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post #1 of 114 Old 09-20-2018, 05:59 AM - Thread Starter
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Stevensville MI: Receiving South Bend/Chicago help

Having moved to southwest Michigan recently, I've been spending weeks researching TV antenna options, with the primary goal receiving all of the UHF channels near South Bend (33 miles, 148 degrees from true north) and Chicago (58 miles, 261 degrees from true north) with antennas on my roof 20 feet above ground level using a tripod and 8 foot galvanizedddd steel fence post. (Only 4 feet extends above the top of the tripod.) (VHF matters very little. Only Chicago has a few VHF channels I might be interested in receiving.)


http://www.tvfool.com/?option=com_wr...90380935603672


REASON FOR THIS POST: I'm trying to find the best combination of antennas/preamplifiers/combiners to use.

-----------------------------------

I've acquired several items via Amazon (many of which will be sent back) and trying to find the correct combination of items to use. Here's a list

TNB-WA2608 Tree New Bee which includes its own preamplifier
HDB91X Xtreme Signal Yagi Style VHF/UHF Antenna (I have one of these and expect to obtain a second one - the last two I ordered were damaged when received)

LNA-200 Winegard Boost XT HDTV Preamplifier,
536041 Televes Three-Input Mast-Mounted Amplifier and Combiner
TVPRAMP1R RCA Preamplifier

CM-0500 Channel Master JOINtenna TV Antenna Combiner
CC-7870 Winegard Antenna Coupler

2512 Linear ChannelPlus DC & IR Passing 2-Way Splitter/Combiner (both paths pass DC voltage)
2532 Linear ChannelPlus 2-Way Splitter/Combiner (neither path passes DC voltage)

Coaxial solid copper RG-6. (I did investigate RG-11 but could not find solid copper RG-11 that wasn't very expensive and difficult to obtain.)
--------------------------------

My initial thought was two HDB91X antennas separated by about 30 inches on a 4 foot mast, connected to a combiner with identical 4-foot coaxial cables, then connected with a 2-foot cable to a preamp and then to the downlead to the TV. (I've recently been experimenting with a single antenna and the Winegard LNA-200 preamplifier at different directions to see which directions and roof positions will work best.)

However, I now have this (expensive) Televes amplifier/combiner which would allow THREE inputs (UHF, UHF, UHF/VHF) where one UHF passes DC voltage, so I could connect the 2608 antenna (very cheaply built and I'd never trust the rotating feature to work through a Michigan winter) to the DC powered UHF port and the two HDB91X Yagis connected to the other UHF and the VHF/UHF port. Likely I would need to dial down the amplification of the 2608 because it has its own preamplifier.

This also has the advantage of only having one item on the mast instead of two (a separate combiner and preamp).

Any thoughts to this configuration and to using this Televes amplifier/combiner? Or any other suggestions on receiving South Bend and Chicago stations? Any thoughts or suggestions are appreciated.

Bud

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

A quick question about use of the items below:



TNB-WA2608 Tree New Bee which includes its own preamplifier
2512 Linear ChannelPlus DC & IR Passing 2-Way Splitter/Combiner (both paths pass DC voltage)
Coaxial solid copper RG-6 used.


When I connected the WA2608 as the only one of the two inputs connected, the preamp worked (and the red light at the antenna was lit).


As soon as I connected another antenna (which did not require any DC power) to the other input port, the light went out on the WA2608.


Is this an anomaly? Or is it normal for a DC powered preamp to not like something connccted on the other side of a combiner?


Bud

Last edited by budh9534; 11-23-2018 at 05:37 AM.
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post #2 of 114 Old 09-20-2018, 06:54 AM
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Here's your link: http://www.tvfool.com/?option=com_wr...90380935603672


I doubt you'll find many people here who recommend trying to combine antennas. You are almost certainly better off with two separate feeds.



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post #3 of 114 Old 09-20-2018, 08:18 AM
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I don't recommend combining two antennas onto one feedline. My recent post explains why:

https://www.avsforum.com/forum/25-hd...l#post56833878

Some of your stations are fairly strong and a high gain antenna plus a preamp may put you into marginal overload territory. There's no easy way to know if this is happening because the symptom is you just don't receive some stations, especially the weaker ones. I think I'd play it safe and use a CM-3410 distribution amp in the house. This amp has a low noise figure, low gain, high resistance to overload and it will improve your reception almost as much as a mast mounted preamp. I don't know about the Televes preamp, but the other two you listed are only so-so with strong signals.

