Questions about OTA setup

[caesar gdi]

This is more of an OTA question than a Dish Network question but I will be connecting to an 811 so I decided to post my question here.

I just installed the Channel Master 4228 8-Bay Antenna and read not use a pre-amp if the cable to the 811 is less than 50 feet. My cable will be about 25-30 feet but I do plan on using diplexers. Should I use a pre-amp and if so, where should I put it. I was told that a pre-amp is useless if put close to the antenna input so should I put the pre-amp behind my TV??

 

[Carl B]

The pre-amp unit itself goes as close to the antenna's downlead connection (after the balun) as possible. The power supply for the pre-amp goes behind you TV or somewhere significantly downstream from the antenna.

I'd try the antenna w/o a pre-amp first to baseline your reception. In some cases, reception can deteriorate with a pre-amp due to severe multi-path issues and/or over-amplification of the TV signal. The latter is a more prevelant problem w/ pre-amps and NTSC tuners, than ATSC tuners.

I can't help you with diplexers except to note two things. First, my limited experience with diplexers versus typical signal combiners/splitters is that diplexers "eat" more ATSC signal, so you need a stronger signal. Second, pre-amps are all powered, but some are DC and some AC (Winegard). DBS receivers also use a power signal and the diplexers are made to accomodate that. Adding the power signal from the pre-amp may be a problem, particularly if it is AC. Something to investigate further as I backed out of trying to use a diplexer with my antenna signal, so I don't know what is possible.

 

[caesar gdi]

I have tried the antenna without the pre-amp and so far I can get 3 channels. 2 channels are in the low 60's tho.

I have only seen pictures of pre-amps so are there two parts to a pre-amp. I don't under stand how the unit can be installed close to the antenna and to the TV at the same time (I must be missing something).

 

[WeeJavaDude]

I have tried the antenna without the pre-amp and so far I can get 3 channels. 2 channels are in the low 60's tho.

I have only seen pictures of pre-amps so are there two parts to a pre-amp. I don't under stand how the unit can be installed close to the antenna and to the TV at the same time (I must be missing something).

I also have a channel master and a preamp.. My Preamp is attached on to the antenna and the power inserter is installed in my HT.

If you are getting a signal ratio of 60%, You are going to have problems. Seems 60% is the magical number with the 811 and you will start to get a lot of drop outs and it will not be too watchable. That has been my experience.

I was getting this before without a preamp when I installed my 921. The preamp in my case raised the ratio to in the high 70s and low 80s in most cases. I would suggest if you try a preamp, put an anntuator in betwen the power inserter output and the 811. This will allow for some tuning.

Also, have you tried adjusting your antenna? I am not sure about the cable distance requirement. I find that odd and never read something like that when I installed mine. In my case the preamp, made what was a borderline signal into something that is most watchable with very little dropouts.

 

[Carl B]

I have tried the antenna without the pre-amp and so far I can get 3 channels. 2 channels are in the low 60's tho.

I have only seen pictures of pre-amps so are there two parts to a pre-amp. I don't under stand how the unit can be installed close to the antenna and to the TV at the same time (I must be missing something)

Do you know how many channels you can possibly get? Try here:
http://www.antennaweb.org/aw/welcome.asp

Click on "Digital Channels Only" after you get the spread sheet. That will tell you which DTV channels are available to you, their compass azimuth, and distance. It also indicates how much antenna you need to receive them. For those that become a real problem, you may find that they are extremely low power DTV outlets. Check here for that information:
http://home.earthlink.net/~w9wi/tvdb/index.htm

It is true that signal strength in the 60s on a Dish 811 is inadequate for continuing good DTV reception. You need to get into the 70s; however, beyond that, higher is OK, but isn't any better. The pre-amp is probably the answer to getting you there.

Pre-amp: Here is a link to a CM Titan pre-amp:
http://www.warrenelectronics.com/antennas/7777.htm

You can see the 2 parts in the picture. The light colored part is just a transformer to take you household 120 VAC power to 18 VDC to power the amplifier. It's the thing that typically is in your HT or behind your TV. The DC current runs through your antenna coax to the pre-amp. The pre-amp is typically mounted on the antenna mast, close to the down-lead connection on the antenna.

 

[caesar gdi]

1. Antennaweb says that I can get 1 HD OTA.

2. That spread sheet is hard to read. I know where my towers are but I don't know if they are at full power yet

3. I order the pre-amp last night and I know understand that the pre-amp has two parts.

 

[caesar gdi]

I got this antenna for the SuperBowl which is one of the channels in the low 60's. I didn't have much time to adjust the antenna when I first installed it so I adjusted the antenna again last night and got the FOX signal up to the mid 70's. I then added the diplexers to the line and the signal dropped back to the high 60's but it is a good lock.

