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Old 18-Apr-2015, 12:06 PM   #1
drew1942
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Question Help with OTA in Ann Arbor two different directions

here is the TVfool report for my location
http://www.tvfool.com/?option=com_wr...f1f0857f78caef

I am at 48103 zip code in Ann Arbor and I want to get all Detroit Stations ( all on uhf except Ch2 now moved to 7 on VHF) and the Toledo PBS stations 30.1,30.2,30.3.
Detroit is 35 miles away and Toledo is 42 miles away as the crow flies.

I tried an indoor antenna in my attic ( I have only one TV) that worked wonders for my friend in Ypsilanti 10 miles away. She got everything I wanted with that antenna and drove three Tvs with it ( Of course she used a winegard 100 preamp) It just gave me 5 channels but then I have a stucco house and the wire mesh in the stucco may have blocked the signal

I have a two storey house moderately wooded at the back but not in the front.
I am thinking of getting an Antenna Direct db8e and pointing one array towards Detroit and the other towards Toledo and coupling each of them with the VHF reflector assembly that Antenna direct also has. Of course

I also plan to use a winegard LNA 200 preamp.Here there is some question whether I should use the 10G221 Antennacraft preamp instead because of reports that the Winegard unit is not well shielded

http://forum.tvfool.com/showthread.php?t=13636

I have several questions about this setup. First I have heard mixed reports about using the db8e multi directionally. It works wonders for some and not for others. The other issue is the loss due to the various combiners involved including combining each VHF reflector assembly with each half of db8e array.

The only VHF channel I am concerned with is Ch 2 from Detroit ( moved to 7) so if this combo does not give me what I want I may add an Antennacraft Yagi 5-7-13 that goes 60 miles for VHF) and add an antenna direct UHF VHF combiner. It is my least favorite channel anyway except for the 2.2 sub channel movies, so I may just not to choose the VHF reflectors at all if they end up attenuating the UHF signals I want

It might be overkill,but I can't afford to experiment as the installer will charge at least $150 and up for his time.

Also I do not want to use a rotor in this part of the country as they both jam and rust especially in the cold. That is why I want to work with antennas in two different directions

Any thoughts anyone?

Last edited by drew1942; 19-Apr-2015 at 2:49 PM.
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Old 18-Apr-2015, 6:24 PM   #2
drew1942
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added to original

Last edited by drew1942; 19-Apr-2015 at 2:50 PM.
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Old 19-Apr-2015, 9:54 AM   #3
Stereocraig
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Quote:
Originally Posted by drew1942 View Post
Also I do not want to use a rotor in this part of the country as they both jam and rust especially in the cold. That is why I want to work with antennas in two different directions

I live in Wisconsin and I too, had my rotor seize up on one of those sub-zero days. I think that the grease may have just thickened up, cause it was fine after a couple days.

An A/B switch, is going to have less insertion loss, but may be a problem for scanning channels, or for multiple viewers, or recording.

There is a remote control A/B selector that was discontinued by Rat Shack, that I see all the time on that auction site and they go dirt cheap. (15-1968)
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Old 19-Apr-2015, 2:50 PM   #4
drew1942
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Thank you StereoCraig, but you hit the nail on the head that the TV will have to be rescanned each time I change the antenna I am using. An idea I will keep in mind though if my situation requires it
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Old 19-Apr-2015, 8:14 PM   #5
rabbit73
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Quote:
I want to get all Detroit Stations ( all on uhf except Ch2 now moved to 7 on VHF) and the Toledo PBS stations 30.1,30.2,30.3. Detroit is 35 miles away and Toledo is 42 miles away as the crow flies......I have heard mixed reports about using the db8e multi directionally. It works wonders for some and not for others.
Quote:
I can't afford to experiment as the installer will charge at least $150 and up for his time.
You have two goals that are mutually exclusive. You want reliable signals from two directions which will require some experimentation, but you don't want the installer to spend his time doing experimentation. Maybe you can do some preliminary experimentation before he comes, to keep the installation cost down.

I don't think there is anyone here that will guarantee that his advice will work for you.

The most we can do for you is to give you advice that has a good chance of success based on the information you have given us.

What you have heard about the AD dB8e is correct. When the two panels are aimed in different directions, sometimes it works, and sometimes not. This is because when the same signals from the two antennas arrive at the combining point they can interfere with each other if they arrive out of phase.

Quote:
The other issue is the loss due to the various combiners involved including combining each VHF reflector assembly with each half of db8e array.
The combiner for the two parts of the dB8e is a low loss device. When a spliter is used as a splitter, the loss is 3.5 dB; 3 dB because the signal was divided in half, and 0.5 dB from the internal loss of the device itself. When a splitter is used as a combiner, there is only the 0.5 dB internal loss.

