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Old 6-Nov-2015, 2:56 AM   #1
scott784
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Can I have two separate antennas in my attic?

I have a new DB8e (serving my out of market Charlotte stations to my SW) (up in my attic) and an older Clearstream 4 (serving my local Greensboro stations to my (E - SE) at a lower level in my home. These are both used to serve two separate TV/receivers. Just to be clear, these are entirely separate with their own dedicated coax lines; and I am not trying to combine them in any way.

With that said, I am thinking about relocating my Clearstream 4 up to the highest point in my attic (to maximize reception) on one local affiliate (WGHP) that is somewhat weak and occasionally pixelates during the day.

However, here's my concern. I've got very limited space in the attic; and I've already got a DB8e up there serving a separate TV. So here's the question, can I relocate my Clearstream 4 up to the attic without causing interference with the DB8e? Again, I am not trying to combine them in anyway. However, I am concerned about multipath interference if I physically relocate the Clearstream 4 in close proximately (about 10 feet away) from the DB8e in my attic.

Can anyone advise me about this? Note: I realize I could place a lower powered preamp on the Clearstream 4 (which might eliminate the occasional day time pixelation on WGHP), but I'd rather relocate the Clearstream 4 higher---if it's realistic to do this without multipath problems with the DB8e. The DB8E will continue to be pointed to the SW and the Clearstream 4 (if relocated) would continue to be pointed to the E to SE. I appreciate any feedback on this.
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Last edited by scott784; 6-Nov-2015 at 3:00 AM.
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Old 6-Nov-2015, 4:11 AM   #2
rabbit73
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It isn't likely to be a problem with a 10 ft separation unless one is in front of the other blocking the signal path. However, there are hot and cold signal locations in an attic and the most convenient location might not be the best signal location. I suggest a temporary setup test before drilling any holes and running coax through walls.

Since you have provided an image of you report and not an active link to your report I'm not able to click on the WGHP callsign to see the terrain profile and make a more accurate analysis.

Quote:
I realize I could place a lower powered preamp on the Clearstream 4 (which might eliminate the occasional day time pixelation on WGHP),
It might help if it is only because the signal is weak, but it wouldn't help if the signal has poor quality, as defined by SNR and errors. If there isn't a good signal coming out of the antenna terminals, an amp can't recreate one; GIGO. The antenna must be located where a good signal exists. Hopefully, you have a TV that not only gives signal strength but also SNR and errors like my Sony.
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Last edited by rabbit73; 6-Nov-2015 at 4:25 AM.
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Old 6-Nov-2015, 4:17 AM   #3
scott784
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Quote:
Originally Posted by rabbit73 View Post
It isn't likely to be a problem with a 10 ft separation unless one is in front of the other blocking the signal path. However, there are hot and cold signal locations in an attic and the most convenient location might not be the best signal location. I suggest a temporary setup test before drilling any holes and running coax through walls.
I appreciate the quick feedback. Yes, most definitely, I would run temporary coax up there first (for the Clearstream 4) before doing anything permanent. I guess I can assume (once I do a test) and assuming it checks out okay...that I wouldn't get any surprises later? Perhaps, there's no way to really know that for sure. But I would sure like to think (hope) that a test would give me typical day to day behavior with that setup.

Here's an active link to my tvfool report (below). As far as a signal meter, all i have is the built in signal meter on my TiVo premiere. And I understand all these non-professional devices are like trying to compare apples to oranges. But I do find them helpful when comparing the placement of an antenna, even though it's not like a professional signal meter. Thanks.

http://www.tvfool.com/?option=com_wr...8e03fd60464f18

Btw- I ran this tvfool report with the default setting (for elevation of the antenna). I believe that first report (image) was ran with 10 feet above ground.

