Re: [digitalradio] Re: Question for experts
The difference between spread spectrum and other systems is the pseudo-random generating of the frequencies and not frequencies determined by the data. It was originally done to prevent decoding without the synchronization code. It is only disallowed under FCC regulations on that basis. SSB also uses frequency spreading as has already been noted, but the frequencies are determined by the code. That is why there is no reason not to allow ROS except that technically the frequencies are independently determined by pseudo-random code generator. Modify the regulations to limit the bandwidth and require third-party monitoring and ROS would be legal, but as the regulations stand, rightly or wrongly, we are required to abide by them. The petition process with public comment prevents harmful emissions from being used. Glad we are at the point you wanted to make. I have spent much to much time on this FHSS vs regulations issue, so I have to go on to something else now. The FCC has spoken, and correctly so, and if anyone wants to petition to change the regulations, they can do so. 73 - Skip KH6TY rein...@ix.netcom.com wrote: Hi Skip, Thanks, we have arrived at the point I wanted to get to, So lets go a little further on this path, suppose I changed the tones in a not so random fashion. Like I had a way to generate tones as I do when I speak or make music or like some of those synthesizers or whatever they are, do not know the details exactly, but they generate tones that make up language that it understandable, with training would that be spread spectrum? You say varying the tones is the same as varying the VFO to the outside world, is that science? Would it make a difference if feed the balance modulator with 100 Hz or 2500 Hz. lets switch between to tunes, teletype, is that SS? If I produce speech it is speech if the tones do not form speech, it is ss modulation? Are you seeing that SSB is SS? as A kid I use to build oscillators I could speak to them, and they would swing, and could hear speach in a radio, unstability or FM , SS? Lets get to the core is WSJT spread spectrum and please explain to me why. I just do not seem to get it... Explain me the physics of it. please I just like to understand this. 73 Rein W6SZ -Original Message- From: KH6TY kh...@comcast.net mailto:kh6ty%40comcast.net Sent: Mar 9, 2010 7:04 PM To: digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts I can't fathom the reason for doing that, but if the tone frequencies are pseudo-randomly generated and then modulated by either on/off keying or some other way, you will have a spread spectrum system, similar to what is done in the ROS 2200 Hz-wide modes. The tones in a ssb transmitter simply generate rf carriers, so varying the tone frequencies is no different than varying a vfo frequency as far as the outside world sees. The distinction in spread spectrum is the generation of the tone frequencies independently of the data. I.e., you first generate a tone frequency in a psudo-random manner and then convey intelligence by modulating the resulting rf carriers. 73 - Skip KH6TY Ralph Mowery wrote: Correct but you still have not answered my question. Indeed If I use one tone and key it on / off I have a cw transmitter, transmitting on the VJO frequebcy = or - the audio frequency. What do I have if I just change the tones in a random fashion? 73 Rein W6SZ If a total random fashion, then you have a bunch of junk. It will not convey any useful information and probably illeagle in the ham bands. There must be order to it to convey any useful information.
Re: [digitalradio] Re: Question for experts
Julian, By definition, it is SS if the pattern is independently generated from the data. The original intent of FHSS was to make third-party decoding impossible without knowledge of the code that generated the tones or carriers. FCC rules disallow encryption because we are required to police the bands ourselves. As long as there is not a pattern to the frequencies generated, that is independent of the data, one of the necessary and sufficient conditions to qualify as FHSS is missing. However, in the case of ROS, the repeated pattern is not there, so, until the regulations are changed, ROS is illegal FHSS, even though the spreading is limited and capable of third-party monitoring. That is a result of a historical attempt to prevent encryption, but this can probably be changed through the petition process with public comment. Until then, hams in the US have no choice but to abide by the regulations as written. In the author's own words, three necessary and sufficient elements make it SS, and a search of the literature says the same: 1. The signal occupies a bandwidth much in excess of the minimum bandwidth necessary to send the information. 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. 