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18-Apr-2012, 3:20 AM
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#1
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Junior Member
Join Date: Feb 2010
Location: NE AR
Posts: 20
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Ch Master 8 Bay & 7777 Pre-amp
I have had a Ch Master 8 bay antenna for several years in my attic. I wanted to increase daytime signal strength with the Memphis TV stations. Purchased a Ch Master 7777 pre-amp.
http://www.tvfool.com/?option=com_wr...9fbec8a386f218
With the pre-amp connected ALL channels were lost except 2- 19.1-4 & 48.1. Without the pre-amp connected around 3PM was receiving channel 3.3 out of Memphis with signal strength of 77.The pre-amp power supply has rated output of 15vdc. The power supply never warmed up or hummed so I checked the output with digital meter with a result of 22.5vdc.
I can't understand what my be at fault?
The instructions for connecting the pre-amp very simple.
Last edited by tony2tall; 18-Apr-2012 at 3:23 AM.
Reason: Forgot to ad link
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18-Apr-2012, 10:12 AM
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#2
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Senior Member
Join Date: Mar 2012
Location: south-central PA.
Posts: 453
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Check the voltage at other end of the line from the power supply to the 7777. If there in no voltage at that point, there may be a splitter in line blocking it. If there is a voltage there and the cable from the antenna to the amp input is good, the amp is DOA.
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18-Apr-2012, 3:50 PM
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#3
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Antennas Direct Tech Supp
Join Date: Jan 2010
Posts: 2,942
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The amp was overloading (inappropriate location for a high-gain amp that's easy to overload). Remove both it and its power supply.
The "old" 7778 was far more tolerant of strong signals. Haven't tested the "new" CM amps yet.
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18-Apr-2012, 4:13 PM
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#4
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Senior Member
Join Date: Mar 2012
Location: south-central PA.
Posts: 453
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The amp may be overloading on the two or three strong stations on the radar, but I have never seen a case where the overload would effect any but the strong stations. If no or few stations are working and the amp is being powered I would still suspect that you have a DOA. You could run without an amp as advised, but if the 7777 is dead I would replace it with the new kinder, gentler 7778 with only 16 db UHF and VHF.
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18-Apr-2012, 5:14 PM
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#5
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Moderator
Join Date: Oct 2010
Location: Greater Seattle Area
Posts: 4,773
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DOA is a possible cause of the trouble. The following is posted @ Solid Signal:
INVENTORY STATUS UPDATE FOR
ANTENNA ROTATORS AND PRE-AMPLIFIERS BY CHANNEL MASTER
In response to several inquiries regarding the delivery status of our antenna rotators and pre-amplifiers, we are sorry to inform you deliveries from our factory are delayed and we are unable to ship the finished goods based on our original promise dates. The delay is a result of difficulties obtaining the necessary raw materials used in manufacturing these products due to tighter restrictions on sub-components necessary for maintaining an acceptable level of quality.
Our apologies for the inconvenience this is causing you and your customers. We are doing everything we can to expedite finished products from our factory once the raw materials are received. We will forward updates to you as they are relayed to us from the factory. Your patience is appreciated during this time.
Sincerely,
Joe
Joe Bingochea
VP of Product Management & Marketing Channel Master
The voltage rating of most consumer equipment 'wall-wart' and 'brick-style' power supplies is based on full-load conditions. 22.5 volts with no-load sounds typical for a 15 volt supply.
In addition to TV signals, the amplifier can also be overloaded by FM and other radio signals. The CM7777 has a switchable FM trap. If you have not already, verify it's 'IN'.
I agree, a low noise, high input amplifier would have been my recommendation. Consider the Antennas Direct CPA-19 and Winegard HDP-269.
__________________
If the well is dry and you don't see rain on the horizon, you'll need to dig the hole deeper. (If the antenna can't get the job done, an amp won't fix it.)
(Please direct account activation inquiries to 'admin')
Last edited by GroundUrMast; 18-Apr-2012 at 5:18 PM.
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18-Apr-2012, 6:31 PM
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#6
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Junior Member
Join Date: Feb 2010
Location: NE AR
Posts: 20
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Quote:
Originally Posted by signals unlimited
Check the voltage at other end of the line from the power supply to the 7777. If there in no voltage at that point, there may be a splitter in line blocking it. If there is a voltage there and the cable from the antenna to the amp input is good, the amp is DOA.
