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Old 22-Feb-2016, 11:06 PM   #1
randomguy
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Join Date: Nov 2013
Posts: 11
Combining antennas...questions. LONG POST

I am using one Clearstream 2V with a preamp. It's works fine and I receive between 50-60 channels (including subs). Yes, that is a lot but there are others that scan but don't quite come in.

I don't have it mounted as high as I could. Since I rent, I am limited as to where I can mount it. Plus, I don't have a ladder to get up to the roof or to eave mount it. It is currently mounted on the side of the building out side a second story window.

I have been considering hiring someone local with a ladder to help me eave mount it. Since I would be up there and only want to do it once, I thought I might as well get all the channels I can.

When I was first testing the 2V out the various second story windows, I would pick up a few different channels that I couldn't get from outside of other windows. So, I settled on where I got the most channels and had to give up a few to do that. Those were in another direction though.

Now, I'm thinking if I had the antenna up higher I might pull in some of the channels I have trouble with (Tree in front of it) in it's current location. Also, I was considering mounting a second 2V in another direction to get those channels that I had to give up.

Here are my questions about combining antennas:

1) Would combing them in series (after aiming them in different directions) then to the preamp be a good idea? (to eliminate using a combiner and another preamp) Or, would that be too much gain? I have a combiner that I bought and never used so it won't cost me anything now.

2) If the antennas are eave mounted I would have to come up with a way to put them on the same mount. Probably a "T" mount (I will have to construct that). What distance would they need to separated by?

3) Would an eave mount hold the weight of two 2V's? They are light, maybe 6-9 pounds?

4) If they have to be mounted to separate preamps then to a combiner...how important is it to use the EXACT same cable length?

5) Is it best to use the same antenna? I thought it would make things easier signal wise but I'm only guessing at that.



I would appreciate your insight.


Thanks.
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Old 23-Feb-2016, 1:00 AM   #2
rabbit73
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Quote:
LONG POST
Thanks for the warning.

LONG ANSWER

We need to see your tvfool report. Your old report is no longer available.
Quote:
I have been considering hiring someone local with a ladder to help me eave mount it. Since I would be up there and only want to do it once, I thought I might as well get all the channels I can.
There is no guarantee that location will be any better than your present location. Some testing will be required.

The antenna needs to be in the location where the signals exist, possibly not where you want it to be.
Quote:
Now, I'm thinking if I had the antenna up higher I might pull in some of the channels I have trouble with (Tree in front of it) in it's current location.
You might, or might not.
Quote:
I was considering mounting a second 2V in another direction to get those channels that I had to give up.
There is a good chance that it will pick up other channels that you don't get now.

Can you tell us what channels you get now, by callsign and real channel number, and what channels you would like to get that you don't get now?
Quote:
1) Would combing them in series (after aiming them in different directions) then to the preamp be a good idea? (to eliminate using a combiner and another preamp) Or, would that be too much gain? I have a combiner that I bought and never used so it won't cost me anything now.
It is possible to combine two similar antennas with a splitter in reverse as a combiner, but it doesn't always work when they are aimed in different directions. This is because when the same signals from each antenna arrive at the combining point, they will interfere with each other if they are not in phase. Sometimes it works, sometimes not.

When it doesn't work, there will be some channels missing that you were able to get from the separate antennas before combining.
Quote:
2) If the antennas are eave mounted I would have to come up with a way to put them on the same mount. Probably a "T" mount (I will have to construct that). What distance would they need to separated by?
They could be side-by-side, one above the other, or back-to-back; you haven't given us enough information about the relative directions.
Quote:
3) Would an eave mount hold the weight of two 2V's? They are light, maybe 6-9 pounds?
Probably, if it was a 5 ft mast.
Quote:
4) If they have to be mounted to separate preamps then to a combiner...how important is it to use the EXACT same cable length?
That might not be the best way to combine them. The current for two preamps would have to pass through a special power passing combiner. Will one power supply be able to provide enough current for two preamps? The two cables only need to be the same length when two identical antennas are aimed in the same direction for more gain. Otherwise, it is irrelevant.
Quote:
5) Is it best to use the same antenna? I thought it would make things easier signal wise but I'm only guessing at that.
It would depend upon the signals in the other direction; they might require a different antenna.
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Last edited by rabbit73; 23-Feb-2016 at 1:45 AM.
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Old 23-Feb-2016, 1:29 AM   #3
randomguy
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Quote:
Originally Posted by rabbit73 View Post
Thanks for the warning.