3. At the receiver, despreading (recovering the original data) is accomplished by the correlation of the received spread signal with a synchronized replica of the spreading signal used to spread the information. The operative phase here is independent of the data. It is just unfortunate that the FCC regulations, as currently written, do not allow ROS on HF and that they really need to be updated. Note that SS is already permittted above 222 MHz, where there is plenty of space to use for spreading that does not exist on HF. In fact, the encryption aspect is not even mentioned, except in other parts of the regulations disallowing encryption. The regulations were obviously written to prevent extremely wide SS signals from interfering with other users. Since ROS is no wider than a phone signal, there is no reason the regulations should not be modified to allow it (perhaps with other necessary limitations), but until then, and right now, ROS is illegal below 222 Mhz. It is that simple! Compare the repeated pattern of MFSK64 to the random pattern of ROS as data is applied. Substituting a 2- page technical description which is COMPLETELY different from the 7-page description of ROS as FHSS in an obvious attempt to circumvent FCC regulations is simply not believable, as an apparent twisting of the FCC's statement of illegality was apparently not true either. Which version is to be believed? Well, we don't need to decide that, and you apparently cannot believe anything the author claims since he keeps claiming something else! Anyone, including the FCC, can simply observe the differences in the spectral footprint of each, which is plainly shown here in a comparison of MFSK64 and ROS 1 baud at 2200 Hz width: http://home.comcast.net/~hteller/compare.zip Note how the repetitive sending of data () does not result in any repetitive pattern on ROS, but it does in MFSK64, and MFSK64 idles with a repeated pattern, but ROS does not. The ROS tones are obviously not determined by the data and are also pseudo-randomly generated - definitely FHSS. The FCC regulations describe permitted and not permitted (i.e. SS and others) emissions. They could care less about what a mode is called or how it is described by someone, because in the final analysis, we are required to maintain our EMISSIONS per the regulations, or have the regulations changed through the petition and public comment process. Had the author not tried so hard to convince everyone that ROS was Spread Spectrum, this debate would probably never have occurred. It was the term, Spread Spectrum that raised red flags among US hams who are knowledgeable of the regulations we operate under, and they were right in realizing that, as a result, ROS is illegal on HF unless the regulations are changed. The FCC then confirmed that through the ARRL. 73 - Skip KH6TY g4ilo wrote: Is the random or pseudo-random manner of generating the tones or carriers an essential element of spread-spectrum? If so, and if the aim of using such a method is not to obfuscate the message but only to provide better immunity to interference and path variations, would you be any worse off using a repeated pattern of tones instead of a pseudo-randomly generated one? And if you did that, would it still be spread-spectrum? Julian, G4ILO --- In digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com, KH6TY kh...@... wrote: I can't fathom the reason for doing that, but if the tone frequencies are pseudo-randomly generated and then modulated by either on/off keying or some other way, you will have a spread spectrum system, similar to what is
Re: [digitalradio] Re: Question for experts
He did, I guess, when he added a 500Hz-wide mode. The footprint of that mode indicates it is probably FSK as he tried to claim for the 2200 Hz-wide mode. He says he submitted a technical description to the FCC but will not release it until he gets an OK. Don't know what to believe from him these days, though! A further problem is the the new mode is included under the ROS name, and the 2200Hz-wide mode still looks like spread spectrum, unchanged from earlier. So if the FCC approves ROS on the basis of the new 500 Hz-wide mode, operators may think the 2200Hz-wide mode is now legal also. Still not a good situation! 73 - Skip KH6TY g4ilo wrote: Skip. Thank you for the comprehensive explanation. I understand why ROS is illegal under your rules. The point of my question was, if FHSS is illegal, why not simply modify the mode (which after all is experimental and does not have a large number of users) to use a non random way of generating the tones? Instead of rewriting the description to falsely claim ROS is not SS, why could he not have changed the mode so that it really was not SS? What does ROS gain by using SS over another mode that carries the same amount of data at the same speed using the same bandwidth and the same number of tones but uses an entirely predictable method of modulation? Julian, G4ILO --- In digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com, KH6TY kh...@... wrote: Julian, By definition, it is SS if the pattern is independently generated from the data. The original intent of FHSS was to make third-party decoding impossible without knowledge of the code that generated the tones or carriers. FCC rules disallow encryption because we are required to police the bands ourselves. As long as there is not a pattern to the frequencies generated, that is independent of the data, one of the necessary and sufficient conditions to qualify as FHSS is missing. However, in the case of ROS, the repeated pattern is not there, so, until the regulations are changed, ROS is illegal FHSS, even though the spreading is limited and capable of third-party monitoring. That is a result of a historical attempt to prevent encryption, but this can probably be changed through the petition process with public comment. Until then, hams in the US have no choice but to abide by the regulations as written. In the author's own words, three necessary and sufficient elements make it SS, and a search of the literature says the same: 1. The signal occupies a bandwidth much in excess of the minimum bandwidth necessary to send the information. 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. 3. At the receiver, despreading (recovering the original data) is accomplished by the correlation of the received spread signal with a synchronized replica of the spreading signal used to spread the information. The operative phase here is independent of the data.
