OP25 Raspberry Pi Audio Sucks A Big DAC

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Ok I’ve been on a roll playing with OP25 and Raspberry Pi and one thing I can tell you is that the onboard audio from the bcm2835 chip is somewhat inadequate.  Oh, it works but you’re going to need a powered speaker or really efficient headphones, and even then it is a bit light.

What to do?

Add a USB Digital to Analog converter (DAC).  Depicted here is a HiFiMeDIY USB DAC.  This is a tad bit expensive for this project but I have like 4 of these things laying around the house.  They are ridiculously good.   If you like music slap one of these bad boys on your laptop in the hotel room and the quality of your music will improve ten fold.

That’s not what we’re doing here though.

There are a LOT of USB DAC’s out there and some cost just a few dollars.  HiFiMeDIY makes some cheaper ones as well that are way more than enough for improving your OP25 sound.

 

 

The Phat DAC costs $15 but you’ll have to solder header pins on yourself.  That may be the cheapest, and best route.  It has the form factor for the Raspberry Pi Zero but it works on all the Pi’s.

 

 

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OP25 on a Raspberry Pi (part 3)

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In my last part I set the Pi up to stream to Broadcastify.  In this one we are just going to pump audio out through the headphone jack.

I’m doing this with an old generic black RTL-SDR and it works and it works fine but it is kind of susceptible to heat and cold and the ppm correction drifts a bit.  I really recommend getting a v3 RTL-SDR or a NESDR Smart as they seem more stable.  At any rate it doesn’t matter, you’ll just have to deal with the drift if you have any.

My assumption here is that you have Raspbian installed on at least a Pi 3.  I haven’t tried it on a lesser Pi but I had it on a Pi 3 B + and then I found a couple Pi 3 B’s laying around and figured I’d reclaim my B+ for another project on another day.  OP25 runs fine on the Pi 3.

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OP25 Raspberry Pi Streaming Part 2

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So I finally figured out OP25 and I have this brand new Raspberry Pi 3 B + laying around doing nothing.  In this segment we’ll install OP25 on Raspberry Pi and then take our police scanner feed and send it to the internet on Broadcastify.

As someone pointed out to me yesterday, “There’s an app for that” they are indeed correct.  You can get Police Scanner Apps for IOS and Android.   Guess where the feeds in those apps comes from?  If you said Broadcastify you’d be correct.  So if no one is feeding your municipality   then there will be no feed in the app.  We will be that feed.

So the assumption is that you have a Pi with Raspbian installed and you kind of know how to use it.

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OP25 For Dummies – Or how to build a police scanner for $30 (Part 1)

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OP25 is a program that decodes P25 Phase 1 and Phase 2 digital radio.  Some municipal areas are upgrading to P25 Phase 2 so almost gone are the days that you can track them with a police scanner since P25 is a Trunked Radio system and not just a lone frequency to monitor.   The only things that do Phase 2 are hardware scanners and hardware radios and OP25 for software radios.  Bear in mind Phase 2 could be encrypted and nothing you can do will decode it.

OP25 is HARD.  I’m a geek and I messed with it on and off for a year or more and it whipped me more than once.  Now that I have it working I find that it is REMARKABLY easy and I’m mad at all the geeks out there who never made a simple tutorial.  There are tutorials out there, some good but everybody leaves out the good stuff or the stuff they took for granted.

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Othernet

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We all know what the Internet is but what in the world is the Othernet?  (It used to be called Outernet).  The Othernet is unofficially dubbed “The Internet in Space” or “The Encyclopedia in Space” and it’s mission is to provide internet type information to the poor or to areas on earth which don’t have active internet.

I kind of view it as a back up to the internet and one more source of information in a SHTF scenario.  When the grid goes down as long as you have an othernet receiver and a generator or some batteries and a laptop the satellite in space will probably still be working fine.

The project is housed here.  Before you jump into the Othernet fire for the first time, know this. When you buy Othernet hardware, that’s all you get.  No manual, no instructions.  Nothing.  That being said one of the users over there made an amazing guide to setting up the Othernet.

If you start digging into this guy a bit he’s highly credentialed and you can better believe this hobbyist believes everything he has to say in this paper.  So it’s really all good.

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Saving Old Stereo Gear From Craigslist – Pioneer SX-650

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Without a doubt the old Silver faced Pioneer Receivers from the 70’s and 80’s was some of the most epic stereo gear ever designed.   Sadly with the advent of cell phones and tablets everybody listens to their music on cheap earbuds while streaming low res music from some far away server.

Well not everybody does that.  But most.  And that means all those old boat anchor sized amps are in the back of the closet, the garage, in the attic and turn up at the estate sale from time to time.

Stupid old guys like me who are trying to relive their childhood will pay top dollar for an old amp that realistically time forgot.   So these days it becomes the challenge of the old audiophile (audiophool) to find one cheap and bring it back to it’s once epic status.

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Emergency NOAA Weather Radio

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  NOAA Weather Radio

In the event of bad weather it really pays to own a NOAA weather radio.

About 6:30 or 7 last night a wicked Thunderstorm with low and frequent lightning was hitting us hard.  There was some nearby property damage although I was lucky. No trouble at Castle Hagensieker.

 

Even though we all have cell phones, internet, TV whatever…….the best resource for weather is YOUR LOCAL NOAA WEATHER STATION.  They transmit weather data 24/7 however they transmit it on a frequency that you probably can’t get on any radio you own.  You either need a real life EMERGENCY RADIO like you can buy at Lowes or maybe Walmart or you need a USB Software Defined Radio hooked to a computer.   NOAA stations start I believe at 162.40 MHz.  Also NOAA has the Emergency Alert System (EAS).

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Panasonic RF-2200 Telescopic Antenna Restoration

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Well I picked up one of the all time great long distance Medium Wave (MW) aka AM Radios, the Panasonic RF-2200.

 

Sadly all but the last two of the 7 section telescopic antenna were broken off.   No problem right?  Quickly, to the internet, GeekMan.

Download the Service Manual.  Check.  Find antenna part number. Check.  Hit eBay.  Epic Fail.  No such part on eBay.  Dr. Google probably knows.   He didn’t.

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DeOxIt – What is it? What ISN’T it?

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Started messing around with “vintage” audio again.  Drug a couple stereos out of the attic and picked up a new stereo or two (or three).   I’ve been heavily involved in vintage audio since around 2001 or so on and off and one thing that any old stereo guy will tell you is that DeOxIt spray is a miracle solution for audio.  Spray it on and rust falls off, light bulbs glow brighter and the gravitational force of the moon gets stronger if you accidentally spray some on the moon.

Bullshit.

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