Category Archives: Station Accessories
Equipment, scopes, monitors, meters
Folks, this has been a fun and hilarious winter project. Yesterday, when I built this air cannon antenna launcher it was -4 degrees outside and this was a perfect evening project to put together. For years, me and my two ham radio buddies (WR8S Bill Shultz and WV8TG Tom Graf), have enjoyed ARRL Field Day activities and usually used a slingshot and a 3/4 ounce fishing sinker weight and an old Zebco fishing reel (with 20 pound test line) to shoot and suspend our doublet dipole antennas high into the trees. Certainly, the slingshot worked pretty much flawlessly… but… boys will be boys, and the idea of an air cannon / spud launcher / potato gun type system seemed to be a new desire. (Most people, our wives included, wouldn’t trust our 3-man team with a slingshot, let alone a potato gun! But I digress.) Actually, our local ham radio club (Monongalia Wireless Association) had a version of a potato gun antenna launcher, so we decided we needed one of our own… and to make some design modifications in the interest of… “science”… plus our own sadistic pleasures. (Make sure you read below WV8TG’s initial “pressure test” experience.) The following pictures hopefully provide the basic concept and parts we used. Tom and I split the cost of the parts needed to make launchers and each built our own version, but they both are the same basic design with only length dimensions of the air chamber and barrel being the difference.
All parts where sourced from our local Lowes store in their plumbing department, except the Schrader valve which can be purchased at an automotive store. Total cost about $40 but you could make a couple of them as a joint project with a friend and reduce that cost per launcher a bit. I got a small rubber gasket for the outside nipple of the Schrade valve to act as another seal on the exterior of the air chamber. You will need to drill holes for Schrader valve, barrel slug stop and projectile slug caps to attach the screw eyes to attach the fishing line. I used 3 inch PVC for air chamber, 1.25 inch PVC for the barrel and short sections to mate the air chamber, trigger valve and threaded barrel. The projectile slugs were made from 3/4 inch PVC and caps and I filed off the nubs on the caps with a Dremel tool for a smooth fit into the barrel. I used PVC Prep on each joint before applying the glue. When gluing joints together, insert the sections together and twist a quarter turn for a solid adhesion. Let all glue set up for 24 hours before testing air pressure chamber. I will pressurize the chamber inside and let it sit overnight to see if it loses any pressure. It’s too cold right now to take outside in -4 degree temperatures to test, but I will use a bicycle pump with a pressure reading valve, and start at 40 psi… then 50 psi… and then 60 psi for test shots to see how it functions and check for any air pressure leaks. We use 60 psi for our club launcher.
WV8TG (Tom) charged his air chamber (barrel not attached) and let it set overnight to test for chamber air leakage. When he opened the trigger value… there was NO leakage… but there was a sudden LOUD release of 60 psi air gush out of a 30 inch long, 3 inch wide fully charged air chamber. He indicated the compressed air release was… impressive. However, his wife was not impressed… nor was she aware of the scientific test that was taking place. #surprise! #WHOOOOOOOSH #loudwifeexpressions I have no reason to doubt Tom will find his projectile slugs in the next county using his design. The club chamber was 12 inches long versus his 30 inch air chamber. #overkill? I designed my air chamber for 14 inches and will conduct all tests… outside. #potentialmeanwife
As soon as I get my Yaesu System Fusion FTM100-DR online, I want to mate my Bencher paddles to the new MFJ-490X Menu Driven Memory Keyer that I picked up at the 2016 Dayton Hamvention last week (May 21, 2016). I am itching to get these two toys working in some CW / More Code Contesting very soon! 5 programmable memories plus all sorts of keyer speed, weighting, side tone, hand key capability, serial number decrements, random code practice, iambic settings, etc.
(See video below!)
MFJ-490X Memory Keyer Instruction Manual
I would venture to say you can’t do better than hearing it from the inventor himself!
Here is an excellent YouTube video from RimstarOrg that breaks down the concept of how crystal radios actually DO their magic! Yes, MAGIC. Radio signals are all around us 24 hours a day. Invisible! You can’t really touch them. You can’t smell them. You can’t hear them without assistance. We don’t really feel them bombarding us. We don’t sense those signals without some mechanical help… but they strike us with many different frequencies constantly… so let’s explore the range of frequencies we can decipher with a homemade crystal radio set!
THE BEST Multimeter Tutorial
The voltmeter… the Volt-Ohm Meter… the Multimeter… digital or analog… continuity… amperage, voltage and ohms… COME ON, MAN! What is it and how hard is it to use in the every day life of a ham radio enthusiast or just someone working in their workshop? Once again, Afrotechmods has an excellent tutorial on his YouTube channel for us to learn from!
CQ Contest… CQ Contest… CQ Contest !!!
Ham radio contesting is exciting and fun to participate in regardless if you are a Rookie Contester or a Seasoned Pro-Contester! As with any big project, proper prior planning makes all the difference in your final score. This QRZNOW.COM article about developing a Pre-Contest Checklist will add to your QSO tally! Click link below for the full article…
These are very handy for all sorts of your 12 volt ham radio projects!
Will be looking for these at the next hamfest!
Recently I remodeled the attached garage into an additional room (which will include my revised ham shack) so that it became a functional area. Before hanging the dry wall I ran both electrical circuits and a network circuit so that I could not only supply power to the whole room but also 2 circuits for my ham radio equipment and computers. After pulling the CAT5 cables I had to terminate them for hooking up the wireless router and computers. This video shows and explains the exact sequence of the individual multicolored CAT5 wires and the order they need to be slipped into the connectors before they are crimped. WRITE DOWN THE WIRE COLOR CODE ORDER GIVEN IN THE VIDEO TO USE WHEN YOU ARE READY TO MAKE THE CONNECTIONS.
How GPS Works
Basic APRS – An Introduction
(Click link above for the ARRL APRS webpage explaining APRS)
“Official U.S. Government information about the Global Positioning System (GPS) and related topics”
GPS Modernization Video
GPS is getting an $8-billion upgrade
“Without it, ATMs would stop spitting out cash, Wall Street could blunder billions of dollars in stock trades and clueless drivers would get lost.”
New Satellites Could Make GPS Harder to Jam
“Without GPS, drones can’t fly, communications networks can’t function, and you don’t have a chance of figuring out how to get to your Aunt Sadie’s place in New Jersey. And right now, GPS is highly vulnerable because its weak signals are coming from an aging constellation of satellites.”
How GPS Receivers Work
“Our ancestors had to go to pretty extreme measures to keep from getting lost. They erected monumental landmarks, laboriously drafted detailed maps and learned to read the stars in the night sky.”
Check out the Air Force Collaboratory:
How Collaboration Leads To Great Ideas
How Robots Help Search And Rescue Teams
Voyager 1: Where To Next?
I have helped build and used two of these Doublet Antennas during the 2014 Field Day Contest and they worked great! Worked many stations on CW, Phone, and PSK31. Works great across many HF bands. A little over 120 feet long. WR8S (Bill Shultz), WD8WQK (Tom Graf) and I are going to make one for my ham shack as soon as I order the parts. Take a look at Ray Heffer’s explanation of the Doublet Antenna and a diagram by N4UJW below.