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SqEyez12

Multiple Wisi Antenna Array Possible?

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Is it possible to have two WISI antennas at different locations on one's roof, connected, so that they act as a single array for TV reception?

The reason I ask is that I am in a fringe area (country NSW) and a signal survey across my roof could find no one location where all 5 channel groups (2,3,5,6,8) are good, there is always one or more channels that fail.

So i was thinking that if you had two locations were, say, 2,3 6 were good and a second location where 5 and 8 were good, if you could have a WISI antenna at each location and connect them in some way so they formed a single array (i.e. one antenna would not interfere with the other) then one should get good reception on all channels.

An antenna tech who did the survey today said it is not possible, but I thought I would ask here anyway.

TIA

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One thought - I would consider a second opinion & ask about the test antenna being used. The survey maybe completely correct. But depending on the antenna being used there maybe scope for a different antenna to pick up all channels from one location. In terms of what your asking above - I don't think it can be done unless the antennas are separate frequency groups - UHF/VHF or they are different polarities H/V. Which your situation doesn't sound like either of these.

In saying this I would be eager to hear from others as my understanding & installing of combined antennas has been limited to VHF with separate UHF antenna.

Edited by rapturedigital

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In some countries it is common practice to have multiple antennas on a single pole (even 4 or 5 of them) pointing in different directions, sometimes many of them are for channels in the same band. How would two antennas in different locations receiving the same frequency band be different? I know it's not as simple as that, but wanted to know the details.

Edited by Ron12

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Hi SqEyez12

This may help and in my case has been in operation on very low signals for some time now.

https://www.dropbox.com/s/a40c46xo6b9qy65/Dual%20Receive%20System%201.png?dl=0

https://www.dropbox.com/s/wm261vluaqmhlrn/Dual%20Receive%20System%202.JPG?dl=0

James

Edit (Of course the filter band pass frequency, antenna selection and polarity of antennas is to suit my purposes, you'll need to select the right filters and antennas for your system.)

Edited by James T Kirk

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Hi SqEyez12

This may help and in my case has been in operation on very low signals for some time now.

https://www.dropbox.com/s/a40c46xo6b9qy65/Dual%20Receive%20System%201.png?dl=0

https://www.dropbox.com/s/wm261vluaqmhlrn/Dual%20Receive%20System%202.JPG?dl=0

James

Edit (Of course the filter band pass frequency, antenna selection and polarity of antennas is to suit my purposes, you'll need to select the right filters and antennas for your system.)

These look like two WISI antennas but oriented at right angles, is this correct? What is the significance of the right angle orientation?

Your use of two MDA20U masthead amps is interesting, what overall gain does this achieve?

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Hi SqEyez12

These antennas are Doss UPA-4's.

The upper horizontally polarised antenna is looking at one transmission site and the lower vertically polarised antenna is looking at a completely different transmission site.

The MDA20U is a very low noise amplifier with only 19dB gain and capable of quite high output levels without producing severe intermodulation products. The filters, splitter wired in reverse and the first MDA20U are all located at the masthead to ensure the carrier to noise ratio is maintained as far as possible. This system is above the garage some 20 metres from the house and so the second MDA20U is inserted in the garage just before cable heads for the house so there is sufficient signal on arrival at the house.

In total there's about 38dB gain in the amps and 5dB loss in the filter/splitter combination resulting in about 33dB gain minus the loss up to the house.

James

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Hi SqEyz12 - Can you provide some more details about your location. You can go to Myswitch, put in your address & see if there are multiple transmission sites available. With this information you can check each transmission site, then check it's available channels then down below is technical details showing channels, frequencies & importantly each channels polarisation. If you do have several transmissions sites with different polarisation (V & H) as with James post above. Just an important point about stacking to keep in mind is to separate the antennas, maybe preventing the need for filters (Except 4G filters) - More details will help to provide you some options!!

Edited by rapturedigital

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Is it possible to have two WISI antennas at different locations on one's roof, connected, so that they act as a single array for TV reception?

The reason I ask is that I am in a fringe area (country NSW) and a signal survey across my roof could find no one location where all 5 channel groups (2,3,5,6,8) are good, there is always one or more channels that fail.

So i was thinking that if you had two locations were, say, 2,3 6 were good and a second location where 5 and 8 were good, if you could have a WISI antenna at each location and connect them in some way so they formed a single array (i.e. one antenna would not interfere with the other) then one should get good reception on all channels.