Last edited by scott784; 6-Nov-2015 at 4:56 AM.
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Old 6-Nov-2015, 12:15 PM   #4
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How about simply splitting the signal from the DB8e and also feeding that set that currently has the C4 on it. The C4 then can be re-purposed to someone else who can use it..
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Old 6-Nov-2015, 8:21 PM   #5
rabbit73
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He wants an antenna for each direction, and is trying to improve the reception of WGHP using the C4.
http://www.tvfool.com/?option=com_wr...8e03fd60464f18

http://www.tvfool.com/?option=com_wr...dALLTV%26n%3d7

His previous thread:
Help me understand signal loss when using a splitter
http://forum.tvfool.com/showthread.php?t=15785

It's confusing when there is more than one thread for the same reception problem. It would be better to keep it all in one thread.
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Last edited by rabbit73; 6-Nov-2015 at 9:08 PM.
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Old 6-Nov-2015, 10:42 PM   #6
scott784
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Quote:
Originally Posted by ADTech View Post
How about simply splitting the signal from the DB8e and also feeding that set that currently has the C4 on it. The C4 then can be re-purposed to someone else who can use it..
As I mentioned at the beginning of this thread, my question is not about splitting the signal of the DB8e. Actually, that was my original intent with the DB8e; however, due to space limitations in my attic, I am forced to keep the DB8e faced to my south (both panels of the DB8e) (for the Charlotte stations)....versus having one of the panels facing SW and the other E-SE for my true locals. And with this setup, the DB8e has the same issues as it relates to WGHP.

But I have moved beyond that; and I am only asking about the C4 in this thread (not about the DB8e) and (not about splitting any signals). That's why I said I have two separate TVs with totally separate wiring.....and the way I plan to keep it at this time. I also don't want to repurpose the C4; because I want to use it on my downstairs BR/office TV for my true locals only on a single TV. And the downstairs BR/office TV using the C4 is what this thread is about.

Fortunately, I am in a situation where I 'can' get the wiring up to the attic for a second antenna (the C4) for my other TV/receiver. I will run some test wiring before I do it. However, I was only posting this current thread to gather any insight from others as it relates to multipath issues. Thanks.

Last edited by scott784; 6-Nov-2015 at 10:50 PM.
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Old 6-Nov-2015, 10:46 PM   #7
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Quote:
Originally Posted by rabbit73 View Post
He wants an antenna for each direction, and is trying to improve the reception of WGHP using the C4.
Indeed, that is correct.
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Old 6-Nov-2015, 11:12 PM   #8
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If it helps any (with my inquiry about multipath), think of a compass inside my attic. And in that round circle, I've got the DB8e facing on the south side). Then the plan would be to put the C4 on the physical north side of the circle BUT facing to the east for my true locals.

But keep in mind, we are only talking a small amount of workable space here. So that's why I said the C4 would only be about 10 feet away from the DB8e.

I am guessing that there would not be multipath with the possible exception of WXII (to my north) since the DB8e grabs that signal off its back side. And if the C4 was placed in the attic, it would have to grab WXII off its side.

I appreciate any other thoughts.

Last edited by scott784; 6-Nov-2015 at 11:45 PM. Reason: Clarify
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Old 7-Nov-2015, 2:41 AM   #9
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Got it. Missed that detail.

Quote:
C4 would only be about 10 feet away from the DB8e.
With 10' of separation, the antennas should have no effect on each other.
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Old 7-Nov-2015, 4:27 PM   #10
Tower Guy
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When placing two antennas close to each other and at the same height the only thing you need to think about is aiming them in opposite directions.

It like the Ghostbusters Movie, cross the streams and you end up in trouble.
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Old 7-Nov-2015, 11:41 PM   #11
scott784
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So if one is facing south and the other is east, does that suffice? Or when you say opposite directions, do you mean total opposite...as in south versus north?

On a different note, I did (briefly) try the C4 up in the attic last night (facing east). Unbelievably, WGHP was still pixelating...moreso than at a lower level in the house! And this was at night when it normally doesn't happen. Perhaps it was a dead space in the attic where I had the C4 temporarily placed? I didn't have time to continue experimenting with the physical location of the C4 due to it getting so late last night.

