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Old 9-Jun-2012, 4:05 AM   #1
sara
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Is a preamplifier needed for antenna reception?

I am very new to the forum. Wanted to get PBS for my little one. Thanks to the experts opinion here, I bought a Clearstream5 antenna. Also bought a distribution amplifier (CM3410 / PCT 1 port distribution amplifier with passive return). My reception report is:
http://www.tvfool.com/?option=com_wr...de6537d4273424. Also see the antenna point report attached.

Currently I have:
C5 antenna trial position at 5 feet from ground -> 40 feet coax cable -> CM3410 distribution amplifier -> 40 feet coax to TV

With this setup, I get all the green color channels including PBS kids. Disconnected Dish and my little one is happy to see her favorite programs. Before adding the distribution amp, the channels were not stable and picture was grainy and went away after some time. With the CM3410 amplifier the green channels are stable. I also bought a) TII 212 Broadband Cable TV Lightning Surge Protector Ground Block and b) 40 inch J-mount, but planning to install them when the cable is run for roof.

I need to fix the antenna at roof (with install help). When I do that, my cable length will increase to 80 to 100 feet before CM3410 amp. The new setup will be C5 antenna at 20 feet -> 100 feet coax cable -> CM3410 distribution amplifier -> 40 feet coax to TV.

My questions to the experts are:

** Do I need to buy Antennas Direct CPA19 pre-amp as I am increasing the cable length by about 60 feet? I think it is better to use same company equipment.
** When I increase the height, add a pre-amp will I gain or lose any additional channels? What can I expect by adding a pre-amp?
** Where do I buy about 100 feet of coaxial cable. I may need to cut the cable with coaxial connection attachment. Crimper tool for one time use?
** I am also not sure where to add power to the pre-amp? Do I need to run another 100 feet cable to the antenna and then get output from the preamp close to the antenna? Are there any smarter alternatives?

The one installer that I spoke to wanted about $250 for labor and another $125 coax and ground. I am thinking of getting handyman help to only install it on the roof and depend on experts advice here for technical advice.

This whole exercise is challenging and confusing. But I am willing to struggle to get it right one time and forget about it (hopefully for a few years). You suggestions are very valuable.
Attached Files
File Type: pdf reception_report.pdf (51.2 KB, 514 views)

Last edited by sara; 9-Jun-2012 at 4:53 PM.
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Old 9-Jun-2012, 11:33 AM   #2
signals unlimited
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This could be complicated. If the installer knows his stuff, $250 is a good deal. If you are a die hard DIY you will find plenty of help on this site. I will put some thought into this and watch the thread.
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Old 9-Jun-2012, 12:37 PM   #3
sara
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Thank You. Yes my location has the TV towers in South to South West. As C5 is more or less omni-directional, I went to that route to avoid a rotator. Right now based on advice here, I have antenna pointed at about 200deg orientation and it works well as I did some trial scans of signals by trial and error.

I am planning to test everything on the ground before installing in the roof. So I think I can do it with help from the forum. Can the power inserter for the preamp be at 80 to 100ft distance from the antenna mast? My distribution amp has passive power return path, so it is not going to affect the upstream signal from antenna. I don't want to overload strong signal stations. I have read something here but I am new and don't have the expertise for the signal calculation. I do not have access to signal meter.

The only reason I am considering the preamp is because of the distance from the antenna mast to distribution amp. I would love to go to a store, buy a preamp, test it and then decide to keep it or return it. But Walmart or Radioshack do not carry a preamp.
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Old 10-Jun-2012, 7:00 AM   #4
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You don't need a preamp and a distribution amplifier.

You can expect the signal quality to improve as the antenna is raised clear of the ground and nearby obstructions. This means you'll have a better signal to work with, and a signal that will be able to travel through more cable.

If you are already seeing good performance, expect a more reliable signal after you give the antenna a proper home.

The CM-3410 is going to be plenty of amplifier. It's designed to be mounted in a dry protected location, but feel free to mount it as close to the antenna as is convenient. Just after the coax enters the building for example.
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Old 10-Jun-2012, 7:12 PM   #5
sara
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Thanks. I am adding about 100 feet of RG6 before CM-3410 amp. 100 feet RG6 has about -6dB of Signal loss. The CM-3410 has a gain of +15dB that covers for a 8-Way Splitter loss of -12dB. So my current setup has

antenna gain at 3 feet -> 40 feet coax (-2.5dB) -> CM-3410 (+15dB) -> 8-way Splitter (-12dB) -> 40 feet Coax (-2.5dB) = -2dB + antenna gain. With this my DTV converter box is showing only 50% of the signal bar.

