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14 posts

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  Reply # 2116404 29-Oct-2018 16:59
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raytaylor:

 

I use phased array antennas at microwave frequencies so i dont have much expierence with UHF but I imagine it to be the same principal. 

 

 

 

A Yagi antenna is a high gain in a specific direction. 

 

If a tree or object blocks the signal, you can suffer significant loss. Higher gain can sometimes compensate for the loss. But if you are further away from the transmitter, you need more gain. 

 

 

 

A phased array antenna uses two smaller antennas side by side. 

 

This gives more physical space for the antenna to 'catch' the signal, but because of their size, they dont make them as big 
They are suitable if you are closer to the source, where you dont need the gain, but where a tree could be blocking the signal and when it moves, you want the signal to stay good by catching it in the new position where is passes between the branches. 

 

 

 

So imagine a tree trunk / branches / leaves that could be causing you signal issues. 

 

By using a phased array antenna, there is a higher chance it will pick up signals passing through either side of the object. 

 

When the signal is received by both antennas on the phased array, it combines and increases in strength. 

 

 

So yeah they are not garbage, but just have a specific use case, and that is trees while being closer to the transmitter. 

 

When your further away and have tree issues, it can be better to make your own phased array antenna out of two standard yagi antennas. 

 

Only when the signal is very bad or being split many ways do you add an amplifier. 

 

 

 

 

Awesome explanation. 

 

 

 

Thanks for that, 

 

So you're saying a phased array would provide a more quality signal pickup even though it may struggle to receive the signal more than a yagi would? (obviously basing this on my location which is in a valley hidden from the Waiatarua transmitter)

 

what are your thoughts on using a phased array for my particular circumstance?




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  Reply # 2116407 29-Oct-2018 17:02
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SATTV:

 

In my previous employ we would use phase array for UHF signals in most locations, yagi have their uses but most of them made for TV are not as good as they could be.

 

Depending on where you are in Lynfield ( I suspect you are close to Subritzky's old place ) you might be able to point the Antenna to Te Aroha, the downside is Waikato adds.

 

The other option is Sky Tower.

 

However in saying that, I would not be keen on doing too much until construction has completed as installing something now might not be good when construction has finished.

 

John

 

 

 

 

 

 

 

 

Hey John, 

 

 

 

yup very close to subritzkys farm (which is now turning into a huge retirement village, ryman constructions building the village)

 

 

 

Rymans have just installed a phased array on their new buildings so i dont see why i shouldnt. most installers ive called to my place hate on them and then i see one go up almost right next to me haha LOL

 

 

 

Still think Waiatarua would be the best option, Te aroha is wayyy to far and apparently sky tower is just a repeater....


 
 
 
 




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  Reply # 2116409 29-Oct-2018 17:07
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alasta:

 

saintblues:

 

alasta:

 

Phased arrays are certainly not rubbish. I have had one for several years and my reception is rock solid.

 

However I almost have line of sight to Mt Kaukau, so a phased array may not necessarily be suitable for all situations.

 

 

Thats good to know. 

 

See this is odd because ive been told phased arrays should be used in areas where there is no line of site of where there are obstacles in the way.... who installed your phased array when you have direct line of sight?

 

 

It was done by the guy in Breaker Bay - I think his name is Lester Goodfellow.

 

I have line of site to Mt Kaukau from the street but the house is a few metres lower, hence why the antenna almost has line of sight but not quite. Down the hill from me most people seem to have long yagis, so if you're in a valley then that may be better suited to your location.

 

 

 

 

What your saying is the opposite of what ive been told. Ive been told that Yagis go narrow and straight to pick up their signals which would be useful when you have line of site. Phased Arrays for shorter but wider pickup range for when you have obstacles in your way (as per my case)

 

 

 

But your saying use the yagi if im in a hill? 

 

 

 

I'm pretty sure both would probably work no matter which one I put up. Im in Auckland so i doubt there would be issues with barely being able to get a signal. its more about how i can absorb more of the available signal since im down in a valley


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  Reply # 2116428 29-Oct-2018 17:29
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If you are doing an install yourself & haven't a signal strength meter you can use the software ( found in the tuning menu) within your TV or Freeview receiver. You should be able to adjust the aerial direction to show the best signal strength & more importantly the quality / error rate.  Using a phased array the direction is less sensitive & normally means it's easier to find a stable signal. Also very important is that the aerial is correctly oriented horizontal or vertically to match the transmitter.  Of course if all your neighbours are pointing in a particular direction & the same way up then that's the best place to start by copying.  Phased array aerials are usually lighter so less rigging / bracing might be required for the mast. 

 

You can also check this website to confirm which transmitter(s) to try & direction / orientation.

 

 https://www.freeviewnz.tv/faq-library/about-digital-tv/coverage-maps/




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  Reply # 2116429 29-Oct-2018 17:31
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B1GGLZ:

 

Nothing wrong with either type. Just the field patterns are totally different. Yagi has a narrow field pattern while Phased Arrays have a wide field pattern. Whichever one you use depends on location, signal strength and other factors. A Yagi would be much better at extreme range and line of site due to it's narrow field and high gain. Google their antenna field patterns for comparison.

