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Channelmaster 7777hd

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Old 06-20-2017, 05:12 PM   #1
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Default Channelmaster 7777hd

Well a few days has past using the 7777hd in the house at the end of the 250' run and I'm getting excellent results....I kinda wonder if these amps have artificial intelligence and and can adjust to the impedience and improve signal....Channelmaster said the amp was not supposed to work this way....so what do they know "it does". I suppose one just has to experiment...to see what works.. I know it works at the antenna but I had no way to power it up at the long run...if there was AC 110 it would have worked there...but anyway this is fine this way....and I don't have the interference at the base of the antenna to have to deal with....so If any of you want to use the 7777hd in the house you may want to give it a try....excellent....
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Old 06-20-2017, 05:16 PM   #2
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long run to antenna
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Old 06-20-2017, 05:54 PM   #3
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If you're going to put the amp at the "WRONG" end of the cable where it's gong to loose most of its effectiveness, you might as well buy a cheap indoor amp from Walmart for $15 instead of an expensive $70 amp. Once the signal-to-noise margin has been lost, all one can do is preserve whatever is left and that's usually a last ditch effort. in overcoming any additional downstream losses and the tuner's noise figure.

The insertion loss of the coax ahead of the amp effectively increases its noise figure. With 250' of RG6, that's a performance penalty in the order of almost 15 dB!!!!

My suggestion is to return the 7777HD and replace it with one or two CM-3410 amps (or the PCT equivalent) with one at the tower powered via a power inserter and another indoors, if needed, to serve as a distribution amp.
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Old 06-20-2017, 06:00 PM   #4
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I've tried them all and there is no noise.....it works unbelievable well....
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Old 06-20-2017, 08:36 PM   #5
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What Channel Master meant was it really wasn't intended to be used that way as a line or distribution amp. But, you are using it that way and it works.

There is a big signal loss in the coax, but you have enough to get away with using it the "wrong" way because your signals are strong enough to start with.

The "right" way is the way that works.

If it works for you, then be happy with it and enjoy it.

Channel Master made a mistake when they decided on a 5V power supply which is not suitable for long coax runs.

They would have been better off if they had just continued to make the original 7777, and so would we.

I miss that amp.
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Last edited by rabbit73; 06-20-2017 at 08:42 PM..
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Old 06-27-2017, 05:30 AM   #6
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Rabbit73: I plan on adding the juice preamp to my run. I think they may have a product that will work. Can I still run through the 7777hd as a distribution amp? By the way I had another preamp and used it inside but it didn't have the strength as the 7777hd. The Juice is supposed to use 12v and work with long runs. I took this from you advise. I only have $56.00 in the 7777hd and I hate to return(which I can) as it may also be a dist. amp or backup as I know it gets most of the stations. I know my signal is strong as up at the antenna I get everything. I can't say enough about your help on this issue. Those pewney low voltage preamps were a waist of time and money as I now know the issues. Nothing like some trial and error. Tks again, Chuck
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Old 06-27-2017, 09:30 AM   #7
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Quote:
I plan on adding the juice preamp to my run.
I think you mean at the antenna.

I can't guarantee that it will work any better than what you have now, but I don't think you will be happy until you find out.

The Juice preamp will probably be able to handle the voltage drop in the long coax better than the 7777hd, but I still don't know if your coax has a solid copper center conductor or copper clad steel. The general rule is copper clad steel is good up to 100 feet; solid copper up to 200 feet.

In your first thread, I showed you how to measure the voltage to the preamp starting with post #5.
http://www.highdefforum.com/local-hd...er-7777hd.html

It would have been better if you had stayed with that thread instead of starting this new one.

If you want to research further, you can call Antennas Direct; you might get a good tech who can answer your question about voltage drop in a long coax run.

Their best tech is ADTech who gives advice on other forums, but not this one. You can ask him on the TVFool Forum, Help with Reception. He gives good advice; more like an engineer than a marketing guy. The rules of this forum do not allow me to give a link to another forum.

The Juice is probably able to resist static damage in your stormy area better than the RCA preamp. If there is a problem, the Juice has a lifetime guarantee and Antennas Direct will replace it.
Quote:
Can I still run through the 7777hd as a distribution amp?
You CAN, but it shouldn't be necessary. If you use both, you might cause tuner overload. I can't be certain because you haven't shown us your tvfool report. If you lived in Whitesville, it would look like this:
http://www.tvfool.com/?option=com_wr...e6a411e2ea525d

If you do get the Juice, keep the 7777hd as a backup.
Quote:
Nothing like some trial and error.
That's how I learn.
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Last edited by rabbit73; 06-28-2017 at 09:20 AM..
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Old 06-28-2017, 08:51 PM   #8
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rabbit73, would the 7777hd serve as a distribution amp along with the juice?
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Old 06-28-2017, 08:58 PM   #9
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rabbit73, I did ask the company if the juice would handle it and they said it would....since it had higher voltage....I'm to get it tomorrow and I'll give you a report...I know my system is putting these preamps to the maximum.....
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Old 06-29-2017, 09:00 AM   #10
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Quote:
Originally Posted by machinery-man View Post
rabbit73, would the 7777hd serve as a distribution amp along with the juice?
You have not given me enough information to give you an accurate answer.