When I add approx another 100 feet of coax, then my setup will have:
antenna gain at 20feet -2db (above calculation) - 6dB (+100ft RG6) = antenna gain at 20feet - 8dB losses.

With a CPA19 I gain +17dB in preamp. That will offset my -8dB loss due to extra 100feet of RG6. I don't know how much gain I will get by increasing the antenna height from 3 feet to 20 feet. That's why I thought I need a preamp. With the preamp, I could safely insert power via the coax of approx 140 feet cable to the antenna.

I am very new to the DTV world and TV fool. I cannot climb the roof and should employ someone to do it. That's why I want to make a right decision on the preamp. Please let me know if I am overlooking something.

With the preamp, I am hoping that I could get the Greensboro Towers at 59mile/60degrees on the backside of the C5 antenna. Currently I do not. I am planning to point the C5 at 210degrees as suggested by "electron" in an earlier thread on antenna selection.
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Old 11-Jun-2012, 2:26 AM   #6
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All questions and answers about Tv reception

A simple reception situation. Install a Antennas Direct DB4e aimed at about 240 degree magnetic compass. And install a Antennas Direct C5 aimed at about 266 degree magnetic compass. Here is how to aim antennas , http://www.kyes.com/antenna/poinying/pointing.html. Install a Winegard AP8700 Preamp.

The C5 comes with a combiner the combines the DB4e and the C5 antennas.

The preamp is connected to the output of the combiner.

Last edited by Electron; 13-Jun-2012 at 8:39 PM.
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Old 12-Jun-2012, 5:52 PM   #7
sara
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Quote:
Originally Posted by Electron View Post
A simple reception situation. Install a Antennas Direct DB4e aimed at about 240 degree magnetic compass. And install a Antennas Direct C5 aimed at about 266 degree magnetic compass. Here is how to aim antennas , http://www.kyes.com/antenna/poinying/pointing.html. Install a Winegard Direst AP 8700 Preamp.

The C5 comes with a combiner the combines the DB4e and the C5 antennas.

The preamp is connected to the output of the combiner.
  1. Is there a particular reason for choosing DB4e over a C4? I want to color to be black to match the roof. Our neighbors and HOA are very picky.
  2. When you use a AntennasDirect VHF/UHF combiner does one lose all the UHF signals coming from a C5? Obviously the UHF stations pointed in the right direction of C5 will have better signals than a DB4e at an angle to the tower. Can you please explain what goes on in such situations?
  3. Is it more appropriate to use a TV antenna coupler? (e.g. Winegard CC-7870 2-Way TV Antenna Joiner Coupler)

Last edited by sara; 12-Jun-2012 at 6:02 PM.
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Old 12-Jun-2012, 8:12 PM   #8
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There are times when both a pre-amplifier and a distribution amplifier are both needed. My home is an example of this as a pre-amp can't do the job alone (yeah, a LOT of coax went into the house!). As it happens I use an extended boom 91XG, a mast-mounted PA18 plus one of our CDA-4 distribution amps in the basement. On one of the output legs, I had to install a third line amp. All this is to preserve two barely receivable stations, one of which my wife really, really wants (quilt shows on PBS) on a Tivo in one specific part of the house.

Given your proximity to your broadcast towers, I suspect you don't need any amplifier at all. Worst case, use an 8-way distribution amp.

As to your questions, Sara, I'll provide a little commentary. I don't know why the particular recommendations were made, but they're certainly valid. It's helpful to understand that the old adage of "There's more than one way to skin a cat" applies to antenna selection. For many locations, there are a number of potential solutions that will work.

1. The C4 is compact, the DB4e is not but it is quite a bit stronger once we get out of the lowest UHF channels. The DB4e is substantially less expensive as it costs much less to manufacture, package, and market. The C4's target customer is a person in a retail store (they hate large packaging!) that wants as much power as can packed into a small package and that yields an aesthetically small footprint once installed. The DB4e is not constrained by these factors. Obviously, this involves some compromises in the C4 as the guys who love huge, shiny aluminum sculptures will gleefully point out. In any event, an aluminum antenna can be painted with Krylon or Rustoleum and it won't affect reception as long as you don't get paint into anything critical like the connections for the coax. Please note that HOAs are powerless under the law to interfere with your antenna installation in most cases. See the FCC's OTARD rule for specifics at http://www.fcc.gov/guides/over-air-r...n-devices-rule