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I just checked voltage at the preamp and there is 22.3vdc available. Soon as the pre-amp is connected to the circuit signal is 0!
Sure glad I didn't have to climb a tall tower to discover faulty pre-amp.
Appreciate everyone who posted replies
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19-Apr-2012, 11:33 PM
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#7
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Senior Member
Join Date: Aug 2011
Posts: 121
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Quote:
Originally Posted by tony2tall
Sure glad I didn't have to climb a tall tower to discover faulty pre-amp.
Appreciate everyone who posted replies
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pssssst,
If you had a tall tower you wouldn't need the preamp! LOL!
Good job trouble shooting!
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19-Apr-2012, 11:43 PM
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#8
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Junior Member
Join Date: Feb 2010
Location: NE AR
Posts: 20
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Quote:
Originally Posted by phone man
pssssst,
If you had a tall tower you wouldn't need the preamp! LOL!
Good job trouble shooting!
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Would like to use your quote when I'm trying to get the front office (wife) to agree with purchasing a tower!
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20-Apr-2012, 12:07 AM
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#9
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Senior Member
Join Date: Aug 2011
Posts: 121
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Sure, you can use that one if you like. I doubt you'll score many points with it if she doesn't see the beauty of a big ole yagi or oven rack bow tie high in the sky above your house. LOL! Saving $70 a month by going OTA was enough of a selling point around here. That and an outside antenna was essential to receiving an adequate signal for our location.
I'm using a CPA-19 preamp. Most of my TV stations are 40 to 65 miles and two edge at that. I have one station 20 miles away and no issue with overload. Antennas Direct is very good about standing behind their products too. I agree with the CPA-19 recommendation. Good luck!!!
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20-Apr-2012, 3:19 PM
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#10
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Senior Member
Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,236
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Quote:
Originally Posted by tony2tall
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In addition to a faulty preamp, you would be better off with an antenna designed for more than UHF channels 14-69.
KAIT is on channel 8
WMC is on channel 5 and not very strong.
WHBQ is on channel 13 and rather weak.
At 60+ miles away you would do better with an antenna on the roof.
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20-Apr-2012, 4:47 PM
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#11
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Junior Member
Join Date: Feb 2010
Location: NE AR
Posts: 20
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Quote:
Originally Posted by Tower Guy
In addition to a faulty preamp, you would be better off with an antenna designed for more than UHF channels 14-69.
KAIT is on channel 8
WMC is on channel 5 and not very strong.
WHBQ is on channel 13 and rather weak.
At 60+ miles away you would do better with an antenna on the roof.
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I'm lucky that I'm close enough to Ch 8 that it is strong even with UHF antenna.
Ch 13 receive it 50% of the time.
Ch 5 is a total loss.
I would like to have an outside antenna but I'm hindered physically from doing so. Other issues gutters on my house prevent securing a push up pole to house and roof is VERY steep which would make roof mount difficult to service.
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20-Apr-2012, 8:29 PM
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#13
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Junior Member
Join Date: Feb 2010
Location: NE AR
Posts: 20
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Quote:
Originally Posted by Electron
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I like the looks of the antenna mount but my house has hip roof on 3 sides. Only gables are on the front of house.
Wouldn't the Winegard HD8200U be a better choice?
http://www.warrenelectronics.com/antennas/HD8200U.htm
Last edited by tony2tall; 20-Apr-2012 at 8:35 PM.
Reason: Added text
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20-Apr-2012, 9:23 PM
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#14
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Senior Member
Join Date: Nov 2011
Posts: 1,832
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Tv antennas and Tv reception
Yes the HD8200U antenna is much better. I am reluctant to recommend it sometimes because the size of the antenna brings on ________. The HD8200U is the All channel antenna to have for receiving the VHF low band channels of 2 thru 6. And for your concideration here are Light Weight Aluminum Free Standing (no guy wires) Lay Over Towers. Do All antenna installation and adjustments and etc. , standing on the ground. http://www.palcoelectronics.com/pe300.aspx
Last edited by Electron; 25-Apr-2012 at 12:32 AM.
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