RG6 Quad clips

Hi Guys,

My cable modem has been a bit flaky lately. My TV pictures have been acceptable but the modem drops in and out. The modem signal is usually around -8 or -9db, the signal to noise ratio is usually around

31, and the upstream power is in the high 40s.

I don't have the cable company "wire guard" on my cable service - just can't see spending $75 or so a year for simple wiring that should be good for many years! The cable company says the signal is good to the house and the problem is in the internal wiring.

The cable comes into the northeast corner of my house, runs up into the attic to cross the living space and comes down the wall that separates the house and the garage. There's a splitter that sends signal to the living room tv that's on the other side of the wall from the garage and down to the family room tv downstairs. The line in the basement has another splitter in it that feeds my cable modem.

The cable in the garage and that feeds the TVs and cable modem is RG-6 quad shield - they replaced it when they installed my digital cable and modem a couple years ago.

The cable that runs from the cable company drop across the attic to the garage is RG59 though -> they just spliced into it when it came into the garage.

The RG59 must be fastened down as I can't pull it and get it to move much (there's a mountain of blown in insuation in the attic and I haven't swam through it to investigate further (and I'm sure that's why the cable company just splied into the existing wiring -> they didn't want to swim through the insulation either!)).

We've lived in the house for 10 years and the cable was there when we moved in, so I'm sure it's pretty old stuff and is ready for replacement.

My plan is to install a new RG quad shield line to the garage, use a Channel Vision HF-2 splitter and split the cable into one lead that goes direct to the cable modem and one to feed the TVs (rather than having my cable modem behind two splitters as it is now).

I don't want to deal with the attic full of blown insulation so my thoughts are to just run it outside along the underside of the soffit till it gets above the rear garage entry door and then to poke it up through the soffit and into the attic above the garage (the attic area of the garage doesn't have the blown in insualtion).

I'd really like the install to look good and perform well and I seem to be having some problems finding good RG6 quad shield clips to support the cable on it's 50' horizontal run across the back of the house. Most are nail in and I dont' like that idea - first I don't want to miss and hammer my cable! And second since it'll be hanging upside down I'd think screws would work better than the more common nails. It seems that most clips are plastic too and I wonder about their durability.

Since I can't find what I want I'm wondering if I can make something? I'm thinking of maybe cutting up a 1by board, using an letter N drill bit (.302"/7.67mm) to drill a hole through it and close to the edge. Then I could screw the board to the soffit and thread the coax through the hole. The hole is just slightly larger than the nominal size of the cable and would be wider than most clips so it should give support wiithout digging into the coax. I could even countersink the ends of the holes so they don't have charp 90 degree edges to dig in.

Does that sound like a good plan? Or is there a good quality clip out there I haven't found? My cable hasn't arrived yet - how stiff is the cable and how much distance should I put between the clips to give good support?

Thanks for any inputs!

-Bob-

Reply to
Svensontini
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Something like this would do the trick: .

Perhaps Just go to Home Depot or somewhere like that and look for cable clips like the phone company used to use.

Svens>

Reply to
Ed Nielsen

Hi Ed,

Thanks for the reply!

I don't think I want to use cable ties - from what I've read they aren't really a good idea for quad shield. Quad shield seems to need a gentle touch - support without binding/pinching, no sharp bends, etc. and I'd think it would be pretty easy to over tighten a cable tie.

The padded clamps look interesting, but I'd like to have a look at them first hand before ordering a bunch - I want something that's a pretty close fit as I don't want the cable drooping or anything.

Doing some poking around I noticed that 1/4" sch 40 pvc is just slightly larger than RG6QS. It'd be nice to just hang a piece of conduit and run the cable through that

-> lots of support without the worry of pinching the cable. Unfortunately I couldn't find any in town. 8-<

I'm thinking I may have to give the improvised wooden ones a shot, but I thought I'd ask first as I'm sure I'm not the only one who has ran this stuff underneath a soffit before so i figured someone would have a good solution.

Actually I'm probably being too anal about it - the ones with nails would probably work just fine since the line will be under and against the soffit so ice and stuff shouldn't really weight it down, wind shouldn't catch it, etc. so the nails probably wouldn't work loose . . . guess I'm more worried about my lack of coordination when running a hammer -> I can just see me squashing my spiffy new cable flat with a misguided hammer blow!

Thanks again!

-Bob-

Reply to
Svensontini

You're afraid of the white plastic ones that have a nail on the side? I mean you can flex these fairly easy with finger tips.

David

Reply to
DLR

I dunno if I'm really "afraid" of them, but since they are hanging upside down I'd rather have screws since they hold better.

I also suck at wood butchering (and I don't like heights and I'll be standing on a ladder to do this) so I can just see myself missing on the very last clip and smashing my nice new cable!

