26 dBi ultra wide-band parabolic grid antenna

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swwifty
Posts: 390
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by swwifty » Tue Jul 09, 2019 3:19 pm

coldknob wrote:
Tue Jul 09, 2019 10:01 am
Well I can't verify exactly what the mf279 is doing because it only shows signal strength and 4g or 4gLTE. However it performs similar to the we826 so I assume it's using the same band.

The we826 would aggregate bands 2 and 12 when set on all bands but I never saw any improvement in speed versus being locked on band 2. Band 12 is only 5mhz in my area.
The problem with the all bands setting was that sometimes the modem would select band 12 as the primary band (even with a 1900mhz yagi) which would kill my speeds. Locking on band 2 solved that problem.
I haven't had that problem yet with the mf279, even though I can't lock bands. I'm hoping that my current signal strength on band 2 (-92dbm) will eliminate that occurrence.

I have no idea what algorithm AT&T uses to select what band you're on but I suspect it's based solely on signal strength which makes sense when you're driving around in order to seamlessly switch between towers.
For data use from a fixed location bandwidth is the key. -115db @ 15mhz=good speeds, -90db@5mhz=crappy speeds.

I should note that I'm in a very rural, mountainous location. Many hills and valleys and many dead zones. Also I'm located on the edge of the National Radio Quiet Zone where cell phone signals are prohibited.
Every area is different but this is what works for me in my specific location.

Also keep in mind these antennas are extremely directional (we're talking millimeters making a difference). I can't actually see the tower I'm connected to but I know it's exact location and elevation in relation to my house by using google earth and other resources. It's akin to aiming a satellite dish, you get a good signal or you get nothing.
Nice work on this. Band selection is indeed done based on signal, but they always try to push you to the higher frequency bands, as the lower frequency bands are more valuable due to range and penetration.

I'm tempted to try this setup my self, but I suspect my wife wouldn't be too happy about an antenna that large on the roof, lol. The tower I connect to for AT&T service is about 5 miles away NLOS.

I had never heard of the National Radio Quiet Zone, super fascinating after reading up on it online.

coldknob
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Joined: Sat Jul 21, 2018 8:50 pm

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by coldknob » Wed Jul 10, 2019 2:25 pm

xdavidx wrote:
Tue Jul 09, 2019 10:05 am
I heard back from the ebay seller. He doesn't have any horns that go down to 700MHz.
My understanding of parabolic physics is limited but I believe for a grid antenna to give 24dbi gain at 700mhz it would have to be more than 6 ft. in diameter. That's probably why you don't see them.

xdavidx
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Re: 26 dBi ultra wide-band parabolic grid antenna

Post by xdavidx » Wed Jul 10, 2019 4:46 pm

coldknob wrote:
Wed Jul 10, 2019 2:25 pm
My understanding of parabolic physics is limited but I believe for a grid antenna to give 24dbi gain at 700mhz it would have to be more than 6 ft. in diameter. That's probably why you don't see them.
Good point. Generally, not as much gain is needed for the lower frequencies, since they travel farther. The antenna this thread started with has the following gain for the low frequencies:

14-17 dBi
600-960 MHz

That would be fine. I'm just not quite ready to give up on the dream of having the lower frequencies available for carrier aggregation too. It might be a foolhardy dream, however, since as @swwifty pointed out, they like to withhold those bands. In my case, I'm not given the 700MHz bands unless it is late at night, when the towers aren't busy.

I even found a tower that has at least 4 bands: B2 20MHz, B30 10MHz, B12 10 MHz and B66 10MHz. It won't give me B12 until late at night. It will give me B2 and B30 all day long, and then adds B12 at night. The only time I got B66 is when I aimed away from the tower enough that it couldn't pick up the higher frequency B30. Then it would give me B66! I haven't tried locking out B30 to see if it will give me B66 when aimed correctly, but that's on my list of things to try. But what is weird is that it will give me B12 if I am physically right next to the tower.