I'm going to try (one more time) trying to get the C4 facing east (and also physically placed in the east part of the attic). But it's tough b/c I've got so little space to work with up there. (It's not a full attic--but what there is of it has pretty good elevation--about 25 feet off the ground). The other location I can try placing the C4 up there might put it under 10 feet away from the DB8e. But I would still have the C4 facing east.

I must say, I find it ironic, that I don't have a bit of problem with the Charlotte stations (not a one of them) when using a long range antenna placed up high in the attic using the DB8e facing South to SW. They never pixelate or give me any problems whatsoever; and they are twice the distance away.

But the one offender I have is my local WGHP. It's not really bad, just tends to pixelate somewhat in the middle of the day. But that channel also happens to be my favorite channel for local news so I don't like it doing that at any time of the day.

I appreciate any other feedback on this issue....particularly my question here about the true meaning of opposite directions (as it relates to multipath) and whether or not the C4 facing east and the DB8e facing south might be sufficient to avoid multipath?

I am not going to fight this issue much longer, because the truth is.....I have very good results (overall) with other channels. But if I can clear up WGHP, I will give it one more try when I have time to get back up in the attic.

Last edited by scott784; 7-Nov-2015 at 11:52 PM.
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Old 8-Nov-2015, 12:29 AM   #12
rabbit73
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Quote:
Unbelievably, WGHP was still pixelating...moreso than at a lower level in the house!
Are there objects outside that block the WGHP signal when the C4 s in the attic, like trees or other buildings?
Quote:
And with this setup, the DB8e has the same issues as it relates to WGHP.
Is that when the DB8e is aimed at WGHP or SW?

Does the TiVo have a diagnostics screen that gives signal strength, SNR, and uncorrected errors to help you find a good location for the c4?

Are you using an amp?
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Last edited by rabbit73; 8-Nov-2015 at 2:45 AM.
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Old 8-Nov-2015, 12:56 AM   #13
Tower Guy
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By opposite directions I meant that the two antennas cannot be aimed at each other. The reflector screens of the antenna in front will block the signal from reaching the second antenna.
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Old 8-Nov-2015, 1:46 AM   #14
rabbit73
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I wonder if your local FM signals are strong enough to interfere with TV reception? I did an FM report based on your estimated location:
http://www.fmfool.com/modeling/tmp/c...9/Radar-FM.png

FM filter:
http://www.mcmelectronics.com/produc...-FM-88-/33-341

You can do your own FM FOOL report here to see how close I came. FM reports don't link like TVFOOL reports:
http://www.fmfool.com/index.php?opti...pper&Itemid=29
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Old 8-Nov-2015, 4:52 AM   #15
scott784
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Your report is almost exact to my address. I've just reran the FM Fool report (see attached). Thanks.
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Old 8-Nov-2015, 4:56 AM   #16
scott784
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Quote:
Originally Posted by Tower Guy View Post
By opposite directions I meant that the two antennas cannot be aimed at each other. The reflector screens of the antenna in front will block the signal from reaching the second antenna.
Okay, that clarifies things. And maybe a 10 foot minimum is not a deal breaker provided the two antennas are 'not' facing each other. In my case, my existing attic antenna (the DB8e) facing S to SW for Charlotte and the other (planned one--the C4) facing E to SE for my true locals. Thanks.

Last edited by scott784; 8-Nov-2015 at 5:01 AM.
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Old 8-Nov-2015, 5:00 AM   #17
scott784
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Quote:
Originally Posted by rabbit73 View Post


I wonder if your local FM signals are strong enough to interfere with TV reception? I did an FM report based on your estimated location:
http://www.fmfool.com/modeling/tmp/c...9/Radar-FM.png

FM filter:
http://www.mcmelectronics.com/produc...-FM-88-/33-341

You can do your own FM FOOL report here to see how close I came. FM reports don't link like TVFOOL reports:
http://www.fmfool.com/index.php?opti...pper&Itemid=29
Does the Winegard LNA-200 have a FM trap? I ask that question b/c I have one of those here at the house. (It's not currently hooked up to the C4).
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Old 8-Nov-2015, 5:35 AM   #18
scott784
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Quote:
Originally Posted by rabbit73 View Post
Are there objects outside that block the WGHP signal when the C4 s in the attic, like trees or other buildings?
Is that when the DB8e is aimed at WGHP or SW?

