DP727L15 - 15dBi 4G LTE Directional Antenna Review (Updated with comparisons)

Topics related to wireless broadband antennas
swwifty
Posts: 382
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by swwifty » Wed Oct 03, 2018 1:54 pm

ph34rful wrote:
Wed Oct 03, 2018 1:37 pm
Can the remote.it service be utilized on devices other than a pi? I signed up but don't see how I can use it with the setup I'm working with, or maybe it's outside my skill set.

Also, this thread is making me wish I could actively tinker with this stuff, very nice results!
I believe it can be, but I haven't set it up yet on any of my devices.

Sorry if I mis-lead you, let me do some research on that and I'll get back to you.

swwifty
Posts: 382
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains
Been thanked: 22 times

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by swwifty » Thu Oct 04, 2018 8:04 am

I was doing some reading last night, and discovered something very interested. I was reading on Shannon's Capacity theory (I have read up on it before, but never compared it to real tests) Here's a link to a good video that explains it: https://www.youtube.com/watch?v=ancDN11C2vg

I started doing some math on the performance I got with various tests, to see how my real throughput compared to the possible maximum throughput.

I was looking at my tests up on the mountain from yesterday, and discovered that they were at the upper limit of maximum possible bandwith per Shannon's capacity theory.

For example, Band 2 test yesterday:
Screen Shot 2018-10-03 at 11.16.59 AM.png
Note that the SINR is about 20.
Screen Shot 2018-10-03 at 11.18.32 AM.png
Speed test from band 2.

Now do the math and guess what? For a 20mhz channel with a SINR of 20 the maximum throughput possible is.... 87.8 mbps!

(You can do the calculations here yourself if you don't believe me: http://www.rfwireless-world.com/calcula ... lator.html).

This also happened with my band 12 test up on the mountain. The ones outside at my house, I ran them through the calculator and they still had a lot of room to improve. If I'm understanding this correctly then, I think this means a few things.

1. The only way to improve my bandwith (at least in the tests at the top of the mountain) is to get a better signal to noise ratio.

2. The antennas were working at full capacity and efficiency if you think about it. The only way to improve from this test, would be to have completely clear LOS (this was close, but you all saw from the pictures that it wasn't quite).

3. Signal to noise ratio is everything. I've noticed this in other tests as well. There's a few reasons for this. (Improving signal strength is a good idea, but SNR is much much more important)

A. LTE modulation rates increase as SINR ratio improves, so you can get more bits per symbol and more throughput. See this link: https://www.researchgate.net/figure/Mea ... 2_47330409. It's not the greatest diagram, but you get the idea.

B. The more narrow the bandwith, the higher SNR one will have. Why is this? Because the less spectrum you are viewing, the less noise you will have. This is why when I'm using both bands the signal to noise ratio is much lower than when I'm isolating the modem to one specific band.

C. I've seen this on my ubiquiti nanostations. They are 2.4ghz, and if I run a 40mhz wide channel, they pick up tons of noise, but if they are only 10mhz wise, the SNR improves greatly.

4. I ordered some B2 yagis yesterday, so it will be interesting to see if they can improve on the SNR at my house, and therefore improve my throughput.
These users thanked the author swwifty for the post:
ira.kirby (Fri Oct 19, 2018 9:28 pm)

User avatar
dajmanjt
Posts: 13
Joined: Tue Jul 10, 2018 11:23 am

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by dajmanjt » Thu Oct 04, 2018 9:35 am

Great info and observations! I completely agree about SNR/SINR, with LTE it is a very very important aspect of the process. Below is a couple of websites further digging into SINR and its relation to high frequency signals (2.4ghz and higher) and general LTE frequencies also.