Re: [digitalradio] Re: Question for experts
El 10/03/2010 7:57, g4ilo escribió: What does ROS gain by using SS over another mode that carries the same amount of data at the same speed using the same bandwidth and the same number of tones but uses an entirely predictable method of modulation? Processing gain. Signals correlated with the hopping sequence add up, non correlated signals do not add up. It does not mean that SS is not a predictable modulation method, you just need to know the key, in the USA, the key must be one of a few specific codes, and if you don't have the key, security by obscurity applies. 73, Jose, CO2JA
Re: [digitalradio] Re: Question for experts
Jose, If you were going to design a mode that filled 2200 Hz, but did not use SS, and was as sensitive as possible in that bandwidth, how would you do it? It would have to be highly resistant to fast Doppler shift also, but minimum S/N would be the most important parameter, as it would be used at UHF. So far, Olivia 16-500 seems to be the best compromise between minimum S/N and Doppler shift survival at UHF. The more narrow Olivia modes, even though more sensitive, do not decode as well if there is noticeable fast Doppler shift, and sometimes, not at all. DominoEx is completely destroyed by the Doppler shift and MFSK16 is not tolerant enough to drift to be usable at UHF. MT63-2000 covers 2000 Hz, has highly redundant FEC, but the minimum S/N is only -2 dB, so that is not an alternative. What I am looking for is a mode that will copy under the visible and audible noise on UHF during deep fades, but survives fast Doppler shift. Olivia 16-500 makes it down to the noise, but not under, during deep fades. CW by ear is just slightly better than Olivia 16-500, and the note is very raspy sounding - much like Aurora communications. Another observation - most stations I copy on ROS 16 are reading a metric of -12 dB or greater. Only once have I copied a station (using 1 baud ROS) that was measuring a metric under -25 dB. Is the ROS metric supposed to correlate with the path S/N? I ask this because even the weakest ROS tones at 1 baud are still visible on the waterfall, whereas weak Olivia 32-1000 signals with a -12 dB minimum S/N stop decoding just about the time the tones become hard to see in the noise, but still can be heard faintly. It is a long way from even -25 dB S/N to -12 dB S/N, so I would expect if the metric is just another way to say S/N, I would not be able to see the tones, yet I can, and not only on the ROS waterfall, but on the DigiPan waterfall as well. 73 - Skip KH6TY Jose A. Amador wrote: El 10/03/2010 7:57, g4ilo escribió: What does ROS gain by using SS over another mode that carries the same amount of data at the same speed using the same bandwidth and the same number of tones but uses an entirely predictable method of modulation? Processing gain. Signals correlated with the hopping sequence add up, non correlated signals do not add up. It does not mean that SS is not a predictable modulation method, you just need to know the key, in the USA, the key must be one of a few specific codes, and if you don't have the key, security by obscurity applies. 73, Jose, CO2JA
Re: [digitalradio] Re: Question for experts
El 10/03/2010 10:51, KH6TY escribió: Jose, If you were going to design a mode that filled 2200 Hz, but did not use SS, and was as sensitive as possible in that bandwidth, how would you do it? Tough question. I believe that on HF the best solution so far is Pactor-III It would have to be highly resistant to fast Doppler shift also, but minimum S/N would be the most important parameter, as it would be used at UHF. So far, Olivia 16-500 seems to be the best compromise between minimum S/N and Doppler shift survival at UHF. The more narrow Olivia modes, even though more sensitive, do not decode as well if there is noticeable fast Doppler shift, and sometimes, not at all. As you add more tones the bin width reduces. The only hope I see is using wide bins to accomodate Doppler, and perhaps, more tones, but that is not possible with 3 kHz radios. Perhaps it is a task for some SDR. I believe wider modes are not a problem in UHF. It may take more CPU power, and higher powered radios for simultaneous tones. DominoEx is completely destroyed by the Doppler shift Doppler is parasitic noise to DominoEx... and MFSK16 is not tolerant enough to drift to be usable at UHF. MT63-2000 covers 2000 Hz, has highly redundant FEC, but the minimum S/N is only -2 dB, so that is not an alternative. Both seem to have been designed for HF, and MT63 seems to require a single ray dominant path. At times it works well, but I have not had luck with MT63, overall. MT63 has many carriers and narrow bins, not good for multipath with doppler. What I am looking for is a mode that will copy under the visible and audible noise on UHF during deep fades, but survives fast Doppler shift. Olivia 16-500 makes it down to the noise, but not under, during deep fades. CW by ear is just slightly better than Olivia 16-500, and the note is very raspy sounding - much like Aurora communications. But CW requires well trained operators... There is a paper by Tim Giles about multitone modems for high latitude HF paths (PhD publication in Sweden) and he avoided sending in contiguous bins in wide Doppler spread conditions, and reassigned contiguous bins on the side to have a wider hat to catch the path shifted tones. That sacrifices thruput, but nevertheless, it is worthless to push nature. In that case, it is better to become its ally, and to me, wider