My only guess at their algorithm is that it it will give 3 bands if you are close and have really good signal strength, since they want to maximize the resources for people who can make the most out of them. The rules change when you don't have as strong of a signal. In that case they seem to want to reserve the lower frequency bands for people farther out (except for B2, which is always the primary and has the most bandwidth, with 20 MHz).

In theory, the towers can use your distance in (estimated by a round trip ping time), to determine which resource blocks to give you vs other users on the same band from another, approximately equi-distant tower, in order to reduce interference for those users in the overlapping coverage areas between the towers. In practice, I'm really not sure how much that is utilized.

Thinking about this more, *if* they are only using signal strength and not using the estimated distance, then if I can get my signal strength high enough, it might treat me like I'm right next to the tower and give me the lower frequency bands, even during prime time usage hours. If it will do that, then it might make sense for me to try a grid antenna, if it could get my signal strength high enough. My problem isn't being too far away from the towers. My problem is having too many towers around and too many people. So even if I only get the signal strength high enough for the primary antenna, that might be good enough, since they probably only look at that, not at some average of the two. My panel antennas get good enough signals for reasonable speeds. I just "need" (want) more bands, so that I have more bandwidth, hence more speed.

Lots of "ifs" here, but if the above works out, I *could* use a cheaper grid antenna that doesn't go down to 700MHz as my primary and, either use one of my panel antennas as secondary, or use the second MIMO connection of the horn style antenna that @coldknob is using. Since I only have a 3CA modem currently, B2 + B30 + B66 would give me as much as I can use anyway, and I wouldn't need B12.

It is a price difference of about $150 between the wide band grid antenna and the feed horn variant. Of course, if someone doesn't have secondary antennas, or needs a very high gain for the secondary antennas to get MIMO, then the feed horn antenna is a greater bargain vs buying 2 of the wide band grid antennas.

This is another MIMO feed horn that is priced less, but it is made for parabolic dishes. Not sure if it could be made to work with a grid: https://www.ebay.com/itm/Dual-polarity- ... 2797598911

I'll add to my list of tests to see at what signal strength, physically getting farther and farther from the tower, it stops giving me Band 12 and 66. Using the gain specs on the panel antennas vs the grid antennas might allow me to do the math to figure out if I'll be able to get to a high enough signal strength to fake out the tower into giving me the lower frequency bands. I'll also need to see if it will give me B30 and B66 at the same time if I lock out Band 12 and I'm close to the tower. They could have some other rule about not giving those 2 bands to the same user, or not support all the allowable CA combinations (of which B2+B30+B66 is one).

The variables never end with this stuff. :shock: :lol:

coldknob
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Joined: Sat Jul 21, 2018 8:50 pm

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by coldknob » Wed Jul 10, 2019 5:41 pm

xdavidx wrote:
Wed Jul 10, 2019 4:46 pm

The variables never end with this stuff. :shock: :lol:
Especially when the carriers give out zero information on this stuff and you have to try and figure out what they're doing,
I know where all the towers are in my area (they're all on top of mountains) but do you think AT&T would tell me which towers were theirs and what bands they use? I had to spend a month driving around with 2 cellphones figuring it out for myself. The cell mapper websites/apps were pretty useless because a lot of them are based on user info and I guess there are not many users in my area.
The best I found was Network Cell Info Pro.

xdavidx
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Joined: Tue May 28, 2019 4:04 pm

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by xdavidx » Wed Jul 10, 2019 5:55 pm

coldknob wrote:
Wed Jul 10, 2019 5:41 pm
The cell mapper websites/apps were pretty useless because a lot of them are based on user info and I guess there are not many users in my area.
I have plenty of people around and they were still pretty useless -- at least regarding location of the towers. I didn't do a ton of comparing the bands they show vs reality.

coldknob
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Joined: Sat Jul 21, 2018 8:50 pm

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by coldknob » Wed Jul 10, 2019 8:55 pm

swwifty wrote:
Tue Jul 09, 2019 3:19 pm
Nice work on this. Band selection is indeed done based on signal, but they always try to push you to the higher frequency bands, as the lower frequency bands are more valuable due to range and penetration.