http://www.wireless-nets.com/resources/ ... alues.html

https://www.cablefree.net/wirelesstechn ... rsrq-sinr/

Keep posting to here with further observations! I will also be posting back here when I complete some tests early next week on some new antennas I am working with.
LTE solutions & research is my favorite past-time and hobby

swwifty
Posts: 382
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by swwifty » Thu Oct 04, 2018 3:39 pm

dajmanjt wrote:
Thu Oct 04, 2018 9:35 am
Great info and observations! I completely agree about SNR/SINR, with LTE it is a very very important aspect of the process. Below is a couple of websites further digging into SINR and its relation to high frequency signals (2.4ghz and higher) and general LTE frequencies also.

http://www.wireless-nets.com/resources/ ... alues.html

https://www.cablefree.net/wirelesstechn ... rsrq-sinr/

Keep posting to here with further observations! I will also be posting back here when I complete some tests early next week on some new antennas I am working with.
Good links, I've read about this some already, but its starting to click more so now that I'm testing in various conditions, locations, etc.

swwifty
Posts: 382
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by swwifty » Fri Oct 05, 2018 11:14 am

Got the band 2 yagis today, comprehensive test results coming soon :-D

swwifty
Posts: 382
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by swwifty » Sat Oct 06, 2018 6:30 am

Update: ran a ton of tests yesterday, full report coming soon

Unfortunately, I don't have time this weekend to do a full write up (It's gonna be long), but wanted to give some spoilers :)

Short story, the DP727L15 is a great antenna across the wideband of frequencies it covers. Band 2 at my house just seems to be all over the place in terms of interference. I think it's because of all the trees in the way. It will be interesting to see what happens when all the leaves fall off the trees for winter.

A quick comparison of the 3dbi omnis / 15dbi flat panel / 17 dbi yagis for Band 2

3dbi omni:
Screen Shot 2018-10-05 at 1.47.32 PM.png
15dbi flat panels (notice band 12 was selected as primary today, in my last test, Band 2 was selected as primary):
Screen Shot 2018-10-05 at 1.59.54 PM.png
17dbi Band 2 Yagis:
Screen Shot 2018-10-05 at 2.13.12 PM.png
More detailed writeup coming later, but that's some good food for thought :)

User avatar
dajmanjt
Posts: 13
Joined: Tue Jul 10, 2018 11:23 am

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by dajmanjt » Sat Oct 06, 2018 4:13 pm

Very interesting! Keep the info coming. I am completing an install refresh at my house tomorrow and will post pics along with info soon.
LTE solutions & research is my favorite past-time and hobby

User avatar
dajmanjt
Posts: 13
Joined: Tue Jul 10, 2018 11:23 am

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by dajmanjt » Sat Oct 06, 2018 6:49 pm

Another thought, maybe get a screenshot of the readings from the 15 DBI locked into band 2, so then you can compare apples to apples on the yagis. The readings from the 15 DBI are only showing the sinr for band 12, not band 2. If you look at the RSSI for band 2 it goes up dramatically from the 15 DBI antennas to the 17 dbi. But we can't see the RSRQ for the 15 DBI antenna correctly because it is not locked to band 2.

I know you prob already know this but I'll paste a summary of the three components below:

"RSRP (Reference Signal Receive Power) is the average power of Resource Elements (RE) that carry cell specific Reference Signals (RS) over the entire bandwidth, so RSRP is only measured in the symbols carrying RS. While RSSI (Received Signal Strength Indicator) is a parameter which provides information about total received wide-band power (measure in all symbols) including all interference and thermal noise.

So it would be safe to write that, in LTE, RSRP provides information about signal strength and RSSI helps in determining interference and noise information. This is the reason, RSRQ (Reference Signal Receive Quality) measurement and calculation is based on both RSRP and RSSI."
LTE solutions & research is my favorite past-time and hobby

swwifty
Posts: 382
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by swwifty » Tue Oct 09, 2018 8:23 am

Sorry for the delay getting this posted up, been really busy the last few days.

I've already posted the results of the 3dbi omnis vs. 15 dbi flat panel vs. 17 dbi yagis (with their respective appropriate bands). I won't post them again, but wanted to share a few other interesting scenarios I tested.