LONG ANSWER

We need to see your tvfool report. Your old report is no longer available.

There is no guarantee that location will be any better than your present location. Some testing will be required.
You might, or might not.
There is a good chance that it will pick up other channels that you don't get now.

Can you tell us what channels you get now, and what channels you would like to get that you don't get now?
It is possible to combine two similar antennas with a splitter in reverse as a combiner, but it doesn't always work when they are aimed in different directions. This is because when the same signals from each antenna arrive at the combining point, they will interfere with each other if they are not in phase.
I wasn't asking about specific channels but here is my report:

http://www.tvfool.com/?option=com_wr...5134333e3902b1

The virt. channels I get now are:

60 69 06 03 10 17 39 65 51 35 12 29 61 48 57

Recently I stopped getting:

02 (KJWP MeTV) and 12 (PBS)
They were fine for a couple of years then one day they no longer came in.

Channels I got from different windows and/or heights (but not now):

21 (CBS) When testing from a different window...which surprised me because it is almost 80 miles away. This was well below the roof line too. about 5 feet above the window.
23 (PBS) WNJS 58 miles away.
52 (PBS) WNJT 42 miles away.

I do get some channels like 08 (NBC) that scan in and show the call letters on screen but there is no picture.

Anything from the N.W. or S.W I can pull in would be good. Like I said if I am going to the trouble of hiring someone with an extension ladder I want to make sure I get all he channels I can because I won't be able to get back up there by myself.

Last edited by randomguy; 23-Feb-2016 at 1:38 AM.
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Old 23-Feb-2016, 3:07 AM   #4
rabbit73
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Thanks for the report. It is needed to give any useful answers to your questions.

You are making it hard for me to do an analysis. I asked for callsigns and real channel numbers and you gave me virtual channel numbers. The virtual channel numbers are not given for some of the channels in the report and it is the real channel number that determines what antenna is needed.
http://www.rabbitears.info/search.ph...pe=dBm&height=

Quote:
Anything from the N.W. or S.W I can pull in would be good. Like I said if I am going to t he trouble of hiring someone with an extension ladder I want to make sure I get all he channels I can because I won't be able to get back up there by myself.
Given the constraints you have stated, your expectations are not realistic. A lot of the channels you want are too weak to be reliable and would require a more extensive installation than you seem to be willing to put up.

What you want would require larger antennas with separate feedlines and a switching system, or a large antenna with a rotator.

I think you should be happy with all the local channels you do get from 165 degrees magnetic. Anything more puts you in the category of a DXer hunting for weak channels in all directions.

Quote:
02 (KJWP MeTV) and 12 (PBS)
They were fine for a couple of years then one day they no longer came in.
KJWP is on real channel 2 which is a VHF-Low channel requiring a BIG antenna like the Winegard HD8200U. PBS on real channel 12 is a VHF-High channel. The "V" dipole of your antenna doesn't have much gain for VHF-High channels. I suspect that tree growth has affected these channels.
Quote:
21 (CBS) When testing from a different window...which surprised me because it is almost 80 miles away. This was well below the roof line too. about 5 feet above the window.
23 (PBS) WNJS 58 miles away.
52 (PBS) WNJT 42 miles away.
Even with a bigger installation these will never be reliable.
Quote:
I do get some channels like 08 (NBC) that scan in and show the call letters on screen but there is no picture.
That is a weaker, 2Edge, VHF-High channel in another direction that would require an antenna like the Winegard HD7698P.
__________________
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; 23-Feb-2016 at 3:29 AM.
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Old 23-Feb-2016, 3:56 AM   #5
randomguy
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Quote:
Originally Posted by rabbit73 View Post
You are making it hard for me to do an analysis. I asked for callsigns and real channel numbers and you gave me virtual channel numbers. The virtual channel numbers are not given for some of the channels in the report and it is the real channel number that determines what antenna is needed.

