Combining 2 DB8 antennas

[Ken]

Please give me a suggestion for an antenna for my area. I have been considering the HD Stacker and the Winegard HD 9032. I have a Winegard Chromstar 2000 Preamplifier to compliment it. Any advice appreciated. My location is a rather frinze area.
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d67d9753c139a90
Thanks.

[GroundUrMast]

The signal from WCYB calls for an all channel antenna design. Few television markets have stations on the low VHF channels, in large part due to a bit more noise and interference in that frequency range. The signal from WCYB is strong enough at your location to expect little or no trouble with reliable reception.

The HD Stacker does not have elements tuned for reception of real channels 2 through 6.

The HD9032 is a UHF only design.

I'd recommend a Winegard HD7082 aimed at 45° compass.

Which model preamp do you have? Chromstar 2000 is the name of a series of preamps, some of which may be less than ideal for your application.

A PBS signal comes from the NW so a rotator or second antenna may be needed. How many sets will you connect to this antenna system? The answer to this question may drive the choice between a rotator or an alternate suggestion.

[Electron]

The FCC web site is showing that only digital channel 5 is transmitting , and not , 21 , 28 or 29 , http://transition.fcc.gov/fcc-bin/tvq?list=0&facid=2455. The antennas you have suggested do not receive the low band tv channels. Install a All Channel antenna that receives VHF Low channels 2 thru 6 , VHF High channels 7 thru 13 and UHF channels 14 thru 69. Install a Winegard HD7082P antenna aimed at about 35 degree magnetic compass. Here is how to aim antennas , http://www.kyes.com/antenna/pointing/pointing.html. Here are some Strong and Sturdy antenna mounts , http://www.ronard.com/909911.html , http://www.ronard.com/34424560.html , http://www.ronard.com/ychim.html

[Electron]

An important question for your location is , how many tv's are/will be connected?? The PBS stations are off to the side of the HD7082P antenna and are weak signal strength and will most likley not be received. So a second antenna or a rotor will need to be installed. How many tv's are/will be connected??

[Ken]

There will be a total of 4 TV's connected. being new at this, some of the terminology will be difficult at first. Thanks for your help.

The Winegard Preamp is model AP-8275.

If the HD stacker and the HD 9032 will not work. What is your suggestion? At the present time, I am using a small cheap Lava digital preamplified antenna that does a good job with the local channels, but will not grab the PBS stations. Prior to Digital, I received channel 41 (old2) PBS and also 13 from Asheville and old channel 8 from Charlotte.

[Electron]

You have 4 tv's to connect. A rotor that turns the antenna to receive tv stations that are not in the same direction is Ok for one tv , however for 4 tv's a rotor is not good because there Will Be disagreement about where the antenna is pointed. I recommend a separate antenna with no rotor , a http://www.antennasdirect.com , DB4e antenna connected to the AP8275 preamp , aimed at about 311 degree magnetic compass for reception of the 2 PBS stations to the west. The DB4e/AP8275 and the HD7082P antenna with a Channel Master CM3414 , 4 way distribution amplifier , Will Be 2 Separate Systems. With Separate coax wiring all the way to the 4 locations of the tv's. The 2 separate systems with separate coax will go to a remote control A/B switch that is located at each tv and the output of the A/B switch will be connected to the tv at each tv location. The A/B switch is a http://www.radioshack.com , #15-1968.

[Electron]

Here are places to buy antennas and etc. , http://www.winegarddirect.com , http://www.channelmasterstore.com , http://www.solidsignal.com , http://www.amazon.com , http://www.starkelectronic.com , http://www.3starinc.com.

[Ken]

Thanks Electron. I haven't had any experience with the DB4e, but what you are saying makes sense and it sounds as if it would be stronger for the west PBS stations over the HD7082. So far your advice is a go. There are 4 TV's, but only one would be on, but I understnd that I would still have to turn a rotor before going to the other room. I like the ideal of the DB4e as it seems to be stronger than the HD7082 with the AP8275.

[Electron]

The wording of your response has me thinking that you do not understand. This is 2 separate antenna systems. The HD7082P aimed at 35 degree magnetic compass with the CM3414 distribution amp. is one system. . The DB4e UHF antenna with the AP8275 preamp. aimed at 311 degree magnetic compass is a second separate system. The 2 systems are not connected together on to one coax. No antenna rotor is used at all with either antenna.

[Ken]

Right. That was the way I understood it and using the Cm3414 with the hd7082 on a separate coax. Thanks.

[Ken]

Is there any way to run the two antenna systems into a diplexer and then one cable to the TV? How can I check signal strength?

[GroundUrMast]

Is there any way to run the two antenna systems into a diplexer and then one cable to the TV? How can I check signal strength?

