Older blog entries for kelly (starting at number 408)

17 Aug 2010 (updated 18 Aug 2010 at 18:12 UTC) »

Frequency coordination

T1A08: Which of the following entities recommends transmit/receive channels and other parameters for auxiliary and repeater stations?

  1. Frequency Spectrum Manager
  2. Frequency Coordinator
  3. FCC Regional Field Office
  4. International Telecommunications Union

The correct answer is B–Frequency Coordinator.

(Authority: 97.3(a)(22))

T1A09: Who selects a Frequency Coordinator?

  1. The FCC Office of Spectrum Management and Coordination Policy
  2. The local chapter of the Office of National Council of Independent Frequency Coordinators
  3. Amateur operators in a local or regional area whose stations are eligible to be auxiliary or repeater stations
  4. FCC Regional Field Office

The correct answer is C–Amateur operators in a local or regional area whose stations are eligible to be auxiliary or repeater stations.

(Authority: 97.3(a)(22))

These questions only briefly touch on an issue in part because going deeper into it would touch on areas on which the amateur radio community is in disagreement. The prior version of the Technician pool had two questions on this issue, and one of the questions set forth the arguably controversial position that coordination "reduce[d] interference and promote[d]  proper use of spectrum". I don't know why the NCVEC dumped those two questions in favor of these, but at least these questions are much more closely tied to the actual definitions in the regulations.

Frequency coordination, in general, is the recommendation of operating frequencies (transmit and receive parameters) and other parameters (such as antenna gain, antenna directionality, and selective squelch) to allow multiple repeater and auxiliary stations operating in the same general area to interoperate with a minimum of interference. In the business services frequency coordination by an FCC-recognized frequency coordinator is mandatory for all applicants, and applicants must generally pay a fee to the coordinator for that service. In the amateur service, coordination is strictly optional; however, the regulations give an advantage to repeater and auxiliary stations that do coordinate by essentially giving them priority over uncoordinated stations in an interference dispute, but only when the other interfering station is also a repeater or auxiliary station.

In principle coordination, when properly done, should reduce interference and encourage better utilization of spectrum. Unfortunately, it rarely works out that way. Frequency coordinators have a tendency to become "old boy" clubs that seek to protect the interests of their friends at the expense of those who are not their friends. My personal recommendation with respect to coordination is that one should avail oneself of the service if and when it is offered under reasonable terms, but not let it get in the way of doing something interesting or useful, especially if the coordination body is nonresponsive or unreasonably obstructive.

The other interesting thing about coordinators is that there's no top-down process for selecting one. Instead, the amateur radio operators (at least those eligible to be repeater or auxiliary station operators, which is everyone except Novices, and the FCC has proposed allowing Novices to be repeater operators, too) in an area choose, by no defined process, who their coordinator is. What this means, as far as I can tell, is if enough hams in an area get together and coordinate frequencies amongst themselves, and are recognized as having done so, then they've formed a coordination body and are acting as a "frequency coordinator". The FCC's regulation is very silent on what happens if there's a disagreement over who has jurisdiction in a particular area or if there are two competing entities both claiming to be "the" frequency coordinator for a given area. The key here is that the recognition process is bottom-up rather than top-down.

Finally, don't confuse frequency coordination with the bands established by the FCC (and consistent with ITU policy directives). FCC-set band allocations establish the limits of the frequencies on which an amateur may operate, with specific power limits and modulations. Also do not confuse frequency coordination with the voluntary band plans recommended by the ARRL (and other entities) for general use of frequencies within the limits of the FCC allocations. Frequency coordination is always a specific recommendation for a specific repeater or auxiliary station, based on the particular characteristics and expected usage of that station.

(Edited 8/18 to add T1A09.)

Syndicated 2010-08-17 20:31:00 (Updated 2010-08-18 18:08:22) from Kelly Martin

17 Aug 2010 (updated 31 Aug 2010 at 06:15 UTC) »

Remote control and intelligence: telecommand and telemetry

T1A06: What is the FCC Part 97 definition of telecommand?

  1. An instruction bulletin issued by the FCC
  2. A one-way radio transmission of measurements at a distance from the measuring instrument
  3. A one-way transmission to initiate, modify or terminate functions of a device at a distance
  4. An instruction from a VEC

The correct answer is C–A one-way transmission to initiate, modify or terminate functions of a device at a distance.