You have not provided a TVFOOL report that would show us how strong the signals are in your area.

And you haven't told us much about what equipment you will have connected after the power inserter, like how many tuners and how long the coax runs are inside.

Using a preamp AND a distribution amp can easily cause overload. There is such a thing as too much signal strength which will degrade the signal quality. It is even possible to have so much signal strength that the overload will make it impossible to receive ANY signals.

More is not always better.

THREE TYPES OF OVERLOAD

There are three types of preamp or tuner overload, in order of increasing signal strength:

1. The strong signals almost cause enough intermodulation distortion (IMD) to interfere with the reception of weak desired signals, but the spurious signals are at or below the noise floor of the weak signals. This is the point that holl_ands uses in his preamp charts to obtain max SFDR (Spurious Free Dynamic Range). No damage will happen.

As the strongest signals continue to increase in strength, more of the weaker signals are damaged until you reach:

2. The strong signals cause overload to the preamp or tuner that makes it impossible to receive any signals. No damage will happen. The strongest signals are still there, but they can't be decoded because the IMD products have damaged them so that they contain more errors (high BER....bit error ratio/rate) than can be corrected by the FEC (forward error correction).

3. The signals are so strong that the input transistor is toast. You are not likely to encounter OTA signals that strong, unless you live next door to a high power transmitter and you have your high gain antenna aimed at the transmitter's antenna.

As a general rule, tuners can tolerate stronger signals than preamps before overload. The difference in strength is approx. equal to the preamp gain.



Interpreting Noise Margin in the TV Fool Report
http://www.aa6g.org/DTV/Reception/tvfool_nm.html
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Last edited by rabbit73; 06-29-2017 at 09:12 AM..
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Old 06-29-2017, 09:16 AM   #11
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Quote:
Originally Posted by machinery-man View Post
rabbit73, I did ask the company if the juice would handle it and they said it would....since it had higher voltage....I'm to get it tomorrow and I'll give you a report...I know my system is putting these preamps to the maximum.....
Thank you for the update. Please let us know how it works out.

I suggest you try the Juice preamp near the antenna before adding the 7777hd inside. Only add the 7777hd if necessary with the low gain setting.
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Old 06-29-2017, 01:45 PM   #12
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Just tried the juice and it doesn't work....went back to the 7777hd....going to live with it...unless I figure a way to get power supply to antenna feasible....but going to stay with what works....tks for all your help...Chuck
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Old 06-29-2017, 05:55 PM   #13
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Thanks for the report, Chuck

Sorry to her that your system is still having problems.

Did you try the Juice without the 7777hd?

Are you able to measure the voltage at the preamp when it is connected near the antenna as I showed you in your first thread?

The question that I have: If the problem for the Juice is voltage that is too low, is it because of the normal voltage drop in a line that long, or is it because there is something else that is causing the voltage to be even lower?

You still haven't told me if the coax center conductor is copper clad steel or solid copper. I use a little magnet if I don't know where the coax came from.
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Last edited by rabbit73; 06-29-2017 at 06:04 PM..
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Old 06-29-2017, 06:18 PM   #14
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I believe the coax is the copper clad...it is the RG6. I think you said RG11 is the full copper. There are a couple of marginal stations I was trying to bring in. They come in after radiation, near sun down....I running about 60 per cent on the Tivo meter for my main stations. I think when it drops below 40 on the yellow signal they drop off...these are low powered UHF that I'm trying to receive. I suppose if I could get power to the antenna I'd use the 7777hd there...but I'm afraid I'd draw lighting there. Here's a pic of my long run. I'm happy with what I've got now....I've got the 7777hd punched to the red 30 db gain and it's good....I'll try to send you a pic....
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Old 06-29-2017, 06:27 PM   #15
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Found one thing also interested....when I called for an RMA from Antennas direct...the girl immediately said they would let me keep it at 50%. I don't think the Juice is any better than some of the other items....I told her it didn't work on long runs so I sent it back....probably an overrated product like some of the others....I wish they could make an amp with a reset.....I'm sure folks in the mountains behind hills and whatever have longer runs on their coax....maybe the issue just isn't being addressed....I suppose I should have ran another coax up the hill to power the unit or added another voltage line. I was experimenting somewhat....thanks for your help...
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