[digitalradio] Re: KH6TY's Post
Skip, The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers so to the observer, there is no difference. Could you elaborate on this please? Tony -K2MO - Original Message - From: KH6TY To: digitalradio@yahoogroups.com Sent: Sunday, February 21, 2010 10:14 PM Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams RF is RF and the FCC does not care how the frequency expansion is done, whether by VFO shift or supressed carrier tone shift. I am shocked that Bonnie does not understand that simple principle. For example, true FSK is done by VFO shift, but FSK is also done on SSB by tone shift. The result is identical, the only difference being that the transceiver does not have to be linear with FSK shift, but it does with tone frequency shift to prevent splatter. The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers, so to the observer, there is no difference. It is the frequency hopping that makes ROS spread spectrum, and unfortunately, that is against the FCC regulations. If it were not, there could possibly be spread spectrum transceivers using tone shifts much wider than an IF bandwidth, even using soundcards, just like SDR's spectrum displays use. In that case, more than one voice channel would be taken up for the benefit of the SS user, to the detriment of adjacent stations, or even those farther away, if there were no other limitations on bandwidth utilized. 73 - Skip KH6TY W2XJ wrote: Bonnie you have a Ham unfriendly addenda. Say what you like but at the end of the day it is BS. From: expeditionradio expeditionra...@yahoo.com Reply-To: digitalradio@yahoogroups.com Date: Mon, 22 Feb 2010 01:09:14 - To: digitalradio@yahoogroups.com Subject: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Given the fact that ROS Modem has been advertised as Frequency Hopping Spread Spectrum (FHSS), it may be quite difficult for USA amateur radio operators to obtain a positive interpretation of rules by FCC to allow use of ROS on HF without some type of experimental license or waiver. Otherwise, hams will need an amendment of FCC rules to use it in USA. Sadly, this may lead to the early death of ROS among USA hams. If ROS Modem had simply provided the technical specifications of the emission, and not called it Spread Spectrum, there would have been a chance for it to be easily adopted by Ham Radio operators in USA. But, the ROS modem designer is rightfully proud of the design, and he lives in a country that is not bound by FCC rules, and probably had little or no knowledge of how his advertising might prevent thousands of hams from using it in USA. But, as they say, You cannot un-ring a bell, once it has been rung. ROS signal can be viewed as a type of FSK, similar to various other types of n-ary-FSK presently in widespread use by USA hams. The specific algorithms for signal process and format could simply have been documented without calling it Frequency Hopping Spread Spectrum (FHSS). Since it is a narrowband signal (using the FCC and ITU definitions of narrowband emission = less than 3kHz) within the width of an SSB passband, it does not fit the traditional FHSS description as a conventional wideband technique. It probably would not have been viewed as FHSS under the spirit and intention of the FCC rules. It doesn't hop the VFO frequency. It simply FSKs according to a programmable algorithm, and it meets the infamous 1kHz shift 300 baud rule. http://www.arrl.org/FandES/field/regulations/news/part97/d-305.html#307f3 This is a typical example of how outdated the present FCC rules are, keeping USA hams in TECHNOLOGY JAIL while the rest of the world's hams move forward with digital technology. It should come as no surprise that most of the new ham radio digital modes are not being developed in USA! But, for a moment, let's put aside the issue of current FCC prohibition against Spread Spectrum and/or Frequency Hopping Spread Spectrum, and how it relates to ROS mode. Let's look at bandwidth. There is the other issue of bandwidth that some misguided USA hams have brought up here and in other forums related to ROS. Some superstitious hams seem to erroneously think that there is an over-reaching bandwidth limit in the FCC rules for data/text modes on HF that might indicate what part of the ham band to operate it or not operate it. FACT: There is currently no finite bandwidth limit on HF data/text emission in USA ham bands, except for the sub-band and band edges. FACT: FCC data/text HF rules are still mainly based on content of the emission, not bandwidth. New SDR radios have the potential to transmit and receive wider bandwidths than the traditional 3kHz SSB passband. We will