What were the results of your initial tests?
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post #4 of 114 Old 09-20-2018, 09:37 AM
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Hey, budh9534 ...welcome to the Sunset Coast of Michigan although I no longer live there.

I lived most of my life in your area (just off of the Washington Rd/Glenlord Rd intersection) and I can tell you that unless you live in a really, really bad spot, picking up the South Bend stations is fairly easy to do. Although my antenna was on a 30' tower that my father and I installed in the late 1960's, I wouldn't be surprised if you could get by with an indoor or attic mounted antenna. My house had aluminum siding and no easy access to the attic so if the tower was not already there, I would have probably just mounted an antenna to the eaves on a J-pole.

With my tower and a Channel Master CM-4221HD 4-bay UHG antenna, the South Bend stations were really strong. I replaced a Channel Master CM-4220 2-bay antenna in hopes of getting more signals. The 4221 did get me stations farther away but made little difference with the strong signals from South Bend.

I did not have a VHF antenna, though. I thought about putting one up in addition to the 4221 but my days of climbing that tower were long over so I just stuck with the UHF band. I am trying to remember, but I think the only VHF channel out of Chicago at the time was Channel 2 (WBBM) and since it was a CBS affiliate, South Bend had WSBT which was mostly the same programming except for the local news, and MUCH easier for me to receive. I also think a lot of Chicago stations direct their transmitting power West to their suburbs now and don't really care if people in Michigan get good reception of their stations. SW Michigan's lower population numbers probably have a lot to do with that.

With a preamp that I think was a CM-7778 and a rotator, I could often get TV from as far away as Milwaukee and sometimes even Green Bay "IF" the conditions were right. That big lake doesn't offer a lot of resistance to signals. I was always envious of people who lived right on the shores of Lake Michigan because their potential TV reception must have been terrific.

I live just south of Greenville SC now (I'm retired from a rather large appliance manufacturer near where you live and my TVFool plot here is dismal, at best. It was so bad that I did not even bother trying an OTA antenna until last year and much to my surprise, I get 58 channels (counting the sub-channels). By the time I weeded-out the duplicate PBS stations, Spanish-language, QVC, etc., I still have more than enough channels to keep me occupied.
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post #5 of 114 Old 09-20-2018, 12:40 PM
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budh9534 has started a new thread to ask a question that should have been asked here.


WA2608 antenna power with use of DC passing combiner


https://www.avsforum.com/forum/25-hd...-combiner.html

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post #6 of 114 Old 09-20-2018, 05:20 PM - Thread Starter
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Quote:
Originally Posted by Frostyboy115 View Post
Hey, budh9534 ...welcome to the Sunset Coast of Michigan although I no longer live there.

I lived most of my life in your area (just off of the Washington Rd/Glenlord Rd intersection) and I can tell you that unless you live in a really, really bad spot, picking up the South Bend stations is fairly easy to do. Although my antenna was on a 30' tower that my father and I installed in the late 1960's, I wouldn't be surprised if you could get by with an indoor or attic mounted antenna. My house had aluminum siding and no easy access to the attic so if the tower was not already there, I would have probably just mounted an antenna to the eaves on a J-pole.

With my tower and a Channel Master CM-4221HD 4-bay UHG antenna, the South Bend stations were really strong. I replaced a Channel Master CM-4220 2-bay antenna in hopes of getting more signals. The 4221 did get me stations farther away but made little difference with the strong signals from South Bend.

I did not have a VHF antenna, though. I thought about putting one up in addition to the 4221 but my days of climbing that tower were long over so I just stuck with the UHF band. I am trying to remember, but I think the only VHF channel out of Chicago at the time was Channel 2 (WBBM) and since it was a CBS affiliate, South Bend had WSBT which was mostly the same programming except for the local news, and MUCH easier for me to receive. I also think a lot of Chicago stations direct their transmitting power West to their suburbs now and don't really care if people in Michigan get good reception of their stations. SW Michigan's lower population numbers probably have a lot to do with that.

With a preamp that I think was a CM-7778 and a rotator, I could often get TV from as far away as Milwaukee and sometimes even Green Bay "IF" the conditions were right. That big lake doesn't offer a lot of resistance to signals. I was always envious of people who lived right on the shores of Lake Michigan because their potential TV reception must have been terrific.

