Category Archives: Transmitter
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
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!
K7AGE has a superb series of ham radio videos and I have learned a lot from them. Subscribe to his YouTube Channel for information on TONS of topics about amateur radio!
These are very handy for all sorts of your 12 volt ham radio projects!
Will be looking for these at the next hamfest!
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 stumbled onto this really cool website called RigReference.Com and was able to find some information on several older pieces of equipment I have in my ham shack. Here is what their website says…
Who we are
RigReference.com is designed for and by Ham Radio enthusiasts. RigReference.com provides information about new and vintage amateur radio equipment (rigs) and allows and encourages members to share their opinions about these rigs.
RigReference.com is always looking for amateur related news, especially new equipment announcements. If you’ve seen or heard anything interesting please don’t hesitate to contact us!
RigReference.com explicitly does not sell ham radio equipment and/or parts.
The Icom 718 HF Ham Radio is suggested by many hams as the ideal beginner’s HF rig. The QRZ.COM website had a good forum post on best radios for beginners HF Rig For Beginners (See reviews of the Icom 718 at the end of this post.)
Receive Range: 0.030-29.999 MHz
Transmit Range: 1.800-1.999, 3.500-3.999, 7.000-7.300, 10.100-10.150, 14.000-14.350, 18.068-18.168, 21.000-21.450, 24.890-24.990, 28.000-29.700 MHz
Mode: USB, LSB, CW, RTTY (FSK), AM
Transmit Power: SSB, CW, RTTY 2-100W; AM 2-40W
Memory Channels: 101 (99 regular, 2 scan edges)The HF bands allow you to communicate over long distances covering many km even to the other side of the world. With the superior performance found in the IC-718 such as wide dvnamic range, high C/N ratio, and full duty operation you will find making these contacts easy. Experience the combination of the latest RF and digital technology, along with the size and simplified operation. You will see the IC-718 will be the most practical rig you will ever own.Front mounted loud speaker
The IC-718 has a speaker mounted on the front panel. With the speaker facing the operator, audio sounds can be clearly heard without impediment during operation. It is no longer necessary to manually increase the volume to try and capture audio sounds.
Superior basic performance
The IC-718 has 0.03-29.999999 MHz* general coverage receive capability. A 4-element system is employed for the 1st receive mixer, providing superior receive IMD, especially from in-band near-by interfering signals. A well-designed double-conversion system to help minimize image and spurious responses for better signal fidelity, is also built-in. A newly designed PLL circuit has been adopted to improve C/N ratio characteristics. The combination of the 4-element system mixer and new PLL circuit allows superior basic performance as that of a commercial grade transceiver.
*Guaranteed range: 0.5-29.999999 MHz
The DSP includes the following to give you superior receiver quality in your shack, vehicle or during DX’pedition. *DSP is built in to U.S. models, but may be optional outside the U.S. Please check with your dealer.
Pulls desired AF signals from noise. Outstanding S/N ratio is achieved, providing clean audio in SSB, AM and FM.
Automatic Notch filter:
This automatically minimizes beat signals and heterodynes while preserving the receive signal. Also, the notch frequency is automatically adjusted to follow interfering beat signals – for example, reducing interference from RTTY signals during SSB operation.
Interference rejection – IF shift
To reject interference, the IC-718 has an IF shift function which shifts the center frequency of the IF passband electronically to reduce adjacent interference.
This feature compresses microphone audio input to increase average audio output level. The result is, that talk power is increased. The compression level is adjustable for your preference. This function is effective for long distance communication, or when propagation conditions are poor.
RF gain control
RF gain control is combined with the squelch control. The RF gain adjusts minimum response receiver gain, and ignores signals weaker than the pre-set level – providing pleasant stand-by, or scanning.
Ample CW features
An electronic keyer with a variable dot/dash ratio (2.8:1 to 4.8:1) control is built-in. By simply connecting a paddle, easy CW operation can be made. The CW pitch and the key speed are also variable from 300-900 Hz, 6-60 wpm, respectively. Of course, full break-in capability is available with the adjustable break-in delay.
A VOX (Voice operated transmission) is included with the IC-718. It provides handsfree operation by detecting audio signals from the microphone. It’ s easy! Flexible filter selection
Flexible Filter Selection
An optional IF filter can be installed into the transceiver to suit your operating preference.
High frequency stability
When the optional CR-338 HIGH STABILITY CRYSTAL UNIT is installed, you get a very high frequency stability of ±0.5 ppm.
Selectable antenna tuner
Either the optional antenna tuner unit, AT-180 or AH-4 can be used with the IC-718 to suit your installing conditions, or operating style. Of course, the AH-4 control circuit is built into the IC-718.
The IC-718 is equipped with a minimum number of switches and controls for superior feature selectability. The 10-key pad on the front panel for entering directly an operating frequency, or a memory channel number. The auto tuning steps function helps quick tuning is activate when turning the dial quickly. And the band stacking register is very convenient when changing operating bands.
Digital S/RF meter
Built-in multi functional digital S/RF meter indicates signal strength level while receiving, and either transmit output power, ALC level or VSWR ratio while transmitting.
Optional voice synthesizer
A clear, electronically-generated voice announces operating frequency, mode and receiving signal strength level when the optional voice synthesizer unit, UT-102, is installed.
• USB, LSB, CW, RTTY(FSK) and AM modes are built-in
• Level adjustable noise blanker
• RF attenuator and Pre-amplifier
• Variety of scanning function types
• Total 101 memory channels are available
• Hand microphone is supplied, and more…
• Hand microphone
• DC power cable
• Spare fuse (FGB 20A)
• Spare fuse (FGB 4A)
Dim: 9.4″w x 3.75″h x 9.4″d; 8.5 lb.
Download Manual: IC-718
Download Brochure: IC-718
Afrotechmods is a very insightful and easy to understand YouTube channel to follow on basic electronics. Here he talks about multimeters and their usage in our ham shack. I have several different digital and analog multimeters and their usage often depends upon the application and project. He does other excellent videos, so check him out!
This is why ham radio operators need to be prepared for such a massive solar event. If the rest of the grid (power and internet) were to go down, it could take a long time for it to be repaired. Ham radio communications might become critical in every community. Are we prepared and proficient to aid our communities?
Link to full article… Near Miss: The Solar Superstorm of July 2012
I had the pleasure of playing with two Elecraft KX3 radios during ARRL Field Day 2014 running CW and PSK31 modes. Both radios worked like a charm off of battery power and we racked up some excellent contacts during the hours of the contest. I want to thank Bill (WR8S) and Tom (KD8WQK) for letting me get may hands on their toys! Definitely on my WISHLIST!
The KX3 HF Radio is pictured above. The optional 100 Watt Amplifier is pictured below.
Watch the Elecraft KX3 Demo Video below…
Connect the KX3 to an iPad…