Please turn off "Stable Volume" in the video playback setting (the first menu item after clicking the gear icon) as for some reason, this new TH-cam playback feature made the video much noisier than usual.
Great teardown video. I found the TH-cam video first. I am an RF engineer and founder of a company serving the DAS (Distributed Antenna System) world, providing in-building cellular and public safety coverage. You gave very clear explanations for anyone. I am also a Cel-Fi reseller. I would recommend you mount your donor antenna above the roofline, outside. If you do, remember to install a lightning arrestor if you do. This will improve isolation, as you pointed out, as well as increase your donor signal level(s). Maybe your high band would become useable? I can answer your question about your phone locking on to the high band, even though its or poorer quality and service then your Band 13 signal. The function of Band 2/25 (1900MHz PCS) or 4 (2100MHz AWS) being preferred over band 13 (700Mhz LTE) is a programmed choice by your service provider. In your case, the service provider wants the phone to use 1900 or 2100, because of more data capacity, before dropping to the 10Mhz channel on band 13 (700Mhz). You receive this signal better at your house because it penetrates trees and free space better than the high hand by at least 6dBm, which is 200% more signal. During the phone's provisioning, the service provider selects 1st, 2nd, and 3rd choice bands along with a lot of other data, like handoff lists, etc. This data is loaded to your phone during this initial programming when the phone is connected to their network. These are regional settings and for example, in the Baltimore-Washington area, VZW's 1st choice is 2100, 2nd is 700 and third is 1900Mhz. On AT&T, 1900 is 1st choice and then 700 is 2nd and so on. The interesting one is the new T-Mobile/Sprint. Since the pandemic hit, they are letting users roam back and forth on all bands between them, depending on what coverage is available where you are at, increasing service availability for their users. If you have any more questions email me. I left you the same comment on your website, so you have my email now. Dan
Interesting, I just bought a Sprint Note 20 Ultra and in some areas I am seeing the 5G icon light up, but Afaik no carrier has turned on 5G in San Antonio. When the weather is clear the 5G connection is very fast, whatever it is, but when the rain hits it starts dropping packets and becomes almost completely unusable. Switching the phone to 4G only mode fixes this at the cost of speed in good weather.
Very interesting to see that this type of product is now available with proper certifications. Those antenna module boxes look like coaxial resonator duplexers. They're there to isolate the transmit and receive frequency ranges for each side of the repeater. From looking at them, it looks like they use ceramic resonators with a very high dielectric constant to make the actual resonators. This is a common technique for making compact duplexers at relatively moderate power levels. Slightly bigger versions were often used in old analog mobile phone systems, where the mobile phone had to be full duplex capable. The unpopulated pads in each section is probably positions for extra duplex filters for additional frequency ranges. Yours only had one set of duplexers installed - so maybe your unit is only built for a single frequency range?
That seems like a much more intelligent unit than we normally find causing interference. Those cheap units can make things much worse in the entire neighborhood when they aren't installed and configured properly.
You are correct. The intelligence and unconditional network safety of Cel-Fi products is why operators globally feel comfortable deploying anywhere in their networks. It took us many years of testing in their labs to get here! :-)
I am an electrical engineer who has been out of school sine 1987. I recently graduated law school and I am ready to take the necessary licensing exams to become a patent attorney. I appreciate Kerry Wong going over the FCC regulations related to Cel-fi's ability to sell the GoX with a 100 dB gain and stay within the parameters of the law, in particular, 47 CFR § 20.21 - Signal boosters. It is important for Cel-fi to be obedient to this regulation to capture a large market when selling their products. By seeing you cite the FCC regulations I see you like to keep a keen eye on the boundaries of the playing field, that is the legal playing field. It is a great adventure for an engineer to look behind all the secret doors in which a law degree allows you to open. I suggest you look into getting a law degree. I believe you will be amazing at it, super-boosted by your ability to handle anything technical that comes your way. I am not a law school recruiter in any way, just someone who has done it and likes the legal-view of the technical world from its perch. Lastly, I would like to mention I too learned from Joseph Schmelzer's contribution in this string. Great information Joseph and thanks for sharing.
Nice video. I also have poor reception in my area and thought of buying something like that, but it was too expensive for me. Hence I grabbed 2 Huawei LTE dongles, plugged into a rasp-pi and made a WiFi access point. Each dongle connects to two different ISPs so I have some more redundancy.
This is absolutely not my area of expertise but the whole soldering area FY35 @13:29 looks identical to FY33/FY28 @13:18 and FX83/FX62 @12:33 -> Looks to me like there are versions of this device with two separate outputs for two indoor antennas. EDIT: On the other hand the case and the rest of that board area are missing the requirements for a second output... OT: Please improve your voice recording setup - the white noise through the whole clips is a bit annoying.
Hi mate I need your help I will pay for your time please I need to do it urgently I want to turn my aneng an888s into a bluetooth multimeter so I can view the readings on my phone I tried following one of ur guides where u was hacking a dtm0660l as I've seen the same ic in mine but no luck
![[TH] 2024 PMSL SEA Finals D3 | Fall | รู้ผลทีมแชมป์ พร้อมตั๋วสู่ PMGC](http://i.ytimg.com/vi/7NxsN0Ch6vk/mqdefault.jpg)
Please turn off "Stable Volume" in the video playback setting (the first menu item after clicking the gear icon) as for some reason, this new TH-cam playback feature made the video much noisier than usual.
Great teardown video. I found the TH-cam video first. I am an RF engineer and founder of a company serving the DAS (Distributed Antenna System) world, providing in-building cellular and public safety coverage. You gave very clear explanations for anyone. I am also a Cel-Fi reseller. I would recommend you mount your donor antenna above the roofline, outside. If you do, remember to install a lightning arrestor if you do. This will improve isolation, as you pointed out, as well as increase your donor signal level(s). Maybe your high band would become useable?