I live just south of Greenville SC now (I'm retired from a rather large appliance manufacturer near where you live and my TVFool plot here is dismal, at best. It was so bad that I did not even bother trying an OTA antenna until last year and much to my surprise, I get 58 channels (counting the sub-channels). By the time I weeded-out the duplicate PBS stations, Spanish-language, QVC, etc., I still have more than enough channels to keep me occupied.
My dad owns a second house in Simpsonville SC, though his primary home is still in Maine (where I lived for my first 38 years before moving to Michiana). Likely close to your new location!


My Stevensville MI house is across the street from the Grande Mere restaurant, so I live almost at the top of that (signal blocking) hill giving me clearly better reception of Chicago than your old location. This makes sense since my TVfool reports for antennas 100 and 500 feet up have very little improvement over a 20 foot elevation antenna for Chicago stations, but a clearly more noticable difference for the South Bend stations.


UHF is all I care about. Chicago's WWBM displaying channel 2 is broadcasting on channel 12.1, so it's still VHF. If I don't pick it up, I won't miss it. Everything else that I would have any care to get is UHF, so a purely UHF antenna and UHF combiner and/or preamp would be perfectly OK with me.


That WA2608 Antenna I might try pointing at Green Bay and/or Milwaukee - I'd be curious if I could get those.


Thanks for the response.


Bud
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post #7 of 114 Old 09-20-2018, 07:57 PM
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Quote:
Originally Posted by budh9534 View Post
.....

My initial thought was two HDB91X antennas separated by about 30 inches on a 4 foot, connected to a combiner with identical 4-foot coaxial cables, then connected with a 2-foot cable to a preamp and then to the downlead to the TV. (I've recently been experimenting with a single antenna and the Winegard LNA-200 preamplifier at different directions to see which directions and roof positions will work best.)

.....

Bud
Quote:
Originally Posted by Calaveras View Post
I don't recommend combining two antennas onto one feedline. My recent post explains why:

https://www.avsforum.com/forum/25-hd...l#post56833878

...
Combining 2 identical antennas with equal length coax feeds to a combiner can work well, it the antennas are pointed in the exact same direction, but the spacing can be very critical, and the optimal spacing may not be the same for every channel.
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post #8 of 114 Old 09-21-2018, 11:12 AM
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Quote:
Originally Posted by Channel99 View Post
Combining 2 identical antennas with equal length coax feeds to a combiner can work well, it the antennas are pointed in the exact same direction, but the spacing can be very critical, and the optimal spacing may not be the same for every channel.
The only time the spacing is critical is when you're trying to null out a station by placing it in the first null of the antenna pattern. See this page for how changing the spacing affects the nulls and peaks:

http://www.hdtvprimer.com/ANTENNAS/ganging.html#TAT

The only other thing you have to consider is that the antennas are not so close together that the aperture of the antennas don't overlap. If they do, the increase in gain will be reduced.

There's a formula here for stacking long boom yagis for which the XG91s qualify.

http://k6vhf.com/antenna-stacking-di...calculatorasc/

You need to know the 3dB beamwidth which is available here:

http://www.hdtvprimer.com/ANTENNAS/XG91.html

For a pair of XG91's the minimum spacing should be something over 33".
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I appreciate the information and links you provided.

Regarding the 33-inch separation for one Yagi above the other on top of the other on the same vertical mast, is that center to center distance? Or top of the bottom Yagi to bottom of the top Yagi?

Also, I am using a tripod and have only 4 feet of mast available. If I have one near the top and the other 33 inches below, there would only be about a foot between the bottom Yagi and the top of the tripod. Would this cause a significant issue with so little free space below the bottom Yagi?

Bud

P.S. Most likely I will try several combinations of distances between the Yagis and top of the tripod and slight changes to the Yagi directions pointed approximately at South Bend and Chicago.

I also could change from an 8-foot 1.625" galvanized metal fence post to a 10-foot 1.375" diameter metal electrical conduit, but the structural aspect of the conduit is less desirable. BUT - there would only be 6 feet above the highest support point of the tripod, so perhaps the conduit would be acceptable.

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post #10 of 114 Old 09-21-2018, 11:48 AM
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budh9534 doesn't want his two UHF antennas aimed in the same direction; he wants them aimed in two different directions. The two feed lines from the antennas to the combiner are not required to be the same length. The signals are already out of phase, so the lengths are irrelevant.

spacing chart

https://www.tonercable.com/pdf/antenna.pdf
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post #11 of 114 Old 09-21-2018, 01:32 PM
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Quote:
Originally Posted by budh9534 View Post
I appreciate the information and links you provided.

