I was tuning around on 17 meters and started listening to a couple of guys chewing the rag. After a few minutes I happened to notice the frequency; 18.1669MHz #(maybe it was 18.167 and I'm a little off). Let me see... #18.167MHz plus 3KHz puts the top end of their transmission up to 18.170MHz, clearly out of the band.
Another 5 minutes goes by and somebody jumped in and said "Check your frequency, you are out of band" but they either didn't hear it or ignored it. They talked for about 10 more minutes when one of the operators said he was going to get off now so he could go watch a sports program. The other station signed off with his call-sign and this guy simply said "bye bye mick", end of transmission.
Shortly after that I hear a station on 18.166MHz asking if the freq is in use and starts calling CQ.
Do we not understand that when we operate USB that we are actually not even radiating on the freq that the VFO says, but rather generating signals well above it?
Was this simply and oversight on the part of both operators? Was it lack of knowledge? Was it apathy?
(I won't post the call-signs but might be sending a few Emails).
You are correct, but it is the sign of the times, many have no clue to the width of a SSB signal or even a CW, or FM signal. #I would bet in this case it was due to ignorance and I see it every single day on the bands. #I have also seen FM with 5 KC deviation operated many times on the lower bands though they should be doing that above 29.3, but I guess it is not as bad as intruders, and other things that go on these days, (fighting, language, lack of courtesy) so guess it does not get much attention. I remember the days when that would be a concern and you could get a pink slip from the FCC, but the attention is on other things now and I guess a lot of hams do not want to be looked at as the radio police so they just move on .
73 N0XE
K9STH
04-22-2002, 01:06 AM
Actually, the frequency is 29.0 MHz and not 29.3 MHz (97.305). Technically, the use of FM on frequencies below 29.0 is limited to a modulation index of 1, which means that if the maximum modulating frequency is 3 KHz then the frequency deviation cannot exceed +/- 3 KHz. If the maximum modulating frequency is 5 KHz, then the frequency deviation cannot exceed +/- 5 KHz.
In a practical sense, the vast majority (if not all) of the commercial equipment that is available for amateur use on the "HF" bands has the audio bandpass limited to a maximum of 3 KHz because of SSB. In this case, the maximum deviation allowed is definitely +/- 3 KHz. And, it is definitely against regulations for an amateur to operate using FM (or PM) on frequencies below 29.0 MHz using deviation that exceeds a modulation index of 1. Thus, those who put out a signal with a maximum audio frequency of 3 KHz who are putting out +/- 5 KHz are definitely violating regulations.
On a practical note, the bandwidth of an FM signal is the deviation + twice the maximum modulation frequency. The FCC used to use terms like 16F3 and 20F3 to designate the emission. The 16F3 has a maximum deviation of +/- 5 KHz and a maximum modulation frequency of 3 KHz. The 20F3 had a maximum deviation of +/- 5 KHz and a maximum modulation frequency of 5 KHz.
Frankly, I would not operate +/- 5 KHz deviation below 29.010 MHz or above 29.690 MHz to keep the sidebands within the band. The same thing goes for SSB. Unless the filter is extremely sharp, and the transmitter adjusted properly (and a great many SSB rigs out there are NOT adjusted properly!), I would not operate within at least 3 KHz of the band edges, and usually 5 KHz. Even though you are operating on one sideband, the other sideband is still there, and is being transmitted as well as the desired sideband. Even if the undesired sideband is 60 dB down, if you are running a "40 over 9" signal, your unwanted sideband will be about "S" 6. That is with the industry standard of 6 dB per S unit (signal increase). Even at an "S" 9 signal level, on a quiet band, the unwanted sideband just might be heard "clear across the country".
Then, there is the "splatter", spurious emissions, etc., that come from improper operation of the transmitter. This can be caused by overdriving, improper use of a speech processor, etc. Those increase the bandwidth of the signal considerably. If you get "caught" with those problems, you can get into "deep do-do".
The fact that a commercial, "latest and greatest", amateur transceiver is being used has no bearing if the microphone gain is turned up too high, etc. Also, unless the frequency standard in the rig has been aligned with WWV (and on a regular basis), you can easily be a KHz or two off of the desired frequency. Just because you can "read" the frequency to the nearest 10 Hz doesn't mean that you really are within 10 Hz of the correct frequency. All frequency standards have tolerances, and the actual frequency is affected by things like temperature, etc. You can definitely be off frequency far enough to be out of band even though your frequency readout says that you are within the band. That is why the FCC requires that a secondary standard (most often a 100 KHz calibrator) that has been "zero beated" to WWV be used to determine the transmitted frequency. How many amateur operators regularily check their crystal calibrators against WWV? Unfortunately, there are a lot who either never calibrate or else never use the calibrator to check their transmitted frequency.
Even on 2 meter SSB some people get "caught up" with the frequency to the nearest 10 Hz. Most SSB operation starts around 144.200 MHz and, if there are more than two amateurs in a roundtable, they often start comparing receiver frequency readout readings. Very seldom are any of these stations anywhere near the absolute frequency that they are saying that they are on. I have three different service monitors that are regularily calibrated to WWV. These are "dial up" to the nearest 100 Hz and, by using the built-in analog meter, you can read frequency to at least an accuracy of 20 Hz. I just laugh when those who are saying that "they" are the one that is "on frequency". Nine times out of ten they are lucky to be within 1 KHz of 144.200 MHz! Things were much more simple when everyone had an analog dial that was accurate to 1 KHz and then you could "estimate" to the nearest 100 to 200 Hz. No one argued about where the exact frequency was. The same thing goes for the lower bands. Unless you have calibrated directly to WWV within a very short period of time, don't think that your rig is definitely reading the correct frequency.
Anyway, people definitely need to recognize that the bandwidth of their signal must also be considered when operating near a band edge.
Glen, K9STH
K7PIG
04-24-2002, 10:32 PM
WELL, if the talker stays 3kcs away from band edges things would just be A-OK. I've been polite on many occasions explaining BLANK BLANK ? ZZZ your audio is out of band-WELL, I got a good cussing-out so, I let them hang themselves. No more trying to help.