I was a bit confused about FCC license renewal process while as ,presented in both the Tech and General courses. The discussion lead me to believe there was no early renewal period, which didn’t make sense. I have since reviewed the FCC rules and found the answer is, as I thought, within a short period of time before license expiration date a ham can renew without having to rely on the grace period.
It’s 90 days. I’ll make a note when I see it in courses that we should update it. We have an update to the Technician course coming since the question pool is changing at the end of June. Thank you!
You are welcome! Each time I reviewed this part of each course it didn’t make sense not to have an early renewal period. It did make sense to teach what to expect on the FCC exam. So, you encouraged me to dig deeper which is a good thing,
Jim, I wonder if you can help me visualize radio wave propagation from a dipole antenna. If it were possible to see the electromagnetic radiation leaving the antenna wire what would it look like? Does it radiate somewhat uniformly in a circular pattern from the antenna wire? Are there any places along the wire where the radiation is stronger than other places? We talk about a critical skip angle in order to achieve a greater transmission distance, how in the world is that controlled off of a round wire? What am I missing here? I understand different frequencies will have different properties under different atmospheric conditions, sunlight and sun activity. I am having difficulty understanding how a dipole antenna can be “pointed” at various angles.
Here’s a Wikipedia GIF about how a dipole manages a signal to give you a better viewpoint.
From a transmitting perspective, lay the number 8 over the top of the antenna, with the poles at the top. The strongest signal will be broadside to the antenna, the weakest direction at the poles. If you have a dipole pointing North and South, your strongest directions are east and west.
To better understand how a dipole can be pointed, look at a Yagi antenna, which is really multiple dipoles. The main dipole (driven element) is reflected and directed to amplify the signal. Given your desire to change “skip angle” you would raise or lower the dipole from the ground to use the reflection of the earth to change the angle.
Hope this helps.
Thank you so much! Makes much better sense, now. This leads me to believe constructing a small dipole antenna such that I can make adjustments in order to maximize its efficiency, before I jump headlong into a larger investment is the best idea. (obviously) The idea of building some of my equipment does intrigue me. I have built electronic equipment in the past and had a tremendous amount of fun and satisfaction doing so. I haven’t bought a winning lottery ticket lately and rising fuel prices are going to push me toward more DYI projects.
I was curious about repeaters in my area. Lo and behold there are not many and none near me. I t will be interesting to see where I end up bandwise as I learn more and become licensed. I am trending toward taking both exams on the same day mainly cause testing is not that close to me. I am confident I can pass the Technician exam now, and I am invoking my best learning practices while studying for the General exam. I want to know more about the why’s that go with the what’s.
Well, sir…on to bigger and better accomplishments. Did I mention the number of dives I made on submarines equals the number of surfaces I made. I am rather proud of that statistic, you know!
Good Morning Deane! It’s always good when dives = surfaces, it’s kind of like takeoffs = landings. You want those numbers to match.
Glad to help with the dipole questions and feel free to come back with any questions. Here’s what I do when building a dipole. I use a tool like
West Mountain Radio - Antenna Calculator to calculate the length of my wire, then I trim it longer (18" or so). I then loop the end through an insulator and wrap the excess to the antenna. Here’s an example. That lets you slide it in and out for minor adjustments until you get it finalized.
This is an FYI type statement I kind of wish I would have known this and stayed on top of my license before it expired and renewed it again before it expired because it seems to be a heck of a lot harder to get things going to get your license and then it did back when I 1st got my Ham Radio license.