Regarding the 33-inch separation for one Yagi above the other on top of the other on the same vertical mast, is that center to center distance? Or top of the bottom Yagi to bottom of the top Yagi?

Also, I am using a tripod and have only 4 feet of mast available. If I have one near the top and the other 33 inches below, there would only be about a foot between the bottom Yagi and the top of the tripod. Would this cause a significant issue with so little free space below the bottom Yagi?

Bud

P.S. Most likely I will try several combinations of distances between the Yagis and top of the tripod and slight changes to the Yagi directions pointed approximately at South Bend and Chicago.

I also could change from an 8-foot 1.625" galvanized metal fence post to a 10-foot 1.5" diameter metal electrical conduit, but the structural aspect of the conduit is less desirable. BUT - there would only be 6 feet above the highest support point of the tripod, so perhaps the conduit would be acceptable.
The spacing is center to center. Mine are stacked horizontal as seen in my avatar. Vertical stacking will leave the horizontal pattern unchanged. You don't want to insert miscellaneous metal near the plane of the elements. A taller mast would be helpful. It's doubtful that you'll see any difference in reception by changing the spacing unless the spacing is too small.
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A quick follow up question regarding a recommendation Calaveras gave to me.


Assume the following two cases with antennas mounted on vertical mast on rooftop:


1. One TV supplied by one Yagi antenna, OR
2. One TV supplied by two Yagi antennas pointing in significantly different directions (in my case, about 115 degrees apart) using a combiner at the mast.


In what cases would it be better to use an amplifier just before the TV inside the house instead of a preamplifier at the mast (which would be immediately downstream of the combiner if two antennas are being used)?
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post #13 of 114 Old 09-21-2018, 08:21 PM
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Quote:
Originally Posted by Calaveras View Post
The only time the spacing is critical is when you're trying to null out a station by placing it in the first null of the antenna pattern. See this page for how changing the spacing affects the nulls and peaks:

http://www.hdtvprimer.com/ANTENNAS/ganging.html#TAT

The only other thing you have to consider is that the antennas are not so close together that the aperture of the antennas don't overlap. If they do, the increase in gain will be reduced.

There's a formula here for stacking long boom yagis for which the XG91s qualify.

http://k6vhf.com/antenna-stacking-di...calculatorasc/

You need to know the 3dB beamwidth which is available here:

http://www.hdtvprimer.com/ANTENNAS/XG91.html

For a pair of XG91's the minimum spacing should be something over 33".
There's still the situation where the signals are arriving from a much higher elevation, a 1 or 2 edge signal, usually - where the relative phase will vary with the spacing, or if there is a ground reflection.
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post #14 of 114 Old 09-21-2018, 08:31 PM
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I will answer you previous quick question first.

Quote:
Originally Posted by budh9534 View Post
A quick question about use of the items below:

TNB-WA2608 Tree New Bee which includes its own preamplifier
2512 Linear ChannelPlus DC & IR Passing 2-Way Splitter/Combiner (both paths pass DC voltage)
Coaxial solid copper RG-6 used.
When I connected the WA2608 as the only one of the two inputs connected, the preamp worked (and the red light at the antenna was lit).

As soon as I connected another antenna (which did not require any DC power) to the other input port, the light went out on the WA2608.

Is this an anomaly? Or is it normal for a DC powered preamp to not like something connccted on the other side of a combiner?

Bud
When you connected your second antenna, an HDB91X, you short circuited the power supply. I measured the DC resistance at the coax connector of my HDB91X; it measures less than one ohm.

Is that normal?
Yes

Is it a good idea?
NO

Does the power supply have short circuit protection?
I have no idea.

Did it survive the short circuit?
I don't know; did it?
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Quote:
Originally Posted by budh9534 View Post
A quick follow up question regarding a recommendation Calaveras gave to me.


Assume the following two cases with antennas mounted on vertical mast on rooftop:


1. One TV supplied by one Yagi antenna, OR
2. One TV supplied by two Yagi antennas pointing in significantly different directions (in my case, about 115 degrees apart) using a combiner at the mast.


In what cases would it be better to use an amplifier just before the TV inside the house instead of a preamplifier at the mast (which would be immediately downstream of the combiner if two antennas are being used)?