You will only need one Antennas Direct VHF Retrofit Kit because it is only needed for CH 7 on one panel. If you mounted a kit on both panels, they would interfere with each other. It might be possible to eliminate the kit if CH 7 is strong enough on the dB8e inspite of the fact that its balun has higher loss on VHF than UHF. The UHF/VHF combiner (AKA a diplexer) in the kit has a low loss.
https://www.antennasdirect.com/store...rofit-Kit.html

Quote:
I also plan to use a winegard LNA 200 preamp.Here there is some question whether I should use the 10G221 Antennacraft preamp instead because of reports that the Winegard unit is not well shielded
The use of a preamp for your situation also has some questions. Pete's review has some questions about the LNA 200. You might not need a preamp for Detroit, but you probably will for Toledo.

There is the question about preamp overload. I see a very strong analog signal WFHD-LP at the top of your tvfool report, but Wiki and rabbitears.info say that it is off the air. There is, however, a very strong FM signal WQKL with a signal Pwr of -10.4 dBm which will mess with CH 7, so you will need an FM trap.



Quote:
Also I do not want to use a rotor in this part of the country as they both jam and rust especially in the cold. That is why I want to work with antennas in two different directions
Correct.
Quote:
An A/B switch, is going to have less insertion loss, but may be a problem for scanning channels, or for multiple viewers, or recording.
Some TVs, like my Sony, can add a channel for the second direction after scanning for the first direction.

If your TV can't add a channel after scan, you can have a separate antenna for each direction and one coax will go to the antenna input of the TV and the second antenna will go to a tuner or converter box with its output going to the A/V input of the TV. You would then use the input switch of the TV to switch from one antenna to the other.

The antenna coax should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge, but the system will not survive a direct strike.
Attached Images
File Type: jpg drew1942FM (2).jpg (142.0 KB, 1383 views)
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Last edited by rabbit73; 19-Apr-2015 at 8:23 PM.
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Old 19-Apr-2015, 9:35 PM   #6
drew1942
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Thank you soooo much Rabbit 73 for your informative reply and for sharing your expertise. especially about stations strengths where overloading may be a problem. I never thought to search for FM channels that might interfere.

The installer, who is from out of town, has not worked with a db8e before and I can't find anyone locally who has. He and I can experiment but it all has to be on the same day. It is hard to find antenna installers in Ann Arbor even though dish installers abound. It seems the antenna installers are all over 70, as am I, and want to sell me a Winegard 7697P with a rotor. I am happy to know that combiners are not a problem. I do know about the coax ground and the mast ground as does the installer.

About needing an FM trap I was told that both the LNA 200 from Winegard and the RCA TVPRAMP1R had FM traps so I assume I will not have to had another one.

I was going to put the combined output for the db8e into a preamp. I am leaning now towards the RCA. You have notified me that I may need to combine the amplified Toledo signal with the unamplified signal from the Detroit array and I will make note of that.
I also do plan to try both DB8e arrays with and without the reflector kit and see what happens.I may not need the kit for the Toledo side as I am not interested in VHF channels there.

Thanks again Rabbit 73 for your unusually sophisticated response. It was considerably more help than I anticipated from this forum and I thank you for taking the time to do it.
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Old 19-Apr-2015, 11:57 PM   #7
rabbit73
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Quote:
I never thought to search for FM channels that might interfere.
Glad that I was able to call your attention to something that might be a problem.
Quote:
It seems the antenna installers are all over 70, as am I
Hello old-timer, I'm 81.
Quote:
About needing an FM trap I was told that both the LNA 200 from Winegard and the RCA TVPRAMP1R had FM traps so I assume I will not have to had another one.
The built-in FM trap is usually enough to prevent overload from FM signals, but sometimes two in series are needed with extremely strong FM signals.
FM Filter
http://www.avsforum.com/forum/25-hdt...fm-filter.html

Overload and FM Trap
http://www.hdtvprimer.com/ANTENNAS/g....html#overload

A HLSJ (VHF-High VHF-Low Separator-Joiner) instead of, or in addition to, an FM Band Elimination Filter (AKA FM Trap) is very effective in eliminating FM interference. It attenuates all signals below CH 7, including the FM Band with low insertion loss (0.5 to 0.7 dB) because it has a high-pass filter between the high and common ports.
Holland Filters and Diplexers

ATTACHMENTS:

There are some attachments you and your installer might find interesting.

The first attachment was done by Antennas Direct, but I was having trouble understanding the screen shot of the spectrum analyzer display. I added some notes to improve my understanding of the results of the FM filter comparison test, and added a credit line for Antennas Direct. Credit, where credit is due.

