Yes, idea: your correspondent might have been better off spending his amplifier money on a passive repeater set-up, two good quality Yagis, a high gain one pointing at the cell site and a wide beamwidth one inside the property simply connected back-to-back with very low-loss everything. Just enough non-resonant co-ax length to get through the wall, ideally. Pretty well as per the self-help system for people in remote hamlets and villages in the Welsh and Scottish mountains to get UHF TV signals when the broadcasters can justify funding a normal repeater. Little or no extra noise added. Only real pre-requisite is that the outside antenna probably does need a good line-of-sight to the cell tower and not to be in fringe coverage area. Might possibly even made to work for more than band with log-periodics.
Andrew, could you confuse the input/output frequencies of the channels from the phone to the base station and back? They are 45 MHz different, so the "outdoor" input works differently than the "home" input. The SAW filters on the traces at the edges of the board are responsible for filtering them.
@@andrewmcneil This repeater is according to its data sheet just as intended blocking any downlink signal at 900 MHz with at least 50 dB. That is exactly how these repeaters should behave. As this kind of repeater is intended for environment with weak GSM fieldstrength is system gain very high in both directions. It is cheap so it does not have any AGC. Due to its fixed gain will its amplifiers goes into saturation for signals above -40dBm. That is no problem in a rural area with weak GSM signals, downlink level will be much less then -40dBm and in uplink will signal from a cellphone neither exceed -40 dBm if at distance of a meter or more from its local antenna. Feeding it with signal stronger then -40 dBm in any direction can in best cause it to go in selfprotection and in worse case burn a transistor just as there is a max power limit your SA can handle or it will also burn. If the saw filters does its job, downlink bandpass is around 925 to 960 MHz and uplink bandpass is 880-915 MHz and feed signal in any direction MUST be less then -40 dBm. Gain is fixed in both direction and feeding an amplifier with 0 dBm is unrealistic as it else would result in an output of +60dBm = 1000W. Its poweradapter will explode long before that and it will probably also kill you spectrum analyzer. These SAW filters are produced by SHOULDER Electronics Ltd.
I live in a very rural area and use a cheap cell repeater for the upper 700mhz band 13. I had to go up on the roof to get any useable signal before but with the booster I can get 25 mb download and 5 upload. The booster even came with the wrong yagi which is tuned for the 800mhz band. I’ve been doing my research and watching lots of your videos and Im about to make my own yagi antennas that are hopefully tuned better for the band my service uses. Thanks for all the helpful information.
Start a new channel, strictly for IoUJT _(InterNot of Useless, Junk Things)_ crappily designed/manufactured/bogus devices, test equip, antenna's, etc, to help the clueless gadget gatherer's to completely avoid ;) ...just thinking out loud ...D'ohhhh ;)~ _"Have a Bloody Good Day!"_
PS: ... take it 1 step further and implement some form of a scale rating based on my own scale rating i have here I call the _"Fix-it to Fuk-it"_ factor. Base each crap device on it's eligibility vs cost vs hrs used in order to bring said device into operational specifications or better.
Check out the Chinese character for "Indoor" (室内 Shìnèi de), marked in place beside the power input, and outdoor (室外 shìwài) which is marked on opposite side of the repeater unit. It would appear that in the Andrew Mcneil youtube video the emitter (indoor) antenna, as shown, appears in fact to be plugged into the outdoor (室外 shìwài) receptacle, not as per the instructions to the "Indoor" (室内 Shìnèi de) receptacle.
The part it SOT89 is not a voltage regulator, but an RF MMIC. I agree with somebody there, that your measurement is not correct (maybe you changed the downlink and uplink paths) and there were nothing about the setting of the overall repeater gain, which is very often a part of the device.
my chinese signal booster work good but it's turning as signal jammer when i place the indoor antenna so close to the outdoor antenna, no signal at all ...so I have to put the indoor antenna at least 15m away from the outdoor antenna maybe you have the same problem ua-cam.com/video/BiV4VtPzIi4/v-deo.html
I guess your mesurement, was wrong this time Andrew. Because probably this amp output is gonna be negative polarization, so ... is proportionally inverted to the surce of signal. That`s why this get -12 of gain at output. Also this kind of amp are designed to be installed outsite and near to the antenna point to point and this kind of antennas have negative polarization in general. The problem with this amp`s and theory, is actually people hope this work as audio Amp, but this don't work that way .This is not amplifying electric signal. This is amplifying the field effect of antenna and magnetic field. That`s why this kind of signal amp`s, works with field effect transistors basically.
Since it is outputting less than the input, would you then call it a Depeater?
Yes, idea: your correspondent might have been better off spending his amplifier money on a passive repeater set-up, two good quality Yagis, a high gain one pointing at the cell site and a wide beamwidth one inside the property simply connected back-to-back with very low-loss everything. Just enough non-resonant co-ax length to get through the wall, ideally.
Pretty well as per the self-help system for people in remote hamlets and villages in the Welsh and Scottish mountains to get UHF TV signals when the broadcasters can justify funding a normal repeater. Little or no extra noise added. Only real pre-requisite is that the outside antenna probably does need a good line-of-sight to the cell tower and not to be in fringe coverage area. Might possibly even made to work for more than band with log-periodics.