As far as I'm concerned #2 is a no go for the reasons I've already stated. "Significantly different directions" doesn't make two antennas combined onto one feedline work as you can see in my spectrum analyzer display.

Here's another problem with the two antenna situation. Even if you have an antenna with huge rejection everywhere away from the main lobe, signals reflect off of nearby buildings and hills giving you stronger off pointed signals than you would expect. That can make an antenna look to have a poor pattern when it really doesn't. One antenna pointed in one direction works best. Two antennas combined onto one feedline is a crapshoot.

Some of your stations are in the +45 dB Noise Margin range or -44 dBm signal strength. When you take into account antenna gain, RCA preamp gain and some losses, you might have a number of signals around -15 dBm at the TV. Signals across the band add together to make it even higher. I'd say this is a borderline overload case. You shouldn't need any preamp for stations with a Noise Margin of +20 dB or higher. But I suggested the CM-3410 indoors in case you wanted to split it for several TVs as a fairly safe compromise.
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Quote:
Originally Posted by Channel99 View Post
There's still the situation where the signals are arriving from a much higher elevation, a 1 or 2 edge signal, usually - where the relative phase will vary with the spacing, or if there is a ground reflection.

I remain skeptical of this. I've read a lot of claims for this sort of thing but I've never seen anyone run any sort of controlled test showing it to be true. Even if it is true, no one will be able to figure out exactly what the spacing has to be for one channel to make sure both antennas are in an equal field. In the real world the best you can do is space the antennas so that the apertures don't overlap.
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I will answer you previous quick question first.


When you connected your second antenna, an HDB91X, you short circuited the power supply. I measured the DC resistance at the coax connector of my HDB91X; it measures less than one ohm.

Is that normal?
Yes

Is it a good idea?
NO

Does the power supply have short circuit protection?
I have no idea.

Did it survive the short circuit?
I don't know; did it?
The WA-2608 survived - I was using it this evening with it at ground level near the southeast corner of my house. It gets reasonably good reception, even at ground level there.
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post #18 of 114 Old 09-21-2018, 09:09 PM
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Quote:
Originally Posted by budh9534 View Post
The WA-2608 survived - I was using it this evening with it at ground level near the southeast corner of my house. It gets reasonably good reception, even at ground level there.
Then, put a DC block on the second port before connecting the second antenna to the 2512 Linear ChannelPlus DC & IR Passing 2-Way Splitter/Combiner.

https://www.amazon.com/s/?ie=UTF8&ke...pm36woyj_e_p38

The DC block contains a capacitor in series with the center conductor. It prevents the preamp DC voltage from getting to the second antenna, but allows the signals from the second antenna to enter the combiner.

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post #19 of 114 Old 09-21-2018, 09:14 PM - Thread Starter
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Quote:
Originally Posted by Calaveras View Post
As far as I'm concerned #2 is a no go for the reasons I've already stated. "Significantly different directions" doesn't make two antennas combined onto one feedline work as you can see in my spectrum analyzer display.

Here's another problem with the two antenna situation. Even if you have an antenna with huge rejection everywhere away from the main lobe, signals reflect off of nearby buildings and hills giving you stronger off pointed signals than you would expect. That can make an antenna look to have a poor pattern when it really doesn't. One antenna pointed in one direction works best. Two antennas combined onto one feedline is a crapshoot.

Some of your stations are in the +45 dB Noise Margin range or -44 dBm signal strength. When you take into account antenna gain, RCA preamp gain and some losses, you might have a number of signals around -15 dBm at the TV. Signals across the band add together to make it even higher. I'd say this is a borderline overload case. You shouldn't need any preamp for stations with a Noise Margin of +20 dB or higher. But I suggested the CM-3410 indoors in case you wanted to split it for several TVs as a fairly safe compromise.
Thanks for the information. And for your time.

I am surprised that an NM in the 20s you would think overload would be a concern. I do remember my first tests I did with no preamp pointing first to Chicago and then to South Bend with a single antenna and even the ones at the top of my list (in the high 40 dB range) weren't giving me more than 3 bars out of 5 for WSBT and WNDU in South Bend along with WLS/WXFT in Chicago which are the strongest signals near me.

But your advice is going to make we look at my initial data with NO preamp and I will check to make sure each and every one of those stations I received is also received with the LNA-200 that I have used so far as a preamp.

