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Foundations of Amateur Radio Recently I built a first attempt at a noise cancelling circuit, on my couch, in GNU Radio, without holding a soldering iron and running the risk of the room smelling like burnt chicken, because if you believe the Internet, sometimes holding a hot piece of metal by the hot end is not the best way. The idea behind the circuit, or more accurately, flowgraph, is that you take a signal from two sources, invert one, combine them, and they cancel each other out. If the signal with the noise only contains noise, then you can, at least theoretically, remove the noise from the actual signal. Before you think that I'm inventing something new, I'm not. I'm merely attempting to recreate the same notion I came across decades ago, where you combine the signals from two microphones, preferably identical, reversing the wiring in one and talking into a microphone whilst holding the other one away from your mouth. I did essentially the same thing using RF signals from two RTL-SDR dongles. Randall VK6WR pointed out that, aside from misusing the word "mix", which in electronics really means multiply, but in audio means combine, Randall suggested I use "add" and "subtract". I'm still working out how best to name things, because we're talking about audio and RF, sometimes at the same time. Perhaps that's where I went wrong. I'm currently using "combine" as my technology neutral word, but I'm happy to take suggestions. All that was the side show, because as Randall points out, doing this in RF is much harder than in audio. This is already something I knew. At the time I didn't really know how to get two different but the same sources of audio to experiment with, so I started in the deep end at the RTL-SDR dongle side. Now, armed with the encouragement from Randall I built a horrible thing, which is easy when you just drag and drop blocks on a screen. I built two independent FM decoders that use the exact same parameters, so they're tuned to the same frequency, they're amplified and tweaked identically. The only difference is that they each decode a different dongle. I then piped each of those into my magic noise cancelling circuit and tried again. Aside from dealing with hardware restrictions, causing things like buffer under-, and over-run, that's when the computer isn't processing all your samples, or is getting ahead of itself and is running out of samples, I can make audio come out of the speaker in my computer. I can prove that there are two signals, by setting the amplification of either to zero, and still get sound from the other source, however, noise cancelling, no matter what I tried, didn't work. Then I decided to simplify, rather than trying to cancel out "the Heat is on", word of honour, I'm not making that up, that's the song that was playing, I went back to basics starting with a tone. I fed the same tone into the noise cancelling block twice, once as signal, once as noise. Magic, the cancelling works. I also learned that changing the frequency of the noise and changing it back gets you into all kinds of problems and even if you send the same tone, one shifted in phase by a known amount, getting the two to cancel each other out is non-trivial. You might think that this was all a complete waste of time and if you're just driving past it looks like a swollen electrolytic capacitor about to burst your bubble, but it's not that bad. Here's what I learned from this little adventure. I can make hierarchical blocks out of flowgraphs. This is important because at some point all the functionality associated with Bald Yak will likely end up being implemented like this. I also learned that such a block can contain user interface elements, which means that we can build blocks that know how to do stuff and tweak how they operate without having to build a user interface every time we use such a block. I learned that we can implement an idea that would be hard using physical components and test it really quickly, in this case my available time was the limiting factor, not the testing. If I'd done this with components I'd still be trying to figure out where to get them from, let alone turn up the heat. Another bonus is that I didn't spend a single dime and I can dispose of it with the click of a button, rather than trying to figure out how to recycle components and circuit boards. I also learned that the idea as I built it doesn't work quite as I expected and that things that I didn't anticipate, like changing the frequency, buffer under-, and over-runs, impacted my efforts in unexpected ways. There's a delay between making a change on the user interface and the effect becoming audible, and I learned I can make a dongle work on my computer and that installing GNU Radio is a challenge at the best of times. In other words, even though I'm unlikely to use the noise cancelling efforts in their current form, there was plenty I learned from the experience. From my perspective, this was a success. What have you experimented with and learned? On a completely unrelated matter, long overdue, and music to the ears of some, can you spell SKCC, I've finally put all the Morse Code versions of my podcast on a thumb drive and plugged it into my car. During the week I've managed to listen to about two hours of Morse. While I don't know most of the letters of the alphabet, I can still detect letter and word boundaries. I'm Onno VK6FLAB
Doug, N3PDT and Ted, K8AQM are here to take your calls about the Straight Key Century Club. They recently hit a major membership mark, and we'll talk about it and their activities.Be sure to CALL in with your questions and comments by calling 859-982-7373 live during the call-in segment of the show. You can also tweet your questions before or during the show to @HamTalkLive.
