DISCLAIMER: I have no association with UVB-76 station, neither do I have any clue what is the content I am relaying. I can only assure, that the signal is received on 4.625MHz AM-modulated 900km NW from supposed origin and retransmitted unaltered. In no way can I guarantee this service, nor be considered responsible of any content re-transmitted. The only purpose for this relay to exist is because lot of people who do not have equipment or are located too far from station seem to be interested about listening to it. Should the UVB-76 station- or transmission content owners feel violated in any way, please contact me at uvb76.repeater@gmail.com and we will work it out.

Note, that because of shortwave radio signal propagation specifics the station can be more or less reliably received from around 4pm to 6am GMT on summertime. It is almost 24h audible during the winter, with short "skip-zone" blank-out around 6pm GMT.

The USB feed is considered as main source of audio today, as the voice messages are much better audible there than on the AM stream. However, the buzzer sound from the AM stream is somewhat more pleasant to listen at, so both feeds are kept simultaneously.

Monday, January 31, 2011

USB for everyone!

Over the weekend, I was playing around with the USB interfacing for the SDR Mk1. And, to a great surprise, Monday, 1:30am I ended up with functional setup consisting of two serial ports and one 192kHz audio recording interface, all embedded inside one composite USB device living inside AT90USB1287!
What makes it really useful is, that it works under Windows7 without the need of any special driver - it manages with the internal ones.

It is unbelievable what Atmel with its AT90USB line and Dean Camera with his LUFA framework have done to USB world! Creating a working HD audio and two serial ports by totally USB-illiterate person with one weekend is a living proof that Dean is a genius and Atmel knows how to make chips!

Thank you, one step closer to a working SDR :)

Thursday, January 27, 2011

Working on the Atmel USB for SDR ...

Assembling the AT90USB1287 prototype board, listening to the fresh episode of the podcast meanwhile .. Life is beautiful! :) Thank you guys for another excellent podcast!

Sunday, January 23, 2011

SDR MK1 Progress - Cypress vs. Atmel

As most of the work is going on at the SDR project right now, I guess I will start posting the status updates here in blog and do not litter the project page with my thoughts about the life, universe and everything.

Anyway, much-awaited Cypress EX-USB FX2LP kit arrived couple of days ago.

After playing around with it for two full days, I put it in my drawer and re-designed the schematic for using Atmel AT90USB1287 chip instead.

Dont get me wrong - its a nice little $29 development kit and does what its supposed to. It works allright with Cypress development tools. CY7C68013 chipset has been used in many different products all around the world (including several SDR designs commercially available) and I havent heard bad words about it. But ... Cypress EZ-USB FX2LP platform its tad too sophisticated for something I am doing here.

First and foremost, its compiler of choice for C/C++ is uVision2, what is included inside development package in its demo form, allowing only 4Kbytes of code maximum. Not only is it a very severe limitation, but the uVision2 tools provided are also two generations behind the current breed of uVision. The the default demo for uVision4 downloaded from their site is further limited to only 2Kbytes of code, so it is practically useless for production. And the full version costs $2-$3K. As I have noone else to write that bill than to myself, this is no go. The alternative is the freeware SDCC compiler for 8051 CPU, but I have seen mixed reports about the usage of it for FX2LP.

Second, equally severe, problem is the examples provided with the development tools. Yes, they did compile allright. Yes they did load on the $29 development board. Yes, I got USB devices appearing on my computer. But ... what devices? Is it too difficult to provide at least one meaningful example of the USB device what would appear as keyboard or mouse on windows?? Instead, the example folder is littered with all sorts of hardcore stuff about the block transfers and different I/O methods on CPU and whatever else. Very clever, I assume, but not too useful for somebody who wants to implement simple composite USB device consisting of USB audio and virtual serial port.

Cypress EZ-USB was one of the very first chips on the market capable of USB2.0 and very fast transfers, but its support and toolsets have not been updated much since. If I would have someone I could bill the hours working on it, I would probably consider it more seriously. At the moment its 1:0 to the Atmel.

Atmel has recently produced many chips natively capable for USB connection in its 8-bit AVR line. More importantly, they have gained a user community support for implementing the USB devices (and hosts) using these chips.

The tool of choice for me is a framework named LUFA (Lightweight USB Framework for AVRs, formerly known as MyUSB), created by Dean Camera. It has all the essential devices, like USB serial, audio in and audio out implemented in its examples folder, and the toolset it uses is Atmel mainstream tools, AVR Studio 4 and WinAVR.

So you need to install these two (you dont need to install AVR toolchain, as GCC tools usage by LUFA are better compatible with WinAVR), download the LUFA and here we go!

Fortunately, the 64-pin AT90USB1287 is relatively pin-compatible with Atmega325 what I use in many designs, so I am able to mount it on already existing board I have and should not worry about the development kit. Chips are supposed to be arriving on Tuesday ..

Tuesday, January 18, 2011

All archive files are now online

Yes, it took 2 whole weeks non-stop to upload these, but all the UVB-76 Temporary Internet Repeater USB archives are now online!
The old ones are using GMT+2+1(daylight time) timestamp and really old ones are actually from AM feed, but this is what I've got from these days.
I am not sure, but this may as well be the largest shortwave radio recording archive ever published! :)
Although Hostgator (bless them!), where it is all hosted, has said that they do not have problem with 100Gbyte space usage as far as traffic is not too high, I would not like to push it too far, so at some point I will likely take some of this offline. However, I am trying to keep entire archive on hard disks here, so if you miss some specific recording, just let me know. 

Monday, January 10, 2011

Sample chips for SDR arriving from National Semiconductor

THAT. WAS. FAST. Amazing! I got e-mail from National Semiconductor on January 7'th saying that they cant ship samples on their own expense and I have to pay for the courier service. It was expensive as hell, but still much cheaper than ordering the same number of chips from DigiKey, so I decided to give it a go. I got confirmation from Singapore warehouse, that the order was shipped on January 8. I got a call from local UPS office today, January 10 at 13:24 asking if I am at the office! Thats less than 48 hours from me making the shipping payment to NSC till doorbell!

Guess I have to start designing now! :)