I should get the amp on Thursday or Friday and I hope this will get the signal back into the 70's. I also noticed that the signal is higher during primetime shows, is this normal. Do they boost the transmit power during primetime? if so I hope they do this on Sunday!

 

[Kevinw]

I got this antenna for the SuperBowl which is one of the channels in the low 60's. I didn't have much time to adjust the antenna when I first installed it so I adjusted the antenna again last night and got the FOX signal up to the mid 70's. I then added the diplexers to the line and the signal dropped back to the high 60's but it is a good lock.

I should get the amp on Thursday or Friday and I hope this will get the signal back into the 70's. I also noticed that the signal is higher during primetime shows, is this normal. Do they boost the transmit power during primetime? if so I hope they do this on Sunday!

Do you have to run a diplexor? Signal fluctuation could be from temperature changes. Tropospheric

 

[oljim]

Run cable from ant to rec forget diplexers

 

[caesar gdi]

-==100th post ==-

Why not use diplexers. I have only lost a few points from the Antenna signal and nothing from the sat. signal. Also I plan on adding a dual tuner to that room and I do not want to run 3 lines.

 

[ats7627]

If depends on which pre-amp your ordered. As mentioned earlier, pre-amps are designed to work with a power supply. The power supply inserts the DC power on the coax line. Most diplexers only pass power to the satellite port. Thus no power to the pre-amp. Channel Master makes 2 pre-amps, the model 0065 DSB and 0265 DSB which are satellite receiver LNB voltage compatible. (+12 to +22 VDC), but require the model 4032IFD diplexer, which passes power on both ports.

 

[caesar gdi]

Damn that sucks.... I got the CM 7777 so I guess I will need to run a second line, cheaper anyways.

Thanks everyone for your help.

 

[caesar gdi]

Do you have to run a diplexor? Signal fluctuation could be from temperature changes. Tropospheric

I don't think that its the temp because I'm in Atlanta (not much temp diff from AM to PM) and the signal went back down at midnight.

 

[Carl B]

The signals have more competition during working hours. Stations don't fluctuate their power unless something goes wrong.

 

[Kevinw]

I don't think that its the temp because I'm in Atlanta (not much temp diff from AM to PM) and the signal went back down at midnight.

Well in Atlanta the antenna of choice is the CM 4228..The signal fluctuation is a mystery. i have never heard of anyone else in the area mentioning it.
Check here for more ATL
http://groups.yahoo.com/group/ahdtv/messages

 

[caesar gdi]

I havent seen the signal flux in a few days so I don't care anymore.

Anyways I installed the CM 7777 amp last night. Now I get all of the locals execpt ABC and CBS. my lowest signal is 67% and highest is 90. I was able to get ABC for one day when I frist installed the antenna so I think that I will try to adjust the antenna again and see what happens.

Kevinw what channels do you get?

 

[Kevinw]

All except PAX and channel 42 the local Atlanta info station- Generally my signal is between 70 and 80 % . On those nights where multipath is more rampant, I have to adjust the direction
I currently run the Radio Shaxk VU-160 ( huge) with a RS 35 DB amp and the ChannleMaster rotor.
I am thinking of switching antennas to the Cm 4228.. Smaller antenna that has better specs.

 

[caesar gdi]

Frys has the CM 4228 for 50 bucks....

I think I can tune in ABC and CBS if I had enough time to mess around with the antenna but I have not had a good chunk of time to work on it and I was most worried about FOX for this sunday so since that's working well, I will focus on getting ABC and CBS. Thanks everyone for your help!

 

[Carl B]

If your DTV channels of interest are below channel 40, Winegard has the PR-8800 that is an outstanding UHF and high VHF antenna. Sold on-line at Stark, Warren, and Solid Signal among others. It is also somewhat smaller and one heck of a lot lighter than the CM 4228.

http://www.hdtvprimer.com/ANTENNAS/comparing.html

 

[Barry Erick]

Our Fox HD antenna is at the same antenna farm as the others, and I receive the others at over 90. I am 15 miles away. But fox, like others, is low power but only 250 feet on a tower. The other low powers are at the 500 foot level. Where I live, there is a ridge blocking the 250 footer from me, while I can see the 500 foot level. When they goto high power, all will be at the 800-900 foot level and will correct this. All will be by Summer. But for now, no SuperBowl, unless I join the party at the FOX HD transmitter site, which they lease from us.