2) why you like your favorite F connector? I need to do some work with coax In my house, and I don't want to have problems with the connectors. TIA
J

On Sat, 14 Aug 2021 11:10:09 -0700, jlarkin@highlandsniptechnology.com
wrote:

>On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joegwinn@comcast.net>
>wrote:
>
>>Recently, I have been bedeviled by unstable Internet service from
>>COMCAST (Xfinity) in the Boston area. The following story is not
>>limited to COMCAST, and it could have been any Cable-TV Internet
>>Service Provider.
>>
>>Starting in late July 2021 and ending in early August 2021, for about
>>one month total, my Internet service became very unstable. (Cable TV
>>service was unaffected, so it was not that the physical cable path was
>>interrupted.) Internet service had been rock solid since about 2016,
>>when I purchased and installed the current cable modem, an ARRIS
>>SB6183. My service tier is 200 Mbit/sec download, which is well
>>within the capabilities of the SB6183, 686 Mbits/sec.
>>
>>The main external symptoms were that browser access would randomly
>>slow and hang, sometimes recovering, something not. Likewise email
>>(POP account). Rebooting the modem (by cycling power) often but not
>>always restored Internet service. As the month progressed, things got
>>progressively worse, although it was always relapsing-remitting - it
>>should spend all night trying to connect, failing, trying again, and
>>so on.
>>
>>Called COMCAST tech support, which forced me to deal with a robot lady
>>that could only follow a script, the main point of which was to get me
>>to power-cycle the modem. This power cycle often did work, probably
>>because she was probably also sending a modem reset signal at the same
>>time, but she never made that clear. (The robot lady here is in fact
>>a machine, not just an unimaginative human, a droid.)
>>
>>Got a human later, after calling back and answering that the problem
>>was not fixed. The human came to the conclusion that my cable modem
>>was too old and likely broken, and insisted that I call ARRIS and have
>>them diagnose the modem, and only if ARRIS declared that the modem was
>>not broken would COMCAST do anything like send a truck without
>>charging an arm and a leg.
>>
>>Called ARRIS. Cost US $50 (out of warrantee). Got a real human, in
>>Chennai, India, who did seem expert in the modem internals, with
>>perfect English and a very good telephone line, and was very patient.
>>
>>COMCAST had claimed that ARRIS could do technical (ie, electrical)
>>tests remotely, but this turned out not to be true. Anyway, I had
>>collected lots of status data from the modem, which we discussed, and
>>he concluded that the modem was not broken and did not need to be
>>replaced
>>
>>Now one mystery had always nagged me: While the Internet was up, the
>>modem would report received signal powers (over 16 parallel RX
>>channels) of +5 dBmV (decibels over one millivolt in a 75-ohm system),
>>and a SNR of about 40 dB, and yet errors (both corrected and
>>uncorrected) kept accumulating.
>>
>>When the link was down, the received signal level would drop by 20 dB
>>to -15 dBmV (which is in the DOCSIS 3.0 Spec Range) , and the SNR
>>would still be 35 dB (also in spec range).
>>
>>How does that work? With 35 to 40 dB SNR, there should be no errors.
>>Neither COMCAST nor ARRIS were able to interpret that oddity.
>>
>>Called COMCAST back. Went through the robot lady yet again, but on
>>the third call, got another real human.
>>
>>He really had no idea what went on inside modems et al, and insisted
>>that if the associated firewall/router was not also rebooted when the
>>modem was reset or rebooted, the ensuing chaos would cause the modem
>>to be unable to measure incoming RF power (at around 500 MHz)
>>correctly on a coax, the claim being that both Ethernet and Cable TV
>>were both "electrical", so they could heavily affect one another Hmm.
>>I'll have to think about that. For a very long time.
>>
>>He was also of the opinion that Ethernet wires wear out and need
>>periodic replacement. I declined to disassemble the house to get at
>>the CAT5e cable that runs from basement (at the modem) to the 2nd
>>floor (where the WiFi base station lives).
>>
>>He worried greatly about cables and connectors in general, saying that
>>they were very often the cause of such problems as I was seeing. After
>>one hour discussing the issue, while his theories of causation were
>>nonsense, this was his direct experience, and thus was my main
>>takeaway.
>>
>>Usually, connectors are the main cause of problems with "cables", and
>>it had to be a coax cable, so I found an 11mm (7/16") open-end
>>ignition wrench, and went around loosening and re-tightening all CATV
>>RF connectors (Type F, for the record). The loosen-then-tighten drill
>>is to physically disrupt any corrosion at contact points.
>>
>>All connections were tight save one, the one where the coax from the
>>modem connects to the RF feed coming from the nearby boiler room. The
>>loose connector is in the wall plate under the table upon which the
>>modem sits, along with my desktop computer, and that connector had
>>managed over the years since 2016 to unscrew itself almost to the
>>point of falling apart. That cable does move a bit when things are
>>added or removed, and so on. Tightened the connector. Bingo!
>>
>>And now the cause of the oddity became clear. The SNR is measured
>>over time, to yield a stable value. But the connection was chattering
>>between normal power (+5 dBmV) and open (-15 dBmV) fast enough that
>>the SNR calculation didn't notice. This was also too fast for AGC et
>>al to react, so symbols sent during the open period were lost. Some
>>could be recreated by forward error correction, and some could not,
>>and these errors accumulated steadily over time despite the stellar
>>SNR.
>>
>>The modulation type is QAM256, and the symbol rate on each QAM256
>>channel is 5120 Ksymbols per second. There are 16 downlink and 4
>>uplink channels. The AM component of the QAM symbols will have a
>>fundamental at 5 MHz or so, far above the spectrum due to a rattling
>>connector.
>>
>>.<https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation>
>>
>>A spectrum analyzer would not have found this problem either. I
>>suppose if one envelope demodulated the received RF, the chattering
>>would have been quite obvious - big AM noise peak in the 10 to 1000 Hz
>>range, or the like. I would think that it would be useful for the
>>modem to do this - loose connectors are pretty common I'd hazard.