I'll probably give the combiner a try, realizing from what you've said that it is, in some respect, a crapshoot. When my second HDB91X shows up in the next few days, I'll post how it worked with the JoinTenna combiner, both with and without the LNA-200 preamp

Bud

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post #20 of 114 Old 09-22-2018, 07:50 AM
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Originally Posted by budh9534 View Post
I am surprised that an NM in the 20s you would think overload would be a concern. I do remember my first tests I did with no preamp pointing first to Chicago and then to South Bend with a single antenna and even the ones at the top of my list (in the high 40 dB range) weren't giving me more than 3 bars out of 5 for WSBT and WNDU in South Bend along with WLS/WXFT in Chicago which are the strongest signals near me.

Whoa! I did not say NMs in the 20's would be an overload concern. I said NM's in the mid to upper 40's plus a 10 dB gain antenna plus a 25 dB gain preamp plus many stations in the UHF band MIGHT be a borderline overload concern. On top of all that I know the strong signal characteristics of the RCA and LNA-200 preamps aren't the best.

TV Fool might predict a NM of +25 dB but that goes up to +35 dB with a 10 dB gain antenna. System losses might take that back down to the low 30's. Take a look at my Noise Margin graphic for TV Fool to get an idea of where you signals are. They're not bad. TV Fool shows all my local stations in the range of -10 dB to +10 dB. Yet when all is said and done I measure +25 dB to +45 dB.

I don't know what 3 out of 5 bars means. I assume it's a Signal Quality meter no matter what they call it. WSBT and WNDU are both strong signals. If the Signal Quality is low then it's due to multipath issues. I don't think you've said anything about how clear your view to the transmitters is. Trees or buildings in the way? No antenna or preamp will fix that.
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Whoa! I did not say NMs in the 20's would be an overload concern. I said NM's in the mid to upper 40's plus a 10 dB gain antenna plus a 25 dB gain preamp plus many stations in the UHF band MIGHT be a borderline overload concern. On top of all that I know the strong signal characteristics of the RCA and LNA-200 preamps aren't the best.

TV Fool might predict a NM of +25 dB but that goes up to +35 dB with a 10 dB gain antenna. System losses might take that back down to the low 30's. Take a look at my Noise Margin graphic for TV Fool to get an idea of where you signals are. They're not bad. TV Fool shows all my local stations in the range of -10 dB to +10 dB. Yet when all is said and done I measure +25 dB to +45 dB.

I don't know what 3 out of 5 bars means. I assume it's a Signal Quality meter no matter what they call it. WSBT and WNDU are both strong signals. If the Signal Quality is low then it's due to multipath issues. I don't think you've said anything about how clear your view to the transmitters is. Trees or buildings in the way? No antenna or preamp will fix that.
I just rechecked my original tests without a preamplifier used pointing to Chicago and South Bend.

Unfortunately, my new TCL Roku based TV does not have (that I am aware of) any signal strength meter, so it shows only the strength from one to five bars, similar to many cell phones.

I do have some trees about 50 feet from the antenna, but fortunately there is a good size gap to aim through in the proper direction (only affecting Chicago - the sight line towards South Bend is reasonably unobstructed).

As it turns out, I did get 4 out of 5 on several stations pointing toward South Bend, although Channel 28 was a disappointing 2 out of 5. Similar for Chicago, where I did receive 4 out of 5 on the more notable higher power stations.

Seeing this, I can see the potential for an overload situation with a preamp, especially if two antennas are connected and they add signals instead of subtract signals for certain stations.

I guess all I can do is try it and see what happens. I know what stations SHOULD be showing up (everything that showed up with a single antenna without a preamp), so I'll quickly know if overload is an issue!

Again, thanks for the information.

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post #22 of 114 Old 09-22-2018, 06:30 PM - Thread Starter
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Stevensville MI: Initial test with two antennas, with and without preamp

Here are my initial results using two identical Yagi antennas pointed in two different directions, both with and without a preamp. In no case did using the preamp lose a station. One station only (WBND-57 in South Bend) failed to be available, despite it often being available with a single antenna pointed at South Bend.

Here are the results of my brief test very late this afternoon.

Bud

Stevensville, Michigan, two HDB91X Yagis, one at 24 feet above ground pointing toward South Bend (154 degrees magnetic), the other 21.5 feet above ground pointing toward Chicago (266 degrees magnetic), no significant obstructions (large gaps in tree trunks available in trees 30 feet away from the antennas. Winegard CC-7870 Antenna Coupler used as the antenna combiner.