 

 

 

 

By the way, do you think I'll need a masthead amplifier (something like the Kingray MDA20U) if I have the Starview DDM8 distribution module at the end of the 20m run from the aerial to the network cabinet?


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  Reply # 2116434 29-Oct-2018 17:45
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Why don’t you save yourself a whole world of pain , and get someone with the correct equipment to do it for you?

Murray River
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  Reply # 2116440 29-Oct-2018 18:25
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Brunzy: Why don’t you save yourself a whole world of pain , and get someone with the correct equipment to do it for you?

 

AND they can remedy it if it goes wrong.

 

 

 

OP, if you buy the stuff yourself, and it doesn't work, what then?

 

 

 

At least if you get a professional in, they'll fix it.


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  Reply # 2116517 29-Oct-2018 21:53
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saintblues:

 

 

 

By the way, do you think I'll need a masthead amplifier (something like the Kingray MDA20U) if I have the Starview DDM8 distribution module at the end of the 20m run from the aerial to the network cabinet?

 

 

Impossible to tell til you measure the signal strength at the end of the cable. You need professional test equipment to set it all up correctly.




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  Reply # 2120121 5-Nov-2018 12:27
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Hi guys, 

 

Thought id give a quick update. 

 

Discussed it with the installer who agreed to bring both new aerials and try them up on the roof. Really cool guy i must say and did a neat and tidy install.  

 

He measured the signal from both the yagi and the phased array and they provided almost the same signal strengths. Decided to go with the Phased Array just based on my circumstances and the fact that as it is getting good signal & it may outperform the yagi in terms of a more quality signal compared to the yagi. Another house near me just went up and also had a phased array put in so now there's 5 houses near each other all with phased arrays. 

 

The installer also advised I won't be needing a masthead amplifier as the signal strength is good enough and will also get boosted by the starview distribution module that will be installed in the network cabinet 

 

Great outcome and great installer. 

 

Thanks for all your help. Really appreciated. 


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Reply # 2120152 5-Nov-2018 13:07
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I am glad to hear you had such a good outcome along with an able, amiable installer.  Out of curiosity I wonder if you know the signal level at the antenna after installation?

 

Measured in dBuV it might be in the +50 to +70 dBuV range.  For our digital TV transmissions it is probable the installer also measures bit error rate (BER) as a measure of signal quality.


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  Reply # 2120458 5-Nov-2018 19:00
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If he is in as bad an area as he thought ,they are more likely to be in the 40’s

The Starview doesn’t really boost the signal, it just overcomes the signal losses that would occur with a conventional splitter
eg 8 way splitter, 50 in around 34 / 36 out, Starview around the same out as in.



14 posts

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  Reply # 2121181 6-Nov-2018 22:32
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mail2mm:

 

I am glad to hear you had such a good outcome along with an able, amiable installer.  Out of curiosity I wonder if you know the signal level at the antenna after installation?

 

Measured in dBuV it might be in the +50 to +70 dBuV range.  For our digital TV transmissions it is probable the installer also measures bit error rate (BER) as a measure of signal quality.

 

 

 

 

Damn forgot what it was. Ill try get in touch with him tommorow and ask him what the readings were. 




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  Reply # 2121184 6-Nov-2018 22:35
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Brunzy: If he is in as bad an area as he thought ,they are more likely to be in the 40’s

The Starview doesn’t really boost the signal, it just overcomes the signal losses that would occur with a conventional splitter
eg 8 way splitter, 50 in around 34 / 36 out, Starview around the same out as in.

 

 

 

I am defo in a bad area. But ill wait and see tommrow what the reading of the signals were. 

 

 

 

The starveiw has a 3db insertion loss which the installer told me would boost the signal... im not sure if thats true or not as you mention. 

 

 

 

I asked him if i needed a masthead amplifier and he said no. The signal strength is more then good enough to run down to the starview and then to 6-8 rooms. I guess we will only really find out when the house in complete and and all the tvs etc are going. 

 

Will keep you guys in the loop tho. 


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  Reply # 2121189 6-Nov-2018 23:00
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Insertion loss implies that the signal drops by 3db by inserting the device into the circuit. 

 

3db is approx half the signal strength. 

 

If it was just an 8-way splitter, i would expect a 9db insertion loss. 

 

However i am guessing that the starview may be an amplifier also. So it can amplify the signal enough to be usable in many situations but still have an overall loss of 3db. If you amplify too much, you introduce noise and the bit error rate goes towards bad so if the signal is slightly worse, but cleaner then its still all good. 





Ray Taylor
Taylor Broadband (rural hawkes bay)
www.ruralkiwi.com

There is no place like localhost
For my general guide to extending your wireless network Click Here






14 posts

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  Reply # 2124487 12-Nov-2018 22:35
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mail2mm:

 

I am glad to hear you had such a good outcome along with an able, amiable installer.  Out of curiosity I wonder if you know the signal level at the antenna after installation?

 

Measured in dBuV it might be in the +50 to +70 dBuV range.  For our digital TV transmissions it is probable the installer also measures bit error rate (BER) as a measure of signal quality.

 

 

 

 

Hi mate, 

 

 

 

checked with the installer, the signal level was 55dB quality was 71%


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