One could also use an analog band-pass filter followed by an amplified
rectifier to envelope-detect the signal, and look for signal power
between 10 Hz and 1 KHz. The modulation will be essentially 100%, so
it should be easy.

>>Anyway, it all works now, the key symptom being that there are no new
>>errors accumulating now.
>>
>>And the takeaway is that if SNR exceeds 30 dB and yet errors
>>accumulate, start re-tightening RF connectors. If that doesn't work,
>>look for a cracked wire or connector, or a loose shield.
>>
>>Joe
>
>I'll go tighten them all now!

Also log into the cable modem and check its status. For the ARRIS
modems, enter <http://192.168.100.1>. This may be standard. Some
modems will require you to enter admin credentials.

>A lot of people complain about Comcast, but it's been excellent here.
>The install/service folks have been great. They keep upping my speed
>for free, probably to compete with Sonic (fiber) and MonkeyBrains
>(short-hop microwave links).

We have that here as well, likely due to competition from Verizon's
Fios (fiber optic) TV-plus-Internet-VOIP offering.

>We do have to reboot the modem now and then, once a month maybe, when
>it quits working.

I dad not had to do that until now. We'll see if I have to do it any
more now that the connectors are tight.

>Their cable TV boxes hang up occasionally too. The wall plug has to be
>pulled to do a real reboot, and then they reload their code for a
>while.

Same here.

>We have Suddenlink at the cabin, the only choice, and they're not so
>good.

Not here, although there are a number of also-rans, like RCN, around
here (Boston area). Things will thin out away from the Boston metro
area.

Joe Gwinn

On Sat, 14 Aug 2021 11:23:24 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:

>On 8/14/2021 8:55 AM, Joe Gwinn wrote:
>> All connections were tight save one, the one where the coax from the
>> modem connects to the RF feed coming from the nearby boiler room. The
>> loose connector is in the wall plate under the table upon which the
>> modem sits, along with my desktop computer, and that connector had
>> managed over the years since 2016 to unscrew itself almost to the
>> point of falling apart. That cable does move a bit when things are
>> added or removed, and so on. Tightened the connector. Bingo!
>
>We've seen that with video, here. It'w annoying as, often, the
>cables "loosen themselves" just as a side-effect of being
>physically moved (back and forth).
>
>POTS, OTOH, would frequently suffer from line imbalance or
>partial shorts to ground. Esp after heavy rains.
>
>Amusingly (annoyingly?) OTA TV now suffers similarly.