2. The U/V combiner will attenuate opposite band signals by more than 20 dB at each of the outputs so as to prevent the signals from one antenna from potentially interfering with the same-band signals from the other antenna. The C5, on UHF, behaves much like an omni-directional antenna and often works well as a single antenna for both UHF and high VHF. However, I'd only suggest it for short-medium range locations with uncomplicated signal paths. Based on your TVFool report, you would be a candidate for such an attempt with the C5. As an example, we only have one antenna on the roof our office in suburban St Louis (an all-UHF city), a C5 with a CPA19 feeding into an CDA-8 distribution amplifier.

3. The Winegard CC-7870 is nothing more than an old-school ferrite core transformer-type splitter (and not a very good one, at that) packaged to be used as either a splitter or combiner. I suspect it's been around for ages.

When using the C5 by itself for both UHF and VHF, do NOT install the EU385 CF combiner. Set if off to the side.

In the event that the C5 doesn't hit all your UHF stations reliably, I'd either back off to our C2v as I originally recommended to you by email last month or add the C2 (instead of the C4 or the DB4e) for UHF reception.
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Last edited by ADTech; 12-Jun-2012 at 8:27 PM.
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Old 12-Jun-2012, 9:17 PM   #9
sara
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I wish my work place allows for a chat with ADTech. I would not have to resort to pages of text on the forum. On the other hand it might be helpful to everyone. As I explained in another post, I did not go for C2V based on price and I thought that C5 has a good VHF and more omnidirectional. I get all the channels reliably after adding a distribution amp. I hope that the situation will improve once I mount it on roof at 25ft. Looks like there is more interest from North Charlotte community and this thread will be useful to others.

ADTech, I have a question on RG6 cables: Why don't you sell quad RG6 with ground messenger wire? Wherever I see RG6 with ground messenger they are not quad shielded. I have seen Dish Network use such cables for proper grounding. For dish they have a switch with ground which is connected to another grounding block (and properly grounded with copper wire to pole) before the cable enters the house. On the antennas there is no place to attach a ground messenger wire to the antenna (unless I add a ground block). Is it sufficient to just attach ground surge protector before the cable enters the house? The preamps are almost as expensive as antennas and I want to make sure (in future when I buy a preamp), that lightning does not kill it. Is it given that any lightning strike nearby will fry a preamp and hence no one bothers to save equipment outside the house.

Last edited by sara; 13-Jun-2012 at 2:08 AM.
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Old 13-Jun-2012, 3:07 PM   #10
ADTech
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RG6 with ground is generally sold in bulk, not in ready-to-use packages of different lengths. We only stock pre-assembled coax assemblies. It is rare that quad shield RG6 is actually needed in an antenna installation.

The ground connection at the mast can be made by scraping a bit of paint off the surface under one of the mounting bolt heads, connecting the wire under that bolt head, then hitting it with some Rustoleum to keep it from corroding. The other end of the ground wire should be connected in accordance with local or national electrical codes.

It's never a given that a near-by strike will take out a mast-mounted amp. Just recognize that there are inherent risks to putting sensitive electronics up in the air. In any event, your TVFool suggests that a pre-amplifier is ill-advised.
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Last edited by ADTech; 13-Jun-2012 at 3:12 PM.
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Old 13-Jun-2012, 11:28 PM   #11
Electron
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ALL questions and answers about Tv reception and more

I recommend the BEST antenna/s for the reception so as to get reception on the first try.

A real and actual UHF/VHF combiner is required to combine the UHF and VHF antennas.
The real and actual combiner has filter network that keep the UHF and VHF antennas from cross talking , cross talking Will Degrade reception.

If a common 2 way splitter used to connect the UHF and VHF together , then cross talk Will Happen and reception Will Be Degraded.

You can try reception , with and witout , the amplifier.

Last edited by Electron; 15-Jun-2012 at 6:09 PM.
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Old 15-Jun-2012, 5:53 PM   #12
sara
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Thanks Electron and ADTech. Based on your recommendation, I am going to use the C5 Antenna as is without Preamp on the roof. If things are not good then, I will come back. With the C5 on the ground at 3ft, I get all the Charlotte area channels without difficulty (with a CM3410 distribution amp).

If I need a second antenna to catch the Greensboro towers at 60miles, then I will go for DB4e.

Thanks everyone.
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