Home |
Search |
Today's Posts |
#10
![]() |
|||
|
|||
![]()
Radium,
I understand how magnetic fields from your treadmill interfere with your reception. The answer is actually quite simple. You need to run the treadmill in reverse, namely, you provide the power and the treadmill acts as a generator. The benefits are 3-fold: 1. The electric bill in your house will be substantially reduced, since you, and not the motor in the treadmill, create the needed energy. Rather than draw power from the wall, you will create a power source. 2. Your personal energy level will rise, and your ability to perform heavy work will improve. The many contaminants which are now (apparently) clouding your thinking process will lift, allowing you to no longer have concerns about SHF, sawtooth waveforms, or other distractions from your basic circulating chi. Your ying and yang will be simultaneously improved as well. 3. Finally, your TV reception will vastly improve, since this force of treadmill magnetic flux will not only be removed, but you will generate a positive ion flux field which will augment both AM and FM reception. It will take you some time to learn how to run backwards on your treadmill to achieve this generator action. Do not be disheartened......since the 3 benefits above are well worth the effort. Always bear in mind that a small squirrel running in its' little cage can do what you are attempting to do. It will help you to repeat the words over and over again: "I am a squirrel" "I am a squirrel" "I am a squirrel" All of us on this newsgroup know you will be successful. Smarty "Radium" wrote in message ups.com... On Jun 6, 10:35 pm, "Smarty" wrote: Radium, Some television is actually transmitted using FM modulation schemes, but not for commercial broadcasting. Examples of FM TV are ham/amateur ATV/SSTV, unlicensed 2.4 GHz surveillance links, and a number of point to point and studio to transmitter systems. FM signaling provides benefits in noise immunity and also permits better channel re-use, since it exploits one of the best features of FM called "the FM capture effect", wherein nearly equal strength signals which would otherwise interfere in AM systems will cause an FM receiver to "capture" only the stronger signal and ignore the weaker, even if differences of 1 dB of signal strength exists. There is no specific answer to what you would see as far as video patterns, and there is no reason whatsoever to expect to see sawtooth waveforms in particular. The demodulated signal from FM will conform to the spectral changes just as the demodulated signal from an AM detector would conform to amplitude changes, and random noise would be considered "snow" in either case. Unless a transmitted signal with a frequency ramp (sometimes called "a chirp") is present, the video would have no sawtooth. A Doppler radar, for example, could generate such a waveform, since some radars create chirped / swept signals. The video scan rate(s) would additionally need to be in the range of the chirp rate to create the appearance of a sawtooth. FM disturbances in the SHF band are likely to be man-made and not atmospheric, and thus only "viewable" if the "FM Video Receiver" you envision had a demodulator / discriminator whose bandwidth was tailored to a specific transmitted waveform, and even then only if sweep rates were suitable. Absent a man-made transmitter, the SHF environment is mostly thermal noise (both circuit and atmospheric) and only a radio telescope or other enormous aperture / antenna will see beyond the atmosphere. The choice of using AM versus FM is really way more complicated than "AM for audio" or "FM for digital video". When designing communication systems of any type, the engineer is faced with balancing many issues, and the channel, media, noise environment, interference sources, power budget, multipath, complexity, and cost are only a few of the considerations involved. A highly reliable cable modem to transmit fast digital content may indeed by phase modulated with an amplitude trellis; a secure and interference resistant link may use spread-spectrum frequency hopping AM for digital signaling; and FM winds up being used heavily in many voice communication systems mostly because the capture effect reduces co-channel interference. The closest I can suggest to what you might enjoy exploring would be a satellite dish and receiver designed for L band which will see and decode some broadcasting which is unprotected / unencrypted. It gets you into the range of SHF, has true TV signaling for public viewing, and is a hobbyist activity with others involved. Smarty, big thanks for your detailed response. One big advantage [that I could imagine] to using FM -- instead of AM -- to carry the luminance (Y) signal, is that you can run on your treadmill without seeing those lines on the screen mask your favorite shows. The magnetic signals generated by the electronics in the treadmill causes blinding interference on AM video. FM video is be immune to such disruptions. |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
VHF signals | Antenna | |||
Strange signals on 3.665 | Shortwave | |||
Need early catalogs and manuals for early video equipment .... love the old reel to reel video machines and cameras! Will buy manuals, the artifacts | Swap | |||
for sale video security professional video stuff | Swap | |||
weird FM signals | Broadcasting |