Category Archives: Scanner

Uniden BCD436HP Speaker Repair

Uniden BCD436HP Speaker Repair

Uniden BCD436HP


I bought a Uniden BCD436HP scanner in July 2022.  I keep it in my wood shop shed and I leave it on.  It is tucked in the corner and is largely forgotten about.   So much so that it took me a while to notice that I hadn’t heard it recently.

Sure enough I see it grabbing calls with no audio output.

And then just to make sure it works I plugged a set of headphones in and the audio output was fine.

A google search turns up quite a few speaker failures for this model. So I hit the Uniden Support site and see that they have a form to fill out and then you are directed to ship the item to Uniden for repair.
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OP25 Revisited

OP25 Digital Decoder Revisited

About 5 years ago I was DETERMINED to figure out a digital voice decoder software program called OP25.  It literally took me a year to figure out how to do it.   I’d work on it for a day or two then give up.  Then try again a week or three later.   Then one day I heard the crackle of a police call over my speaker.   It was at that moment I decided to take what I learned and wrote a dummies guide about it.   To this day,  it is still the blog that gets the most hits, and attention.  And that blog is mostly still relevant.  It pretty much works in the same way.

Just last night I took my old OP25 installation and noticed that it was on Raspberry Pi OS “Buster”.  I tried to upgrade it to the current distribution code named “Bullseye” and things rapidly began going south.  Before I fouled it up too bad I downloaded 4 files:

  • – a script file I made to launch the program
  • trunk.tsv – a file that tells OP25 what Frequency and NAC to listen to
  • newbern.tsv – my local configuration for the police talk groups here
  • viper.tsv – the NC statewide talk groups

I decided to start fresh and within about 20-30 minutes I had a fresh installation of Raspberry Pi OS and OP25 running.  I think I can streamline my installation process a bit more.


I have absolutely nothing to do with the development of OP25.  I’m just the guy who wrote the dummies guide on it.  And I’m doing it again.
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Uniden SDS200 GPS

Uniden SDS200 GPS


I’ve been on a Uniden Police Scanner GPS DIY tear lately and my last radio scanner to need a GPS accessory is my prized Uniden SDS200.  Sure you can buy a GPS unit for about $50, but our goal is to make one for less than that.

Oddly enough, this was the easiest one to make.   Here’s what you need:

  • GPS Module STM32 (not serial) – $12NOTE:  The previous GPS I had linked is no longer available.  This one should work but I haven’t actually bought this one.  It is probably counterfeit as well.   Also on these breakout boards there is usually a chip for flash memory for upgrading the firmware.  If no flash memory exists you won’t be able to upgrade.
  • Any 4 wire RJ14 telephone cord.  You can get them at Walmart for about $4.  I’d be willing to bet you have one laying around in a junk drawer or hooked to an old phone you’ll never use again.
  • 3D printed case (optional)

Oddly enough I bought a NEO-6M board from one seller on eBay for $8 and it is authentic which really surprised me.  The NEO-6M is a pretty old chip though so I guess I’m not surprised old authentic stock is still out there.  An $8 NEO-6M is HIGHLY RECOMMENDED for this project……..if you can find one.

Conversely, lots of different GPS units will work but they must not be serial devices.  Additionally, make sure you get a 3.3 Volt, TTL logic unit and not an RS-232 serial device.

Let’s wire it up!
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GPS Cable Wiring For Uniden BCD436HP Police Scanner

I have two scanners, a Uniden Home Patrol 2, and a Uniden BCD436HP.  They have the following in common:

  • Both made in 2014
  • Both GPS compatible
  • Both use the same Mini B 4 pin connector for the GPS connection



To make your own GPS cable you need:

  • ProMaster #3696 6′ cable – The first people to do this hack used a Rosewill RCW-109 cable.   Good luck finding one of them these days.  What you need is a USB 2.0 Type A Male to Type Mini-B 4-Pin Male.  Make sure it is a 4 pin.  I found some other branded cables on eBay as well
  • BR-355S4 GPS Puck

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Programming a Uniden Scanner With Sentinel

I bought a new Uniden BCD436HP scanner and decided to install the programming software Sentinel.  I have a couple of computers and decided to do this clean.   And that’s when I realized that using Sentinel for the 1st time is really kind of a beast.  There are a LOT of settings that you probably should run through prior to writing your configuration to your scanner.

The BCD436HP and all of its big brothers are touted as being EASY to program..  By golly you can just plug your zip code into it and it will just start scanning.   While that is true almost constantly on the scanner forums you will see someone do just that and then post:

“Why can’t I hear the Fire Department?  Why can’t I hear…….xxxxxx?

Well, it’s because certain service types aren’t turned on by default.


Let’s get to it, shall we?

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Uniden BCD436HP Scanner

Always wanted one of these Uniden BCD436HP scanners but the cost was always prohibitive.  For some reason Amazon is running them at around 30% off currently.