Who invented the F connector? Let's find out and punish him.

--

Father Brown's figure remained quite dark and still;
but in that instant he had lost his head. His head was
always most valuable when he had lost it.

On Sat, 14 Aug 2021 13:45:23 -0700 (PDT), Three Jeeps
<jjhudak4@gmail.com> wrote:

>On Saturday, August 14, 2021 at 4:10:32 PM UTC-4, jeff.li...@gmail.com wrote:
>> On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joeg...@comcast.net>
>> wrote:
>> >All connections were tight save one, the one where the coax from the
>> >modem connects to the RF feed coming from the nearby boiler room. The
>> >loose connector is in the wall plate under the table upon which the
>> >modem sits, along with my desktop computer, and that connector had
>> >managed over the years since 2016 to unscrew itself almost to the
>> >point of falling apart. That cable does move a bit when things are
>> >added or removed, and so on. Tightened the connector. Bingo!
>> "The consequences of coaxial connector problems"
>> <https://www.ppc-online.com/blog/the-consequences-of-coaxial-connector-problems>
>> Note that this is from Belden, who blames the F connector and would
>> never suggest that the coax cable might also be a problem.
>>
>> Try this experiment... Unscrew the F connector nut on your modem
>> about 3/4th of the way out. Nice and loose. Watch the numbers on the
>> modem status page. This works for most Comcast modems:
>> <http://192.168.100.1/RgConnect.asp>
>> I'm watching a random YouTube video at 720p. No loss of bandwidth, no
>> intermittents, no loss of carrier, no stops, and no hangs. SNR and
>> upstream power are unchanged. I wiggled the cable/connector around
>> trying to make it fail for about 5 mins. No change. In my never
>> humble opinion a loose connect isn't going to cause a problem.
>>
>> For fun, I monitored the modem status page, and unplugged the coax
>> cable from my modem. Modem power was left on at all times. I kept
>> hitting the browser refresh button waiting for the modem status page
>> to change. That took about 100 seconds. After plugging the coax
>> cable back into the modem, it took about 200 seconds for my modem and
>> the Xfinity CMTS to shake hands and agree to reconnect. In other
>> words, a carrier loss of less than 100 seconds might not be noticed. I
>> should try this again while streaming or running a benchmark program,
>> but I'm short on time today.
>>
>> In some cases, where the complaint was allegedly a "loose connector",
>> it turned out to be a corroded center wire, or insufficient exposed
>> center wire from the F connector. The connector may have been loose,
>> but what caused the failure was the center wire being retracted from
>> the F receptacle. The standard field test is to put your finger over
>> the male F connector. If you feel the center wire, it's ok. If it
>> drill a hole in your finger, or you can't feel the center wire, it's
>> time for a new connector.
>>
>> You might want to revisit the connector you tightened and see if you
>> have a center pin problem. My guess(tm) is that there's something
>> else wrong besides a loose F connector.
>>
>> Some of my CATV tools:
>> <http://802.11junk.com/jeffl/antennas/Misc/slides/CATV-tools.html>
>> Favorite F compression connector (Belden SNS1P6U red):
>> <https://www.ebay.com/sch/i.html?_nkw=SNS1P6U>
>>
>> I can also rant endlessly about crappy coax, crimpers, strippers,
>> connectors, and tools, but I'm short on time today.
>> --
>> Jeff Liebermann je...@cruzio.com
>> PO Box 272 http://www.LearnByDestroying.com
>> Ben Lomond CA 95005-0272
>> Skype: JeffLiebermann AE6KS 831-336-2558
>
>Actually, I'd like to have your take on 1) good F-connector crimpers and 2) why you like your favorite F connector? I need to do some work with coax In my house, and I don't want to have problems with the connectors. TIA

In my case, the longer-term root cause was that cable was not snubbed
to anything solid on the end going into the wall, and so the cable was
able to work the connector back and forth over the years.

The specific setup is that the wall plate has a F-connector female
(outside thread, female center-pin socket) mounted perpendicular to
the wall, so the cable would stick out a foot, so I added a well-made
metal 90-degree adapter, so the wire is parallel to the wall at the
wall plate. It's this adapter assembly that loosened. If the wire
was snubbed to the wall, probably no loosening.