(Authority: 97.3(a)(43))

T1A07: What is the FCC Part 97 definition of telemetry?

  1. An information bulletin issued by the FCC
  2. A one-way transmission to initiate, modify or terminate functions of a device at a distance
  3. A one-way transmission of measurements at a distance from the measuring instrument
  4. An information bulletin from a VEC

The correct answer is C–A one-way transmission of measurements at a distance from the measuring instrument.

(Authority: 97.3(a)(45))

Many of the questions in the first section of the licensing exams are about regulatory jargon, and these two are no exception. I've combined these two into one post because they're basically opposite sides of the same coin. Both are examples of one-way transmissions. Also, notice that the correct answer to each question is a distractor on the other one; it is therefore important to read the question closely to see which one you got.

Telecommand is what your TV remote does: it sends commands to your TV, causing your TV to "initiate, modify, or terminate functions" based on what button you pushed. Of course, your TV remote is probably infrared (very few television remotes are RF these days), but the principle is the same. Perhaps a better example that almost always uses RF is a garage door opener.

Telemetry is using wireless communication to receive data from a measuring device without a physical connection between the measuring device and the reporting or recording device. If you have a wireless weather station, what that uses to send the gathered data back to the base station is telemetry. The same would apply to a wireless security camera; in this case the data being reported back are the images being captured by the camera.

In the context of amateur radio, telecommand is the use of amateur radio frequencies to remotely control a device. This device can be anything at all, but two specific categories stand out: remote control of model craft (often model airplanes), and remote control of space stations; these two categories receive special treatment within the rules. But nearly anything, even another amateur radio station, may be controlled by telecommand.

One of the most common telemetry activities in amateur radio today are APRS telemetry stations (often called "beacons", which is technically a misnomer, as they're not really beacons, but instead telemetry stations). APRS telemetry stations periodically transmit their location (and possibly other data, such as weather observations, environmental conditions, or anything else the station operator feels like reporting) via a packet data format which may then be received by an APRS digipeater and eventually captured by an APRS gateway and published on the Internet.

Syndicated 2010-08-17 16:08:00 (Updated 2010-08-31 06:02:44) from Kelly Martin

17 Aug 2010 (updated 17 Aug 2010 at 18:12 UTC) »

Space stations: it's all about altitude

T1A05: What is the FCC Part 97 definition of a space station?

  1. Any multi-stage satellite
  2. An Earth satellite that carries one of more amateur operators
  3. An amateur station located less than 25 km above the Earth's surface
  4. An amateur station located more than 50 km above the Earth's surface

The correct answer is D–An amateur station located more than 50 km above the Earth's surface.

(Authority: 97.3(a)(40))

Yet another question about radio regulatory jargon. The term "station" is, itself, specialized jargon in the radio services; despite the name, a "radio station" does not have to be stationary. A "space station" is, within the context of regulated radio (and thus amateur radio), simply a radio station in space. "Space" is defined as "anything more than 50 kilometers above the earth's surface".

The common notion of a space station typically requires that the station be manned; however, this thinking will again throw one off the radio definition. Space stations, in the radio sense, may be remotely operated or automatically controlled, just as any other station, and so a manned presence is not required. Nor is a space station required to be in earth orbit (although as far as I know there are presently no amateur space stations which are not in earth orbit). An especially high-flying balloon would count (although typically amateur radio ballooning activities tend to top out below the roughly 160,000 feet that defines "space"); so would a station on an object in solar orbit (such as, say, Mars) or even on a solar escape trajectory.

Amateur radio space stations have a lot of special rules that apply to them, but unless you plan on launching something into orbit you probably won't need to worry about them. The key to getting this question right on the exams is remembering two things: stations do not have to be manned, and anything over 50 kilometers is "space".

Syndicated 2010-08-17 15:25:00 (Updated 2010-08-17 17:27:47) from Kelly Martin

16 Aug 2010 (updated 17 Aug 2010 at 18:12 UTC) »

Harmful interference

T1A04: Which of the following meets the FCC definition of harmful interference?

