I am just a SEU (stupid end user).  Comcast Performance level 75 MPS and
Cable TV at the house and  Comcast Bidness (FAS - Fast As S..) here at work.


 

At both locations things couldn't be better.  Internet tech support has been
excellent.   When I had trouble at the house the tech that came out was WELL
qualified and the perfect age, about 37.    He walked me through his
procedures, tests and results, once he realized that I knew what he was
talking about.   He was at least equivalent to our (very) nerdy IT cats here
at work.

 

When the TV tech came out to the house, same thing..she was very
knowledgeable, knew what she was doing, explained what they were testing,
etc. and answered my SEU questions. 

 

Not disputing y'alls side of the story, but just balancing your derogatory
tech comments and telling you how it is from the other side of the Comcast
bitcoin. 

 

FYI - phone lines are absolute crap in my neighborhood, at least on my
block.  So my "choice" is Comcast.

 

Sincerely hope your issues all work out, however you wish to solve them.
Nothing like not being able to send snippets of technical info to the BVARC
reflector   HI   

 

73.RH

 

From: BVARC [mailto:[email protected]] On Behalf Of Bruce via BVARC
Sent: Thursday, March 31, 2016 9:27 AM
To: BRAZOS VALLEY AMATEUR RADIO CLUB <[email protected]>
Cc: Bruce <[email protected]>
Subject: Re: [BVARC] RF Power - How to Not spend 3 hours with Comcast level
1 support

 

this was the main reason i got away from comcast. the guy that comes out to
fix a problem is lower than level 1 support. he is somewhere between a
supermarket sacker and and parking lot shopping cart retriever. they hook up
their little box to your connection in the house, look at the signal. then
do the same test outside your house and then do the same thing at the
pedestal in your backyard somewhere. with those 3 values he comes up with
'the problem is the wiring in your house' or 'you have a bad modem'. at this
point he would swap out the modem and then do one test in your house and say
its working fine and leave. of course this has not solved anything. or....
he comes up with the next thing... the problem is on the pole and i have to
call for a lineman to come out. mind you... you have already waited 3-4 days
for this first service call. it will be 3-4 more days for the lineman to
come out. the lineman goes to the amplifier up on the pole and says its
overheating and tweaks it a bit. then things seem to work fine for awhile
until the weather changes and then you go down again. 

i went with at&t first with adsl and then with uVerse when it came to my
area. did it for one reason and one reason only. when you call for tech
support and they have to come out, they come out the next day (except
sunday). they fix it right then. if your a pair from the pedestal is bad, he
hooks you up to another pair in the pedestal. always a fix that can be done
and it is done. i am quite happy with 12meg downstream, i would be even
happier if it were cheaper for 6meg downstream. 125meg down, take a look at
what you are using and i bet you have a ton of bandwidth unused. i think
when i looked at walmart's vudu video streaming, they require 3meg down for
standard def, 6meg down for high def and 10meg down for super high def. so
my 12meg is just fine for most things. i think most people think the faster
their speed the better. however, they charge you more and more for the
faster speed and try to convince you that it is absolutely necessary to be
able to watch tv and surf the internet at the same time.  

back in the day i had a bonded isdn line to my house. this was when that was
as almost not heard of. problem back then was that isdn did not give a line
level signal on the line when tested and other repair techs would swap out
someone's bad line for your nice clean line. when they installed them back
then they had to red tag the line all the way back to the central office so
that no one touched it. was a great plan. now-a-days they are a bit more
careful as almost everyone has adsl or uVerse on the phone lines and they
have a few people out there with a real pots line. 

73...bruce 

On 3/31/2016 8:40 AM, Bill Crowell via BVARC wrote:

Hi All,

 

I'm writing this note in the hope that it will help other hams not have to
waste hours with the level 1 support people over this issue.

 

Yesterday, my connection was dropping more than usual. I was losing data.
And, for those who don't know me, I'm very competent in the ways of
networking.

 

We all go to some site like speedtest.net to see what our speed is. I have
the Xfinity BLAST service that gives me up to 125Mbps downstream. That
doesn't tell the whole story. The upstream speed and reliability are just as
important. This is because the protocols used for most traffic are TCP and
the link layer is wanting an ACK packet (among others.) If the ACK packet is
not received, the link retries. And, when things get bad, the entire channel
is spending all of its time thrashing.

 

To test link integrity, I started running a ping to my server in Dallas. You
can do this on Mac or Linux rather easily. Windows ping gives you only 4
pings by default. I'm sure that someone who is a Windows person will give
the appropriate syntax for a continuous ping. You can ping a DNS server at
4.2.2.1.

 

So, start a ping to a target computer somewhere. THEN do the speed test. If
you see "request timed out", you're having an upstream issue.

 

Now to my equipment. I'm running a Motorola 6141 cable modem. This has been
the very best modem for a long time. I don't pay Comcast for their piece of
junk. The modem connects to a Juniper SSG5 firewall and then to my network.
This is a DOCSIS 3.0 modem. What this means is that it gets configuration
settings from Comcast. These settings include which channels to bond for the
downstream and upstream connections. What I had not realized is that the
network sets the TRANSMIT power levels of the modem.

 

During the protocol negotiation and then periodically, the ISP's gear will
tell the modem to increase or decrease power. If the receive signal strength
is too low, Comcast will tell my modem to "QRO old man".

 

You can see the RF side on the Signal page of the modem. This is the
Motorola:

 



 

 

I've got one, measly channel and the modem is just below it's absolute
maximum power of 57dBmV!!!! Yesterday, it was at 57 dBmV all day. This is
when packets are definitely lost.

 

The downstream channels are all fine at 0 dBmV - parity.

 

Now, how to correct this. Ideally, Comcast would deal with the RF link
between the modem and their gear. They're sending someone next week. They'll
likely say that the splitter should be removed, but then I have to choose
between TV and Internet. You know the drill.

 

For those of you not paying attention, the whole system is digital and this
issue manifests itself with the digital TV as well.

 

What is needed is to even out the TX/RX levels. I'm not expecting the
$15/hour tech to understand this. So, I'm getting an amplifier designed for
this purpose. The key here is "active return". That's the part where the amp
boosts the upstream signal from the cable modem.

 

The splitter is being replaced with this:

 

https://www.amazon.com/gp/product/B003T2SLIO/ref=oh_aui_detailpage_o00_s00?i
e=UTF8
<https://www.amazon.com/gp/product/B003T2SLIO/ref=oh_aui_detailpage_o00_s00?
ie=UTF8&psc=1> &psc=1

 

 

I'm expecting the TX power to be a more reasonable 30-40 dBmV and the
problems to disappear.

 

73!

 

Bill

 

 

 

Bill Crowell, N4HPG

Pearland, TX

Text messaging one-handed since 1982






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