Coax

[slomeaux]

Is there a method or madness to troubleshot coax. I believe I have problems with coax. My large Tv won't work, hooked small TV to coax and it wouldn't work either.
I am on antenna and campers near me are having great reception.

[SteveC7010]

Originally Posted by slomeaux

Is there a method or madness to troubleshot coax. I believe I have problems with coax. My large Tv won't work, hooked small TV to coax and it wouldn't work either.
I am on antenna and campers near me are having great reception.

Is the amplifier turned on? It is the little switch on the tv antenna panel, probably in the bedroom. That drives all outlets in the trailer that are connected to the antenna. If it is not on, there will be no reception anywhere in the rig.

Looks like this:

[slomeaux]

Thanks for the reply. The amp is turned on. Ihave since hooked my TV to my buddies antenna and it work fine.

[hankaye]

slomeaux, Howdy;

Had a similur problem, mine was picture blinking on an off... Get a 7/16ths wrench, and go find ALL the connections and ensure that they are finger tight then go 1 flat (1/6 of a turn), tighter with the wrench.
I have a long (20'), length of coax that I've had for years. With a multi-meter I can connect it to one connection and check the continuity of the rest.

All of mine were like the installer at the factory only gave them a twist an that was that.
You may have to pull the antenna from the roof to check the connection on the bottom of it.

Good luck, hope this helps.

hankaye

[hankpage]

Could be a lot of things ... knowing what model trailer you have would help some ....... are you wired for sat/cable/antenna?? How many RF connectors do you have on the wall plates? are there any jumper cables (or were there any) on one of the wall plates. Is the tv set for cable or antenna and has it been scanned to receive antenna channels. Is the antenna up and facing the same direction as your neighbors'. This is just some of the info needed to trouble shoot antenna reception in your trailer.

[geo]

There are some other issues with coax that might challenge your ability to get to the connections.

Hankaye has an excellent point, with the vibrations of a RV, a 1/6 securing turn is called for, but NO MORE THAN THAT! (Not a five ringer twist!) Normally, one would only tighten finger tight.

Turn OFF the amplifier before continuing!!!!!!!!!!!!!!

First, go past HD, Lowe's, Radio Shack, WalMart, etc., and pick up a female adapter - like a cheap wall mount plate and the shortest length of cheap coax you can get (either RG-59 or RG-6). Short the center post out to the side of the adapter. Connect the short length of coax. Now, on the unconnected end of the coax, test with a multimeter to make sure you have continuity. If you don't have a multimeter, take a flashlight bulb, a D battery, and some wire. Strip two pieces of wire, put one end of each wire on different ends of the battery (one wire on the + and the other wire on the -, don't short the battery and fry the wire!) and securely tape it in place. Ripped in half duct tape will work. Now, connect one end of one of those wires to the outside contact (base) of the flashlight battery. Voila! Continuity tester! Hold the end of the flashlight bulb to the coax wire and hold the wire from the battery on the woven neutral of the coax. Does the bulb light up? Yes, then continuity.

Now, look at two "things". Take the coax off the wall connector of the TV. First, look at the coax connection. You would be surprised how many times someone in manufacturing will knick the center wire when making a coax connector and that wire will separate (and stay inside the female fitting). Does the coax fitting have a center wire and is it solid? Now, connect your shorting apparatus to the connector, and go outside to test for continuity. Stick the wire from the battery in the female connector center and the bulb end on the threads. If you are using a multimeter, use a thin wire to stick in the female connector. Keep doing this all around and see if you have continuity to all the coax runs.

Get up on the roof and examine the connection to the antenna. This is really one connection you want to follow Hankaye's advice! Test the continuity down to the connection with the amplifier (which of course is turned off).

Now, if you do find any coax that needs replacement, you MUST use RG-6 coax. Yes, back when Rover was a pup we used RG-59. But now days, cable, satillite, and I suspect the RV amplifier, all want the RG-6.

Now, if this doesn't work, let us know and someone (or me) will try a Plan B. But for now, this will at least assure you have solid wiring and connections.