Joe Gwinn

On 8/14/2021 2:00 PM, Joe Gwinn wrote:
> The specific setup is that the wall plate has a F-connector female
> (outside thread, female center-pin socket) mounted perpendicular to
> the wall, so the cable would stick out a foot, so I added a well-made
> metal 90-degree adapter, so the wire is parallel to the wall at the
> wall plate. It's this adapter assembly that loosened. If the wire
> was snubbed to the wall, probably no loosening.

You can buy wall plates (and keystones) with the connector slightly
recessed and downward facing at a 45 degree angle -- so it more
matches the droop of the mated cable.

On Sat, 14 Aug 2021 14:37:27 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:

>On 8/14/2021 2:00 PM, Joe Gwinn wrote:
>> The specific setup is that the wall plate has a F-connector female
>> (outside thread, female center-pin socket) mounted perpendicular to
>> the wall, so the cable would stick out a foot, so I added a well-made
>> metal 90-degree adapter, so the wire is parallel to the wall at the
>> wall plate. It's this adapter assembly that loosened. If the wire
>> was snubbed to the wall, probably no loosening.
>
>You can buy wall plates (and keystones) with the connector slightly
>recessed and downward facing at a 45 degree angle -- so it more
>matches the droop of the mated cable.

Yeah, but that's not what was there. I suppose I could change that.

Joe Gwinn

On Sat, 14 Aug 2021 13:10:21 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Sat, 14 Aug 2021 11:55:38 -0400, Joe Gwinn <joegwinn@comcast.net>
>wrote:
>
>>All connections were tight save one, the one where the coax from the
>>modem connects to the RF feed coming from the nearby boiler room. The
>>loose connector is in the wall plate under the table upon which the
>>modem sits, along with my desktop computer, and that connector had
>>managed over the years since 2016 to unscrew itself almost to the
>>point of falling apart. That cable does move a bit when things are
>>added or removed, and so on. Tightened the connector. Bingo!
>
>"The consequences of coaxial connector problems"
><https://www.ppc-online.com/blog/the-consequences-of-coaxial-connector-problems>
>Note that this is from Belden, who blames the F connector and would
>never suggest that the coax cable might also be a problem.
>
>Try this experiment... Unscrew the F connector nut on your modem
>about 3/4th of the way out. Nice and loose. Watch the numbers on the
>modem status page. This works for most Comcast modems:
><http://192.168.100.1/RgConnect.asp>
>I'm watching a random YouTube video at 720p. No loss of bandwidth, no
>intermittents, no loss of carrier, no stops, and no hangs. SNR and
>upstream power are unchanged. I wiggled the cable/connector around
>trying to make it fail for about 5 mins. No change. In my never
>humble opinion a loose connect isn't going to cause a problem.

The loose wall connector was far enough out that a short center pin
would allow the circuit to open.

>For fun, I monitored the modem status page, and unplugged the coax
>cable from my modem. Modem power was left on at all times. I kept
>hitting the browser refresh button waiting for the modem status page
>to change. That took about 100 seconds. After plugging the coax
>cable back into the modem, it took about 200 seconds for my modem and
>the Xfinity CMTS to shake hands and agree to reconnect. In other
>words, a carrier loss of less than 100 seconds might not be noticed. I
>should try this again while streaming or running a benchmark program,
>but I'm short on time today.
>
>In some cases, where the complaint was allegedly a "loose connector",
>it turned out to be a corroded center wire, or insufficient exposed
>center wire from the F connector. The connector may have been loose,
>but what caused the failure was the center wire being retracted from
>the F receptacle. The standard field test is to put your finger over
>the male F connector. If you feel the center wire, it's ok. If it
>drill a hole in your finger, or you can't feel the center wire, it's
>time for a new connector.
>
>You might want to revisit the connector you tightened and see if you
>have a center pin problem. My guess(tm) is that there's something
>else wrong besides a loose F connector.
>
>Some of my CATV tools:
><http://802.11junk.com/jeffl/antennas/Misc/slides/CATV-tools.html>

I have the one on the right.

I have more tools for attaching modular connectors for phones and
Ethernet.

