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Messages - audiokaos

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General Radio Discussion / Re: Using HF rig as AM radio receiver
« on: November 10, 2014, 1821 UTC »
It also depends on what you're after from it. Looking to pull in distant signals or good audio? I have an Icom PCR100 that was fairly deaf RF wise, but you could really open up the audio bandwidth & it sounds great. But if there are high power local adjacent stations, you'll want tight bandwidth. In the States I hear IBOC is also a huge challenge for MW dx'ers, so not sure what the best route for that issue is. I'd guess you'd be stuck with squeeky sound, but could be wrong.

Software / Re: What Radio related software would YOU like to see?
« on: October 27, 2014, 1903 UTC »
fldigi ported to android... Heard it's not possible due to the graphics library that it uses though...:(

Winlink 2k would be neat too.

The RF Workbench / Re: Symptoms of an oscillating amplifier?
« on: October 24, 2014, 1843 UTC »
makeRF: I'm using the LM386 chip as an amp.

kaliic: The audio sounded fine, just quiet. The LM386 chip would get warm when transmitting.  It would get really hot running a speaker without resistors. It wouldn't get warm when running a speaker with resistors. 

Its not assembled anymore.  It was bugging me why the sound didn't carry very far.  I thought maybe because it was oscillating? I'll reply here if I tweak with it.


FYI you do realize that on a frequency such as 6925, the signal doesn't go that far locally right? It skips. Could have been clear as day 150 miles away.

Huh? / Re: Chuck Norris the DXer
« on: October 08, 2014, 1411 UTC »
Chuck Norris can wipe out all communication when he gets mad, by simply pounding his fist & causing a solar flare.

Equipment / Re: Good Antenna for Raspberry Pi
« on: October 01, 2014, 2201 UTC »
It's dead easy to build one. Just check out the ARRL's website - Loads of plans for antennas for pretty much any situation. Dipoles are very easy to construct - Just a T shape with the top bits cut to a specific length. Can be quite large though depending on the frequency. eg, for 6.925Mhz it is 33ft. 9 - 1/2in. or 10.299 M for one side...

General Radio Discussion / Re: RNI - Radio New York International
« on: October 01, 2014, 1805 UTC »
Very cool, thanks!

On top of what has been said about the TV sound aspect & it being out of band, it would be dead clear that it is a pirate signal. I personally wouldn't use it apart from tossing a signal from my living room to the bedroom..

Equipment / Re: Good Antenna for Raspberry Pi
« on: October 01, 2014, 1615 UTC »
Got it. So essentially, after I get the LPF, I'll just need an antenna tuned for the shortwave band I choose. Any broadcasters recommend a frequency or band, or is 6925 kHz good? Other than that, Woo hoo! I can combine my two favorite hobbies!

Pretty much - However afaik Raspberry Pi only uses the FM mode so apart from digital & actual FM I'm not sure what you might use it for. AM/SSB I believe is not possible with it - at least yet..<g> Check this out for some info on setting up LPF's and antennas-


Equipment / Re: Good Antenna for Raspberry Pi
« on: September 29, 2014, 1402 UTC »
After a LPF, the proper antenna for the band that you'd be using it for... The Raspberry Pi's GPIO is *very* noisy & harmonic. A LPF is very much needed.

Huh? / Re: Drone, ham radio destroyed amid headbutting assault
« on: September 17, 2014, 2024 UTC »
Hmmmmm, I wonder how big a drone would have to be to hold an antenna aloft....

Equipment / Re: Noise canceling systems
« on: August 27, 2014, 1353 UTC »
Good Day All :)!

I could get: Daiwa All Mode Active Filter AK606K , Datong FL1 and a Datong FL3, all in good condition!
All three in one 'packet' for 160 european coins ;D

My Question,anybody get some experience with this stuff?

Good DX!

First off, I'll say that I've never touched those, but I do work for a DSP company. Won't say the name as I don't want to come off as trying to sell - Amateur radio isn't our market & I don't want to come off like that.

Having said that, DSP processing is much tighter than anything analog in terms of EQ's. I can create notch filters at 48db per active using IIR filters or even more with FIR. Tighter than a nun's.. um, well, you know. At *any* frequency that I want. Analog can be good in certain bands, but aren't really configurable & have good bandpass cutoffs. Our processors are made for live sound/studio applications, but I've been using mine on my HF rig as well for just that. On top of it, I also do all my mic processing (ALC, Compression & EQ (I have a crappy mic)) in the same box. I'm sure that something like this has been developed for Amateur radio as well. Just something to consider.

Equipment / Re: Audio Processing
« on: August 25, 2014, 2115 UTC »
Well, just listening to folks like Wolverine Radio & I'm just amazed that they get the audio (music) sounding as good as they do out of SSB. I do audio work myself & just wondered what processing they used for SSB. I understand the AM/FM requirements very well, just that SSB seems that it would require much more work to get it sounding good.

Equipment / Audio Processing
« on: August 20, 2014, 1528 UTC »
So, what sort of audio processing best for SSB broadcasting? I'm guessing 6Khz bandwidth (Or 10?) ALC & Compression?

General Radio Discussion / Re: My "Kinda" legal station
« on: August 08, 2014, 1648 UTC »
I was also told on another forum if I could have 2 transmitters synced at my house, and 2 transmitters synced at my brothers house, penetration into homes should be perfect.  So for the time being, my plan is to use this illegal transmitter when it arrives to get the 1 mile range into houses, using the minimum power needed to achieve this.  I'll cross my fingers that I don't get the "knock of doom", and buy 3 more legal transmitters in the next 3-6 months and try and get 2 synced on each property and see how it goes. 

Syncing the audio is one thing, to eliminate phase cancellation, but all the transmitter's carrier freq would need to be in phase as well. Without doing this, you'd just make a mess of your station, canceling your own signal out in parts & there being a terrible beat frequency oscillation at places where you can get it. You will get a 'knock of doom' doing this as it would just be a real mess of rf with no real signal intelligence.

Best bet is to go the carrier current route & stay legal, or just toss that to the wind & go with just a single transmitter.

The RF Workbench / Re: High Powered Pirates
« on: June 06, 2014, 1430 UTC »
I doubt you'd feel the RF from a 7 MHz TX at 10KW, unless you were right next to the antenna.  FM is a different story.  I've foolishly been within 3 feet or so of FM bays running 1KW on my parents roof.  You can definitely feel that, it feels like a burning sensation.  I also recall working on a few 50 KW AM's during which my knees and elbows would start to hurt after a while.

The power levels I play with these days, I don't feel a thing ;)


I had the opportunity to go up to the transmitter / combiner room of Toronto's CN Tower. It's got a whack of commercial FM & TV stations on it. In the combiner room, there is one section of coax that feeds the main antenna. Close too a million watts of VHF/UHF rf on it. You could feel a warm fuzz as you put your hand closer to it. Started about 2 foot away & got too strong at 1ft to go closer..:)

Stuck my head out of the 'roof' too. Wickedly neat.

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