Sorry.You can cross reference them in the Analysis Report you asked for.
I wasn't asking about other antennas just the 2V as I stated.


http://www.rabbitears.info/search.ph...pe=dBm&height=

Given the constraints you have stated, your expectations are not realistic. A lot of the channels you want are too weak to be reliable and would require a more extensive installation than you seem to be willing to put up.

If I was able to get a reliable signal from 80 miles away with an antenna angled on a stick out a window , there is a good chance I can get others in the same area when the antenna is up higher and not blocked by the building.

What you want would require larger antennas with separate feedlines and a switching system, or a large antenna with a rotator.

I think you should be happy with all the local channels you do get from 165 degrees magnetic. Anything more puts you in the category of a DXer hunting for weak channels in all directions.

I never said I wasn't happy with what I have.



KJWP is on real channel 2 which is a VHF-Low channel requiring a BIG antenna like the Winegard HD8200U. PBS on real channel 12 is a VHF-High channel. The "V" dipole of your antenna doesn't have much gain for VHF-High channels. I suspect that tree growth has affected these channels.

As I stated, these channels were very reliable. They are not that far away either. They are broadcast from the same antenna farm that many of the stations I get now broadcast from. Plus it is the middle of Winter. The one tree near the antenna has no leaves on it. I may have to angle the antenna more upright because it may have bent sideways a little from the recent winds. That could be the reason they are not coming in.


Even with a bigger installation these will never be reliable.
That is a weaker, 2Edge, VHF-High channel in another direction that would require an antenna like the Winegard HD7698P.
Thanks for the reply. It seems like you are trying to help but you are going into areas I didn't ask about and you are not familiar with my situation. That is what I tried to explain in my OP.

I will have to try it myself and see what happens. The only thing I need to buy is an eave mount and 2nd antenna as I have cable and a preamp available. I have plenty of pipe to build a stand.
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Old 23-Feb-2016, 12:57 PM   #6
rabbit73
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Location: S.E. VA
Posts: 2,565
Quote:
It seems like you are trying to help but you are going into areas I didn't ask about
Every reception location is unique and requires a custom solution. Generic general questions will only get you generic general answers.

If your mind is closed to new ideas that don't agree with your old ideas, how can you learn anything new?

It is not in your best self-interest to be hostile to someone who is trying to help you. It tends to stop the flow of useful ideas.
Quote:
I will have to try it myself and see what happens.
Since you seem to resent my questions and advice, I think that is an excellent idea.

Good luck with your project.

Best regards,
rabbit
__________________
If you can not measure it, you can not improve it.
Lord Kelvin, 1883
http://www.megalithia.com/elect/aeri...ttpoorman.html

Last edited by rabbit73; 24-Feb-2016 at 11:25 AM.
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Old 23-Feb-2016, 2:50 PM   #7
rickbb
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Join Date: Dec 2014
Posts: 321
Combining antennas is always a trial and error situation. There just is not a reliable and repeatable method to do so.

The signals do all kinds of strange things, they get reflected and bounced off buildings, the atmosphere, the ground, roofs, split apart by tree limbs and other objects then they re-combine behind the object, and so on.

Just the placement of one antenna can, (and often is), trial and error. To try to combine them is more so.

Here is some good reading on the subject. (At least it helped me understand the issue better.)

http://www.hdtvprimer.com/antennas/merging.html
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