Can a Uniden BC785D scanner be used as a tuner for rtl-sdr?

Talk about other SDR products like the FunCube, HackRF, BladeRF etc.
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Gcarmich
Posts: 2
Joined: Tue Jan 03, 2017 10:03 am

Can a Uniden BC785D scanner be used as a tuner for rtl-sdr?

Post by Gcarmich » Thu Jan 12, 2017 3:13 pm

I have a Uniden BC785D scanner - is it possible to use it with rtl-sdr?

AD5NL
Posts: 34
Joined: Fri Sep 16, 2016 7:00 pm

Re: Can a Uniden BC785D scanner be used as a tuner for rtl-s

Post by AD5NL » Fri Jan 13, 2017 7:30 pm

Probably, but it will require carefully gathering information about your device, carefully soldering in some tap wires, and it will definitely void your warranty.

Here is what you would do:

1. Get the User Manual, Service Manual, and Schematic for the radio. You might also want to get the FCC Database information if it exists. Also look into getting info from user groups and technical support.

* The User Manual is floating around online, for example: https://www.manualslib.com/manual/18494 ... c785d.html
* For the FCC database the first step is to get the FCC ID. According to Google that is AMWUB316. Then go to https://www.fcc.gov/oet/ea/fccid and put in the codes (AMW for grantee, UB316 for product)

2. You need to use the documentation to figure out these questions:

* What is the 1st intermediate frequency of the receiver? Unfortunately I can't find that in searching the User Manual. The FCC emissions report keeps showing test frequencies around 370 MHz so I suspect that might be near the IF or possibly a harmonic of the IF. But that's just a guess. You need to make sure the 1st IF is a frequency that the RTL-SDR can receive.

* How would someone tap the 1st IF? You really need a schematic for this. This is where you might want to check with a Bearcat use group, see if anyone knows the layout of their board.

3. Once you have a plan together for tapping the IF, you will then need to carefully tap the IF, by soldering a piece of skinny coax (like RG174). The center will go to the IF tap and the shield to ground. You will then need to put an appropriate plug (SMA, MCX) onto the coax.

NOTE: if you are not extremely careful in doing this you can brick your receiver.

4. Once your tap is in place, you should be able to plug the coax into your RTL-SDR and tune around!

Gcarmich
Posts: 2
Joined: Tue Jan 03, 2017 10:03 am

Re: Can a Uniden BC785D scanner be used as a tuner for rtl-s

Post by Gcarmich » Sun Jan 15, 2017 1:26 pm

Thank you! I'll see if I can locate the schematic.

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