  1. Radio transmissions that annoy users of a repeater
  2. Unwanted radio transmissions that cause costly harm to radio station apparatus
  3. That which seriously degrades, obstructs, or repeatedly interrupts a radio communication service operating in accordance with the Radio Regulations
  4. Static from lightning storms

The correct answer is C–That which seriously degrades, obstructs, or repeatedly interrupts a radio communication service operating in accordance with the Radio Regulations.

(Authority: 97.3(a)(23))

"Harmful interference" is another term from the jargon of radio regulation. Interference, broadly speaking, is anything that tends to disrupt communication, regardless of source. Not all interference is "harmful", though. Merely being "unwanted" or "annoying" is not enough to rise to the level of "harmful"; the disruption has to be significant or repeated, or must completely prevent all communication, before it rises to the level of harmful. Finally, "harmful interference" never originates from a natural source, so static from lightning storms, no matter how annoying or disruptive, doesn't count as harmful interference.

All radio licensees, including amateurs, are prohibited from causing harmful interference with any other station. Stations who are suffering from harmful interference are entitled to relief from that interference, which means that the station causing the harmful interference can be made to stop, by force if necessary, by the governing administration that has authority over that station.

Harmful interference doesn't have to be intentional, although it often is. Jamming (that is, transmitting on top of other transmissions in order to block them) is an especially pernicious form of harmful interference. But that's not the only form of harmful interference; far more common are things like spurious emissions caused by malfunctions or maladjusted transmitters, leakage from cable television systems, and unwanted noise from defective household electronics like computers or televisions. All of these, if severe enough, count as harmful interference that can result in enforcement actions from the FCC.

In practice the FCC's effort to abate harmful interference is proportional to what the licensee suffering the interference pays in licensing fees for their license; since amateurs pay nothing for their licenses the FCC doesn't work terribly hard to resolve interference complaints. Basically that means we have to investigate the circumstances ourselves and wrap the whole thing up nice and pretty so all they have to do is some quick work to verify the complaint before they'll act. Fortunately the ARRL is actually pretty good at this; one of the few things they do do well.

This particular question is one that was improved in this version of the question pool; in the 2006 question pool the question misstated the definition of "harmful interference", leading me to complain about it when I blogged about it about a year ago.

Syndicated 2010-08-16 16:53:00 (Updated 2010-08-17 17:27:47) from Kelly Martin

16 Aug 2010 (updated 17 Aug 2010 at 18:12 UTC) »

Part 97 of how many?

T1A03: Which part of the FCC rules contains the rules and regulations governing the Amateur Radio Service?

  1. Part 73
  2. Part 95
  3. Part 90
  4. Part 97

The correct answer is D–Part 97.

The FCC, as I mentioned in the previous post, regulates all nonfederal use of radio for communication in the United States. In the course of doing this it issues lots and lots of regulations. These are gathered together (along with selected regulations from certain other agencies) in Title 47 of the Code of Federal Regulations. For bureaucratic reasons, the regulations are divided into numbered "parts"; the FCC is allotted parts 0 through 199. The first twenty parts (0-19) are for administrative and general rules that apply to the FCC and its licensees generally. The remaining parts, 20 through 101, are rules for different types of licensed radio uses, or "services", as they are known in radio regulatory jargon.

The four answers the NCVEC offers for this question are therefore all rules for specific radio services. Part 73 contains the rules for the broadcast media services, including AM and FM radio, television, and the international broadcast service (shortwave). Part 90 contains all the rules for what is known as the "private land mobile" service; this rather large division includes business radio and public safety radio (such as police and fire services). Part 95 covers the "personal radio" services such as CB and GMRS. And, finally, Part 97, the correct answer, covers the amateur radio service. It's generally a good idea for hams to have a copy (at least in electronic form) of Part 97 simply because the FCC expects us to be aware of the rules of the service.

The astute reader will already have noticed that when I quote the questions in these posts, there is often an "authority" section at the bottom of the question (although not in this post, because the NCVEC didn't provide an authority for this question). These are references, provided by the NCVEC, to the portion of the FCC regulations that the question under discussion is testing. These references are hotlinked to the Government Printing Office's Electronic Code of Federal Regulations Service, which is updated daily and is therefore the most up-to-date and official source for these documents (even more so than the FCC itself). There are other sources for Part 97 out there, but if you use a source other than the GPO, please ensure that the source you use is up-to-date; the FCC has amended Part 97 twice already this year alone.

