I will try to keep this short and not too technical. ALL radio waves reflect off of the ionosphere and ground, that is how they travel around the world. There are exceptions however like microwave and satellite signals as they are "Line of Sight" communications and are lower power and higher frequencies. How far between bounces (skips), is dependent on frequency (higher frequencies penetrate to higher layers of the ionosphere before being reflected), signal take off angle (TOA) due to antenna type and height, and of course, power. Each hop reduces the signal power by 3dB (50%), so more power gets you further of course. Not all communications needs MAGA Power though. There are guys that communicate using "QRP" signals that are 5w or less. Under proper conditions, 1w is enough to circumvent the globe.
As far as available power sources that were brought up, most radios use a 12 VDC power source and can run off of batteries and solar setups. Switching or analog power supplies plugged into commercial power can be used to provide the 12VDC as well as generators. The simplest radio receivers back in the day used an antenna, a coil and capacitor, and a rectifying device (diode) that would create the audio from the signal into an earpiece. A lot of radios usually run up to 100w, but some can put out 200w, but not on 12VDC but rather 50VDC. Basically, different radios for different situations and operating conditions.
Now, for power, yes you use an amp, but there are different amps, power output levels and methods of amplifying the signal. There are linear amplifiers capable of full legal power (1500w) or more that use tubes that are glass or metal/ceramic. You also have "Solid State" amplifiers that use transistors for amplification and are "instant-on" and no warmup. But, like I said earlier, depending on your operation, it is not always necessary to use an amp.
As already said, in 2000, the code was removed for all class licenses, and Novice/Advanced licenses were also removed. Code was still required for the Extra Class license, but not long after, it was removed from Extra also. Your license level dictate what bands/frequencies you can use, and power levels too. Extra Class obviously gives you all privileges. For Technician/General licenses, you need to know: Rule & Regulations, RF Safety, and technical aspects of the hobby commensurate with the level of license you are going for. By the time you apply for Extra Class, it is mostly technical. I had to memorize 25-30 formulas IIRC. Now, yes, you can just memorize the test question pool and answers and pass the test, because they can rearrange the order of answers a/b/c/d, but they cannot change ANY of the wording in the question or the answers. But, where is the fun in that? I used the ARRL books that contained the theory behind the questions so that I knew how they arrived at the answers.
Anyway, I have been licensed since 1976 at the age of 11, and while having some dormant periods, I am quite "Radio-Active" now and know what I am doing thru my retirement. Cars & Arthritis do not seem to mix well!! Anyone want to buy a 1955 331 10:1 Hemi shortblock??
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the post removes the spaces...