If I could find a nice meaty plastic clip with a screw I'd be happy . . . have you seen any?

Reply to
Svensontini

I'd walk over a few aisles and buy some screw that would fit in the nail hole and have slotted hex head so my powered drill on a low torque could run them up. Magnetic socket driver and all that. :)

David

Reply to
DLR

Just go to Home Depot or somewhere like that and look for something like this: .

Perhaps cable clips like the phone company used to use.

CIAO!

Ed N.

Svens>

Reply to
Ed Nielsen

Sorry for the double post.

Ed Nielsen wrote:

.
Reply to
Ed Nielsen

Hi Ed,

That link isn't showing a specific product, it's showing some cable ties which I don't want to use and some cable clamps but like I said I'd like to physically see them before ordering some. I'd like the fit to be as tight as I can get it without pinching the cable so that the cable doesn't droop.

I have no idea what they used to use.

-Bob-

Reply to
Svensontini

Hi David,

I thought of that but the nail in the clips I've seen is pretty small in diameter and the wall of the hole it goes through looks pretty thin so I think we'be be dealing with really tiny screws . . . looks like the nails are around .085" so that'd be around what, a #4 screw?

-Bob-

Reply to
Svensontini

Hi Bob,

Actually, what I had in mind but didn't have time to find yesterday was cable clamps . I've used them many times for securing cables to walls.

Just make sure you use a size that will hold the cable firmly in place without pinching the cable. I would place 1 at every beam to give it as much support as possible and to avoid too much sag. Realize that it is going to sag just a little bit. That sagging will go away as it gets cold outside. If you pull it too tight now to try to make it as straight as possible, the center conductor may snap if the temperature drops enough in the winter.

PVC was a good idea if you can get your hands on some.

CIAO!

Ed N.

Svens>> Just go to Home Depot or somewhere like that and look for something like >> this:

Reply to
Ed Nielsen

Hi Guys,

I seriously considered making little wooden holders but I'm just cramped for time right now.

I think I found some nice clips though - mjsales has some that are made of aluminum instead of plastic. They have nails but I'll see if there's enough to drill out for a decent sized screw, if not I'll just use tiny screws and buy a lot of them as I'm sure my big ole fumble fingers will drop several!

They also had some "Stuf Dielectric water proofing filler for coaxial connectors" that looks kind of interesting - apparently you fill the connector with it before you assemble the connection and the "Stuf" keeps out the water without impedeing the signal.

Here's the particulars on what I ordered:

formatting link
Item SKU - 53-MB7.63 Item Name - M&B Aluminum Cable Fastener for Single Quad Shield RG6 Coax Quantity Ordered - 50 Price each - $0.19 Item Total - $9.50

Item SKU - STUF Item Name - Stuf Dielectric water proofing filler for coaxial connectors. Quantity Ordered - 1 Price each - $6.79 Item Total - $6.79

Thanks for everything - wish me luck! (now if I can just figure out how to use that spiffy new coax stripper and Phillips tool for putting on Snap-n-Seal ends!)

-Bob-

Reply to
Svensontini

I have none nearby just now but I think the clip is big enough that you could move up a size on the screw and just let it cut threads in the clip. I'm talking off the top of my head so this is all speculation. :)

David

Reply to
DLR

Hi Guys,

Just an update - I finally got time to work on the re-wire today.

These clips SUCK! They painted the aluminum clip with the nail in it so the nail is covered in paint too, which keeps it from driving in easily. Nails suck as if you aren't directly over a stud then the surface bounces as you hit the nail with the hammer, and the way these are constructed you can't easily replace the nail with a screw.

I got the job done, but next time I will take the time to just make my own clips - either out of wood or maybe some type of plastic.

I did get the job done and my cable modem is reporting right at 0 db now and my signal to noise ratio has risen and my upstream output power has decreased, so I think I did myself some good!

The Channel Vision 38db amp was a bit much though! I had to turn the gain all the way down to get things working! (I'm using a single coax feed with taps instead of splitters to feed the TVs since I don't have access to run a ton of wires around the house)

Also, I ordered the Philips S-n-S tool off of an eBay vendor. I dunno if it's the tool or a problem with the T&B connectors but I am having problems with the rubber o-ring getting pinched as the connector comes down to seat. When it happens I just replace the end so all my ends are picture perfect, but it happened enough to annoy me! I dunno if the ends aren't lining up right or what. I thought about putting a spritz of silicone on the o-ring before crimping but didn't know if it would affect the holding power of the end.

TTYL,

-Bob-

Reply to
Svensontini

Glad you ultimately got everything working. Turning the gain on that amp all the way down has it at a gain of 20dB. It would be best if you installed a 12dB pad on the output of the amp and then turned it up a bit. That would increase the SNR coming out of the amp.