spaced tones and reusing contiguous bins seems a good idea. I read it a long time ago and maybe I am not remembering all details, but it was interesting enough so I haven't lost the big picture. The 3 kHz channel limit on HF is a straitjacket that might be avoided on VHF - UHF if clear frequencies are available and you need speed. Another observation - most stations I copy on ROS 16 are reading a metric of -12 dB or greater. Only once have I copied a station (using 1 baud ROS) that was measuring a metric under -25 dB. Is the ROS metric supposed to correlate with the path S/N? I ask this because even the weakest ROS tones at 1 baud are still visible on the waterfall, whereas weak Olivia 32-1000 signals with a -12 dB minimum S/N stop decoding just about the time the tones become hard to see in the noise, but still can be heard faintly. It is a long way from even -25 dB S/N to -12 dB S/N, so I would expect if the metric is just another way to say S/N, I would not be able to see the tones, yet I can, and not only on the ROS waterfall, but on the DigiPan waterfall as well. I really don't know what does METRIC mean in the ROS case, Skip. I really did not pay much attention to it, as most times there was packet or pactor QRM, being ROS so wide. What caught my attention is how bad it performs under QRM, having seen Olivia 500-16 under similar conditions unaffected. I believe I know the reasons, as you may as well know, but won't elaborate further about it on this list. 73, Jose, CO2JA
Re: [digitalradio] Re: Question for experts
Jose A. Amador wrote: It does not mean that SS is not a predictable modulation method, you just need to know the key, in the USA, the key must be one of a few specific codes, and if you don't have the key, security by obscurity applies. And the FCC does not consider a code used to create modulation patterns as encryption as long as that code is available for review upon demand. Not the program code itself, but the algorithm. I have stashed away somewhere a copy of the document used for that exact exercise in the mid-80's with the FCC. This could be a convolutional code as used in several modems, or a randomizer, or even one to improve decoding (viterbi). Another example: One of the gripes about P3 is that it is difficult to monitor. But that does not make it illegal, as the code algorythm has been published. Not the trade secret codecs themselves, just the method. And that's all that's required. Have fun, Alan km4ba
Re: [digitalradio] Re: Question for experts
- Original Message From: rein...@ix.netcom.com rein...@ix.netcom.com To: digitalradio@yahoogroups.com Sent: Tue, March 9, 2010 11:51:52 PM Subject: Re: [digitalradio] Re: Question for experts Hi Ralph, You got me again. Indeed the Commission requires that it has to be intelligent information, and certainly any ID needs to be made in the English language or in Morse code, not quite sure about Morse only, or other methods allowed. One could speak as a member of an Indian tribe as was done in WWII as long as the the ID was in English, Germans and Japanese had a lot of trouble with that sort of communication, would that make it perhaps SS if it was done on the wireless? If I listen to smears of rattle, many Khz wide below 14.001 or so ,most of the time one can hear at the end an Id in CW. When I run WSJT, I ID in CW every couple of minutes. Lets say, it were a number of tones, no particular order looks like it, but I could down load a piece of nice freeware from the internet and it all became intelligent info what then? 73 Rein W6SZ. * The content of the signals and the modulation of the signals are getting confused. The tones you are sending out must conform to some type of acceptabel modulation. The content does not even have to make sense. Some examples are , you can not transmitt music, but you can send ascii characters. If music is converted into ascii data or just a bunch of 1's and 0's and sent and then reconverted at the receiving end , you have just sent data as far as the FCC sees it. In reality you have sent a music file , but not music. It will become music when the computer converts the data file back to music. Another example is a RTTY picuture or ascii art. This looks like a random ammount of numbers and letters. If you step back and look at the paper comming off a real teletype machine, you have a picture. I have sent many of the rtty pix in years past.
Re: [digitalradio] Re: Question for experts
El 09/03/2010 03:55 p.m., rein...@ix.netcom.com escribió: Hello All, Suppose I would build an transmitter with a x-tal oscillator, lets say running at 7040.000 Hz Part of the system was a balanced modulator and just to make sure a a high quality crystal filter, with a 1:1.05 shape factor, was added in the driver stages for the final amplifier. With a lot of tweaking a carrier suppression of the balanced modulator was reached of 67.3 dB and the balanced modulator was kept temperature stabilized within .1 degree Fahrenheit. On the modulation section, I constructed a tone generator which could be changed in steps of 7.3 Hz starting from 1354 Hz to all the way up to 1646 Hz. I went out and got the xtal filter ordered for a lot of money. Center frequency of xtal filter ordered and delivered for 7041.500 Hz filter at - 80 dB BW 500 Hz. My question is what would the modulation be of this transmitter? The amount of audio was set in such a way that the output of the transmitter had no distortion what so ever totally linear! 73 Rein W6SZ All that trouble for MFSK ? :-) 73, Jose, CO2JA