Hosts Jack West & Charu Aggarwal speak with immunotherapy expert Dr. Patrick Forde about unique advantages of the pre-operative platform for systemic therapy, especially immunotherapy, in early stage cancer & pathologic response assessment from surgery.
Episode 27 Watt Elmer? Show Notes Song: 00:00 Intro: 00:54 Feedback: 01:23 Regarding episode 25 Thomas, WC5B, says he has changed his mind about what he recommends to new hams for a first radio, based on Richards comments. Ray, KO4RB, also talks about episode 25 and his thoughts on a handy-talk as a first radio. Jerry, KD0BIK, of The Practical Amateur Radio Podcast disagreed with some of Richard's comments about media coverage of hurricane damage (Ike and Gustav) along the gulf coast. Richard's comments were meant to be specific to his local media. Ray, KO4RB, also writes to thank Richard for the podcast, and extols their virtues as a tool for elmering new hams. He's also exploring Linux for use in his shack, experiments with digital modes, DStar, and more. He also made a donation! Rich, AB6TY, says he listens as he works in the welding shop, and enjoys the information and music. He loves CW and encourages others to give it a try, and recommends FISTS and SKCC. He reminds Richard that new hams should be aware of split-frequency operations while chasing DX. He asks "What is a 'lid'?" A lid is a bad operator. www.fists.orgwww.skccgroup.com Donations: 17:25 Rich AB6TY, Ray KO4RB made donations, which allowed the purchase of a microphone, and a new machine to record the podcast. Consider a dollar per episode. Every dollar helps. Remember, we have to pay for the hosting service. shop at Amazon through the link at the website. Thanks! 19:55 Russ K5TUX and Richard released the first episode of Linux in the Ham Shack. Give it a listen Song: 22:07 "Night Time is the Right Time" by Elvin Bishop, featuring John Nemeth & Angela Strehli, from the album "The Blues Rolls On" Buzzword: 23:19 SWR and Watt MetersMeasures power out in watts and the SWR (standing wave ratio). Higher SWR is bad, as most modern radios will reduce their output if the SWR is too high, so it's a good idea to monitor the SWR. They can also be used to tune your wire or mobile antennas. Song: 31:58 "What Is That You Got" by Magic Slim & the Teardrops from the album "Midnight Blues" Topic: 34:17 How can you be a better Elmer? Elmer is the amateur radio term for a mentor. Anyone can be an Elmer. It just takes the desire to share what you know with someone else. It does take patience. Talk up the hobby with other folks. Teach a class. Get involved with one of the scouting organizations. Wear a shirt that proclaims your interest in the hobby. Be available at a special event station to answer questions. Song: 57:17 "Sleep" by Albert Cummings from the album "Feel So Good: Albert Cummings" Closing theme:65:04
“Our research population should match our community population.” That’s one of the takeaways from Christopher Gantz’s interview with WCG President of Patient Advocacy Steve Smith. He describes several programs that help connect researchers with minority communities to increase engagement and access enrollment in clinical trials. Gantz is senior director of the Regional Liaison Office at the Sidney Kimmel Cancer Center (SKCC) at Thomas Jefferson Hospital in Philadelphia. Since 2005, he has worked on multiple clinical trials projects with recruitment goals ranging from 500 to 10,000 participants. He describes establishing an “honest broker network” and engagement of resources within the hospital and within the community to ease communication, build trust and facilitate trial enrollment. He also discusses some of SKCC’s language and cultural resources as well as its outreach into area schools.Listen to learn how SKCC’s success offers a model for other organizations to transform clinical trials. “We have so many resources and so many opportunities to engage with people. I think if we're smart about it and really thoughtful in how we do it and create these longstanding relationships, it really will create a change.”