>Favorite F compression connector (Belden SNS1P6U red):
><https://www.ebay.com/sch/i.html?_nkw=SNS1P6U>
>
>I can also rant endlessly about crappy coax, crimpers, strippers,
>connectors, and tools, but I'm short on time today.

These are expensive if any good.

I generally buy catv coax jumpers, versus making my own. I have
exactly one customer to support.

On 8/14/2021 3:22 PM, Joe Gwinn wrote:
>> You can buy wall plates (and keystones) with the connector slightly
>> recessed and downward facing at a 45 degree angle -- so it more
>> matches the droop of the mated cable.
>
> Yeah, but that's not what was there. I suppose I could change that.

I had a few drops located behind furniture that was pushed up against
the wall. Using a store-bought cable to mate with a "straight out"
F connector required a good 2+ inches of clearance in order to
accommodate the bend.

I tried the right-angle (metal) adapters but they loosen up too easily.
I suspect because it turns the cable into a nice *lever* with the
pivot at the center of the F connector that easily loosens the connection
with each "jostle".

I debate whether I should have just run an extra CAT5 drop (for video)
instead of the damn coax!

[I have coax drops in my equipment closet for things like modem,
CATV tuners, FM tuners, etc. where they will see less abuse/disturbance]

On 8/14/2021 3:37 PM, Joe Gwinn wrote:
>> You might want to revisit the connector you tightened and see if you
>> have a center pin problem. My guess(tm) is that there's something
>> else wrong besides a loose F connector.
>>
>> Some of my CATV tools:
>> <http://802.11junk.com/jeffl/antennas/Misc/slides/CATV-tools.html>
>
> I have the one on the right.

Ditto. Plus some special tools for cutting the outer
insulation (without damaging the braid) and the inner insulator
(without knicking the center conductor).

> I have more tools for attaching modular connectors for phones and
> Ethernet.

I've a nice one for stripping the jacket, cutting/trimming the
individual pairs to length and then crimping. My biggest
complaint is related to not using it enough to instinctively
*know* which side to insert the cable to trim to length,
which side to insert the connector body, etc.

>> Favorite F compression connector (Belden SNS1P6U red):
>> <https://www.ebay.com/sch/i.html?_nkw=SNS1P6U>
>>
>> I can also rant endlessly about crappy coax, crimpers, strippers,
>> connectors, and tools, but I'm short on time today.
>
> These are expensive if any good.
>
> I generally buy catv coax jumpers, versus making my own. I have
> exactly one customer to support.

I would like to be able to buy (custom) "solid" coax jumper/cable
assemblies instead of having to rely on luck to hold a cable
in a particular form.

E.g., out of wall plate, bend to parallel/hug wall, 90 degree
up turn, 90 degree right turn, mate to DTV tuner connector.

On 8/14/2021 4:00 PM, Don Y wrote:
> On 8/14/2021 3:22 PM, Joe Gwinn wrote:
>>> You can buy wall plates (and keystones) with the connector slightly
>>> recessed and downward facing at a 45 degree angle -- so it more
>>> matches the droop of the mated cable.
>>
>> Yeah, but that's not what was there. I suppose I could change that.
>
> I had a few drops located behind furniture that was pushed up against
> the wall. Using a store-bought cable to mate with a "straight out"
> F connector required a good 2+ inches of clearance in order to
> accommodate the bend.

<https://www.amazon.com/Leviton-41081-4WP-Angled-QuickPort-Wallplate/dp/B003ATOCDO>

On Sat, 14 Aug 2021 13:54:02 -0700, jlarkin@highlandsniptechnology.com
wrote:

>Who invented the F connector? Let's find out and punish him.

<https://en.wikipedia.org/wiki/F_connector>
The F connector was invented by Eric E. Winston
in the early 1950s while working for Jerrold Electronics
on their development of cable television.
<https://patents.google.com/patent/US3537065>

The F Connector has 10 major advantages over other connectors. It's
cheap, cheap, cheap, cheap, cheap, cheap, cheap, cheap, cheap, cheap,
and cheap. Did I mention that is also inexpensive?

Many years ago, I got involved in a mechanical design competition of
sorts. The task was to cost reduce the male F connector without
reducing performance (return loss over frequency range), mechanical
specifications (per SCTE standards), or introducing difficult to
obtain materials. I tried and failed badly. The winner contrived a
plated plastic threadless compression connector, which only broke one
key features. It was only good for about 10 insertion cycles before
it fell apart.