CIAO!

Ed N.

Svens>

Reply to
Ed Nielsen

Hi Ed,

Thanks for the input.

I'm just getting back to where I have a little time to play with the system . . . from what I read in the user manual I'm wondering if I don't want to put the attenuator on the input? It seems wrong, one would think you would want the full signal available to amplify but turning the "gain" down brings the picture right in. The term "gain" seems kinda misleading since according to the manual you're actually adjusting an attenuator on the input. We don't really get a herringbone pattern when it's turned all the way up, we just get static and what appears to be a low signal and turning it down clears the picture right up. The picture clears just before we get to the lowest setting and I've got it at the lowest right now just because that's where I left it when I ran out of time.

The manual says: Gain control ... The gain control is a variable attenuator that will reduce the level of the signal before the gain stage of the CVT-38BID. The number one problem with video distribution systems is inter- modulation (IM) distortion caused by over driven amplifiers. The symptom of IM is a herringbone pattern on one or more channels.

1) Connect the CVT-38BID to the incoming cable signal and view a TV connected to the output test jack. 2) Set the gain to MAX. 3) Examine all channels for herringbone patterns. 4) While viewing a herringbone pattern on one channel, decrease the gain until the pattern goes away. (If the pattern does not change, the CVT-38BID is not the cause of this problem.) 5) Examine all channels to be sure this gain setting is appropriate. The ideal gain setting is one that eliminates IM distortion, but is not so low as to introduce noise into the system.

Since the cable TV cable install was sooo much fun I decided to run some phone lines yesterday too . . . I'm a glutten for punishment! I shouldda just bought the four handset cordless . . . Oh, OK, it wasn't THAT bad! I'm definately getting older though and I just have a hard time getting motivated to crawl in the actic!

Thanks for your guidance Ed!

-Bob-

Reply to
Svensontini

Yeah, it is sort of misleading in a way. The amplifier itself always runs at 38dB gain. As you wrote, when you adjust the "Gain" control, you actually adjust the signal level going into the amplifier.

Amplifiers always generate a certain amount of noise, regardless of the amount of signal at the input. That's just the way active electronics work. As you lower the amount of signal going into the amplifier, the Signal to Noise Ratio goes down. The higher the SNR, the better. Like an audio amplifier in a church or a public address system. If you have the microphone input turned all the way down and turn the master volume all the way up, you hear a whooshing sound coming out of the speakers. That's noise generated by the amplifier. As you turn the mic input up and you start hearing the speaker, the whooshing seems to go down. Actually, it doesn't go down -- it just becomes less noticeable because the signal from the mic is being introduced to the amplifier and you are starting to hear the speaker. As you turn the mic up even more, you no longer hear the noise. It is still there, though. You're just giving the amplifier a signal that is strong enough to drown out the noise. As you turn up the mic input, you are increasing the Signal to Noise Ratio.

Those distribution amps are intended for places such as hotels/motels, arenas, office buildings, schools, hospitals, etc. Assuming you have a signal level of +12dBmV at the input of the amp, at full gain it is pumping out +50dBmV. The first tap in your distribution system would need to be a 30dB tap, and the level at that outlet would still be too high. So you turned the gain all the way down, which has it pumping out

32dBmV. Actually, what happened was that you turned the input down from +12dBmV to -6dBmV. If I had to utilize that amp, I would either install a 20dB pad (attenuator) on the output and turn the gain back up, or connect my distribution system to the output test point (install a terminator on the output port) and turn the gain back up.

A standard $30, 15dB gain drop amp most likely would have sufficed.

CIAO!

Ed N.

Svens> Hi Ed,

Reply to
Ed Nielsen

Hi Ed,

I see, it's better to drop it after the amplifier output than it is to drop the input as dropping the input increases the signal to noise ratio . . . makes perfect sense once one thinks about it!

The problem was that I didn't know what signal level I had to start with as I couldn't find a cheap/easy way to check it - it seems ya really do need some expensive gear to measure it.

I was going by "seat of the pants" - my cable modem was showing -8 to

-10dbmv all the time and if I hooked to the cable direct to a tv and then hooked just one splitter up it made a difference so I figured I was at 0db or less coming in (anyting over 0 you really aren't supposed to notice are ya?). One splitter wasn't bad, but any more and the picture got worse in leaps and bounds. I had a 15 db amp downstairs and it helped, but not a great deal. Since the cable modem was showing -8 to -10 and it was behind two splitters (I didn't do it

- the cable company did!) I think I was figuring 0 to -3 for an initial signal level.

My other problem is that I don't have ready access to pull in new wires. A home run system was just out of the question, so I decided to run a single line and use taps instead of splitters (well, sorta - I tap off and then put a splitter on the tap so I can feed a cable box and dvr or vcr.