Does the TiVo have a diagnostics screen that gives signal strength, SNR, and uncorrected errors to help you find a good location for the c4?

Are you using an amp?
There are no objects outside in the immediate area of house to block WGHP. And the location of the WGHP tower (about 32 miles away as the crow files) is not too much different from the tower farm where the other Greensboro channels are located (about 30 miles from here). (The WGHP tower is in Sophia, NC--just north of Asheboro NC on the map you posted).

The DB8e has always been aimed at the S to SW. It just worked out this way because my attic space is so tight, I was never able to rotate either one of the DB8e panels. But facing this direction, it does allow me to get outstanding reception on all the (out of market) Charlotte stations 24/7. The DB8e does has a preamp on it; and it does manage to pick up my local Greensboro stations (on the side). But obviously the Greensboro signals are weaker since I could not rotate the DB8e. Still, the other Greensboro stations manage okay with this setup. But with this setup-yes, it also has difficulties locking in WGHP 24/7 without pixelations. It's not a problem all day--typically just middle of day.

But, again, this thread is about my C4 antenna and the fact that I still want to use it (on one of my TV's) to keep it positioned to the E SW for my true locals in Greensboro. Based with what happened with my DB8e (tight attic space) and the fact that I have the DB8e facing S SW.....I would be satisfied to watch all my shows on the Charlotte networks. However, the only issue is local news; and the fact that I would prefer having my true locals for that. This is why I would prefer to keep one TV dedicated to the Greensboro channels and the reason why I want to continue using the C4 (and especially too since I already own it). And since WGHP is my preferred local (for local news), this is why I have been attempting to resolve this reception problem with this station. Obviously, the advantage of the C4 is the fact that it is smaller than the DB8e; and I do have the ability to aim it in any direction I want...so I will continue to use the C4 for one of my receivers. I just need to find a good place for it (up high--and preferably in the attic). Currently, there is no preamp on the C4 and it remains at a lower level in the house.

As for my TiVo, it does have a signal meter on it, which is great when trying to optimize location of an antenna. But I am not aware of it having any other advanced features such as a SNR or diagnostic error readings for OTA.

If relocation of my C4 becomes a problem, I could throw a preamp on it to see if it will resolve the issues on WGHP (as I mentioned at the beginning of this post). However, my understanding of preamps is that they are only really an advantage in cases of long cable runs or where a single antenna stream is split off for multiple TV receivers. And since I am not currently trying to split anything at this time, I don't know if that is a viable solution. And thus, the whole point of this thread about moving my C4 up to the attic. I appreciate the replies here.

Last edited by scott784; 8-Nov-2015 at 6:08 AM.
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Old 8-Nov-2015, 1:44 PM   #19
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Quote:
Does the Winegard LNA-200 have a FM trap?
Yes, but, based on a recently purchased sample, it's largely ineffective below 100 MHz.

You need a full-band filter as all your local strong FM signals are in the lower half of the FM band.
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Old 8-Nov-2015, 4:43 PM   #20
scott784
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Quote:
Originally Posted by ADTech View Post
Yes, but, based on a recently purchased sample, it's largely ineffective below 100 MHz.

You need a full-band filter as all your local strong FM signals are in the lower half of the FM band.
So I now understand a full band FM Trap can help. And rabbit73 previously shared the following link:

http://www.mcmelectronics.com/produc...-FM-88-/33-341

These are so inexpensive. Is there a recommended full band FM Trap that I could buy at my local Home Depot, RadioShack, or other electronics store versus paying for the shipment of such item online? Also, where in the coax line is it generally recommended to install these full band FM Traps? Does it need to go right at the antenna before any preamps or anything else? Thanks.
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