Re: [digitalradio] Re: Question for experts
Jose, Oversight, we are certainly not allowed to transmit Music! 73 Rein W6SZ -Original Message- From: José A. Amador ama...@electrica.cujae.edu.cu Sent: Mar 9, 2010 1:26 PM To: digitalradio@yahoogroups.com Cc: rein...@ix.netcom.com Subject: Re: [digitalradio] Re: Question for experts El 09/03/2010 03:55 p.m., rein...@ix.netcom.com escribió: Hello All, Suppose I would build an transmitter with a x-tal oscillator, lets say running at 7040.000 Hz Part of the system was a balanced modulator and just to make sure a a high quality crystal filter, with a 1:1.05 shape factor, was added in the driver stages for the final amplifier. With a lot of tweaking a carrier suppression of the balanced modulator was reached of 67.3 dB and the balanced modulator was kept temperature stabilized within .1 degree Fahrenheit. On the modulation section, I constructed a tone generator which could be changed in steps of 7.3 Hz starting from 1354 Hz to all the way up to 1646 Hz. I went out and got the xtal filter ordered for a lot of money. Center frequency of xtal filter ordered and delivered for 7041.500 Hz filter at - 80 dB BW 500 Hz. My question is what would the modulation be of this transmitter? The amount of audio was set in such a way that the output of the transmitter had no distortion what so ever totally linear! 73 Rein W6SZ All that trouble for MFSK ? :-) 73, Jose, CO2JA Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Suggesting calling frequencies: Modes 500Hz 3583,7073,14073,18103, 21073,24923, 28123 . Wider modes e.g. Olivia 32/1000, ROS16, ALE: 14109.7088. Yahoo! Groups Links
RE: [digitalradio] Re: Question for experts
One exception to that would be if it is part of a NASA rebroadcast IE: Wake-Up or Morning music on the Shuttle David KD4NUE -Original Message- From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com] On Behalf Of rein...@ix.netcom.com Sent: Tuesday, March 09, 2010 5:15 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts Jose, Oversight, we are certainly not allowed to transmit Music! 73 Rein W6SZ -Original Message- From: José A. Amador ama...@electrica. mailto:amador%40electrica.cujae.edu.cu cujae.edu.cu Sent: Mar 9, 2010 1:26 PM To: digitalradio@ mailto:digitalradio%40yahoogroups.com yahoogroups.com Cc: rein...@ix.netcom. mailto:rein0zn%40ix.netcom.com com Subject: Re: [digitalradio] Re: Question for experts El 09/03/2010 03:55 p.m., rein...@ix.netcom. mailto:rein0zn%40ix.netcom.com com escribió: Hello All, Suppose I would build an transmitter with a x-tal oscillator, lets say running at 7040.000 Hz Part of the system was a balanced modulator and just to make sure a a high quality crystal filter, with a 1:1.05 shape factor, was added in the driver stages for the final amplifier. With a lot of tweaking a carrier suppression of the balanced modulator was reached of 67.3 dB and the balanced modulator was kept temperature stabilized within .1 degree Fahrenheit. On the modulation section, I constructed a tone generator which could be changed in steps of 7.3 Hz starting from 1354 Hz to all the way up to 1646 Hz. I went out and got the xtal filter ordered for a lot of money. Center frequency of xtal filter ordered and delivered for 7041.500 Hz filter at - 80 dB BW 500 Hz. My question is what would the modulation be of this transmitter? The amount of audio was set in such a way that the output of the transmitter had no distortion what so ever totally linear! 73 Rein W6SZ All that trouble for MFSK ? :-) 73, Jose, CO2JA Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensw http://www.obriensweb.com/skedpskr4.html eb.com/skedpskr4.html Suggesting calling frequencies: Modes 500Hz 3583,7073,14073,18103, 21073,24923, 28123 . Wider modes e.g. Olivia 32/1000, ROS16, ALE: 14109.7088. Yahoo! Groups Links
Re: [digitalradio] Re: Question for experts
Hello Jose, Multiple Frequency Shift Keying, OK, but you really did not answer my question, I think. Suppose I replaced the modulation device with a filtered piano ( no harmonics ) a microphone. I am serious, trying to find out the question we can't address here any longer. I used a x-tal oscillator. Limited my BW to some 300 Hz 73 Rein W6SZ -Original Message- From: José A. Amador ama...@electrica.cujae.edu.cu Sent: Mar 9, 2010 1:26 PM To: digitalradio@yahoogroups.com Cc: rein...@ix.netcom.com Subject: Re: [digitalradio] Re: Question for experts El 09/03/2010 03:55 p.m., rein...@ix.netcom.com escribió: Hello All, Suppose I would build an transmitter with a x-tal oscillator, lets say running at 7040.000 Hz Part of the system was a balanced modulator and just to make sure a a high quality crystal filter, with a 1:1.05 shape factor, was added in the driver stages for the final amplifier. With a lot of tweaking a carrier suppression of the balanced modulator was reached of 67.3 dB and the balanced modulator was kept temperature stabilized within .1 degree Fahrenheit. On the modulation section, I constructed a tone generator which could be changed in steps of 7.3 Hz starting from 1354 Hz to all the way up to 1646 Hz. I went out and got the xtal filter ordered for a lot of money. Center frequency of xtal filter ordered and delivered for 7041.500 Hz filter at - 80 dB BW 500 Hz. My question is what would the modulation be of this transmitter? The amount of audio was set in such a way that the output of the transmitter had no distortion what so ever totally linear! 73 Rein W6SZ All that trouble for MFSK ? :-) 73, Jose, CO2JA Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Suggesting calling frequencies: Modes 500Hz 3583,7073,14073,18103, 21073,24923, 28123 . Wider modes e.g. Olivia 32/1000, ROS16, ALE: 14109.7088. Yahoo! Groups Links