I'm tempted to try this setup my self, but I suspect my wife wouldn't be too happy about an antenna that large on the roof, lol. The tower I connect to for AT&T service is about 5 miles away NLOS.

I had never heard of the National Radio Quiet Zone, super fascinating after reading up on it online.
Thanks, my location has a lot of similarities to yours and reading your posts verified a lot of my own experiences. Thanks for sharing your expertise.
When I first got my z700a home base I thought I was in heaven because I could get 5 down, 1 up on HSPA+. Little did I know then what I was getting myself in to.
My wife thinks I'm obsessed and she's probably right but its been fun.

swwifty
Posts: 390
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by swwifty » Wed Jul 10, 2019 9:04 pm

coldknob wrote:
Wed Jul 10, 2019 8:55 pm
Thanks, my location has a lot of similarities to yours and reading your posts verified a lot of my own experiences. Thanks for sharing your expertise.
When I first got my z700a home base I thought I was in heaven because I could get 5 down, 1 up on HSPA+. Little did I know then what I was getting myself in to.
My wife thinks I'm obsessed and she's probably right but its been fun.
It literally is a rabbit hole for sure! So glad to hear I was able to help in some way.

My wife thinks I'm obsessed too, but all of this has lead me to start a WISP where I live, so I think it's a good thing :)

xdavidx
Posts: 258
Joined: Tue May 28, 2019 4:04 pm

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by xdavidx » Wed Jul 10, 2019 9:30 pm

swwifty wrote:
Wed Jul 10, 2019 9:04 pm
My wife thinks I'm obsessed too, but all of this has lead me to start a WISP where I live, so I think it's a good thing :)
Now *that* is an idea!

Wonder how long it would take for the cable company to get me shut down if I tried that. Our house and the handful around ours can't get cable, but a lot of other people on the street can. I'm sure the cable company would wonder what is going on when all their customers drop, since DSL is *horrible* here.

swwifty
Posts: 390
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by swwifty » Wed Jul 10, 2019 9:48 pm

xdavidx wrote:
Wed Jul 10, 2019 9:30 pm
Now *that* is an idea!

Wonder how long it would take for the cable company to get me shut down if I tried that. Our house and the handful around ours can't get cable, but a lot of other people on the street can. I'm sure the cable company would wonder what is going on when all their customers drop, since DSL is *horrible* here.
well I'm not trying to resell my internet. I'm doing a full blown ISP with a carrier grade whole sale connection :)

DSL is the only option for most people around here, and the average speed is about 3-5mbps. I'm fortunate and actually get about 20mbps where I live, but not the case for most folks as I live close to the high way and the DSLAM.

You could setup some Ubiquiti radios to give your neighbors internet that have LOS for "free" and they give you something else for "free" every month (You don't hear that idea from me :lol: )

xdavidx
Posts: 258
Joined: Tue May 28, 2019 4:04 pm

Re: 26 dBi ultra wide-band parabolic grid antenna

Post by xdavidx » Wed Jul 10, 2019 10:32 pm

swwifty wrote:
Wed Jul 10, 2019 9:48 pm
well I'm not trying to resell my internet. I'm doing a full blown ISP with a carrier grade whole sale connection :)
I was saying the cable company could try to create problems (even if there weren't any FCC rules being broken) on the RF front through the long range wifi network being set up. And it wouldn't be reselling of a cable connection. I'm sure they'd *really* love that!

How are you getting the carrier grade wholesale connection? Cellular or some form of wired?
swwifty wrote:
Wed Jul 10, 2019 9:48 pm
You could setup some Ubiquiti radios to give your neighbors internet that have LOS for "free" and they give you something else for "free" every month (You don't hear that idea from me :lol: )
Trust me, that has been discussed in the past with one neighbor. Then they got their DSL upgraded. Mine was upgraded a few days after that. It worked for a month with fewer issues than I had previously. Then it all fell apart. The phone company tech couldn't figure out how to fix it, so I had to have them put me back to a slower speed that has issues now and then.

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