Foundations of Amateur Radio With the growing availability of new ways of communicating across the globe, from digital voice such as CODEC2, through weak signal modes like WSPR, JT65, MSK144 and FT4 to name a few, with Internet linked radio such as Brandmeister and DMR and the newly granted access to all Australian amateurs to all those modes, it's easy to overlook the one mode that started this adventure. Morse Code. It's no longer required to obtain your amateur license, so if that was putting you off from getting your license, you can breathe easy and get right to it. Among all the shiny new modes Morse Code continues to hold its own and for good reason. It's simple, reliable, has an amazing signal to noise ratio and if you're driving in your car and you're stuck without a Morse Key, you can always just whistle into your radio. If you've been following my journey through the hobby you'll know that I've been attempting to learn Morse Code. For a while now. It's been a challenge, more so since I spend less and less time in a car and more and more time behind my keyboard appeasing my clients. That's not to say that I've forgotten, just that what I've tried so far has eluded success. A little while ago I received an email from a friend, Shaun VK6BEK who let me know that there was a discussion happening on a mailing list he was a member of and in that discussion I cracked a mention. Being the shy and retiring type I had to have a look for myself. To read the message I had to join, which is fine, since Charles NK8O has been bugging me to do that for years, well perhaps not bugging, perhaps keying me - hi hi. Turns out that the Straight Key Century Club, the SKCC, was having a recurring discussion about the topic of Head Copy or Head Reading. To give you a sense of what that is, consider what I'm saying to you right now. It doesn't matter if you're reading this in an eBook on your Kindle, reading it on an email or online, listening to it on your local repeater, or via your favourite podcast player, for each of those the same process is happening. You are not absorbing individual letters or sounds, but getting the meaning from the entire structure of a sentence. For uncommon words you might need to calibrate your brain, but for the most part you're just bobbing along understanding what I'm saying. In essence you're doing the equivalent of Head Copy. In Morse Code the same can be achieved. Ultimately it's a language, a tonal one, but a language none the less. Hearing the individual dits and dahs, followed by letters, words and sentences, eventually you'll get to a point where it all just flows. I speak a few different languages, a curse or a blessing depending on your point of view. It means that I've become exposed to how language is built up. Initially when you hear a new language your brain is trying hard to figure out where the individual sounds belong, which sound belongs to which word, how a word begins and ends, how you make a plural, all the things you take for granted after you've learnt a language. In Morse that is no different. Within that context of discussing Head Copy, Gwen NG3P mentioned that she used the text edition of this podcast to convert into a Morse Code MP3 file so she could learn to hear Morse and bring them with her on her mobile phone. Gwen and I had similar aims. In the past I'd done the same with a book, Huckleberry Finn if I recall, as well as random letters and also the ARRL Morse practice downloads, but nothing seemed to work for me. For Gwen my podcast was an obvious source, so much so that I completely missed it, since they are short and on the topic of amateur radio. The language in use is likely going to be things that you'll hear on air and there's a smattering of callsigns, so all good. Long story short, I spent last week converting all 454 episodes of the podcast to Morse Code for your Head Copy practice enjoyment. They're encoded at 25 WPM, or Words Per Minute and the tone is 600 Hz. I even put them online and made it possible for you to add them to your podcast player. Best part? I now get to hear Morse Code at a pace that I'm looking for, on a topic that's relevant and I have been receiving plenty of emails from others who are just as excited as I am. You can find these episodes on the podcast homepage at http://vk6flab.com. Let me know how you go. I'm Onno VK6FLAB
First on the show this week is Janine DeFeo, co-founder of the Teal Butterfly Challenge. The Teal Butterfly Challenge is a non-profit 501 (c3) organization whose mission is to raise awareness about the early signs and symptoms of ovarian cancer by educating the public through community events and social media campaigns. September is Ovarian Cancer Month so the Teal Butterfly Challenge encourages people to paint their nails teal and make a butterfly sign with your hands and post on social media with the hashtag #tealbutterflychallenge to raise awareness. For more information you can visit www.tealbutterflychallenge.com Next on the program is Karen Knudsen, PhD, Enterprise Director of the Sidney Kimmel Cancer Center at Jefferson Health and Editor-in-Chief of Molecular Cancer Research, a journal of the American Association for Cancer Research. Yes, that is an impressive title for a very impressive woman! Dr. Knudsen oversees all aspects of cancer research and cancer patient care at all 13 SKCC sites within the Greater Philadelphia region. Under Dr. Knudsen’s leadership, SKCC is consistently ranked as one of the top hospitals for cancer care in the nation by US News & World Report. Dr. Knudsen also serves as Chair of the Department of Cancer Biology at the Thomas Jefferson University, and holds joint appointments in the departments of Urology, Medical Oncology, and Radiation Oncology. Dr. Knudsen’s expertise is in developing new means to treat advanced cancers, and her laboratory is genetic alterations that contribute to disease progression. Dr. Knudsen is highly active in the cancer field, serving as the Editor-in-Chief of the AACR journal Molecular Cancer Research, as a member of multiple national and international review panels including the NCI Parent Committee, holds leadership roles in national organizations including ASCO and AACR, and is Chair-Elect for both ASCO-GU and AACI.