The AC7 or CMN7 combiner products from www.tinlee.com (http://www.tinlee.com/MATV_headend.php?active=3#ANTENNASIGNALINJECTORS) are possible solutions. You'll need to contact the vendor directly re. pricing and availability.

[Ken]

I'm new at this and it is an exciting challenge. I got to thinking about Electron's reply that I would have to use two different systems with two lines using an A/B switch. Would a combiner work with the UHF antenna from the NW connected to the UHF terminal of the combiner and then I would be connecting the other antenna cable to the VHFterminal that has to carry VHF and UHF signals. Will it work?

[Ken]

I have one DB8 antenna pointed around 310 degrees using a winegard 8275 preamp and another DB8 pointed around 40 degrees also using another Winegard 8275 preamp. At the present, I am using an A/B switch. Is it possible to take these two leads from their preamps and feed into a combiner and then a single in line to the TV? I was afraid to try this in danger of damaging a preamp if that is possible. Any suggestions appreciated. By the way the DB8 brings in the VHF channel WCYB. These antenn's are supplying signals to 3 TV's. Thanks for your advice.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d0b86f7e1e9da9e

[GroundUrMast]

There should be no cause for harm to the preamps.

The question is, will the signals from each source combine positively or negatively. Typically, you'll get both, that is, some signals will improve at the TV and others may be made worse.

A 2-way splitter/combiner is cheap... I expect the cost of that part is all you're risking.

[Dave Loudin]

The normal answer is: no you should not combine the two feeds. It is not a matter of damaging anything. It is, instead, a matter of net loss of signal strength in the combined feed.

What do you receive with the 310 degree antenna?

[Ken]

Thanks. I'll give it a try. I was afraid of damaging the preamp. The two antenna's are mounted on the same mast. I thought once about disconnecting one preamp and run a 300 ohm twin line from one antenna to the other, but I figured it would lose signal strenght then.

[Ken]

Dave I receive 6 channels 2.1, 2.2, 2.3, 47.1, 47.2, 47.3.
which is 32 & 41.

[Dave Loudin]

Ok, that makes sense. I was looking at some simplification strategies, but I see how they wouldn't work.

[Electron]

So is WCYB channel 5 NBC bring received with the UHF antenna. I do not recommend combining the two DB8 UHF antennas antennas on to one coax. the two antennas will cross talk and some channels will be better and some channels will be worse , over all it will be worse but go ahead and try it any way.

[Ken]

Electron, I started to order the DB4E as you suggested, but thinking the DB8 would be stronger, not realizing that the DB4E was as powerful. I installed the DB8 pointing around 300 degrees for channels 32 and 41. I was really impressed when it picked up a few channels from the back angle at 39 and 41degrees, including WCYB. I ordered another DB8 to catch all the channels from 14 to 41 degrees and needed a multi directional so as to pick up 14 degree channel 49 (68.1) which also broadcasts (68.2 My Family) So far I have great pictures without any fading or picture loss, but I would like to have one lead in if possible. I have no way of checking the signal strength.

[Electron]

Most newer digital tv's have a signal strength meter that you can find in the menu of the tv's. What are the make and model numbers of the tv's??

[Ken]

One is a Sony KDL-40SL130
One is a JVC LT 32EM49
One is a Vizeo VA26L

[Electron]

Looks like the Sony has signal diagnostics , pages 29 -30 of owners manual. http://www.manualowl.com/m/Sony/KDL-40L130/Manual/70234

[Electron]

So you are saying that the UHF antenna receives WCYB channel 5 with no problems??

[GroundUrMast]

The question about WCYB stems in part from the fact that they are also licensed to broadcast on UHF 21 and 29.

[Ken]

Thank you Electron. I found the signal strength meter on the Sony. WCYB was very weak, but still held a picture. I went out and tried some adjustments on the antenna and now the picture breaks up and I can't get it to hold and can't get it back like it was. You were right. I had signal loss on every channel with one supply line. The current level dropped and average of 20-30 points on the meter on every channel. Using a single line of the two supply lines, the major channels held a 82-93 signal strength and the weakest other than WCYB was channel 41 and 47. I can't get WCYB to hold now and that is the only NBC station I can get. I'm open for suggestions now.
I think that the SNR reading means signal noise ratio.
What does AGC percentage stand for?

[Ken]

I can't get 21 or 29.

[Dave Loudin]

They're probably not on the air yet. The applicant has yet to apply for a license to cover constructing those facilities.

