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#13
January 2nd 05, 01:33 AM
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"Lenof21" wrote in message ... In article , "JAMES HAMPTON" writes: Hello, Len That commercial license wasn't a particularly big deal, except that you were expected to memorize the "band plan", as it were, for VHF television. I had to laugh, no problem with the video or audio carrier nor the allotted 6 MHz per channel space. First question, I think, was "what is the frequency of the video carrier of channel 6 television in the United States?". Well, I guessed they couldn't all be that bad, so I flipped a couple of pages, put my finger down, and examined the question by my finger. "What is the color burst frequency?". Ah, simple. 3.58 MHz .... oops, all of the 4 answers started with 3.579 ..... NTSC color subcarrier is exactly 3.579545454545454545454545.... MHz. :-) Frankly speaking, I don't give a damn about that FCC field office test I took in Chicago in March, 1956. It DID allow me to work at some broadcast stations and earn a bit of money. I don't remember that four-part test for a 1st 'Phone as being exclusively about broadcasting. Maybe it changed later. Irrelevant. A whole lot of changes have taken place in radio and electronics in the last almost 49 years. So, I had to take it a second time and this time I simply memorized the splits and took a good hard look at how tightly various frequencies were specified. Then it was easy. I took mine just once. Everything. My "Q&A" book was a borrowed Regulations set then printed up in loose-leaf form. All I did was memorize what seemed to be important regulations. The theory I'd already learned from the military experience, high-power HF trans- mitters plus VHF, UHF, microwave radio relay. No real problem. Not exactly IEEE stuff. It was never intended to be such...any more than the amateur written test is some kind of academic accomplishment. The commercial telegraph license and radar endorsement were also not very difficult. Such brain-strainers as "why do you avoid long horizontal sections of waveguide". Why would you? :-) A commercial license is not a noble title indicating a licensee is "superior" to all other human beings (amateurs included) LOL I've never stated that nor implied it was. However, a lot of hams go on and on, terribly full of themselves, on implying that Their accomplishment is academic PhD level stuff. :-) [ ptui...] Since 1958 I've been working in the microwaves, topping out at the top of Ka Band (25 GHz) with only a brief time with some 2mm wavelength stuff where the waveguide had to be coin silver electro-deposited on a polished copper mandrel (due to RF surface conduction being too high a resistance with ordinary silver plated guide...too much loss). I think of that lil-bitty guide stuff as my "first SMT" exposure... :-) A couple good reasons why amateur operations aren't widespread at microwaves, particularly above X Band (greater than 12 GHz) are Co$t of guide, flanges, measuring equipment, and RF sources; there's no "magical" round-the-world bounce off the ionosphere as with HF; so few amateurs know what they're doing at those very short wavelengths (nearly all the present-day record setters have commercial/military microwave experience). One big plus at microwaves is that antenna gain can be terrific due to beam-forming. Very little power is needed. Sure, there's no "skip" at those frequencies, it's all line-of-sight, but eventually there's going to be humans out there, far away. HF techniques won't be good for interplanetary QSOs. :-) Hello, Len I don't know how many amateurs are going to even get much above 1 GHz. As you point out, high power is not necessary due to high gain antennas being easy to make (or, perhaps, purchase). The problem might be in the aiming. I got a bit lucky when I put in my Direct Tv system some years ago. Running the coax and feeding into the house was easy; the antenna pointing became a bit more problematic, both due to a bad compass and a poor choice of help. I invited a couple of friends over. Since they weren't hams and I didn't have (as I now do) a cordless phone with both a base and remote (that is *great* for work on the antenna), nor did we have cell phones, I needed one guy to watch the set and report signal strength and holler to the second guy in the kitchen who would holler to me on the roof. I checked the mount to set up and verify the supporting rod was indeed vertical, set the elevation, and, using a compass, set the direction of the antenna. They reported nothing. I went to check the compass again as the elevation was easy to set. I noticed that the needle was *not* pointing where it should be. I know that from my porch, the North star sits exactly in line with the back of my neighbor's house and I was in the proper position, albeit higher, and North should be exactly in line with the end of my neighbor's house. The needle should have pointed a bit East of that, but was pointing considerably towards the East. Sigh. I came back down and got the manual as it shows the deviation from true North. I went back on the roof, pointed the N on the compass exactly towards the neighbor's house, and carefully looked across the compass to see where the antenna should point (with the proper true headings from the installation manual). I made the adjustment to the antenna and yelled down. I tried for a couple of minutes and got no response from below. Irritated, I packed up the tools and went back down - and found everyone drinking my beer!!!! Sigh ... ok, I went in to the television to turn it off - and there was a signal indication of 85! I pulled out the credit card and called Direct Tv. Bam! On came the whole 9 yards. Further testing the following day revealed that I could not get a better signal. Lucky indeed. BTW, by the next day, I had run coax both upstairs to the bedroom and also into the kitchen, so I only needed one helper. He could watch the signal strength in the kitchen and yell directly out the window to me. I chose my helper a bit more judiciously  What does that have to do with 10 GHz transmission? Even purchasing equipment, someone is going to have to be able to aim the darn thing (gain comes at the expense of beamwidth, naturally) - and have some idea of local topography if they wish to take advantage of either natural or man-made objects. Of course, if the object is moonbounce, taking a dish which will develop the proper gain (and I'm guessing here - likely approaching 30 dBi), that thing is going to have to be fairly accurately pointed. My Morse key has two settings: up and down. I can handle that, but some folks might not be able to handle something a bit more complex than that (although many can). Interplanetary QSOs might prove *very* interesting. You certainly can't call CQ. You'd have to set up pre-arranged transmit times. Both could transmit information at a given time and the both wait .... and wait ... and wait whilst the electromagnetic radiation made its' way at the speed of light for a number of minutes (or hours, depending upon how close the planet - likely mars - was at the time). Obviously, mars is quite close to us only at certain times and even then is what - 35 million miles away? Don't forget to adjust for Doppler shift as the planets are moving closer or farther away. Narrow bandwidths can give you better signal to noise ratio, but narrow bandwidths can also make that Doppler shift a lot more difficult to deal with. I doubt wideband FM would cut the mustard due to a *huge* increase in noise with the much larger bandwidth over narrow bandwidth modes. I don't think I'm likely to be around by the time ordinary folks can take a trip to mars .... Dang, where'd I put my Morse key?  )73 from Rochester, NY Jim AA2QA |
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