The BCD436HP is circa 2014 which makes it OLD in electronics years, and back then digital trunking scanners weren’t really designed to combat Simulcast distortion.  That is where a digital system has multiple antenna towers that broadcast the exact same signal at the exact same time.   Some scanners getting hit with multiple signals will distort, have choppy voice, or robot voice.

The only two scanners on the entirety of planet earth designed from the ground up to deal with Simulcast are the Uniden SDS100 and the Uniden SDS200.

So it doesn’t make a lot of sense to spend big money on a scanner that might choke when just a bit more money gets you a sure thing.  Where I live there is a P25 Phase 1 LSM system that will bring most scanners to their Simulcast knees.  Within moments of slapping some batteries in a scanner I will know if it can deal with Simulcast or not.  Remember when you could actually go to a local store and test a radio before you bought it?  Sadly those days are no more.

Anyway, I didn’t even want to take a chance on an old scanner that was expensive and might not work.  That is, until the price dropped dramatically.  After turning it on for the first time within seconds I received a call on my local Simulcast system and the BCD436HP dealt with it PERFECTLY.  This scanner is a keeper.

NOTE:  Simulcast is odd as hell.  Just because it works in my location doesn’t mean it will work across town, on the system in the next town over, or at your location, wherever that is. 

Now lets talk about a few things I learned about the BCD436HP…………
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Scanner Selection – Part Three

I have many scanners.  Too many.  After dabbling with all of them the last couple weeks I have come to the conclusion of which one a scanner enthusiast should purchase.

That’s it.  But with some exceptions which I’ll get to in a minute.   You’d think in this day and age there would be dozens and dozens of choices and price wars in the radio scanner market.  There isn’t.   In fact there really are maybe only 15 or 20 choices AT ALL.

I count 8 Uniden digital scanners and 4 Whistler digital scanners.  You can get Unication digital pagers which will track P25 digital systems and there are a couple other offerings (old) from GRE and Radio Shack.   I’m sticking with my estimate of 15 to 20 choices.

Most digital systems out there have multiple towers that transmit the same data at the same time for maximum coverage over the First Responders area of operations.  That is called Simulcast.  It can also produce distortion ESPECIALLY if a couple towers are a few milliseconds out of whack.

Currently there are only TWO scanners that have circuitry designed to deal with Simulcast.

  • Uniden SDS100
  • Uniden SDS200

Hence my recommendation above.  Here are the exceptions.
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Uniden BCD325P2 Mini Review


I recently picked up a Uniden BCD325P2 and am currently putting it through its paces.  The scanner is circa 2015 so it isn’t a new offering and I got mine used which is probably the cheapest way to buy one of these.

I don’t regurgitate specs here.  I can’t give you the specifications better than Uniden can.  What I can do is to use something from the common man standpoint and tell you what I think of it.

There is a lot to like about this scanner and first and foremost my favorite feature may be that it uses AA batteries.  Scanners with rechargeable brick batteries are cool but when they drop dead they must immediately be tethered to a power source.  You can also use AA rechargeable batteries in this scanner so you kind of have the best of both worlds.

Also the scanner is really lightweight compared to my Uniden SDS100 or Whistler TRX-1.  Much more suited to the backpack or belt clip or just carrying it around in your hand.

On the “I Don’t Like” side of the equation, it just doesn’t do well with my local Simulcast system, New Bern Public Safety which is a P25 Phase 1 LSM system.   I’m not done playing with P25 threshold settings or using a lesser antenna to try to cut reception from one of the two towers near me.

Now that I have one good, and one bad……Let’s dig in a little deeper.
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Getting a Police Scanner Part Deux

I recently wrote a blog on selecting a Police Scanner and I wanted to do a deeper dive on how to select one and how to begin the set up process.

The process begins at

The first thing we are going to do is inspect our area and determine what systems we want to follow.

Then we’ll take a peek at the antennas used to transmit and determine whether or not we have something called Simulcast.

Simulcast is when multiple radio towers transmit the same thing at the same time.  This is obviously done to provide a larger coverage area to ensure our First Responders don’t hit any dead radio zones in their area of operations.  But, Simulcast can cause horrific distortion and some radio scanners simply cannot do Simulcast systems very well at all.
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Uniden SDS100 Proscan Server Audio

USB Sound Card

I have a Uniden SDS200 which has an ethernet jack and it is a breeze to set the scanner up as a server over my network using the excellent software, Proscan.  That includes streaming the audio across the network.

My SDS100 is a slightly different animal and it requires a a physical connection via USB so that Proscan software can see the scanner.  That won’t carry your audio though,  so it needs a separate physical connection from the Line Out (headphone jack) on the SDS100 to the controlling computer.

I don’t know about your laptop or computer but mine DOES NOT have an input jack for a microphone.  So what you have to do is add a USB sound device that has a separate microphone input.
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