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Cellular Phone Test Set fun

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Cellular Phone Test Set fun

Postby spectreman » 2013 Sep 27, 09:56

Hi all collectors.
I just recently bought a secondhand JRC NRZ-900 Cellular Test Set. It is brilliant !
It acts as a fully fuctional mini AMPS base station. Any AMPS phone will register with it, and then you can originate calls to and from the test set to the phone. The test set has a handset attatched to it for full two way voice calls. So all my old AMPS phones are back alive again, yay ! Lots of fun.
The transmit power from the test set is very low (less than 1mW), but just covers my whole house without causing any unwanted interference.

But be warned, you must be technical minded like me to do this sort of thing, lots of setting of parameters to be done, otherwise it will not work at all. But definately worth considering if you are a collector, and addictive ! There are other test sets around that cover the ETACS standard.

Cheers, Chris.
spectreman
 
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Re: Cellular Phone Test Set fun

Postby muxaun » 2013 Oct 10, 15:50

sounds great :) is it expensive?
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Re: Cellular Phone Test Set fun

Postby spectreman » 2013 Oct 12, 11:58

Hi. Ok, I wrote the wrong model number for my test set !
It is a JRC NJM-900A.
Was not too expensive, especially since I sourced it locally in Australia.
Cost me $275 AUD.
Have not seen any ETACS versions of this test set either.
I have now got several bag phones set up around my house as a wireless intercom system, works very well.
Would be even better if I could call one mobile to another, but I would need a second test set to do this, set up as a kind of repeater system.
Soon I will be buying a recieve preamplifier to add onto the test set, as the reciever in it is still pretty deaf. This should improve the systems performance a fair bit.
Will be picking up three more bag phones next week, more testing to do, yay !

Cheers, Chris.
spectreman
 
Posts: 276
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Location: Australia

Re: Cellular Phone Test Set fun

Postby spectreman » 2013 Oct 25, 23:22

Update on my test set operation.
I have now added a 800MHz Rx preamplifier to the Rx input of the test set, and it has made a huge improvement in the operating range. The extra 40dB of gain makes all the difference, Rx sensitivity is now around -80dBm.
All my handheld phones will now work fine from one end of the house to the other. Previously they would only work up to 6m from the test set before dropping out.
I have not even tested any of the 3W phones yet ! I think the range will be very good with them now.
I am still transmitting the same low power level from the test set.
Cheers, Chris.
spectreman
 
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Location: Australia

Re: Cellular Phone Test Set fun

Postby spectreman » 2013 Nov 13, 14:14

Hi. Have just added a document to the library that I wrote about my AMPS test set.
Hope some of you find it interesting !
spectreman
 
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Location: Australia

Re: Cellular Phone Test Set fun

Postby oldmobil » 2013 Nov 13, 21:00

Hello,
I've read it, great article about using this interesting test set!
I hope it will useful to others who try to bring back from the dead old analogue cellphones.
Thanks!
(There was a little bug with uploading files with long filenames but I corrected...)

Regards,
Peter
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Re: Cellular Phone Test Set fun

Postby mobira » 2014 Jan 21, 00:29

Hello, i´m interrest about test sets too but here we can´t use this because we can get lot of troubles with telecommunication govement. It´s loo low with GSM freq.

But in Europe, we have too popular NMT-450 system and some phones with him. My question is, do you know anybody acceptable NMT cellular phone test set ? I can´t buy Stabilock radio tester for ?3000 and NMT card for ? 600. I don´t have this money. Thanks !
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