Amp cutting out

TDiddy · 27-Dec-2014, 2:15 PM

http://www.tvfool.com/?option=com_wr...2c153742f6ab97

Hey all,

I have a ClearStream 2 antenna, and until recently it has worked brilliantly. I can get upwards of 40 stations. But about one year after I has it installed, the signal dropped and I only got 3 local stations.

The installer put a CM 0747 amp on the cable inside the house that really helped boost the signal. I assumed this unit had failed, and that was the problem. So I ordered a replacement 0747 ... and it worked perfectly for about 2 weeks, then it stopped working.

Then I ordered the 7777... and only connected the power supply. My antenn is on the top of my chimney, and I am not comfortable going up that high.

Simply connecting the power supply worked great, for a couple of days... but then it stopped working and I went from nearly 40 channels back to only 3.

Any idea what is happening here? It does come back on from time to time for a couple of days before cutting out for a few days...

The antenna is on the chimney, I have about 65 feet of cable. And it is split 3 ways about 15 feet after the power supply

Thanks!

ADTech · 27-Dec-2014, 2:21 PM

As I explained in your other thread, the 0747 is only the power supply, it is not an amplifier. You need to find out specifically what's mounted up on the chimney.

Based on your TVFool plot, you should absolutely NOT be using a pre-amp indiscriminately, especially the CM7777, as your close by stations from the CN Tower will overload the amp and cause a LOSS of reception.

TDiddy · 27-Dec-2014, 2:37 PM

Thanks, AD Tech.

I don't believe there is a pre-amp on the antenna.

The installer put the CM 0747 on the line because we were getting weak reception when he first put it up, and it immediately made a huge difference. He said it was needed because once the cable run exceeds 50 feet, the signal needs a boost.

What I don't understand is why it worked perfectly for a year, and when I put a new one on it will work for either a couple of weeks, or a couple of days.

I don't know much about antennas, but that seems curious to me.

ADTech · 27-Dec-2014, 3:57 PM

Okay, one more time.

The 0747, by itself, is only a power supply. It looks like this:http://www.channelmasterstore.com/CM..._p/cm-0747.htm

The amp will look like this one although, if it's the older one, it will have two inputs: http://www.channelmasterstore.com/TV..._p/cm-7778.htm

By itself, the power supply would do nothing. Go outside and look and see if there's a box mounted near the antenna, perhaps on the mast, perhaps somewhere else along the coaxial cable run. If your installer stuck a power supply in your system without an amp, he didnt know what he was doing.

If you remove the power supply from a CM amp, it turns into a 30 dB attenuator which will wipe out anything except your strong local stations.

TDiddy · 27-Dec-2014, 4:15 PM

Oh, good. Attitude. How refreshing.

There is no preamplifier on the antenna mast.

And yet the 0747 brings in plenty of channels, with a strong signal. So, clearly, it does something even without a pre-amp. And it did so for more than 1 year. Not saying the installer knew what he was doing, but it did work.

I did try other in-line amplifiers, but they only pull in about a dozen channels.

The unanswered question is why it works for short periods of time when I get a new power supply, with sporadic cut outs. Anyone else have this experience?

ADTech · 27-Dec-2014, 5:23 PM

It's actually persistence in emphasizing that you have what appears to be either an illogical or an incompletely identified configuration. If installed by itself, the 0747 will do only two things: 1) Apply an unneeded +18 volts to the coaxial cable at the output (antenna side) of the 0747 and 2) Provide a dB or 2 of attenuation of the input signal. There's nothing else it can do.

Until the confusion is eliminated it's pretty much impossible to identify the issue with your reception.

TDiddy · 27-Dec-2014, 5:39 PM

Ok, so I spoke with the company that installed the antenna.

They confirmed they did not install a pre-amp on the antenna. He says the cm 0747 ... Which is discontinued, as you know, and is hard to get a hold of now, for some reason works great in boosting the signal when there is a long cable run... Over 50 feet in his experience.

He said the signal strength is great at the antenna, but it loses strength over the run of the coax. The cm 0747 simply pulls the signal along.

Does that make any sense? If not, some advice on the ideal setup based on my antenna (CS2), location and cable run of 65 feet would be appreciated.

Tim · 27-Dec-2014, 6:20 PM

Quote:

Originally Posted by TDiddy

Ok, so I spoke with the company that installed the antenna.

They confirmed they did not install a pre-amp on the antenna. He says the cm 0747 ... Which is discontinued, as you know, and is hard to get a hold of now, for some reason works great in boosting the signal when there is a long cable run... Over 50 feet in his experience.

He said the signal strength is great at the antenna, but it loses strength over the run of the coax. The cm 0747 simply pulls the signal along.

Does that make any sense? If not, some advice on the ideal setup based on my antenna (CS2), location and cable run of 65 feet would be appreciated.

No, it does not. A power supply would have absolutely no effect on the signal and it would make no sense for the installer to put one in your installation unless there is an amplifier somewhere in the feedline. This installer may have placed the preamp at some point other than close to the antenna.

If this antenna system was working fine before, then something has changed.

Sounds like someone needs to physically trace the whole installation from the antenna to the TV set(s) to see what is taking place. There is something awry somewhere. Some possibilities:
Has the direction the antenna is pointed changed? Even a few degrees can make a difference.
A distribution amp or pre-amp somewhere in the line that has gone bad
A defect in the antenna
A loose or corroded connection at the antenna
A loose or bad coaxial connector
A bad splitter (if any)
A bad grounding block
Water ingress/corrosion into any connector
Kinked or damaged coaxial cable
If there is no visible problem then it is a matter of testing or substituting components until you find the actual problem.

If you don't have the knowledge or physical capability to perform such an inspection, then you will probably have to call upon a knowledgeable friend or resort to a professional (preferably one who does not think that a power supply can amplify a signal).

ADTech · 27-Dec-2014, 7:47 PM

Actually, the CM0747 power supply is readily available as a replacement part, I gave you its web store link earlier. However, the amplifiers that it was sold with, the "old" 7777 and 7778, are NLA. The "new" 7777 and 7778 amps utilize a different power supply.

Is there any chance they installed a distribution amplifier (powered splitter) and used the 0747 as its power supply? That would be the only thing that would make any sense. Otherwise, their excuse is nonsense.

As far as the antenna itself is concerned, the only likely fault that it might have is water ingress into the loop which was an intermittent issue with units manufactured several years ago. It that is found to be the case, call our customer service department for a warranty replacement loop.