OK, the system looks like this (wish I could upload a drawing!)

*) the cable comes in, I was expecting 0db or so I think. *) it runs through a splitter - channel vision hs-2, one leg goes to the cable modem and the other feeds the house TVs. *) it runs into the amp. *) from the amp it runs through a splitter, another hs-2. One side continues on to feed the TVs, the other side will be an injection point for a modulator that has yet to arrive (fleabay purchase - we'd like to be able to send the cable box to our master bedroom (we have a wireless unit now that's crapping out)). Currently the unused side has a 75ohm terminator on it. *) the TV feed now runs to a Blonder & Tongue 20db tap, the tap feeds a hs-2 splitter so I can feed a cable box and digital video recorder in the living room. I was figuring there would be about 11db available on each leg of that splitter. *) the TV feed continues on to a 9db tap with a 8db attenuator on the tap output for a total drop of 17db, then another hs-2 splitter to feed a cable box and dvr in the family room. I was figuring about 11.8db on each leg of the splitter. *) from there it continues on to a 12db tap with a 3 db attenuator for a total drop of 15db and then a splitter for my son's bedroom cable box and vcr. I was figuring this would be around 11.8 db also. *) from there it continues on to a 12db tap and splitter to feed the master bedroom, this I figured would be around 11db to each leg of the splitter. *) from there it continues on to a 9db tap and splitter to feed a spare bedroom. I was figuring 11.1 db available there. *) from there it goes to a 6db tap, the tap feeds a splitter and the output of the tap is terminated with a 75 ohm terminator. I was figuring 11.1 db available at this splitter's output.

The coax is qualcomm quadshield, the terminals are T&B snap-n-seals, all unused splitter outputs are terminated with 75ohm terminators.

I don't recall my exact guesstimate at the input db, or my exact reasoning but I figured it, the cable loss per foot, the loss through the taps, the loss through the splitters, etc.. All the outputs of the splitters should be within .8db of each other (11,11.8, 11.8, 11,

11.1, 11.1). Taps aren't available in a lot of db drops and from what I gathered one should try for around +10db, with +15 or so being a maximum (though most new stuff can go higher?) so I opted to go a little over 10 rather than under it (and that's why some have taps with attenuators - I did that to get a value that wasn't available in a tap).

It appears my ancient RG-59 in the actic was cutting more signal that I thought though! My cable modem is running right at 0db now, so it's gained 8 to 10 db. That seems to have thrown my guesstimate way off!

I'm thinking I may try the 15db amp I had in the basement and see how it works, though I may also just try as you suggested and hook to the test port or use some attenuators on the output. The 15db amp didn't do a lot when it was in the basement, but that's probably because the signal was already crap when it got there and garbage into an amplifier just means bigger garbage out.

BTW, I won the 38db amp on eBay . . . I paid $9.99 and $14 shipping, so I've only got $23 in it so if I bought something I don't need I'm not overly upset!

So far I'm pretty pleased - once I turned the amp down all the TVs cleared up and they all look good, none of this stuff where the closest one looks the best and the one at the end of the series looks the worst -> using the single line and taps they all look about the same! If I can increase the signal to noise ratio by following your suggestions I think I'll be even happier! (btw, taps are kinda hard to find . . .MCM electronics had the best price/selection of taps I found).

Lemme know if I'm way of base or on the right track here Ed - I really appreciate your help!

Take Care,

-Bob-

Reply to
Svensontini

It is, unless you saturate the amplifier. That is why yours has the attenuator on the input.

Measuring the total (over all frequencies) isn't so hard, but the power in a given band (channel) is more difficult.

When I first got a cable modem, it didn't work reliably. When I called up, the installer knew the problem without looking: too much signal. It had +16dBmV, which was too much for that modem. (Most will take it, but not all.)

The tap idea works well for large buildings (apartments, hotels). One central amplifier, and passive taps. The taps have enough attenuation that the system isn't bothered much by mismatch on the branch, such as unterminated cables.

(snip)

It should be a series resistor large enough for the specified attenuation, and 75 ohms across the cable. The voltage on the tap for 20dB should be 1/10 that on the input, 75ohm cable across 75 ohms, so 9*75/2 or 337 ohms for the series resistor.

Two resistors and an F connector with faceplate.

-- glen

Reply to
glen herrmannsfeldt

Hi, Bob;

With the setup as described below, what is the input to your cable modem as found at ? How far from that first splitter to the cable modem and on what cable -- RG 6 or RG 59? Also, what are the approximate cable lengths in the rest of your system as described below?

Dropping the input decreases the SNR. The higher the SNR, the better.

CIAO!

Ed N.

Svens> Hi Ed,

Reply to
Ed Nielsen

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