From: Rich
To: "soldersmoke@yahoo.com"
Sent: Thursday, January 22, 2015 9:22 AM
Subject: Cheap, open source Arduino SDR project
BillFirst, thanks for Soldersmoke and all you do for us QRP hackers around the world. I'm a big fan!
I've detected you are getting sucked into the world of microcontrollers of late. I know you are not really that excited about SDR but this is a radio that combines Arduino, the currently popular SI5351 and a Softrock to make a very functional SDR. I started this project last year which uses the fabulous Teensy 3.1 and companion audio shield. I recently packaged it all up and it looks like a QRP radio now. Still doesn't transmit but as I like to say thats "just a small matter of software".
There are several posts about it on my blog. The most recent:
There's a link to a video and a link to the code in that post.
Rock on Bill!
73, Rich Heslip
VE3MKC
Sent: Friday, January 23, 2015 4:09 AM
To:
Subject: Re: Cheap, open source Arduino SDR project
Wow Rich that is really beautiful. Amazing! I am also sending this to Pete Juliano, but I was at first hesitant about this because I feared that your combination of Si5351 and TFT display might be TOO exciting for him. Deep breaths Pete...
73 and Thanks, Bill
From: jessystems@verizon.net
To: soldersmoke@yahoo.com;
Subject: Re: Cheap, open source Arduino SDR project
Date: Fri, 23 Jan 2015 06:03:40 -0800Hi Rich & Bill,
Wow –really exciting project Rich! Congratulations and Bravo!
This is so exciting, for all hams, as this just shows the power of the available low cost technology that is now on the market. Your project is really tempting as I have a V6.2 15M softrock sitting in a box (somewhere). I was somewhat put off with the Power SDR as the opposite sideband rejection is not too good –it is clear you have cracked that nut.
Thanks for sharing Rich and yes Bill I am taking very deep breaths.
73’s
Pete N6QW
Thanks guys! When I saw the Teensy 3.1 with the companion audio codec board the first thing that came to mind was a portable SDR. Since its Arduino compatible I am able to leverage the SI5351 library, encoder library etc so its mostly just putting software blocks together. The digital filter design is a bit tricky but Loftur VE2LJX did quite a bit of work on that and now it works really well.
I hope to add CW decoding and PSK31 at some point. I've used less than half the flash on the Teensy so lots of room for new features. I'm hoping if the word gets out I won't have to do this all myself!
Pete - too bad you missed the Black Friday sale - Teensy 3.1 and the audio shield for $18. Deep breaths...
: )
73, Rich
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20
We were all understandably concerned when Todd VE7BPO announced this Fall that he was taking down his beloved QRP POPS web site. I'm pleased to report that Todd has transitioned from Web Site to blog. The spirit of QRP POPS lives on here:
http://qrp-popcorn.blogspot.com/
There are also links on this blog to all the great stuff that was on Todd's site:
Todd Gale, VE7BPO, is a true HOMEBREW HERO. His QRP POPS website has been a source of inspiration and information for many years. Todd wrote in yesterday on the trivialization of regens and what we should do about it. Thanks Todd!
Dear Bill:
With due respect, I challenge the statement that many feel regenerative receivers are trivial. I submit that most of us know that regens offer good sensitivity + selectivity despite their few parts, however, we ourselves, may trivialize the regen by our lack of literature reviews, experiments, imagination and attempts to improve its downfalls.
Where are the bench experiments and inspired discussion that address issues like designing circuitry to reduce overload and blocking while still maintaining high sensitivity when needed, hum + noise reduction, AF filtration, or ways to reduce RF pollution into the RF lab environment?
Much work on regens and of course, its amazing sister, the super-regen dots the literature. People did make many experiments to explore topics like vario-couplers, litz wire coils with low applied power regen detectors, sensitivity analysis, noise analysis and frequency domain calculations.
We now tend to see or present über basic regenerative receivers complete with LM386. Yet, still we authors somehow feel people might not respect the regen? Really?
Another factor: as my regen grows in complexity, shouldn’t I just make a zero IF radio (now just as simple with a dongle or two I/Q mixers going into sound card), or perhaps make a simple superhet with some computer crystals for the IF filter?
Regenerative receivers remain cool. Perhaps putting both hands on the controls plus the antenna coupling are just part of the regen experience and like a standard versus automatic transmission, offers more visceral listener engagement?
No doubt, nostalgia and love for simplicity color the regen experience. Now is the time to make a regen — If you listen carefully — inside many big cities the crashing sound you hear is yet another SW tower coming down.
Hats off to you Bill and also to Dave, AA7EE for his stellar blog presentation.
Todd, VE7BPO
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20
Bill:
I think I’ve finally earned the right to contact you. I have a really severe case of the knack. I did not realize it until I discovered amateur radio. My thinking is that there is no hope for those afflicted with the knack. I believe that amateur radio helps those afflicted to deal with the condition. It alleviates the symptoms.
For years I wandered through the technical wilderness dabbling in physics (I have a M.Sc. in Nuclear Physics), aircraft (I was a tow pilot at a gliding club for several years), high power rockets (www.napas.net), electronics and amateur radio. The most enjoyable part of radio is not the QSOs it’s the building and the satisfaction of a working device.
I am relatively new to amateur radio but I’ve always had a passion for all things electronic (and technical). I am a self-taught electronics geek and have been playing around with digital electronics (PIC microcontroller) for some time know. I starting building altimeters for high power rockets that has the capability of setting off onboard charges to separate the rocket. When your rocket reaches 10,000 feet, you cannot open a chute at apogee because it’s going to drift too far and you need to open the rocket at apogee (no chute) and then open the main chute at about 1000 feet to minimize drift. I routinely travel to the US to attend LDRS (large dangerous rocket ships).
Anyway I had to get my amateur ticket for onboard video camera and trackers (beacons). Once I got my license and got into radio, it was like a drug!!
I am now home brewing everything in my shack.
When I came across Soldersmoke that was like a super drug. I downloaded and listened to EVERY episode (seriously!). I followed you and Mike’s journey and I learned soooo much. I was devastated when I found out about Mike.
You inspired me to build my own transmitter. Earlier this year I built a 20m CW transmitter for my rocket that will eventually send telemetry (in CW from a PIC microcontroller) completely from scratch – no kits – no one’s design. Your early episodes also pushed me to learn LTSpice which I used extensively to model transmitter design of others as well as my own. I’m thinking of calling the transmitter “kaputnik”.
My design is based on a Chinese AD9850 DDS module which generates a square wave followed by a class E amp (with a tuned circuit). Puts out 1 watt of power with harmonics down by about 40db. The reason I used this module with that I can easily change frequency (with mod to tuned circuit) – after all the DDS module is programmable. All I need to do now is clean up key clicks because the carrier is turning on too fast. I playing around with slowly increasing the bias on the mosfet to allow the power output to increase slowly. Any advice/tips/tricks would be appreciated.
Next project is a remote antenna switch. However, you have me close to tackling a SSB transceiver.
Anyway, keep up the great work and I’m looking forward to listening to another 150 episodes!!
Take care and “stay thirsty” my friend.
73
Dave Rajnauth, VE3OOI
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20
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