Personally, I wouldn't mind seeing the inventors of the BNC connector
(Paul Neill, Carl Concelman, & Octavio M. Salati) punished for
contriving an abomination instead of designing what should have been
more like an F connector. I cringe when I halucinate that home
theater electronics could have been interconnected with BNC connectors
were it not for the invention of the F connector.
<https://en.wikipedia.org/wiki/BNC_connector>

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

jlarkin@highlandsniptechnology.com writes:

>On Sat, 14 Aug 2021 11:23:24 -0700, Don Y

>Who invented the F connector? Let's find out and punish him.

A CATV beancounter looking for the cheapest possible item.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Sat, 14 Aug 2021 13:45:23 -0700 (PDT), Three Jeeps
<jjhudak4@gmail.com> wrote:

>> Some of my CATV tools:
>> <http://802.11junk.com/jeffl/antennas/Misc/slides/CATV-tools.html>
>> Favorite F compression connector (Belden SNS1P6U red):
>> <https://www.ebay.com/sch/i.html?_nkw=SNS1P6U>
>>
>> I can also rant endlessly about crappy coax, crimpers, strippers,
>> connectors, and tools, but I'm short on time today.

>Actually, I'd like to have your take on 1) good F-connector crimpers and 2) why you like your favorite F connector? I need to do some work with coax In my house, and I don't want to have problems with the connectors. TIA
>J

Sure. However, please realize that my selection of connectors, coax,
tools and methods are dictated by commercial installations and
repairs, and don't fit well for home users requirements. My tools
need to last for hundreds of crimps, cuts, strips, and pushes while
your requirements are a few crimps per year. I'll try to keep it
reasonable for a home user.

Tools:
- 7/16" open end wrench to tighten the male connector.
- 1/2" open end wrench for the matching nut (usually on wall plates).
I use the wrenches more for loosening connectors than installing them.
If you want to get fancy, there are specialized F connector wrenches.
<https://www.google.com/search?q=f+connector+wrench&tbm=isch>
If you don't have a good feel for how tight to install the connector,
get one of the torque wrench tools.

- Coax cable rotary hand stripper.
Something like one of these:
<https://www.google.com/search?q=rotary+rg6u+stripper&tbm=isch>
They all work well, as long as the blade is sharp. It can't be
re-sharpened so buy a spare blade.

You probably can't justify the expense of a cable prep tool:
<https://www.google.com/search?q=rg6u+cable+prep+tool&tbm=isch>

The official Snap-n-Steal tool is the IT1000:
<https://www.google.com/search?q=IT1000+tool&tbm=isch>
It's expensive (about $90) and goes through blades rather rapidly.
However, it combines a rotary stripper and a compression tool into one
tool, which is very handy. This is what I like to use. More on
compression tools later.
<https://www.youtube.com/watch?v=43n7vxTMxow>

- SNS1P6U (T&B or Belden ProSNS) connectors.

This is where the problems begin. I do more rework then new installs.
Therefore, I need a connector that will fit most types of RG6/u cables
that I encounter. Yes, there are many types of cables and cable
qualities. There are also many types of male F connectors with
varying lengths which will NOT fit every possible type of compression
tool. So, I pick a connector that covers most cable types, which
turns out to be the SNS1P6U.

Unfortunately, there's a bit of a muddle with this connector. T&B
(Thomas and Betts) invented the connector. Belden bought T&B in 2010,
and continued to sell the T&B connectors for a while. Belden then
conglomerated their F-Conn connectors with T&T Snap-n-Steal and
renamed it ProSNS and renumbering the connector as FSNS6U. I really
don't know if the new and improved connector is any better than the
previous version(s). I have about 200 older T&B connectors in stock,
which at my current usage level is a lifetime supply.

<http://www.tnb.com/pubint/docs/snapnseal.pdf>
<https://info.belden.com/hubfs/resources/technical/product-brochures-bulletins/snap-n-seal-prosns-compression-connectors-product-bulletin.pdf>

In terms of quality, both the old an new connectors are mostly brass,
UV proof plastic, EPR/EPM rubber (ethylene propylene) o-rings that
don't harden or crumble and nickel-tin (or tin) plated. I do have
some aluminum F-connectors, which last about 5 years outdoors and then
RIP (rust-in-place).

