Combining 2 DB8 antennas - Page 2

Ken · 31-Mar-2012, 11:32 AM

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 · 31-Mar-2012, 2:50 PM

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 · 31-Mar-2012, 4:37 PM

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

Electron · 31-Mar-2012, 6:09 PM

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

Electron · 31-Mar-2012, 6:13 PM

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

GroundUrMast · 31-Mar-2012, 11:52 PM

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

Ken · 31-Mar-2012, 11:58 PM

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 · 1-Apr-2012, 12:49 AM

I can't get 21 or 29.

Dave Loudin · 1-Apr-2012, 4:22 AM

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

Electron · 1-Apr-2012, 5:48 AM

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/Auto...in_Control.pdf

Electron · 1-Apr-2012, 5:53 AM

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 · 1-Apr-2012, 6:01 AM

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 · 1-Apr-2012, 6:49 AM

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 · 1-Apr-2012, 6:57 AM

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 · 1-Apr-2012, 6:57 AM

@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 · 1-Apr-2012, 7:19 AM

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 · 1-Apr-2012, 7:56 AM

SNR. A signal with less noise is better.

Ken · 1-Apr-2012, 11:17 PM

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 · 1-Apr-2012, 11:37 PM

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 · 2-Apr-2012, 12:01 AM

I understand now. I'm learning a lot.