Category Archives: Propagation
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!
Well… the 2015 ARRL Field Day adventure is in the books… the logbooks, that is. Having experienced decades of Field Day excursions, this one takes the cake! What started out as a hot, sunny, humid Friday afternoon setting up our station high atop Chestnut Ridge, ended on Sunday afternoon having operated under conditions of torrential rains, a downward shift of 40 degrees in temperature, one antenna failure, one operator unable to man a station due to illness, a generator choked-out by all the moisture in the air and eventually walking around in a literal cloud! We had three layers of clothes on and could see our breath on Sunday morning! To say the least, it was a unique set of challenges to overcome.
Plan A was to slingshot and hang 3 doublet antennas, run 2 KX3’s for CW and PSK31, and run an Icom 7200 with a new Heil Pro 7 headset on voice. We had a 5500 watt generator and 25 gallons of fuel to keep us purring along. With 4 operators we had a good chance to keep all rigs racking up points for the duration. Laptops were ready to log and the plan sounded solid. The goal was to beat our score from Field Day 2014 and thought a good mix of voice and data would do the trick.
Our usual set-up has us mooching off of WR8S’s generosity when he goes to the trouble of of hauling his camper to the top of the mountain. We extend the awning and set up a table or two to operate from. Field Day 2014 was done via battery power and QRP mode.
The video below is a typical contest exchange using CW (Morse Code) and in the ARRL Field Day Contest an exchange of information would be the call sign of the other station, your operating mode (how many radios are you running and what sort of power and station are you running), followed by your section of the country. Then you return your own exchange to the other station and move on the to next contact by calling “CQ FD CQ FD de WT8WV WT8WV” and hope for a return of your call sign for a confirmed contact to log. CQ means “calling anyone”… FD means your are calling for the “Field Day” contest… de is French and means “from”… and WT8WV is our station’s “identifying call sign”. (You will see Bill (WR8S) make a contact and then write down the exchange from the other station on the log paper… then he begins calling CQ FD CQ FD de WT8WV using a memory keyer that he can program with the CQ message, our contact information and a thank you good bye message. He just needs to use the keyer paddles to send the other stations call sign during a contest.) Our return message to the other station to enter into their own log was, “WT8WV 2A WV”.
The pictures below tell the story of our challenges and our solutions. I have to admit I thought we were DOA when the generator croaked at 4:30 am on Sunaday… but we quickly came up with Plan X and realized WR8S had a converter in his truck! Back to battery power to finish of a good run of PSK31 and CW for 2 points each!
The original team plan was to use my new call sign WT8WV and be “3 Alpha West Virginia” but Jay got sick on Friday so we were now down 1 team member and 1 radio. Then we had a balun issue with 1 doublet antenna. So now we are WT8WV 2A WV with 2 Elecraft K3’s and 1 antenna. We decided to salvage our potential scores by focusing on PSK31 and WR8S’s speedy left hand on CW… and forgo voice comms.
20 Meters Ham Radio Band is one of the most popular bands for long range (DX) communications. It holds up in most conditions and is were a lot of exciting DX contacts OfficialSWLChannel tells us all about finding signals on the 14 MHz part of the band.
10 Meter Ham Radio Beacons (28 MHz) help us know where propagation is working in our favor for communicating around the world. OfficialSWLChannel provides another excellent video on how to take advantage of these beacons!
OfficialSWLChannel tells us what we can expect on the exciting 40 Meters amateur radio frequencies.
OfficialSWLChannel video about the activity on 80 Meters.
160 Meters is another challenging ham radio band to work. This video tells you what listen for and what to expect. This is another OfficialSWLChannel video.
This is an interesting but challenging ham radio frequency band. Sporadic E propagation is pretty cool but takes some effort. Aurora activity in the upper atmosphere helps. The Officialvhfuhfchannel does a good job on this video.
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!
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?
From the U.S. National Weather Service YouTube page… click video links below…
We rely on advanced technology for almost everything we do today. Satellite communications, GPS applications, and the electric power grid provide the backbone to our Nation’s economic vitality and national security. This technology however, is vulnerable to a threat from space — our Sun. Eruptions from the Sun can have a profound impact on society. In Boulder, Colorado NOAA space weather forecasters maintain a constant vigil on the Sun, alerting a diverse customer base when storms are imminent. Operators from many sectors will take mitigating actions to protect the critical infrastructure that we have come to depend on.
An Introduction to Space Weather and the Space Weather Prediction Center
Space Weather Impacts: Communications
Space Weather Impacts: GPS
Space Weather Impacts: Power
Did you ever wonder what some of those strange radio signal beeps, boops, squeals and braps are when you tune across the radio frequencies? Click the link below for a neat wiki page, off one of The DXZone and Sigidwiki.com website pages, that not only allows you to listen to short audio segments of them but also shows what the signal looks like in a waterfall image.
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.
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