The second attachment compares the analog signal with the digital signal. The comparatively rapid loss of the signal at the "Digital Cliff" is caused by the FEC (Forward Error Correction system) that has a limited ability to correct errors in the digital stream. When that limit is exceeded, the signal drops out. If it weren't for the FEC, we would see the errors increasing as the signal got weaker, and a "glitch" (picture freeze or pixilation} even once a minute would be more irritating than a dropout.

The third attachment illustrates the Noise Margin concept. I drew it to help me learn the concept, and thought that it might also help others.

A signal must have a NM of at least 0 dB to be received. If it is listed on your tvfool report as having a negative NM, you can add the gain of your antenna. You can also add the gain of your preamp, but must subtract the Noise Figure of the preamp, because its internal noise reduces the SNR of your signals.

The fourth attachment is a multicolored NM (Noise Margin) chart that refers to the NM column on your tvfool report. Credit to Calveras of AVS.

The fifth attachment is a calibration chart, showing equivalent dBmV and dBm values, of the Signal Strength scale on the Diagnostics Screen of my latest Sony TV. What is really neat about it is that each step is equal to one dB, so it is very useful for antenna experiments. I got a signal level meter (SLM) and a TV for the price of a TV!

The last two are charts from an old copy of the CATJ. If your installer has been doing antenna work for a long time, he might enjoy them. When I started doing antenna work, I had to make signal field strength measurements in microvolts (μV). Later, I had to make measurements in dBmV, which is signal power, not voltage, in spite of the fact that the reference level of 0 dBmV is defined as 1 mV across 75 ohms. And now I have to think in terms of dBm, which you see in the signal power column of your tvfool report.

Quote:
Thanks again Rabbit 73 for your unusually sophisticated response. It was considerably more help than I anticipated from this forum and I thank you for taking the time to do it.
My pleasure. Please let us know how it works out; we need the feedback to let us know if our advice was accurate.
Attached Images
File Type: jpg ADvsRSFMfilter.JPG (135.6 KB, 513 views)
File Type: jpg AnalogVSDigital_1.jpg (59.7 KB, 1272 views)
File Type: jpg NoiseMargin.jpg (60.1 KB, 517 views)
File Type: jpg NMChartC.jpg (69.0 KB, 499 views)
File Type: jpg SSCHART KDL32R400A_1.jpg (170.7 KB, 703 views)
File Type: jpg CATJ SIGNAL LEVELS (2).jpg (182.3 KB, 1607 views)
File Type: jpg dBmV To uV Conversion Table (2).jpg (187.1 KB, 523 views)
__________________
If you can not measure it, you can not improve it.
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http://www.megalithia.com/elect/aeri...ttpoorman.html

Last edited by rabbit73; 20-Apr-2015 at 3:41 PM.
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Old 21-Apr-2015, 4:15 AM   #8
skatingrocker17
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I'm about 25 miles south of Toledo in North Baltimore, Ohio and I had an AntennaCraft Y10713 vhf antenna and a DB8e aimed at Toledo/Detroit an obviously I got all of the Toledo stations but a few Detroit stations as well. I would get Fox 2 sometimes but more often I would get WTVS PBS, WXYZ ABC, and WDIV NBC. So, the DB8e is a very good antenna but I never tried rotating the panels because it was all generally in the same direction for me.
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Old 21-Apr-2015, 9:07 AM   #9
drew1942
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Thank you, that is heartening news Skatingrocket17. Your VHF, UHF combo is one powerful one and if anything would work I guess that would be it. What did you use to combine/amplify the signals? Were they on one mast or on separate masts. If on one mast how far apart were they and I would assume that the UHF antenna was above the VHF antenna? When I set my combo up sometime early next month I hope to report on how it went. Not enough of a fanatic however to relocate to North Baltimore to solve my problem
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Old 21-Apr-2015, 3:25 PM   #10
skatingrocker17
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Quote:
Originally Posted by drew1942 View Post
Thank you, that is heartening news Skatingrocket17. Your VHF, UHF combo is one powerful one and if anything would work I guess that would be it. What did you use to combine/amplify the signals? Were they on one mast or on separate masts. If on one mast how far apart were they and I would assume that the UHF antenna was above the VHF antenna? When I set my combo up sometime early next month I hope to report on how it went. Not enough of a fanatic however to relocate to North Baltimore to solve my problem
I used the Antenna's Direct EU385CF combiner. When I used the DB8e I actually used it by itself, now I use the separate VHF antenna and Antennas Direct 91XG (because it takes up less space vertically). They are maybe 2-3 feet apart on the same mast. I'm only using a distribution amp to split the signal 4 ways.

I'm actually moving to Canton next month so then I'll be trying to get my Toledo stations still. But it shouldn't be too hard.
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Old 21-Apr-2015, 3:29 PM   #11
drew1942
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Thanks much I am surprised that the 91XG would do better than the DB8e
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