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Ever wonder what's inside one of those big cellular "panel" antennas?


jeremyandrew
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Lots of little antennas :cool:

 

IMG_2352.JPG

 

IMG_2353.JPG

 

This single-pole/single-band antenna is nowhere near the beasts being used for NV, but the concept remains mostly the same. In the multi-pole/multi-band antennas, the elements are at 90-degree angles to each other, which allows for port-to-port isolation, there are some larger elements for 800 MHz and there is an internal remote tilt mechanism.

 

This poor fella was being 'flown' to the top of the tower on a particularly blustry winter afternoon many years ago and smacked the tower leg on the way up. The radome was instantly destroyed but we had a spare on-hand, so it was taken back to the office and given an autopsy. I found a special place for it in the dumpster yesterday, but though I should take a few pictures.

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Lots of little antennas :cool:

 

This single-pole/single-band antenna is nowhere near the beasts being used for NV, but the concept remains mostly the same. In the multi-pole/multi-band antennas, the elements are at 90-degree angles to each other, which allows for port-to-port isolation, there are some larger elements for 800 MHz and there is an internal remote tilt mechanism.

 

This poor fella was being 'flown' to the top of the tower on a particularly blustry winter afternoon many years ago and smacked the tower leg on the way up. The radome was instantly destroyed but we had a spare on-hand, so it was taken back to the office and given an autopsy. I found a special place for it in the dumpster yesterday, but though I should take a few pictures.

 

I know this may be hard to believe for some, but I had never seen inside a panel that close up before. Thanks for sharing!

 

Robert

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Just like AJ taught us to call them sites instead of towers I find myself calling these the proper name of antennas and not panels.

 

Sent from my little Note2

 

Yeah, I suppose technically the panel is just the housing. And the housing provides no functionality except to protect the internal antennas from the elements. So the panel ain't nothing but a thang, all things considered.

 

Robert

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Lots of little antennas :cool:

BULK OF ORIGINAL POST REMOVED -----

multi-pole/multi-band antennas, the elements are at 90-degree angles to each other, which allows for port-to-port isolation, there are some larger elements for 800 MHz and there is an internal remote tilt mechanism.

 

Can somebody clarify this a little. In Multi-band antennas, if the elements are at 90 degree angles to each other, does this mean that the 1900 signal and the 800 signal will be sent in entirely different directions?? If your home is in the "Poor Spot" for a 1900 signal because of the 1900 signal not being aimed at your location, is it possible that the 800 signal might just be leaving the cell site in a different direction and be aimed at your location even by default? Would the 800 signal leave the cell site at a 90 degree angle to the 1900 signal.

 

I know that they can have the capability to move the aiming left or right or up and down slightly, but is the starting point off by 90 degrees as the default??? Good technical question maybe.

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I know that they can have the capability to move the aiming left or right or up and down slightly, but is the starting point off by 90 degrees as the default??? Good technical question maybe.

 

I am not certain of this, but some of the antenna elements may be horizontally polarized, others vertically polarized.

 

AJ

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I am not certain of this, but some of the antenna elements may be horizontally polarized, others vertically polarized.

 

AJ

 

I always thought that Cell/PCS signals were always vertical polarization probably because of the old pull-out antennas on the older cell phones. Horizontal polarization is not normally a good thing for portable devices. At least that is what I was taught many years ago.

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The bands will have roughly the same azimuth. The elements have a polarization offset from each other for diversity reasons not to be confused with the azimuth or downtilt.

 

Sent from my little Note2

 

 

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I always thought that Cell/PCS signals were always vertical polarization probably because of the old pull-out antennas on the older cell phones. Horizontal polarization is not normally a good thing for portable devices. At least that is what I was taught many years ago.

 

If memory serves me correctly, the FCC required AMPS signals to be cross polarized on the uplink and downlink. And as I sort through FCC OET filings for my device authorization articles, the uplink ERP/EIRP figures that I see are almost always greater with horizontal polarization than with vertical polarization -- though, I do spot an occasional anomaly, in which the vertical polarization for a particular band/band class is greater.