An antenna tech who did the survey today said it is not possible, but I thought I would ask here anyway.

TIA

Years ago we did some tricky things with diversity digital receivers hooked to two antennas to achieve this, haven't had any for quite some time. but if you want to experiment I'd try looking around for a dual or quad diversity receiver (quite a few made for cars). There are other ways using single channel amplifiers and tight filters fed from different antennas but you're talking $$$$ and typically only done in commercial installs

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The reason I ask is that I am in a fringe area (country NSW) and a signal survey across my roof could find no one location where all 5 channel groups (2,3,5,6,8) are good, there is always one or more channels that fail.

It helps if you post where you are.

Signal surveys should use a selection of antennas and/or masthead amplifiers at different heights & locations, not just on the roof either.

WISI antennas may not be as effective at the frequencies your local transmitter uses when compared with a narrow band yagi - again, only a proper site survey could determine this.

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It helps if you post where you are.

Signal surveys should use a selection of antennas and/or masthead amplifiers at different heights & locations, not just on the roof either.

WISI antennas may not be as effective at the frequencies your local transmitter uses when compared with a narrow band yagi - again, only a proper site survey could determine this.

I am in an obscure rural area called Martinsville, a valley surrounded by mountains and known for poor TV reception. MySwitch indicates Mt Sugarloaf as the relevant transmitter and that there is likely to be mountainous terrain intervening. However I am slightly elevated on a hill and can see Mt Sugarloaf.

How does a "site survey" differ from the rooftop signal survey that I have just had done, and what is the approximate cost?

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I am in an obscure rural area called Martinsville, a valley surrounded by mountains and known for poor TV reception. MySwitch indicates Mt Sugarloaf as the relevant transmitter and that there is likely to be mountainous terrain intervening. However I am slightly elevated on a hill and can see Mt Sugarloaf.

How does a "site survey" differ from the rooftop signal survey that I have just had done, and what is the approximate cost?

MySwitch is only an indication of possible coverage, as there can be instances where MySwitch says no coverage & that is not so, and also the opposite.

The site survey I do (if there is a reception problem) consists of testing for reception with a number of antennas/masthead amplifiers at different heights & locations all over the property. Not just the roof. This could take up to an hour before deciding if VAST is a better option.

I have mounted antennas on outbuildings, fence lines, on the ground etc if a useable signal is available, and it's possible to get a cable to the main residence without too much trouble.

The cost? I can't say for where you are, depends on what the locals charge.

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You would not install Wisi phased arrayed antenna in different locations but you would phase stack, combining two Wisi on the same mast pointing in the same direction to try and improve incoming signal for amplification. I have in the past done installations at Sandy Hollow which is far distance from Mt Sugarloaf and have used single Wisi antenna. The most critical part of those installations was the height of the antenna and it was not a case of height mean might in regards to receiving a better quality signal.

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You would not install Wisi phased arrayed antenna in different locations but you would phase stack, combining two Wisi on the same mast pointing in the same direction to try and improve incoming signal for amplification. I have in the past done installations at Sandy Hollow which is far distance from Mt Sugarloaf and have used single Wisi antenna. The most critical part of those installations was the height of the antenna and it was not a case of height mean might in regards to receiving a better quality signal.

What extra gain would you get from two WISI antennas as compared to one?

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If I remember correctly 3-4db.If you are a fair way from the transmitter and in undulating terrain the signal will be all over the place ie. some channels not all from the same location and this same result from multiple test locations. Stacking antennae basically increase signal receiving surface area of the antenna and hopefully this greater surface area captures all signals from the one location on the roof.

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Hi debruis - If I am reading you right are you creating a higher gain antenna from two same antennas phase stacked? If Yes - I am interested in your further thoughts & Info on installation requirements of Phase Stacking these antennas. Do they require specific separation distances & combining requirements eg. same length cabling to combing point? Also does this improve Signal Quality reading or just Signal Power? - Just wanting to learn more!!

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Yes that is correct. You are right about cable lengths and antennae separation. Luckly enough there is mounting hardware available that is really good for setting up these type of installations. Generally this is only minor adjustments done with a field strength meter. There are also specific stacking combiners available as well. Yes it does improve both signal strength and quality. As it is used in fringe signal area mainly you are trying increase quality and strength so you can the amplify a half decent signal and not just amplifying crap/noise. Matchmaster used to have a good diagram on their website explaining stacking while of course plugging their equipment at the same time but it is not there anymore. You might want to try Wisi site for the information. I hope this has been some help.

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