Good luck,

Ron

[hankaye]

Howdy All;

Should have mentioned that I use the 20' length to connect to the distant connections (Outside, bedroom, ect.), and do my testing from the "Main" outlet (the one with the amp. light and button).
I un screw each coax from the terminal plate and check each one, re connect it, move on to the next. I guess a regular auto test light would let you know if you have any voltage at the antenna. Not how much, just that there is some there. In case the installer wired it wrong..... always a possiability nowadays.

hankaye

[SteveC7010]

One other point:

Every wall connector has a connection on the back side that needs to be checked, too. It is the same as the front side. Most of them are just a female/female adapter bolted to the plastic wall plate.

Here are the front and back sides of a couple of different coax wall plates:

[ktmracer]

I had a similar problem after installing a new sensar pro amp. had to add some coax to the new location of the amp. First time out noticed others had reception I didn't. After the obvious checking on to more troubleshooting. Using a external coax as substitiution in each of the lines, I found that one connecting section of coax between the new amp and old TV line was extremely lossy. close to 40db in 6 ft. It was brand new, high quality coax that was bad from the factory. replaced it and viola, back in business. Now to the hard part. You CAN NOT determine if coax is bad by just looking for continuity. Repeat- Continuity tells you virtually nothing about the performance of the cables RF Performance. All it will tell you is IF you have a completely open connection. substitution is the quickest and least expensive approach for most folks. I verified mine was bad after substitution with a TDR setup I had, but that kind of equipment is out of price range of most everyone.

and as mentioned in a previous post use RG-6 coax, RG-6 quad shield if possible.

[hankaye]

ktmracer, Howdy;

You have some good info you are posting. I'm courious though.

What kind of ohmage does coax display per foot? I'm aware that different types probably read different. Would it be possiable to test out the wires that way?

I find myself compelled to ask. Can't help it.

hankaye

[hankpage]

Hank, Most of today's RG-6 coax has a copper plated steel center conductor instead of solid copper. If the plating is good it works very well because the signal travels over the surface of the wire, not through it and the steel is much cheaper. Most signal loss is through poor or damaged shielding or connectors. That is why quality cables have more shielding and thicker dielectric insulators to keep the signal in and interference out. Most people would have no reason to have the equipment to test for signal loss so swapping cables is much more practical. JM2Ω , Hank ... I meant ¢

[ktmracer]

Originally Posted by hankaye

ktmracer, Howdy;

You have some good info you are posting. I'm courious though.

What kind of ohmage does coax display per foot? I'm aware that different types probably read different. Would it be possiable to test out the wires that way?

I find myself compelled to ask. Can't help it.

hankaye

If only it was that easy. Sorry but testing the ohms/ft in a DC measurement is only good to tell if the cable has a broken and open center conductor or ground. it should measure in the fractions of an ohm for any reasonable length of cable.

What you need to know is the loss in db/ft at the frequencies of interest which takes pretty expensive equipment to verify and a real understanding of electronics to do a proper setup and measurement. I'm lucky enough to have the equipment on hand, having worked as a test and measurement electrical design engineer most of my career. But even then, it was easier and quicker to do a cable substitution than to dig out and set up equipment. I only tested my bad cable after the fact out of curiosity.

the impedance (basically ac resistance) of coax is determined by it's construction. center conductor diameter, dielectric material and thickness. For TV applications the impedance is a nominal 75 ohms. specific types of cable will specify nominal impedance and loss/100ft in db. RG-6 and RG59 are both 75 ohms, but RG-6 is a much lower loss cable at the frequencies used in TV.

and stay away from RG-6 that has copper plated steel center conductor. IMHO it's JUNK, very cheaply made, likely to give problems at some point in the future.

so, if your signal is poor and others have good signal, and you've determined that everything is connected properly and the amp is in the correct mode (Air or cable) and you still get bad reception, especially with cable, the easiest way to troubleshoot is substitution of each piece of cable with known good cable starting by connecting to the TV directly, then if that works, working backwards to the amplifier.

[hankaye]

ktmracer, Howdy;

Sounds like a plan ... thanks for the more in depth explaination.

Thanks for your time.

hankaye

[slomeaux]

Howdy All

I am now home and will try some of the ideas everone has given. Hankaye mentioned that more info would be helpful. I have 09 Cougar 276RLS. There is a 12 volt outlet and a outlet for TV antenna. Beside it is a coax jumper.
There is another coax coming thru the wall to the TV all located behind the TV. I have other antenna connections in the storage area, and a cable hookup on the outside and one more in the bedroom. I may try some of the great ideas tuesday if I don't go fishing. Ain't retirement nice

Thanks everyone
Slomeaux