1. 15dbi flat panels locked to band 2 vs. 17dbi yagis locked to band 2.
2. A hybrid setup (like previously suggested) of the primary antenna connected to the 17dbi band 2 yagis, and the secondary antenna connected to the 15 dbi flat panel.
3. I've always tested them mounted on the same pole, so I separated the antennas between two different poles about 5 feet apart to see if there was any difference.

The weather during these tests was great. Partly cloudy, about 85 degrees and about 65-80% humidity.

15dbi flat panels vs 17dbi yagis

15dbi flat panels locked to band 2:
Screen Shot 2018-10-05 at 2.54.45 PM.png
15dbi flat panel speed test
Screen Shot 2018-10-05 at 2.55.53 PM.png
17dbi yagis locked to band 2:
Screen Shot 2018-10-05 at 2.13.12 PM.png
17dbi yagis speed test locked to band 2 (this was the best one, speeds varied a lot from 20mbps to 40mbps):
Screen Shot 2018-10-05 at 2.21.46 PM.png
It's interesting cause the performance is about the same, which was a bit surprising to me. That being said, when the 15dbi flat panels weren't locked to a band, they selected Band 12 as the primary over Band 2. It seems that the RSSI value for Band 2 is all over the place, and I don't understand why. See the signal values below for the 15dbi flat panel with both bands enabled (to see what I mean):
Screen Shot 2018-10-05 at 1.59.54 PM.png

Hybrid setup of primary antenna (as described earlier)
Screen Shot 2018-10-05 at 2.30.52 PM.png
It was interesting here that even with the 17dbi yagi that is designed for band 2, it still selected band 12 over band 2. This tells me it always uses the diversity antenna (the second antenna used for MIMO) as input on which band to select. You can also see the difference in signal performance between the two antennas for various bands. Note that the band 2 signal is about the same for both antennas. I didn't save the download speeds for this, because they weren't worth mentioning. Upload didn't work at all, because the primary antenna isn't designed for band 12, so it couldn't upload anything at all. This helped clarify for me that uplink on 4G doesn't use MIMO or Carrier Aggregation at all (at least in my area).

I'll be posting the results of the results in a second post in a min (hit the attachment limit i think, heh)

swwifty
Posts: 382
Joined: Thu Aug 30, 2018 8:21 pm
Location: NE GA Mountains

Re: DP727L15 - 15dBi 4G LTE Directional Antenna Review

Post by swwifty » Tue Oct 09, 2018 8:35 am

Separate pole setup

15 dbi flat panels (both bands)
Screen Shot 2018-10-05 at 3.29.22 PM.png
Note here that Band 2 was selected over Band 12, which is very interesting, and perplexing.

15 dbi flat panels speed test (both bands)
Screen Shot 2018-10-05 at 3.30.53 PM.png
15 dbi flat panels (band 12)
Screen Shot 2018-10-05 at 3.25.51 PM.png
15 dbi flat panels speed test (band 12)
Screen Shot 2018-10-05 at 3.26.48 PM.png
15 dbi flat panels (band 2)
Screen Shot 2018-10-05 at 3.21.48 PM.png
15 dbi flat panels speed test (band 2)
Screen Shot 2018-10-05 at 3.22.59 PM.png
17 dbi yagis (band 2)
Screen Shot 2018-10-05 at 3.48.17 PM.png
17 dbi yagis speed test (band 2)
Screen Shot 2018-10-05 at 3.49.37 PM.png
I really don't understand why RSSI is all over the place for band 2, but also when I lock specific bands to the modem. I suspect that when the modem isn't locked to a band it picks up a lot more interference from the antenna, and when its locked to a band it filters that out (hence the better RSSI and SNR). More than likely, I'll keep the flat panels, and return the yagis, since using the yagis limits me only to band 2 and its so inconsistent it doesn't make sense to lock myself to that hardware wise. In the future, if i want to lock to band 2, I can do that with the flat panel antennas and not have to be swapping hardware on the roof, etc.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post