Case 1 is with NO PREAMP.
Case 2 is identical to Case 1 but an LNA-200 Winegard preamp is installed one foot downstream of combiner.

My only signal strength indication I have available on my new TCL Roku based TV is one to five bars out of five maximum. I'll show the notable South Bend and Chicago stations I'm interested in, first giving you the signal strength without the preamp and then with the preamp.

All stations are Chicago unless identified as South Bend.

Headings used:

Virtual/Display channel, (actual channel), station, network, signal strength without preamp, signal with preamp

5.1, (29), WMAQ, NBC, 4, 5

7.1, (44), WLS, ABC, 4, 5

9.1, (19), WGN, 2, 4
11.1, (47), WTTW, PBS, 3, 5
16.1, (42), WNDU, NBC, 3, 5 (South Bend)

20.1, (47), WYCC, MHz, 3, 5
22.1, (22), WSBT, CBS, 4, 5 (South Bend)

25.1, (25), WCWW, CW, 2, 4 (South Bend)
26.1, (27), WCIU, 3, 5
28.1, (28), WSJV, H&I, 4, 5 (South Bend)

32.1, (31), WFLD, Fox, 3, 5
34.1, (35), WNIT, PBS, 3, 5 (South Bend)

38.1, (43), WCPX, ION, 3, 4
44.1, (29), WSNS, Telemundo, 4, 5
46.1, (48), WHME, 4, 5 (South Bend)

48.1, (32), WMEU, 2, 3
50.1, (51), WPWR, CW, 3, 5
57.1, (34), WBND, 0, 0 (this low power South Bend ABC unfortunately didn't come in, but interfering Chicago WDCI-Daystar unfortunately did)

57.1, (30), WDCI, Daystar, 2, 2
57.2, MeTV, 0, 4 (tied to WBND, but WBND channel 57.1 could not be received)

57.3, Movies, 0, 4 (tied to WBND but WBND channel 57.1 could not be received)

60.1, (44), WXFT, 4, 5
66.1, (38), WGBO, 2, 4
69.1, (39), WMYS, 2, 5 (South Bend)

CONCLUSION? I did not lose ANY channels (presumably to overload) when the LNA-200 preamp was connected and NEARLY all the channels I'd want had signal strengths of at least 4 out of 5 with the preamp in use. It takes a very solid 2 out of 5 on my TV to be able to watch it with few "glitches", but I consider needing at least 3 out of 5 to be acceptable for viewing.

That WBND channel 57 station really annoys me that I could not receive it all, especially when I could receive it with a single antenna pointed at South Bend. Otherwise, I was very pleased with these initial results using two antennas in different directions.

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post #23 of 114 Old 09-22-2018, 07:25 PM
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^^Sometimes combining 2 antennas can cancel out or interfere with a certain channel. Sometimes it works and other times it can be a problem.
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post #24 of 114 Old 09-23-2018, 07:46 AM
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Originally Posted by budh9534 View Post
Here are my initial results using two identical Yagi antennas pointed in two different directions, both with and without a preamp. In no case did using the preamp lose a station. One station only (WBND-57 in South Bend) failed to be available, despite it often being available with a single antenna pointed at South Bend.

Stevensville, Michigan, two HDB91X Yagis, one at 24 feet above ground pointing toward South Bend (154 degrees magnetic), the other 21.5 feet above ground pointing toward Chicago (266 degrees magnetic), no significant obstructions (large gaps in tree trunks available in trees 60 feet away from the antennas. Winegard CC-7870 Antenna Coupler used as the antenna combiner.

My only signal strength indication I have available on my new TCL Roku based TV is one to five bars out of five maximum.

57.1, (34), WBND, 0, 0 (this low power South Bend ABC unfortunately didn't come in, but interfering Chicago WDCI-Daystar unfortunately did)

57.1, (30), WDCI, Daystar, 2, 2
57.2, MeTV, 0, 4 (tied to WBND, but WBND channel 57.1 could not be received)

57.3, Movies, 0, 4 (tied to WBND but WBND channel 57.1 could not be received)

That WBND channel 57 station really annoys me that I could not receive it all, especially when I could receive it with a single antenna pointed at South Bend. Otherwise, I was very pleased with these initial results using two antennas in different directions.
Thank you for the interesting detailed report. Your combining worked better than I expected.