RE: [digitalradio] Re: Question for experts
David, Agreed, the exception to the rule! 73 Rein W6SZ -Original Message- From: David Little dalit...@bellsouth.net Sent: Mar 9, 2010 2:21 PM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] Re: Question for experts One exception to that would be if it is part of a NASA rebroadcast IE: Wake-Up or Morning music on the Shuttle David KD4NUE -Original Message- From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com] On Behalf Of rein...@ix.netcom.com Sent: Tuesday, March 09, 2010 5:15 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts Jose, Oversight, we are certainly not allowed to transmit Music! 73 Rein W6SZ -Original Message- From: José A. Amador ama...@electrica. mailto:amador%40electrica.cujae.edu.cu cujae.edu.cu Sent: Mar 9, 2010 1:26 PM To: digitalradio@ mailto:digitalradio%40yahoogroups.com yahoogroups.com Cc: rein...@ix.netcom. mailto:rein0zn%40ix.netcom.com com Subject: Re: [digitalradio] Re: Question for experts El 09/03/2010 03:55 p.m., rein...@ix.netcom. mailto:rein0zn%40ix.netcom.com com escribió: Hello All, Suppose I would build an transmitter with a x-tal oscillator, lets say running at 7040.000 Hz Part of the system was a balanced modulator and just to make sure a a high quality crystal filter, with a 1:1.05 shape factor, was added in the driver stages for the final amplifier. With a lot of tweaking a carrier suppression of the balanced modulator was reached of 67.3 dB and the balanced modulator was kept temperature stabilized within .1 degree Fahrenheit. On the modulation section, I constructed a tone generator which could be changed in steps of 7.3 Hz starting from 1354 Hz to all the way up to 1646 Hz. I went out and got the xtal filter ordered for a lot of money. Center frequency of xtal filter ordered and delivered for 7041.500 Hz filter at - 80 dB BW 500 Hz. My question is what would the modulation be of this transmitter? The amount of audio was set in such a way that the output of the transmitter had no distortion what so ever totally linear! 73 Rein W6SZ All that trouble for MFSK ? :-) 73, Jose, CO2JA Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensw http://www.obriensweb.com/skedpskr4.html eb.com/skedpskr4.html Suggesting calling frequencies: Modes 500Hz 3583,7073,14073,18103, 21073,24923, 28123 . Wider modes e.g. Olivia 32/1000, ROS16, ALE: 14109.7088. Yahoo! Groups Links
Re: [digitalradio] Re: Question for experts
- Original Message From: rein...@ix.netcom.com rein...@ix.netcom.com To: digitalradio@yahoogroups.com Sent: Tue, March 9, 2010 5:11:30 PM Subject: Re: [digitalradio] Re: Question for experts Hello Jose, Multiple Frequency Shift Keying, OK, but you really did not answer my question, I think. Suppose I replaced the modulation device with a filtered piano ( no harmonics ) a microphone. I am serious, trying to find out the question we can't address here any longer. I used a x-tal oscillator. Limited my BW to some 300 Hz 73 Rein W6SZ - If you are doing what I think, you have just built a complicated CW transmitter. Start with a crystal oscillator, go to a ballanced modulator and then filter out one sideband. This is similar to how cw is often generated in a SSB transceiver.
Re: [digitalradio] Re: Question for experts
-Original Message- From: Ralph Mowery ku...@yahoo.com Sent: Mar 10, 2010 12:25 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts - Original Message From: rein...@ix.netcom.com rein...@ix.netcom.com To: digitalradio@yahoogroups.com Sent: Tue, March 9, 2010 5:11:30 PM Subject: Re: [digitalradio] Re: Question for experts Hello Jose, Multiple Frequency Shift Keying, OK, but you really did not answer my question, I think. Suppose I replaced the modulation device with a filtered piano ( no harmonics ) a microphone. I am serious, trying to find out the question we can't address here any longer. I used a x-tal oscillator. Limited my BW to some 300 Hz 73 Rein W6SZ - If you are doing what I think, you have just built a complicated CW transmitter. Start with a crystal oscillator, go to a ballanced modulator and then filter out one sideband. This is similar to how cw is often generated in a SSB transceiver. Hello Jose, Correct but you still have not answered my question. Indeed If I use one tone and key it on / off I have a cw transmitter, transmitting on the VJO frequebcy = or - the audio frequency. What do I have if I just change the tones in a random fashion? 73 Rein W6SZ
Re: [digitalradio] Re: Question for experts
Sorry Ralph, I did not read the header. 3 Rein W6SZ -Original Message- From: Ralph Mowery ku...@yahoo.com Sent: Mar 10, 2010 12:25 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts - Original Message From: rein...@ix.netcom.com rein...@ix.netcom.com To: digitalradio@yahoogroups.com Sent: Tue, March 9, 2010 5:11:30 PM Subject: Re: [digitalradio] Re: Question for experts Hello Jose, Multiple Frequency Shift Keying, OK, but you really did not answer my question, I think. Suppose I replaced the modulation device with a filtered piano ( no harmonics ) a microphone. I am serious, trying to find out the question we can't address here any longer. I used a x-tal oscillator. Limited my BW to some 300 Hz 73 Rein W6SZ - If you are doing what I think, you have just built a complicated CW transmitter. Start with a crystal oscillator, go to a ballanced modulator and then filter out one sideband. This is similar to how cw is often generated in a SSB transceiver. Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Suggesting calling frequencies: Modes 500Hz 3583,7073,14073,18103, 21073,24923, 28123 . Wider modes e.g. Olivia 32/1000, ROS16, ALE: 14109.7088. Yahoo! Groups Links