 

AJ

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I always thought that Cell/PCS signals were always vertical polarization probably because of the old pull-out antennas on the older cell phones. Horizontal polarization is not normally a good thing for portable devices. At least that is what I was taught many years ago.

 

The elements are +45 and -45 degrees so technically not completely vertically or horizontally polarized.

 

Sent from my little Note2

 

 

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The elements are +45 and -45 degrees so technically not completely vertically or horizontally polarized.

 

Sent from my little Note2

Designing antennas for Cell/PCS phones has to be a very tough job. The phone can be in any position at any time. When held up to the ear, it rarely is totally vertical and can be almost horizontal. The phone can be laying on its back on a desk. Or in a holster on a guys belt or upside down in a ladies pocketbook. It has to be able to pick up a signal of almost any polarization.

 

Did we determine that the multi-band antennas used at a NV site would normally transmit a 1900 and a 800 signal in the same direction with Sprint having the ability to possibly shift one of the two signals slightly if desired? This is what I originally believed to be true, but the earlier statement about a 90 degree difference in the elements really can be interpreted in several ways.

I am thinking it may be that the 800 signal might need to be shifted in direction slightly at some sites to keep the more powerful 800 signal from being aimed at another nearby site. You would not really want two adjacent sites blasting out a 800 signal directly at each other. This might cause issues where it did not with 1900 signals.

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The three sections for the six antennas have independent remote downtilt adjustments. I haven't seen anything for remote azimuth though.

 

Sent from my little Note2

 

I haven't seen them installed at any of the NV sites, but antennas with remote steering(azimuth) are available. Take a look at this KMW catalog. http://www.kmw.co.kr/popup/KMW_Antenna_Cata_Rev1.0.pdf

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I haven't seen them installed at any of the NV sites, but antennas with remote steering(azimuth) are available. Take a look at this KMW catalog. http://www.kmw.co.kr...Cata_Rev1.0.pdf

 

Figured someone had them as it would be relatively simple. Now if only Sprint would install them so they could easily fix the cheeseball mistakes the RF interns made in several areas with the NV rollout ;)

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I would have assumed that the mechanical steering is only for gross adjustments and the majority of the steering is in the DSP processing. Maybe it isn't that advanced yet but you can use the interference from multiple antennas and a lot of horsepower to steer the signal or even pick out multiple transmitters on the same frequency at the same time by discriminating in the spatial dimension. Anyone stuck in the old world of basic antenna design and mechanical tilt adjustments is far behind the times ;)

 

 

Anyone with deeper knowledge of LTE and how the new NV equipment works have more info? Are they at this level yet?

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  • 7 months later...

Haven't posted in a while, but I happened across one of the antennas being used in the NV deployment that is defective and was replaced. I couldn't help but see what makes it tick and thought I would share. This is a 6-pole, dual band(800/1900) antenna from Andrew with Remote Electrical Tilt.

 

The antenna is about 6 feet tall
IMG_4118.JPG

 

The RF and RET connections

IMG_4119.JPG

 

Under the radome. The 800 arrays are in the top-most and bottom-most positions

IMG_4121.JPG

 

 

The 800 array

IMG_4123.JPG

 

 

The backside. You can see the RET motors, all of the tiny hardline and the Electrical Tilt arrays

IMG_4124.JPG

 

 

The 1900 tilt array

IMG_4125.JPG

 

 

Enjoy.

 

http://imgur.com/Jw5yMTd,v8BqWTg,eDfn2ni,CS6NFRb,gPhTV6O,5tGPZsk,AZ327Sw,SMaNEKe

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It'd be awesome to take a look inside an RRU as well. I used to take our VCRs, the TV and my Atari and Nintendo apart when I was growing up. My parents nearly had a heart attack since back then, our Zenith VCR was nearly $700. Fortunately, I was good at putting things back together, too. It's amazing how many screws and wires you really don't need inside most things...

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