Andrew, could you confuse the input/output frequencies of the channels from the phone to the base station and back? They are 45 MHz different, so the "outdoor" input works differently than the "home" input. The SAW filters on the traces at the edges of the board are responsible for filtering them.
interesting question I am going to remove those filters and save them.
@@andrewmcneil This repeater is according to its data sheet just as intended blocking any downlink signal at 900 MHz with at least 50 dB. That is exactly how these repeaters should behave. As this kind of repeater is intended for environment with weak GSM fieldstrength is system gain very high in both directions. It is cheap so it does not have any AGC.
Due to its fixed gain will its amplifiers goes into saturation for signals above -40dBm. That is no problem in a rural area with weak GSM signals, downlink level will be much less then -40dBm and in uplink will signal from a cellphone neither exceed -40 dBm if at distance of a meter or more from its local antenna. Feeding it with signal stronger then -40 dBm in any direction can in best cause it to go in selfprotection and in worse case burn a transistor just as there is a max power limit your SA can handle or it will also burn.
If the saw filters does its job, downlink bandpass is around 925 to 960 MHz and uplink bandpass is 880-915 MHz and feed signal in any direction MUST be less then -40 dBm. Gain is fixed in both direction and feeding an amplifier with 0 dBm is unrealistic as it else would result in an output of +60dBm = 1000W.
Its poweradapter will explode long before that and it will probably also kill you spectrum analyzer.
These SAW filters are produced by SHOULDER Electronics Ltd.
I live in a very rural area and use a cheap cell repeater for the upper 700mhz band 13. I had to go up on the roof to get any useable signal before but with the booster I can get 25 mb download and 5 upload. The booster even came with the wrong yagi which is tuned for the 800mhz band. I’ve been doing my research and watching lots of your videos and Im about to make my own yagi antennas that are hopefully tuned better for the band my service uses. Thanks for all the helpful information.
Start a new channel, strictly for IoUJT _(InterNot of Useless, Junk Things)_ crappily designed/manufactured/bogus devices, test equip, antenna's, etc, to help the clueless gadget gatherer's to completely avoid ;)
...just thinking out loud ...D'ohhhh ;)~
_"Have a Bloody Good Day!"_
PS: ... take it 1 step further and implement some form of a scale rating based on my own scale rating i have here I call the _"Fix-it to Fuk-it"_ factor. Base each crap device on it's eligibility vs cost vs hrs used in order to bring said device into operational specifications or better.
Check out the Chinese character for "Indoor" (室内 Shìnèi de), marked in place beside the power input, and outdoor (室外 shìwài) which is marked on opposite side of the repeater unit.
It would appear that in the Andrew Mcneil youtube video the emitter (indoor) antenna, as shown, appears in fact to be plugged into the outdoor (室外 shìwài) receptacle, not as per the instructions to the "Indoor" (室内 Shìnèi de) receptacle.
Probably GSM jammer 😄
Garbage for intended purpose but a nice source of MMICs, case etc. I hoover these up at swapmeets, hamfest etc.
Haha, these boosters really suck! I got a similar one many years ago, before they were outlawed here.
i cant say i'm surprised .... nice work buddy
Thanks!
"HDF902H-S6" is saw filter with the hdf6988 print.
Thanks
The part it SOT89 is not a voltage regulator, but an RF MMIC. I agree with somebody there, that your measurement is not correct (maybe you changed the downlink and uplink paths) and there were nothing about the setting of the overall repeater gain, which is very often a part of the device.
my chinese signal booster work good but it's turning as signal jammer when i place the indoor antenna so close to the outdoor antenna, no signal at all ...so I have to put the indoor antenna at least 15m away from the outdoor antenna
maybe you have the same problem
ua-cam.com/video/BiV4VtPzIi4/v-deo.html
In the pic of the set up on youtube, isn't the emitter arial fitted on the wrong side of the repeater unit?
Yes it would make thinks really bad. You could get authorities knocking on your door for sending all that noise in gsm network.
This type of repeaters are using reputed companies. If this is useless then why should they use this type
Make a video about the best 3G 4G antenna for rural areas with many mountains and opening the antenna to see how it is made thanks brother
Andrew, would a passive repeater work better than this one? Or would a passive repeater work at all?
A GSM jammer 😂
Thank you
Good job sir ...keep it ...
Thank you, I will
Good video Andrew.
Glad you enjoyed it
I guess your mesurement, was wrong this time Andrew. Because probably this amp output is gonna be negative polarization, so ... is proportionally inverted to the surce of signal. That`s why this get -12 of gain at output. Also this kind of amp are designed to be installed outsite and near to the antenna point to point and this kind of antennas have negative polarization in general.
The problem with this amp`s and theory, is actually people hope this work as audio Amp, but this don't work that way .This is not amplifying electric signal. This is amplifying the field effect of antenna and magnetic field. That`s why this kind of signal amp`s, works with field effect transistors basically.
mmh/// no.
Whatever is negative polarisation?
Surprise