I think your 57.1 problem is caused by a PSIP error in your tuner. It picks up 57.1 virtual for Daystar instead of ABC.

https://en.wikipedia.org/wiki/Progra...ation_Protocol

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post #25 of 114 Old 09-23-2018, 07:58 AM - Thread Starter
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Thank you for the interesting detailed report. Your combining worked better than I expected.

I think your 57.1 problem is caused by a PSIP error in your tuner. It picks up 57.1 virtual for Daystar instead of ABC.


https://en.wikipedia.org/wiki/Progra...ation_Protocol

Excellent observation on the 57.1 display WDCI Daystar (physical 30.1) that I do NOT want to see, and the 57.1 display WBND ABC (physical 34.3) that I DO want to see.

Is this really caused by a PSIP "error" in the TV tuner? What should the TV tuner do if two channels with different physical channels but the exact same display channel are encountered by the tuner? How does it decide which one to choose to be (in my case) the display 57.1 channel?
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post #26 of 114 Old 09-23-2018, 08:31 AM
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I'm not certain there is anything you can do other than a separate antenna and separate tuner for that ABC. You can look in the TCL menu to see if you can do a channel edit. Some network tuners, like the Silicon Dust HDHR, might be able to do an edit.


http://www.atscforum.org/psip_reasons.html
Quote:
Top Reasons for Using PSIP

There are a number of good reasons for doing PSIP right. Here are a dozen for you to consider:

Cool acronym
Facilitates navigation of multiple program offerings
Will work with translators with no fuss or bother
Directed Channel Change for customized program services
Broadcaster Major Channel Number survives repacking of DTV RF channels
Provides accurate time of day
Supports delivery of electronic program guide (EPG)
Delivery of content advisory information
Maintains broadcaster analog channel branding
Announcement of caption services
Some receivers may not work correctly if you don't do PSIP right
Provides viewers with easy access to DTV programming

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I'm not certain there is anything you can do other than a separate antenna and separate tuner for that ABC. You can look in the TCL menu to see if you can do a channel edit. Some network tuners, like the Silicon Dust HDHR, might be able to do an edit.

http://www.atscforum.org/psip_reasons.html
I suppose there are all sorts of little things I can try, some of which will probably make very little, if any, difference:

1. Try different length cables from antennas to combiner in a several combinations.
2. Point the South Bend antenna a bit closer to east a few degrees, near 150 degrees magnetic instead of 154 degrees (likely better for display channel 57.1 WBND).
3. Point the Chicago antenna closer to southwest (approximately 225 degrees) instead of 266 degrees to help cut out WDCI-Daystar and hopefully not degrade too much the other Chicago stations.

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post #28 of 114 Old 09-23-2018, 04:46 PM
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^^TCL tuners have problems with PSIP. If there are two of the same virtual channels, it will only list one. The other virtual channel will be identified as the real channel.
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Stevensville MI - mounting methods

Initially, I planned on an eaves mount with a 60-inch horizontal member attached to the left and right side. But with the pitch of my roof being very shallow (12:4), that would mean the attachment point at the peak of the roof would be only about a foot above the horizontal piece, which seemed like it would not be sturdy enough, especially to hold a mast close to 8 feet tall with two Yagi antennas pointed in different directions.

Then I briefly considered a J-mount attached to the side of the roof beam near the peak - but to use it needing about 8 feet with two antennas, that seemed like it might not be that sturdy.

So I settled on the tripod I received a few weeks ago. But.....now I realize I can get two of the three tripod legs attached to joists for good strong attachment - but not the third leg which would be drilled into something much less solid, which is concerning me.

So I'm back to the drawing board with the possible eaves mount or J-mount.

Anyone have experience using one of these with a mast near 8 feet with two antennas attached, and in the eaves mount case using it with a shallow pitched roof?

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post #30 of 114 Old 09-23-2018, 06:34 PM - Thread Starter
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^^TCL tuners have problems with PSIP. If there are two of the same virtual channels, it will only list one. The other virtual channel will be identified as the real channel.
BINGO! I didn't notice that WNIT-PBS 34.1 in South Bend has a 34.2 channel - but it does NOT have a third 34.3 channel.

WBND-ABC in South Bend has a PSIP of 57.1, but broadcasts on physical channel 34.

Imagine my surprise to find a displayed mystery channel 34.3 which should not be there....but it IS the 57.1 WBND that broadcasts on physical 34.

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