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Author Topic: Transmitting standards for Amateur radio transmitters  (Read 3155 times)
KD7HVL
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Posts: 66




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« on: August 29, 2012, 09:40:54 AM »

Can anyone tell me where to go to find the present and past standards for transmitting equipment for the amateur radio service???  I am looking for things like how many DB down for carrier supression , oppsite sideband rejection etc.  Gotta be out there someplace but I keep running into regulations and rules reguarding your responsibilities as an operator and what you can and can not do, nothing really about the standards or required specifications for the equipment here in the US.  Frank
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WB4SPT
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Posts: 141




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« Reply #1 on: August 29, 2012, 09:53:29 AM »

USC title 47 part 97.307 is a good start.  

http://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol5/pdf/CFR-2010-title47-vol5-sec97-307.pdf

It does ref. xmitters before 2003 and after 2003.   And, almost a free for all before 1978 devices.
« Last Edit: August 29, 2012, 09:56:12 AM by WB4SPT » Logged
WB2WIK
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« Reply #2 on: August 29, 2012, 11:34:14 AM »

There isn't any standard for carrier suppression or unwanted sideband suppression in the amateur service.

You could have zero for both and simply be running DSB AM, and that's legal anywhere that "voice" operation is permitted.
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K6AER
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« Reply #3 on: August 29, 2012, 02:48:57 PM »

All the FCC cares about is harmonics, Part 15 and case radiation. The last part makes no sense for we connect the radio to antennas over our head.
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WA3SKN
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« Reply #4 on: August 29, 2012, 03:32:07 PM »

The FCC has been very kind in what we can or cannot radiate.  However, there was a big change in the "spurious radiation" specs on January 1, 1978... the before and after specs did get tightened-up quite a bit, and the PI filter in our transmitter finals became the Pi-L filters that are popular now.  But we are still allowed to use AM, DSB, along with the various SSB modes.  Plus video and pulse are allowed on high enough (UHF+)frequencies... they still want you to experiment!  Note that you can no longer use A2 below 6 meters also.
73s.

-Mike.
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WX7G
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« Reply #5 on: August 29, 2012, 07:03:38 PM »

All the FCC cares about is harmonics, Part 15 and case radiation. The last part makes no sense for we connect the radio to antennas over our head.

I think you mean our radios need to meet radiated emissions standards. They do need to meet these outside amateur bands where they could interfere with other services. In that sense it makes sense. For two examples these emissions could come from oscillators and digital circuitry inside the radio.
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G3RZP
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« Reply #6 on: August 30, 2012, 01:02:27 AM »

ITU-R Task Group 1/3 in 1994/5 revised the ITU-R Recommendation SM329 on Spurious Emissions. Prior to that, there were no requirements in the international Radio Regulations regarding transmitters in the amateur services. The revised SM329 introduced limits on spurious (which includes harmonics) of 43 + 10 log P dB, not exceeding 50dB for transmitters operating below 30 MHz, and not exceeding 70 dB for transmitters operating above 30 MHz. The FCC managed when Part 97 was revised to make this a straight 43dB for transmitters below 30MHz: basically, it seems  because of mistake in reading the recommendation. Despite the fact that the FCC delegate to the ITU meeting was an amateur, and the FCC man writing the Part 97 rules is an amateur! So that's why the US has 43dB but everybody else has 50dB. The Rec SM329 is, through a complex set of recommendations and footnotes, effectively part of the Radio Regulations, which are considered international law. 
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WB4SPT
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« Reply #7 on: August 30, 2012, 04:59:46 AM »

Let's be careful in our use of "dB".  It is not a unit of power.  "dBm", "dBW", are units of power.  dB by itself is not typically useful without some reference.  THe last poster, I think, wants to say dBW, and dBc  (used in industry to describe dB's below carrier).  But a spec of 43dB and 50dB is not complete, and that is a big source of confusion when comparing these spec limits.
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KB1LKR
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Posts: 1899




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« Reply #8 on: August 30, 2012, 06:08:38 AM »

"dB" in this case is relative to the power of the transmitter, not an absolute power level, e.g. dBm, dBW, etc.

i.e. "Part 97 was revised to make this a straight 43dB [below the fundamental mean power emission] for transmitters [operating] below 30MHz"
The reference, unstated by the prior poster is the fundamental emission power.

