Most operators, however, still preferred spark transmitters because of their uncomplicated design and because the carrier wave (carrier) stopped when the telegraph key was released, which let the operator “listen through” for a reply. With other types of transmitter, the carrier could not be controlled so easily, and they required elaborate measures to modulate the carrier and to prevent transmitter leakage from de-sensitizing the receiver.
Some arial pictures from the club picnic at Pat’s place. Glad people enjoyed my demo and got a chance to try their hand at piloting the aircraft. Next time maybe I’ll have a few more batteries…
Glad everyone enjoyed my presentation. Here are the pictures that Gerry, Brian, Pete and I took while flying. Word around the club is that Debbie N0LDB is going to get one for her birthday this year!
As usual, don’t shoot the videographer, he’s playing as best as he can…
Ken, KB0HP gives an excellent talk and live demo of JT-65 weak signal mode and Bob K9MWM has a report from his and Sue’s (N0DBY) trip to Quartzite RV meeting and hamfest. As usual, sorry about the production quality, but I think I’m getting better at the one-man-band production system. This month I ditched Switcher Studio and tried out Rico Live multicam, which doesn’t do realtime streaming (which didn’t work all that well and gobbled up data), but does record all footage locally and render it later, which I think does a much nicer job.
Notes for Phil’s presentation on contesting.
- Good way to get awards such as WAS or DXCC in a hurry
- lots of activity from those rare locations
- What exactly is a contest?
- Rules for the contest
- power class
- specific bands
- time limits
- spotting networks
- logging and reporting
- computerized logging
- contest information
- vacation contesting
Here’s the handout from today’s SDR presentation, in .pdf format. The footnote links should all be clickable in the text.
Yesterday we held the Raspberry Pi bootcamp at the Silt branch library. This was a course to introduce the small inexpensive computer to novice users. More and more hams are finding uses for it in the shack. My prior presentations have always generated a lot of questions and interest in the club, so I thought it would be a good idea to show how easy it is to get your feet wet. We had 7 members in the class: Larry (N0ACW), Bob (K9MWM), Bob (KI0G), Bryan (N0THY), Betty (KD0YDH) and Ken (KB0HP).
Here’s a link to my notes. This is a dynamic document using OneNote. Some of you will see the irony in taking notes for a Linux class using a Microsoft product. I’ll be cleaning this notebook up and adding to it over the next few days, but I wanted to get something out there while it was still fresh.
The day was split roughly into 2 sections. In the morning we covered basic navigation and operation of the Raspberry Pi and the Linux operating system, some history of Unix and educational computers, and making sure everyone was able to get their Pi booted up and working -which might have been the most important lesson of the class (HIHI). The afternoon was spent actually setting up a simple SDR program called dump1090.
This program, which Chuck (N0NHJ)
uses to upload data to Flight Aware (actually Flightaware.com uses their own software) from locations throughout the west slope and Pete uses to display “virtual aircraft radar” on his web site, seemed to be a fairly good introduction to installing and compiling software on the Pi. The instructions are mostly clear and easy to follow too. It uses a USB dongle that was designed for picking up European standard off-air digital television (DVB-T). The engineers actually created the front end of a software defined radio platform. Hams quickly picked up on this fact and began using it for all sorts of activities. I picked up one last fall and have had a lot of fun playing around with it, both with my Macbook and with the Raspberry Pi. Take a look at my previous post with the parts list for the class for ordering information if you want to try it out.
Once we had some of the bugs worked out, we set to work getting the software sorted out. I’m happy to report that all five attempts worked. But the real good news is that there are seven more people who can poke around the terminal screen and have a little better chance of understanding what all that gibberish means.
Ken gets extra credit for stumping the teacher – he pointed out that the instructions I was using showed how, if I had just scrolled down a little further, you could use any web browser to connect to the Pi and display a moving map of the planes received.
