Electrical Tilt

[sakibd2k]

HI Everyone,

I am new to RF forum as well as not enough experience in Rf job.
I want to know how electrical tilt is performed?(practically)and so remotely(RET)
I know it is by phase change but how we can change phase angle?
Is it the phase of power? but how?

Is there any relation with VSWR and so ATU(Antenna tuning unit) for this tilting purpose?

Please let me know.

Thanks.

Mushfiq

[Tomas Delgado]

Hi mate, is like this. If you remember transmission line theory, EM waves have a freq and a wavelenght that in mean of meters in the feeder counts. So you can change phase with the lenght of the transmision line inside the antenna. Inside antenas maybe you have 4 to 6 dipoles so if you change phase to the ones in the upper part in a total the signal will be more greater in the upper dipoles and in some vectorial sum it will make the beamwidth go down. Well i think its ok, if not please tell me the thruth.

[gc_sw]

practically (mechanically) tilt is done by tilting antenna physically. but this results in "increased front lobes" on the other hand "decreased back lobes" of the antenna. but in electrical tilt both of the lobes increase.

[gc_sw]

http://www.rfsworld.com/index.php?p=314&l=1

[sakibd2k]

Thanks For replying everybody.

To Tomas,i see your answer acceptable and i know by varying the length of cable to dipole we can have different phases and so following your quote
" So you can change phase with the lenght of the transmision line inside the antenna" is close to my answer.

But thats where my problem how are you changing feeder length remotely
for just changing electrical tilt? thats why i do not get it. Feeder(transmission line) are huge and changing length frequently is not a quite easy thing for installer.

Something i am missing here.

Please let me know.

Thanks

[pathloss]

Hello my dear friend.

Hope I can help you. There are two types of tilt "mechanical" and "electrical" one.

mechanical tilting an antenna, is by changing its phisical angle on the pylon or wall it is attached to.

electrical tilting an antenna is done, by setting an electrical circuit to the desired setting. This is for example done by opening a cap on the antenna itself, and turning on a weehl (potientometer) till you reach the desired tilt.

Just have a look to the attached file, and search for "Adjustment Mechanism". And the RET system only adds an engine to the hole tilting, so the noone has to get up to the antenna to manualy change the electrical tilt!

Am I right or not?

regards

[sakibd2k]

Hi Pathloss,

sorry for delay reply. I could not open the attached file as i think i dont have enough previlage to open any attached doc.
How i can get those previlege?
and how to earn more credit also?

Thanks you are correct but i need to learn also from the book as you told me to see "adjustment mechnism".

[Tomas Delgado]

Ok mate, you can change the transmission line lenght inside the antenna to change electrical tilt with a mechanical device that you can move from outside of the antenna package(dont get confused what im saying is not mechanical tilting!) is something like the old tv chanel selector(2,3,4,...grades). This "selector" can be changed remotely if you connect a device that will do the mechanical job and conected to the rnc maybe via IUB.

[pathloss]

Hello sakibd2k,

Please have a look here, http://www.kathrein.de/de/mcs/produkte/download/9363161c.pdf

For your questions about credit and reputation (previlage to download), have a look here.

http://www.finetopix.com/showpost.php?p=88604&postcount=1

best wishes

Hi Pathloss,

sorry for delay reply. I could not open the attached file as i think i dont have enough previlage to open any attached doc.
How i can get those previlege?
and how to earn more credit also?

Thanks you are correct but i need to learn also from the book as you told me to see "adjustment mechnism".

[gc_sw]

electrical tilt is the coverage optimization process done in condition of down cells. 3-10 degree tilted antennas helps "down cell" to coverage area up. the matter is how to do it remotely (RET) or automatically.

[pathloss]

Do you mean manualy by saying, automatically? As i'm sure that preatty none deployes RET-systems or am I wrong?


electrical tilt is the coverage optimization process done in condition of down cells. 3-10 degree tilted antennas helps "down cell" to coverage area up. the matter is how to do it remotely (RET) or automatically.

[coursekec]

Good explanation pathloss...

[sakibd2k]

Dear Pathloss,

I saw your link and i have 10 posts now at least but still
i cannot download any attachment.

Can you or anybody please help me out with this ?

Thanks

[sakibd2k]

Dear Pathloss,
Thanks for your links and attachments.
But how could i earn reputation and also how i give someone reputation?
could you please tell me?

I still cannot read the doc as i dont have enough reputation.

Can some one advise me?

thanks

[pathloss]

hello sakibd2k,

You can give reputation, by clicking on the balance sign on the left side of someones post. This is to show that you approve someones contribution to the forum.

To be able to download attachments you need to get promoted to the state of "Member", for now you are "Junior Member". To get promoted to "Member", you need 15 reputation, for now you have 10.

So for now basically, you will have to post your most valuables things, and soon other will approve them and your promoted. (it took a week for me)

Regards


Dear Pathloss,
Thanks for your links and attachments.
But how could i earn reputation and also how i give someone reputation?
could you please tell me?

I still cannot read the doc as i dont have enough reputation.

Can some one advise me?

thanks

[sakibd2k]

Thank you path loss
yes i add reputation to your post now i know.
Thanks very much