I can answer your question about your phone locking on to the high band, even though its or poorer quality and service then your Band 13 signal. The function of Band 2/25 (1900MHz PCS) or 4 (2100MHz AWS) being preferred over band 13 (700Mhz LTE) is a programmed choice by your service provider. In your case, the service provider wants the phone to use 1900 or 2100, because of more data capacity, before dropping to the 10Mhz channel on band 13 (700Mhz). You receive this signal better at your house because it penetrates trees and free space better than the high hand by at least 6dBm, which is 200% more signal.
During the phone's provisioning, the service provider selects 1st, 2nd, and 3rd choice bands along with a lot of other data, like handoff lists, etc. This data is loaded to your phone during this initial programming when the phone is connected to their network. These are regional settings and for example, in the Baltimore-Washington area, VZW's 1st choice is 2100, 2nd is 700 and third is 1900Mhz. On AT&T, 1900 is 1st choice and then 700 is 2nd and so on. The interesting one is the new T-Mobile/Sprint. Since the pandemic hit, they are letting users roam back and forth on all bands between them, depending on what coverage is available where you are at, increasing service availability for their users.
If you have any more questions email me. I left you the same comment on your website, so you have my email now.
Dan
Interesting, I just bought a Sprint Note 20 Ultra and in some areas I am seeing the 5G icon light up, but Afaik no carrier has turned on 5G in San Antonio. When the weather is clear the 5G connection is very fast, whatever it is, but when the rain hits it starts dropping packets and becomes almost completely unusable. Switching the phone to 4G only mode fixes this at the cost of speed in good weather.
Very interesting to see that this type of product is now available with proper certifications.
Those antenna module boxes look like coaxial resonator duplexers. They're there to isolate the transmit and receive frequency ranges for each side of the repeater.
From looking at them, it looks like they use ceramic resonators with a very high dielectric constant to make the actual resonators. This is a common technique for making compact duplexers at relatively moderate power levels.
Slightly bigger versions were often used in old analog mobile phone systems, where the mobile phone had to be full duplex capable.
The unpopulated pads in each section is probably positions for extra duplex filters for additional frequency ranges.
Yours only had one set of duplexers installed - so maybe your unit is only built for a single frequency range?
That seems like a much more intelligent unit than we normally find causing interference.
Those cheap units can make things much worse in the entire neighborhood when they aren't installed and configured properly.
You are correct. The intelligence and unconditional network safety of Cel-Fi products is why operators globally feel comfortable deploying anywhere in their networks. It took us many years of testing in their labs to get here! :-)
Thanks for the long over due video. I sure hope you get the engineering sample to take teardown and test for us.
I see a Mr. Wong video, I click like and I watch it. I know from experience it's going to be a good one :)
I am an electrical engineer who has been out of school sine 1987. I recently graduated law school and I am ready to take the necessary licensing exams to become a patent attorney. I appreciate Kerry Wong going over the FCC regulations related to Cel-fi's ability to sell the GoX with a 100 dB gain and stay within the parameters of the law, in particular, 47 CFR § 20.21 - Signal boosters. It is important for Cel-fi to be obedient to this regulation to capture a large market when selling their products. By seeing you cite the FCC regulations I see you like to keep a keen eye on the boundaries of the playing field, that is the legal playing field. It is a great adventure for an engineer to look behind all the secret doors in which a law degree allows you to open. I suggest you look into getting a law degree. I believe you will be amazing at it, super-boosted by your ability to handle anything technical that comes your way. I am not a law school recruiter in any way, just someone who has done it and likes the legal-view of the technical world from its perch. Lastly, I would like to mention I too learned from Joseph Schmelzer's contribution in this string. Great information Joseph and thanks for sharing.
Nice and thorough review, Mr.Wong! Thank you.
That duplexer at 12:50 is pretty neat. Looks like the used a vertically mounted PCB to form the resonators.
Nice video. I also have poor reception in my area and thought of buying something like that, but it was too expensive for me. Hence I grabbed 2 Huawei LTE dongles, plugged into a rasp-pi and made a WiFi access point. Each dongle connects to two different ISPs so I have some more redundancy.
FYI, You can use the FCC ID of the booster to look at the internal photos
Tanks Greg for the info.
subscriber... but didn't get any notification of this. Just checked in randomly cos it seemed like a long time since the last video
I used to have a Wilson 3G booster.
This is absolutely not my area of expertise but the whole soldering area FY35 @13:29 looks identical to FY33/FY28 @13:18 and FX83/FX62 @12:33
-> Looks to me like there are versions of this device with two separate outputs for two indoor antennas.
EDIT: On the other hand the case and the rest of that board area are missing the requirements for a second output...
OT: Please improve your voice recording setup - the white noise through the whole clips is a bit annoying.
If your tower has band 66 that usually works better than band 13.
Hi mate I need your help I will pay for your time please I need to do it urgently I want to turn my aneng an888s into a bluetooth multimeter so I can view the readings on my phone I tried following one of ur guides where u was hacking a dtm0660l as I've seen the same ic in mine but no luck
Will this work on international band like in Asia?
I don't believe so, in their product details page it is listed as carrier specific and the one I bought only supports US North America carriers
How does it compare to a 4G router/hotspot?
4G router/hotspot is a client. Translating data for consumer WiFi
Cel-Fi Go X is a client/repeater/server for 3G / 4G / LTE
Did you get that free from China ? Are you shilling this product for money?
He did say that he bought it himself...
Nextivity is not even a Chinese company, first of all. Second of all, relax