Also important is pull strength. 30 lbs minimum for indoor. 40 lbs
minimum for outdoor. Try pulling on a connector pair with a luggage
scale:
<https://www.ebay.com/itm/324022488009>
Many do-it-thyself cables will fall apart. I made my own crude
tester. I can usually go to 80 lbs before things start to fall apart.
See ANSI/SCTE 99 and 124 for applicable standards and fixtures:
<https://www.scte.org/standards-development/library/standards-catalog/>

- Matching compression tool (it's not really a crimper).

One of the reasons that I have so many DIFFERENT compression tools is
that many of the connectors I need to crimp are different diameters
and lengths. Some manufacturers design their connectors so that only
the compression tool they are selling works with their connectors. So
much for standards. I thought I had solved the problem with this
compression tool:
<https://www.ebay.com/itm/160683459028>
Sheesh...$51. It was $17 when I bought two perhaps 15+ years ago. The
big advantages are that the connector length is screw adjustable and
it comes with ends to fit F connector, RCA plug, and BNC. That was
fine for a few years, until some vendor released a connector that was
too long to fit in this tool. It's clumsy to use, doesn't support the
cable properly, and sometimes (when I'm not paying attention) produces
lop-sided connections. Not quite recommended, but since I have it, I
use it.

I previously mentioned that I use an IT1000 tool. It fits the SNS1P6U
connectors most of the shorter connectors. It doesn't work with
longer connectors. It's also expensive. It's the black thing on the
left:
<http://802.11junk.com/jeffl/antennas/Misc/slides/CATV-tools.html>
So, what else is available? Please, ignore the hex crimper on the
right. It's made for converting cylindrical connectors into hex
connectors. It can survive about 10 lbs of pull before everything
falls apart. Not recommended.

The little compression tool in the middle fits most connectors, but
has so little leverage that I get tired after a few crimps. No
recommended unless you do finger strength exercises.

The gray and blue compression tools are some of those I previously
mentioned that were designed to fit exactly one manufacturers
connectors. Avoid, unless the seller includes the connectors at a
good price.

Having eliminated everything I own, I can't offer a recommendation for
a compression tool. Looking at what's available on eBay:

<https://www.ebay.com/itm/172387459182>
Looks ok but is only for F connectors. It's difficult to tell, but it
looks like it might fit the longer connectors.

<https://www.ebay.com/itm/154198794969>
Better and does F, BNC, and phono. Again, not sure about long
connectors.

Drivel:

1. Junk (Radio Shack) RG-6/u. Maybe 30% outer shield coverage:
<http://www.learnbydestroying.com/jeffl/crud/RG6-junk-coax.jpg>

2. Don't use RG59/u. It's all made for low frequency use as in
security video cameras. It doesn't work at UHF frequencies.

3. You might consider buying a proper cable cutter:
<https://www.harborfreight.com/10-inch-cable-cutter-40507.html>

4. Lots of videos on how to attach compression connectors on YouTube:
<https://www.youtube.com/results?search_query=compression+coaxial+connector>

Good luck.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

In article <oanghgpv7onur2nnhbfooj2t8u0nprtn54@4ax.com>,
jeffl@cruzio.com says...
>
> >Actually, I'd like to have your take on 1) good F-connector crimpers and 2) why you like your favorite F connector? I need to do some work with coax In my house, and I don't want to have problems with the connectors. TIA
> >J
>
> Sure. However, please realize that my selection of connectors, coax,
> tools and methods are dictated by commercial installations and
> repairs, and don't fit well for home users requirements. My tools
> need to last for hundreds of crimps, cuts, strips, and pushes while
> your requirements are a few crimps per year. I'll try to keep it
> reasonable for a home user.
>
>
>

For someone that just wants to do a few connectons around the house you
can get a coax stripper, compression tool, and 20 connectors for about
$ 15.70 all in one place.