Whoops –I mean “I meant to skip that part to see who would be the first to figure it out…”
The only other thing I’ll mention is that we had more interest from other members. I know that scheduling can be difficult. If we had a better idea of the actual number of people who could attend it might have saved us needing to rent space for the event. I’m thinking I might want to try doing another class in the fall. If we do it would be nice to get a more realistic head count. If only a few people plan on attending it would be better to hold at someone’s home or other location. The Garfield County libraries are good locations for these activities, but unless we open events to the public, they aren’t free even for non-profits. Don’t get me wrong, I’m thrilled with the turnout we had and I think everyone got more out of it than if it were a packed room, just that we could have saved a fair amount of hassle if we knew to plan for a smaller crowd. (end rant)
Anyway, I hope everyone enjoyed the day as much as I did. As a bonus, Phil (N0KE) and I finally made a contact on 1200 Mhz, between 7th street in downtown Silt and the N0KE global communications center. I had the IC9100 in the hatchback of my car, pumping about 5 Watts into half (11 elements) of my 24 element Yagi antenna. Phil had his 30 element loop Yagi pointed north, completing the link with his trusty (crusty?) Yaesu 736R. I need to get it in the log so we have another grid worked!
http://www.rtl-sdr.com/adsb-aircraft-radar-with-rtl-sdr/ – HowTo guide for everything to build an ADSB receiver, including antenna designs. Not just Raspberry Pi, although scroll down to the section about dump1090 for instructions.
by Eric K0JEG
We’re still planning the agenda for the Raspberry Pi bootcamp, but I have a plan for the class room build phase. I think a good project will be to build an Aircraft ADSB receiver, using a USB tuner and GNU (SDR) radio. This ADSB Radio Receiver (combined kit) can then be used to upload ADSB Real-Time digital flight data to FlightAware.com or just used as a launching pad for more SDR projects. (below an example)
We were aiming for sometime in May, but it turns out May is a very busy month. Must have something to do with pent-up demand from winter… Anyway, we’re now looking at June 4th for the date. Ken White, KD0YDH has permission for us to use his WiFi classroom at Rifle High School. Thanks Ken for doing the legwork! (Update: 30APR2016 – note date may change)
The project will require a Raspberry Pi 2 or (preferred) Pi 3. The Pi 3 is shipping in quantity so it should be fairly easy to pick one up, although you might pay a little more than the $35 target price. The Pi 2 is more than powerful enough though, so don’t worry if you can’t get a Pi 3. Pi3 advantage? WiFi (and Bluetooth) built right into the tiny motherboard. Pi2 has to add WiFi externally via one of its USB ports.
http://www.amazon.com/dp/B00T2U7R7I – Link to the Pi 2
For the Price of (2) Baofeng’s you can get a complete Pi3 – Kit (case, micro-SD hard drive and Power Adaptor and HDMI cable $69.99
http://www.amazon.com/Wifi-Antenna-Raspberry-Pi-Instructions/dp/B00H95C0A2 – good WiFi/USB adapter for the Pi 2. Has a removable (SMA-RP) antenna connector
http://www.amazon.com/dp/B00MARDJZ4 – Micro-USB power supply, 2.5 Amps, more than enough to power the Pi and a few USB devices. You can use a minimum of 1A phone charger, but if you’re going to do anything permanent it’s a good idea to pick up a good power supply.
http://www.amazon.com/dp/B00JRSPSZI/ – Micro-SD card. This acts as the Pi Computers (hard drive). The Pi 2 and 3 switched to micro-SD cards and a much more stable card reader. 16 GB is the minimum I’d get, 32 GB is better. Get a higher-class (read: faster disk drive) micro-SD card so that it doesn’t become a bottleneck.
http://www.amazon.com/NooElec-NESDR-Mini-RTL2832-Antenna/dp/B00P2UOU72 – USB-SDR module (photo). There are others that are a little less expensive, but the manufacturer of this model claims they use a more stable TXCO circuit, which means lower phase noise and more precise frequency control. Your mileage may vary… Just make sure whatever model you buy is based on the RTL2832 chip.
You’ll also need a keyboard, mouse and HDMI monitor.
Check out this amazing list of the number of USB-SDR Receiver projects this NooElec $22.50ea adaptor is capable of…and the list is GROWING! (Click Here)
You can’t beat this $23.99 Logitech Wireless Mouse and Keyboard (uses just 1 USB tiny connector) Logitech even includes the batteries for the Mouse and Keyboard.
Once you get your Pi working you’ll be able to access it remotely on your home network. We can show you how to download the (free) Remote Desktop App for the Pi – that allows your home PC to “Remote Desktop” to the Pi for complete control. But for the class we’re going to be connected directly. A case would be a good addition too, especially if you plan on using the Pi permanently. There are lots available, at lots of different price points. You don’t really need to worry too much about heat dissipation unless you are going to overclock your Pi, which won’t be necessary for the class (but I will go over the process).
Anyway, we have 13 people who signed up during last months’ meeting. I’ll also have a sign-up sheet at the foxhunt in May or just drop me an email if you plan on attending.