Re: [digitalradio] Re: KH6TY's Post
The comment was made that ROS is different from a FFSS mode that accomplishes the spreading by shifting the VFO frequency. The point is that in a SSB transmitter, the RF frequency is equal to the suppressed carrier frequency plus (USB) or minus (LSB) the tone frequency. So it does not matter how the RF frequency gets moved, either by VFO shift of a carrier, or by tone shift on a SSB transmitter. Unfortunately, Jose went to great lengths to establish that ROS is a FHSS mode. He does this by using different tone frequencies but the result is the same as shifting a VFO frequency in a traditional FHSS transmitter. The RF is still shifted according to a pseudo-random code in both cases. To the observer, there is no difference except perhaps in the degree of spreading used. It is just unfortunate that the FCC regulations were undoubtedly written in order to keep really wide FHSS transmissions from covering all of a band, and in the aggregate, have a multitude of stations seriously interfering with many narrow bandwidth modes. By keeping the spreading within the bandwidth of a SSB phone signal, Jose sidesteps the problem, but it still takes a clarification, or exemption, or modification, of the rules as written to make it possible for us to use ROS on HF. In other words, the FCC could say that as long as the spreading is no wider than a phone signal, it is legal to use SS on HF, but this would have to be done in advance of regular use. If not, I could use a SDR with FHSS capability and spread over 100 KHz for whatever benefit that might bring and if others did that, seriously interfere with the use of the band by many other stations on a different base frequency. Since there is lots of room on UHF compared to HF, FHSS is already legal there and a reasonable degree of spreading is not of so much importance. This is why ATV is only allowed on UHF. It is so wide that it takes a wide band to leave room for others to share and operate. 73 - Skip KH6TY Tony wrote: Skip, The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers so to the observer, there is no difference. Could you elaborate on this please? Tony -K2MO - Original Message - From: KH6TY To: digitalradio@yahoogroups.com Sent: Sunday, February 21, 2010 10:14 PM Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams RF is RF and the FCC does not care how the frequency expansion is done, whether by VFO shift or supressed carrier tone shift. I am shocked that Bonnie does not understand that simple principle. For example, true FSK is done by VFO shift, but FSK is also done on SSB by tone shift. The result is identical, the only difference being that the transceiver does not have to be linear with FSK shift, but it does with tone frequency shift to prevent splatter. The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers, so to the observer, there is no difference. It is the frequency hopping that makes ROS spread spectrum, and unfortunately, that is against the FCC regulations. If it were not, there could possibly be spread spectrum transceivers using tone shifts much wider than an IF bandwidth, even using soundcards, just like SDR's spectrum displays use. In that case, more than one voice channel would be taken up for the benefit of the SS user, to the detriment of adjacent stations, or even those farther away, if there were no other limitations on bandwidth utilized. 73 - Skip KH6TY W2XJ wrote: Bonnie you have a Ham unfriendly addenda. Say what you like but at the end of the day it is BS. From: expeditionradio expeditionra...@yahoo.com Reply-To: digitalradio@yahoogroups.com Date: Mon, 22 Feb 2010 01:09:14 - To: digitalradio@yahoogroups.com Subject: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Given the fact that ROS Modem has been advertised as Frequency Hopping Spread Spectrum (FHSS), it may be quite difficult for USA amateur radio operators to obtain a positive interpretation of rules by FCC to allow use of ROS on HF without some type of experimental license or waiver. Otherwise, hams will need an amendment of FCC rules to use it in USA. Sadly, this may lead to the early death of ROS among USA hams. If ROS Modem had simply provided the technical specifications of the emission, and not called it Spread Spectrum, there would have been a chance for it to be easily adopted by Ham Radio operators in USA. But, the ROS modem designer is rightfully proud of the design, and he lives in a country that is not bound by FCC rules, and probably had little or no knowledge of how his advertising might prevent thousands of hams from using it in USA. But, as they say, You cannot un-ring a bell, once it has been rung.
