Home |
Search |
Today's Posts |
#11
![]() |
|||
|
|||
![]()
N2EY:
that is all wet. Although an increase in bandwidth can be used to transmit more data, what we are discussing is the protocol of binary transmission in the form of video data and in an agreed upon structure over a roughly ~5K audio bandwidth--or--simply put, data throughput measured in bits (or bytes, or words (16 bits), or double-words (32), etc, per second. This all can be done with existing, common equipment modified to do so, and easily at rates of 56K, over the audio bandwidth of most transceivers (or with minor modifications of the transceivers audio circuits), with most remain ignorant to the fact it is being done at all! If some hams want to jack around all the standards and methods which are already in place--screw with current terminology and "encode" all this to "ham words/terminology/technology" with the hope of obfuscating the facts and making it appear that the hams have invented the internet, have at it! I am sure the digital youngsters will find this a strong draw to amateur radio. The technology has been out there for over a decade, in everyday use for 5 years or better, and now is used widely in industry for security monitoring, etc. You can buy it off the shelf... The real experimenters have now moved on and use nothing less than 100MBS+ nic cards and wireless wans interfaced to transceivers through computers over spread spectrum... which some one will point out is a violation of FCC regs for amateur radio bands. It will probably be another 10 years before hams "invent" this new gig. Possibly longer if they sit around and argue whether it can be done or not... ROFLOL John wrote in message oups.com... John Smith wrote: N2EY: Most of that is incorrect. Most of what? First you use "on the fly" encryption/decryption/"data compaction" and have it occurring in "real time." This has the effect of being "transparent" and the user is not even aware that it is going on. That's what "Convert the pictures and video into highly-compressed digital formats for transmission." means, John. Whether it's done in "real time" is just a detail. Next, forget the sn/noise ratio other than it has to acceptable for transmission of understandable communication (however, this is required no matter what the form of data--i.e., voice, ssb, cw, etc) Signal-to-noise is an integral part of Shannon's thereom. It cannot simply be "forgotten". Next, listen to digital signal occupying audio bandwidth (it is audio bandwidth that is of concern here, NOT rf bandwidth, No, that's not correct. The discussion is about transmitting pictures and video on the amateur HF/MF bands. RF bandwidth is a very important thing there. except with the possibility of fm and how you implement the data compression and transmission, i.e., just make it fit the existing rf bandwidth and NO changes are needed--however, larger rf bandwidth will ALWAYS result in a drastic increase in transmission speed and wideband fm can easily offer itself to 1MBS and faster) a digital signal can be treated just like a analog signal if desired, the use of CRC checksums and error checking of the data is just more intense under these circumstances and there is NO standard established for this--so you MUST be able to make and use your own custom hardware and software. To avoid this, just grab off the shelf digital hardware/software. And the simplest way for hams to do that at HF/MF is to use an SSB transceiver and a computer with a sound card. But that's not the only issue. Next, for every patented form of audio video protocols there are FREE forms, usually the free ones are more acceptable, efficient and suitable to ones needs, an example: Use ogg vobis compression of audio as opposed to mp3 --in video-- Use xvid as opposed to divx 4-5 And make sure the folks at the other end are similarly equipped. However, any of this requires a sound and current education and knowledge of the state of technology--and something which is obviously lacking here. Yes, John, your lack of a sound and current education about amateur HF/MF communications is quite evident. Good to see you admitting it. There's also the issue of FCC regulations. Of course those regulations can be changed, and there are several proposals in development or before the FCC to change them. But until they are changed, amateurs will be constrained by the current rules, such as the 300 baud limitation on HF. The vast majority of hams are not going to break those rules, regardless of the available technology or their education. The question raised by KB3EIA and N8UZE remains: How can video be sent in a 2.5 kHz RF bandwidth on the amateur HF bands? I've answered that question in a theoretical way. I don't think you even understand the question and all its implications, John. wrote in message oups.com... Mike Coslo wrote: Dave Heil wrote: wrote: How we be gonna scale those pictures and live video to fit into 2.5 KHz? Two steps: 1) Convert the pictures and video into highly-compressed digital formats for transmission. 2) Use different modes/modulations/protocols Shannon's Theorem tells us that we can get very high data rates through very narrow bandwidths *if* we have adequate signal-to-noise ratio. Note that "noise" takes many forms, not just the thermal noise we're used to. For example, PSK has an advantage over OOK when dealing with thermal noise. But when dealing with other types of noise, OOK can have an advantage. It all depends on the transmission medium. What works on a telephone line may not work on an HF path of the same apparent bandwidth. I thought that we were going to be able to send live video and digital images on HF? You can do that now - just need enough S/N. Simply by hooking our computers to our rigs via the proper interfaces. And software. Now it seems that the *idea* is that we are going to use DRM, and we're going to need to get more spectrum in which to use. There are all sorts of solutions. But there's a world of difference between people talking theory and actual application. Most of all, some folks confuse the journey and the destination. Does complex and newer equal better? Sometimes. Not always. Is analog simpler than digital? Sometimes! Does having a computer that attaches to the Internet make a person a digital expert? Some folks think so! I don't. And besides - "digital expert" doesn't mean someone knows much about radio. I ask for enlightenment, I get invective. Are you surprised? Appears to be what there is to offer. Now consider how effective such a person would be trying to sell amateur radio - with or without a code test. 73 de Jim, N2EY |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Doing Battle? Can't Resist Posting? | Policy | |||
Why You Don't Like The ARRL | General | |||
Response to "21st Century" Part One (Code Test) | Policy | |||
My response to Jim Wiley, KL7CC | Policy | |||
Tech Licensee USA Morse Code Freedom Day is August 1st | CB |