Re: [digitalradio] Re: Question for experts
El 09/03/2010 17:11, rein...@ix.netcom.com escribió: Hello Jose, Multiple Frequency Shift Keying, OK, but you really did not answer my question, I think. Suppose I replaced the modulation device with a filtered piano ( no harmonics ) a microphone. I am serious, trying to find out the question we can't address here any longer. I used a x-tal oscillator. Limited my BW to some 300 Hz 73 Rein W6SZ Rein I failed to see the twist and I still do not see what you are after. I took My Way (MP3), played on the piano by Richard Claydermann, and processed it with Audacity, mixing it to mono, resampling to 11025 Hz, saved it as wav, and played it back thru both Spectran and HDWinrad, one at a time, both very steeply filtered, and what you hear are pings, tingling noises with a very slight trace of musicality. There are also some harmonics of the lower frequencies that bleed thru the filter, since their spectrum falls in the selected bandpass. Can you give any further hints? You might reproduce that yourself, without spending a lot of money and waiting for your filter to be made. 73, Jose, CO2JA
Re: [digitalradio] Re: Question for experts
Correct but you still have not answered my question. Indeed If I use one tone and key it on / off I have a cw transmitter, transmitting on the VJO frequebcy = or - the audio frequency. What do I have if I just change the tones in a random fashion? 73 Rein W6SZ If a total random fashion, then you have a bunch of junk. It will not convey any useful information and probably illeagle in the ham bands. There must be order to it to convey any useful information.
Re: [digitalradio] Re: Question for experts
I can't fathom the reason for doing that, but if the tone frequencies are pseudo-randomly generated and then modulated by either on/off keying or some other way, you will have a spread spectrum system, similar to what is done in the ROS 2200 Hz-wide modes. The tones in a ssb transmitter simply generate rf carriers, so varying the tone frequencies is no different than varying a vfo frequency as far as the outside world sees. The distinction in spread spectrum is the generation of the tone frequencies independently of the data. I.e., you first generate a tone frequency in a psudo-random manner and then convey intelligence by modulating the resulting rf carriers. 73 - Skip KH6TY Ralph Mowery wrote: Correct but you still have not answered my question. Indeed If I use one tone and key it on / off I have a cw transmitter, transmitting on the VJO frequebcy = or - the audio frequency. What do I have if I just change the tones in a random fashion? 73 Rein W6SZ If a total random fashion, then you have a bunch of junk. It will not convey any useful information and probably illeagle in the ham bands. There must be order to it to convey any useful information.
Re: [digitalradio] Re: Question for experts
Hi Skip, Thanks, we have arrived at the point I wanted to get to, So lets go a little further on this path, suppose I changed the tones in a not so random fashion. Like I had a way to generate tones as I do when I speak or make music or like some of those synthesizers or whatever they are, do not know the details exactly, but they generate tones that make up language that it understandable, with training would that be spread spectrum? You say varying the tones is the same as varying the VFO to the outside world, is that science? Would it make a difference if feed the balance modulator with 100 Hz or 2500 Hz. lets switch between to tunes, teletype, is that SS? If I produce speech it is speech if the tones do not form speech, it is ss modulation? Are you seeing that SSB is SS? as A kid I use to build oscillators I could speak to them, and they would swing, and could hear speach in a radio, unstability or FM , SS? Lets get to the core is WSJT spread spectrum and please explain to me why. I just do not seem to get it... Explain me the physics of it. please I just like to understand this. 73 Rein W6SZ -Original Message- From: KH6TY kh...@comcast.net Sent: Mar 9, 2010 7:04 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts I can't fathom the reason for doing that, but if the tone frequencies are pseudo-randomly generated and then modulated by either on/off keying or some other way, you will have a spread spectrum system, similar to what is done in the ROS 2200 Hz-wide modes. The tones in a ssb transmitter simply generate rf carriers, so varying the tone frequencies is no different than varying a vfo frequency as far as the outside world sees. The distinction in spread spectrum is the generation of the tone frequencies independently of the data. I.e., you first generate a tone frequency in a psudo-random manner and then convey intelligence by modulating the resulting rf carriers. 73 - Skip KH6TY Ralph Mowery wrote: Correct but you still have not answered my question. Indeed If I use one tone and key it on / off I have a cw transmitter, transmitting on the VJO frequebcy = or - the audio frequency. What do I have if I just change the tones in a random fashion? 73 Rein W6SZ If a total random fashion, then you have a bunch of junk. It will not convey any useful information and probably illeagle in the ham bands. There must be order to it to convey any useful information.