I bought one a while back. Have only used about 5 connectors and it was
ok. Would not get if I wanted to do more than the 20 connectors that
come with it.

https://www.ebay.com/itm/333829121341?_trkparms=aid%3D1110006%26algo%
3DHOMESPLICE.SIM%26ao%3D1%26asc%3D233198%26meid%
3D681f5df1ed504a4e880b78e705dad004%26pid%3D101195%26rk%3D4%26rkt%3D12%
26sd%3D160683459028%26itm%3D333829121341%26pmt%3D1%26noa%3D0%26pg%
3D2047675%26algv%
3DSimplAMLv9PairwiseWithPLXWebKnnNlpRecall&_trksid=p2047675.c101195.m185
1&amdata=cksum%3A333829121341681f5df1ed504a4e880b78e705dad004%7Cenc%
3AAQAGAAABAGOPdX1sQDPwtbbm3w2kp3G59teBI7E4PfgADf%
252BH1Twd5yZ8vz6qLdoLoTO3WhBS%252FcZbLfaFCsG5H4VrcGgSqlRSh8%252Bt%
252Fw0JY3Fb7OyowCSBjj5OPJEGdwMYYlAj7JD4X2AAbHwFsNxT8TyFOUqnbbgw1mhhiE9aK
UYRX%252F0hxViYeh4Ie7WqeILo1XAlujBXV31fvcIlPIohqf3y4C95p3PYhM%
252BHyRQLqB%
252FBtRk9Z4EyCxwUIVPQsar57khEAhiZPk4V2pQYelIYU9YHPRbZ15qVrT8oNzylxoiTFFC
w2q%252B0m2G57fz6R76J5%252BT71ucQXBwXTd7L3iHUbMEGxK%252BchrQ%253D%
7Campid%3APL_CLK%7Cclp%3A2047675&epid=4009501522

On 8/14/2021 8:33 PM, Ralph Mowery wrote:
> For someone that just wants to do a few connectons around the house you
> can get a coax stripper, compression tool, and 20 connectors for about
> $ 15.70 all in one place.
>
> I bought one a while back. Have only used about 5 connectors and it was
> ok. Would not get if I wanted to do more than the 20 connectors that
> come with it.

If you're reasonably competent AND they are YOUR cables that you
will be "living with", you can also take care not to be abusive of
them -- as you know what's involved if they fail!

It's a different story if you are doing the work for someone else
and unsure how htey will abuse the cables/connections.

On a sunny day (Sat, 14 Aug 2021 13:17:53 -0700) it happened Jeff Liebermann
<jeffl@cruzio.com> wrote in <4t8ghgph5ci4qhp7dfkqfcgc5u348mb4fi@4ax.com>:

>On Sat, 14 Aug 2021 19:02:28 GMT, Jan Panteltje
><pNaOnStPeAlMtje@yahoo.com> wrote:
>
>>So I canceled the cable and are now using KPN 4G, modem is a simple USB stick you can put in the PC
>>or laptop (sits in an old raspberry here that now works as router).
>>Uses a fraction of the power the cable modem did, I pay less and have over 900 TV channels
>>via my movable satellite dish.
>
>FTA (Free to Air)?

Yes counting FTA TV stations only, small 25 Euro or so DVBS-2 box from ebay / China finds them scanning,
had to remove some sats as its memory was full.
I you want a sat, transponder frequency and PIDs: just search for program name or satellite name.
or click on the satellite icons on the top to see what is there:
https://en.kingofsat.net/

I have a sat card in a PC too, and also software (not mine) to decode DVB-S2 (as for QO100 ham TV at low bitrate).
SSB via QO100 I did too.
Is amazing, in contrast to all the noise and fading on shortwave a totally clear signal from .. S Africa, Russia, Midlle East .. Japan, where not...
Not US, but maybe one day they will have some transponder on some sat too.
You can listen here via Goonhilly ground station in the UK online to what is going on:
https://eshail.batc.org.uk/nb/

The wide band transponder spedtrum, TV:
https://eshail.batc.org.uk/wb/

><https://www.youtube.com/watch?v=kOpadmYJoeY>

Yes!!!

><http://www.americandigitalsatellite.com/all_free_to_air_satellite_channels.html>

Maybe from Europe there is more to see.

My dish positioner program seems to be used in many places:
http://panteltje.com/pub/xdipo_in_action.gif
source code:
http://panteltje.com/panteltje/satellite/

I even have voice control on the old PC: 'show BBC' calls the 'show' script that calls xdipo.

All Linux code of course...