There are several organizations that promote Morse code and the CW operating mode. One of the very best is the Straight Key Century Club (SKCC). The organization officially began on January 2, 2006 and currently has over 18,800+ members worldwide. The SKCC offers one of the broadest assortments of awards, contests and activities available from any organization for every level of CW operator to participate in. Ted Rachwal, K8AQM, is a member of the SKCC board and editor of the "Rag Chew", the official newsletter of the Straight Key Century Club. We spent a little time talking with Ted about the SKCC, the resources and benefits the club has to offer, and why it's no surprise that many of the nicest people you'll ever meet in the CW bands are SKCC members!
Ham Radio: CW for the Newbie! with Justin, KI4WFJ. In a Fo Time First, we have a 'Studio' Guest. My Friend and Neighbor, Justin Hornby KI4WJF, came down to chat with us about Learning CW and getting your code on the air! Justin has been licensed for a while now, and over the course of time had an on and off relationship with Morse Code...until Now! Justin got serious and finally took the bull by the horns. He shares with us his secrets to learning the Code and how he makes use of it as he continues to enjoy the hobby! Make sure you check out his show notes below! From Justin: http://lcwo.net/ free browser based teaching tool; uses Koch method and has plain text training; I use this now to practice on lunch at work or whenever I want to practice without a radio. http://morsefusion.com/ free week long trial but normally $9.99 a month; this is what I used to really get through learning the characters and practicing; I highly recommend. http://www.skccgroup.com/ what sets SKCC apart is it's membership is free. Members are friendly and they have monthly scheduled activities that give a reason to get on and practice. Have morse elmer program for practice buddies and the sked page helps find contacts. http://naqcc.info/ North America QRP CW Club; I also have joined the NAQCC and play in their contests and activities as well. Another friendly free club/group that has a lot of participation. Contests are laid back and fun; a great way to practice and improve your speed once on the air. My kit radio: http://www.qrpkits.com/pfr3.html Check Ebay or junk boxes at hamfests for straight keys--try to get one that is fully adjustable--bearings,spring force,gap; it makes all the difference in the 'feel' of the key; I use this one: http://www.ebay.com/itm/NOS-Vintage-Classic-Oval-Speed-X-Telegraph-Key-c-1967-Nye-H15-682-New-/161911306817?hash=item25b2aa7a41:g:LzkAAOSw9mFWGtS1 The capacitive touch paddles I have I use sometimes is model P6: http://www.cwtouchkeyer.com/home.htm http://www.americanmorse.com/ A practice sidetone oscillator helps to get timing and feel for sending-just practice imitating sending good code you have listened to.; many radios can be setup to create the sidetone w/o transmitting for practicing; the IC-718 can do this The ARRL W1AW practice transmissions are a good way to get used to listening to morse over the radio and practice decoding before jumping in making QSOs. There's a big change between listening to practice code on the computer and dealing with QRM and QSB!! Also, all the files, text and mp3 are available on the website so you can listen, decode, and check your work w/o having to stick to the broadcast schedule or have a radio handy. http://www.arrl.org/code-practice-files http://www.arrl.org/w1aw-operating-schedule 73, K4CDN