[Electron]

AGC percentage. The simple way to understand it is , think of a amplifier/deamplifier that both increases the signal strength and also decreases the signal strength to keep a constant signal strength on the output of the circuit. (( Many pepoles now'a days think I'ma gonna get me the biggest antenna ampli-frier I can find and snatch the tv transmixers fron de air. )) What happens is the tv tuner can not adjust such strong signal strength , the AGC runs out of adjustment range and the tv tuner says O no don't and shuts down. Here is explanation of AGC. http://www.qsl.net/va3iul/Files/Automatic_Gain_Control.pdf

[Electron]

I did my best to recommend antennas that would have done the job the first time. Now I recommend a Winegard HD5030 connected to the DB8 with a UVSJ and both antennas aimed at about 32 degree magnetic compass. The UVSJ will make the HD5030 and the DB8 UHF antenna you have into one All Channel Antenna ,, What you could have had with one antenna the HD7082P. The other DB8 will remain aimed at about 311 degree magnetic compass. Type the letters uvsj in the solidsignal search box. http://www.solidsignal.com The UVSJ is a UHF/VHF Separator/Joiner. The UVSJ connects the HD5030 and the DB8 together to make one antenna a all channel antenna. The HD5030 is best at receiving channels 2 thru 13 and the DB8 is best at receiving channels 14 thru 69. The UVSJ has a circuit inside that does not allow VHF antenna and the UHF antenna to cross talk and the circuit in the UVSJ allows two separate frequency bands to go on to one coax.

[Electron]

I recommend that you Do Not combine the 2 DB8's on to one coax , the DB8's are aimed in different directions , the DB8's will cross talk and the result will be bad reception. I recommend that you Do Not connect ALL 3 antennas on to one coax , you will not like the reception results. But then it won't hurt anything so go ahead and try it anyway.

[Electron]

Subject : Antenna cross talk. As you have observed , the UHF antenna aimed to the west receives channels from the north east. And the UHF antenna aimed at the north east receives some channels from the west. The two UHF antennas are out of phase with each other because they are not the same antenna and they are not pointed in the same direction. If the two UHF antennas are connected together on to one coax with a 2 way splitter connected so the two connections go into one , then the two UHF antennas will send , as an example UHF channel 14 down the same coax , the two channel 14's will be out of phase and the Tv tuner will not like it.

[Electron]

Here are the 3 television bands. VHF low band 2 thru 6 , VHF high band 7 thru 13 , UHF band 14 thru 69. Tv antennas can be constructed to receive all 3 bands or primarly 2 bands or primarly one band or primarly even only one channel.

[GroundUrMast]

@Ken, I've taken the liberty to merge both of your threads.

I agree with Electron, reliable reception of WCYB, real CH-5 calls for an antenna that is designed to receive low-VHF signals. The DB8 is an excellent UHF antenna but not the right choice for reception of VHF channels 2 through 13.

As I reread the combined thread, I'm reminded that an all channel antenna was recommended from the beginning. A couple of options were suggested regarding how to integrate the PBS signals with the main group. Both the A/B switch and TinLee combiner options have merit. Did you ever contact tinlee.com?

[Electron]

And here is something else that is good to know , Their are the REAL digital tv channels , the real digital tv channels are the channels that are actually transmitted and received. And then there are the Virtual channel numbers , in most cases the virtual channel numbers are the tv stations channel before the switch to digital. It's called the Legacy channel number. The real channels are is what is received by the tv antenna. The Virtual channel is what showes on the tv screen. Tvfool lists both the REAL Channel and the Virtual channel in the tvfool radar report.

[Electron]

SNR. A signal with less noise is better.

[Ken]

I have had a 90 day OTA course in the last 24 hours. I wish that I had listened to you guys to begin with and I would have saved a lot of money. After a better understanding, I still have no idea how I received WCYB on the DB8, but it did, but now there’s not a solid signal after fooling with the antenna. Please don’t take me wrong or being hard headed, but I have one more question. Would it require an antenna as big as the HD5030 to pick up WCYB? The HD5030 and the UVSJ is the way I will go if that’s what you recommend. I have a lot of money invested by not listening and will not make that mistake again.

[GroundUrMast]

Using a UHF antenna to receive a VHF signal is a bit like using a small tack hammer to drive a large framing nail... It can be done if the nail is sharp and the wood is soft, but that doesn't mean the right tool was chosen.

The signal strength of WCYB is strong enough that you are right on 'the edge' of gathering enough signal with the DB8.

The size of an antenna is determined by the frequency range it's intended to receive and the gain needed. As the frequency goes up, element length gets shorter. That means an antenna covering the low-VHF band needs longer elements than a UHF antenna with the same gain.

[Ken]

I understand now. I'm learning a lot.

[Electron]

You can buy the HD7082P and instal it and put the DB8 in the garage sale.