Likewise I believe the prior poster meant:
"... 43 + 10 log P dB [below the fundamental power], not exceeding 50dB [below the fundamental power] for transmitters operating below 30 MHz, and not exceeding 70 dB [below the fundamental power] for transmitters operating above 30 MHz"
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G3RZP
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« Reply #9 on: August 30, 2012, 06:45:41 AM »

Strangely, it's dB below PEP below 30 MHz and dB below carrier above 30 MHz. (Nobody told them about SSB existing above 30 MHz!)

Even more confusing........does the 43 dB below PEP for transmitters operating below 30MHz refer to harmonics that fall below 30 MHz, or to harmonics that fall above 30 MHz? If so, why tighter levels for transmitters above 30 MHz? It appears to mean that a 1kW output transmitter on 28 MHz can have a 4th harmonic 50 dB down, but a 1kW tx on 54MHz would need to have a 2nd harmonic 70dB down.......

The more realistic authorities (that includes FCC) in practice appear to don't really care unless you are causing a problem - which is what it always used to be. Why Task Grpoup 1/3 had to pull in the amateur services, I don't know. Some people just like to increase regulation..

There's even more problems when you look at the realistic phase noise at UHF and beyomd.
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KB3HG
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Posts: 404




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« Reply #10 on: August 30, 2012, 09:26:30 AM »

I remembered the old 43db standard, but are we not also supposed to keep up with the technology? Part 15 is one thing but knowing that you are using something like a dirty radio should really bother the operator. Yes it is a hobby but we are supposed to be aware of the rules and regulations that pertain to us. I am guilty of not having  a current or near current hard copy of the regs. My last copy is about 5 years old.

For the hams in the rest of the globe, these regulations are our minimum standards for equipment and operating procedures.

Sorry, had to put that in due to the fact I have been slammed for taking a strictly American point of view. I should have included the above line.

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K7KBN
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« Reply #11 on: August 30, 2012, 10:55:00 AM »

I don't believe the requirement to have a current hard-copy of Part 97 at one's shack has applied for a LONG time.
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73
Pat K7KBN
CWO4 USNR Ret.
KB3HG
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« Reply #12 on: September 01, 2012, 10:28:57 PM »

"I don't believe the requirement to have a current hard-copy of Part 97 at one's shack has applied for a LONG time."

Could be, but I find the book easier to make notations in as I do not have internet access everywhere I go. I only look at it as a better practice than not having one. Also, I can get better answers than opinions from the book. Just a flaw I have, I prefer having a book over a screen. That might change if it were available in an eBook form since the various readers are getting bigger. So in the meantime I have my paperback book to use as a reference.

Tom Kb3hg
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W8JI
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« Reply #13 on: September 02, 2012, 05:17:48 AM »

The more realistic authorities (that includes FCC) in practice appear to don't really care unless you are causing a problem - which is what it always used to be. Why Task Grpoup 1/3 had to pull in the amateur services, I don't know. Some people just like to increase regulation..

There's even more problems when you look at the realistic phase noise at UHF and beyomd.

The only thing the FCC cares about in amateur service is harmonics and spurious out the antenna port, unless there is a computing device inside the device. They don't give a hoot about case radiation, hum, noise, or much else.

If there is a computing device, the device has to pass part 15 requirements, but they require no paperwork.

The real burden falls on end-users. The catch is:

ยง 97.307   Emission standards.
(a) No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice.

(b) Emissions resulting from modulation must be confined to the band or segment available to the control operator. Emissions outside the necessary bandwidth must not cause splatter or keyclick interference to operations on adjacent frequencies.

(c) All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice.



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G3RZP
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Posts: 4502




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« Reply #14 on: September 02, 2012, 09:03:26 AM »

Plus very few administrations have the money to spend on monitoring or enforcement where ham radio is concerned - unless there's a problem.
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