Re: [digitalradio] Re: Question for experts
Hi Jose, Thanks much for your time. I am trying to understand the difference between a certain unnamed modulation mode and single sideband with high carrier suppression. Looked upon from the inside and the outside but still with stable x-tal carrier as input to a balance modulator or perhaps a quadrature mixer. I am serious Jose, at least trying hard in my own mind. Or you could also say trying to prepare myself if I were to asked questions about radio amateur operations and had to answer them. We here is the US are responsible for our doings on the amateur bands as the ARRL newsletter informed us, the view of the Commission is. 73 Rein W6SZ -Original Message- From: Jose A. Amador ama...@electrica.cujae.edu.cu Sent: Mar 9, 2010 9:24 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts El 09/03/2010 17:11, rein...@ix.netcom.com escribió: Hello Jose, Multiple Frequency Shift Keying, OK, but you really did not answer my question, I think. Suppose I replaced the modulation device with a filtered piano ( no harmonics ) a microphone. I am serious, trying to find out the question we can't address here any longer. I used a x-tal oscillator. Limited my BW to some 300 Hz 73 Rein W6SZ Rein I failed to see the twist and I still do not see what you are after. I took My Way (MP3), played on the piano by Richard Claydermann, and processed it with Audacity, mixing it to mono, resampling to 11025 Hz, saved it as wav, and played it back thru both Spectran and HDWinrad, one at a time, both very steeply filtered, and what you hear are pings, tingling noises with a very slight trace of musicality. There are also some harmonics of the lower frequencies that bleed thru the filter, since their spectrum falls in the selected bandpass. Can you give any further hints? You might reproduce that yourself, without spending a lot of money and waiting for your filter to be made. 73, Jose, CO2JA Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Suggesting calling frequencies: Modes 500Hz 3583,7073,14073,18103, 21073,24923, 28123 . Wider modes e.g. Olivia 32/1000, ROS16, ALE: 14109.7088. Yahoo! Groups Links
Re: [digitalradio] Re: Question for experts
Hi Ralph, You got me again. Indeed the Commission requires that it has to be intelligent information, and certainly any ID needs to be made in the English language or in Morse code, not quite sure about Morse only, or other methods allowed. One could speak as a member of an Indian tribe as was done in WWII as long as the the ID was in English, Germans and Japanese had a lot of trouble with that sort of communication, would that make it perhaps SS if it was done on the wireless? If I listen to smears of rattle, many Khz wide below 14.001 or so ,most of the time one can hear at the end an Id in CW. When I run WSJT, I ID in CW every couple of minutes. Lets say, it were a number of tones, no particular order looks like it, but I could down load a piece of nice freeware from the internet and it all became intelligent info what then? 73 Rein W6SZ. -Original Message- From: Ralph Mowery ku...@yahoo.com Sent: Mar 9, 2010 9:52 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts Correct but you still have not answered my question. Indeed If I use one tone and key it on / off I have a cw transmitter, transmitting on the VJO frequebcy + or - the audio frequency. What do I have if I just change the tones in a random fashion? 73 Rein W6SZ If a total random fashion, then you have a bunch of junk. It will not convey any useful information and probably illeagle in the ham bands. There must be order to it to convey any useful information. Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Suggesting calling frequencies: Modes 500Hz 3583,7073,14073,18103, 21073,24923, 28123 . Wider modes e.g. Olivia 32/1000, ROS16, ALE: 14109.7088. Yahoo! Groups Links
Re: [digitalradio] Re: Question for experts
El 09/03/2010 21:15, rein...@ix.netcom.com escribió: Sorry Ralph, I did not read the header. 3 Rein W6SZ -Original Message- From: Ralph Moweryku...@yahoo.com Sent: Mar 10, 2010 12:25 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Question for experts If you are doing what I think, you have just built a complicated CW transmitter. Start with a crystal oscillator, go to a ballanced modulator and then filter out one sideband. This is similar to how cw is often generated in a SSB transceiver. Well, actually FSK or ASK of two tones is hard to tell from each other on the air. A friend built such a modem, I contributed a couple of ideas, using ASK with TTL logic to key a solid state laser from a crystal derived clock. The optical link worked flawlessly. What you see as result of using your example are random frequency and amplitude tones in the spectral display, sometimes simulteneously, sometimes, not. So, what? 73, Jose, CO2JA
