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Discussion Starter · #21 · (Edited)
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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Discussion Starter · #22 · (Edited)
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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^^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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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/Program_and_System_Information_Protocol

 

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Discussion Starter · #25 ·
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/Program_and_System_Information_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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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
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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Discussion Starter · #27 · (Edited)
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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Discussion Starter · #29 · (Edited)
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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Discussion Starter · #30 · (Edited)
^^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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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.

Could the broadcasters and FCC have made this whole situation any more confusing and complicated for the average OTA end user? Not sure exactly how. I feel sorry for manufacturers of TV tuners and/or OTA set top boxes who have to work with this mess. :frown:
Wait for ATSC 3.0 when it will get even crazier.
 

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Discussion Starter · #32 · (Edited)
Tripod mounting on top of roof - question on type and dimensions

I purchased a Skywalker Signature Series 5 ft Heavy Duty Tripod (https://www.amazon.com/gp/product/B01MDUK022/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1 ) because it had three points of contact with my expected 8-foot mast. I've had it almost a month and only today did I look into installing it on the roof, now that I know exactly where I want it located.

Unfortunately, geometry got in the way, and a large part of that is that none of the legs are adjustable in length.

When the tripod legs are fully spread, there is 28 inches between the feet. The rafters supporting my roof are 16 inches apart (which is very common). If the legs spread far enough so there was 32 inches between the feet, it would be easy - two points of contact 32 inches apart above two different rafters one side of the peak, and the third point of contact on the other side of the peak at the rafter in between the first two.

But it's only 28 inches. Only if I brought the legs together (making it less stable) could I reduce it to 16 inches and then I could get only two feet (both on the same side of the peak) attached at a rafter. But the lone attachment point on the other side of the peak would be half way between rafters and not allowing good support. And being the lone attachment point on that side of the peak ma3kes it worse.

If that third leg could be shortened, I could attach the two long legs to the rafters, one on each side of the peak, and attach the third leg AT the peak. But no dice - all legs are the same length.

Is it reasonable to try using this tripod with only 16 inches between the feet and only two attachment points at a rafter?

Are there any tripods out there with installation much clearer with standard 16-inch rafter separation?


 

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Don't change the spacing of the legs. If the sheathing isn't strong enough to fasten the single leg even with an added plywood plate inside, attach a piece of wood inside across the two rafters, which will provide a middle attachment point for the single leg with a long bolt.


DISCLAIMER


I'm not a contractor or an engineer. The final decision is your responsibility.
 

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Discussion Starter · #34 · (Edited)
Don't change the spacing of the legs. If the sheathing isn't strong enough to fasten the single leg even with an added plywood plate inside, attach a piece of wood inside across the two rafters, which will provide a middle attachment point for the single leg with a long bolt.


DISCLAIMER


I'm not a contractor or an engineer. The final decision is your responsibility.
You just made me realize I can spread the legs out the full 28 inches between the feet, rotate the tripod slightly, and have one foot over one rafter and a second foot diagonally on the opposite side of the peak over an adjacent rafter. Then those two feet can be adjusted staying over their associated rafter and probably the third foot, which will NOT be over a rafter can be positioned to keep the mast vertical.

The tough part is how to firmly attach that third foot. If the wind is coming from the direction of the third foot, it will want to be pulled out of the roof which is the danger situation!

Just because I have a master's degree in physics with a minor in mechanical engineering doesn't mean I'm very good at home repair stuff. Especially something like this.
 

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Another alternative (because I didn't fully understand the problem):

Bolt 2 x 4s against the side of the rafters on the two-leg side to have 28 inch spacing; the 2 x 4s can be spaced out with thinner boards if necessary, or use 4 x 4s. The leg on the other side will match the middle rafter on the other side.

http://www.dennysantennaservice.com/1475651.html
 

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Discussion Starter · #37 · (Edited)
If my math is correct, maybe this will work:


I appreciate the drawing, with the graph paper accurately depicting the 1.5 inch width of the (16 inch center to center) rafters.

I will be sending back to Amazon my SkyWalker three points of contact to the mast tripod which max'd out at 28 inches between the feet and I ordered yesterday from Solid Signal a Winegard 3 Foot Heavy Duty Galvanized Tripod Antenna Mast Mount (SW-0010) for $24 which presumably is shorter and wider, maxing out at 32 inches so it will hit three consecutive rafters when stradling the peak of the roof.

Bud
 

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Discussion Starter · #38 · (Edited)
I've tested the TVPRAMP1R RCA Preamplifier with my two antenna setup and it appears to be working as well as the LNA-200 Winegard Boost XT HDTV Preamplifier.

The RCA TVPRAMP1R preamplifier, unlike the LNA-200, has TWO inputs (a "UHF/COMBINED INPUT" and a "VHF SEPARATE INPUT"), and the latter VHF only input will be unused.

1. What should be put on the unused outdoor VHF only connection to protect it from the elements? A "75 ohm terminator" of some kind?

2. Does anyone have an opinion of the Winegard LNA-200 preamp being any better than the RCA TVPRAMP1R?
 

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Discussion Starter · #39 · (Edited)
I searched for any information about MOUNTING the Winegard CC-7870 coupler (combiner) but there was little information.

The directions that come with it are almost useless, plus the picture of how to mount it so that the three ports are facing down looks incorrect. Plus the holes don't line up and even if they did, the strength of attachment doesn't seem like it would withstand a stiff wind.

My concern is how to attach the CC-7870 to the bracket. Not the bracket attachment to the mast which seems straightforward.

Has anyone out there installed a CC-7870 on a mast before (successfully) and if so, how?

https://manuals.solidsignal.com/Manual_for_CC7870.pdf
 

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Discussion Starter · #40 ·
I searched for any information about MOUNTING the Winegard CC-7870 coupler (combiner) but there was little information.

The directions that come with it are almost useless, plus the picture of how to mount it so that the three ports are facing down looks incorrect. Plus the holes don't line up and even if they did, the strength of attachment doesn't seem like it would withstand a stiff wind.


My concern is how to attach the CC-7870 to the bracket. Not the bracket attachment to the mast which seems straightforward.


Has anyone out there installed a CC-7800 on a mast before (successfully) and if so, how?

https://manuals.solidsignal.com/Manual_for_CC7870.pdf
LOL - things have gone from bad to worse in mounting the CC-7870. The hardware is made for 1.5 inch maximum masts, but mine is 1 5/8"..........
 
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