Syndicated 2010-08-16 14:52:00 (Updated 2010-08-17 17:53:19) from Kelly Martin

16 Aug 2010 (updated 17 Aug 2010 at 18:12 UTC) »

What does the FCC have to do with amateur radio?

T1A02: What agency regulates and enforces the rules for the Amateur Radio Service in the United States?

  1. FEMA
  2. The ITU
  3. The FCC
  4. Homeland Security

The correct answer is C–The FCC.

(Authority: 97.1)

This is another question that's in the question pool to ensure that aspiring licensees are educated about something that is very important to know: that amateur radio, in the United States, at least, is regulated by the Federal Communications Commission, or FCC, and not by any other entity.

The FCC has been charged since its creation in 1934 with the regulation of all uses of radio frequency energy for communication within the terrority of the United States, its coastal waters, and ships at sea sailing under the flag of the United States, except for use by instrumentalities of the federal government itself (over which the FCC has no jurisdiction). Amateur radio falls within this scope, and so amateur radio is regulated by, and the rules for amateur radio written and enforced by, the FCC. 

Two of the other three entities listed are other federal agencies that have no authority over radio: FEMA and Homeland Security. Hams have no specific duties, functions, or responsibilities with respect to either FEMA or Homeland Security. The third entity offered as a distractor is the ITU, or International Telecommunication Union. The ITU, unlike the others, is not a federal agency; it is instead an agency of the United Nations, formed originally in 1865 as the International Telegraph Union in 1865 by a multilateral treaty amongst 20 nations. The United States is a charter member of the ITU and, as a member nation, agrees to abide by the regulations the ITU sets forth regarding radio. However, while the FCC will only rarely write regulations that are inconsistent with those issued by the ITU, it remains the case that it's the FCC regulations, and not the ITU regulations, that apply to amateur radio in the United States. Which is just as well, because the FCC regulations anyone can get for free from the US Government Printing Office, while the ITU regulations are not available without the payment of a fee to the ITU, or more accurately the ITU's publisher.

The FCC isn't the only entity that a ham has to care about. Hams must also follow FAA regulations (when erecting towers over a certain height, as set forth in Part 17). Hams must also be aware of and follow certain regulations of the National Technology and Information Agency (NTIA), issued as part of the latter's authority to coordinate the use of radio by the federal government. Several amateur bands are shared with federal users (including the military) and amateurs must be aware of the NTIA's regulation of those shared bands and observe any restrictions placed by NTIA in the use of those bands. Finally, while FCC regulation preempts state and local regulation of radio with respect to radio frequency interference and radio frequency exposure safety, state and local authorities may still enforce "reasonable" regulations on antenna structures for the purpose of electrical and mechanical safety and other "legitimate" purposes.

In practice, the FCC governs with a relatively light hand. Amateur radio is a tiny tiny piece of the FCC's pie. Amateur radio licensing generates very little revenue for the FCC (as the licenses are free), and they put relatively limited resources into the amateur radio area. In general the FCC expects us to take care of ourselves. This is a mixed blessing: on one hand it means that the FCC isn't something we generally have to deal with much; on the other hand, when there is a problem, getting the FCC to act on it can be difficult. It's not clear to me that a heavier hand would be better for amateur radio, though, and the other alternative (no amateur radio at all) is clearly worse.

Syndicated 2010-08-16 12:45:00 (Updated 2010-08-17 17:27:47) from Kelly Martin

16 Aug 2010 (updated 17 Aug 2010 at 18:12 UTC) »

Who Is Amateur Radio For?

This is the first post in what is likely to be a long series that discuss the material on the Amateur Radio licensing examinations. Each post will typically focus on one question from the question pools; there are thousands of these questions so this will probably go on for some time. Some of this material will likely be repetitive with prior posts in this blog, but I will try to make it interesting nonetheless.

T1A01: For whom is the Amateur Radio Service intended?

  1. Persons who have messages to broadcast to the public
  2. Persons who need communications for the activities of their immediate family members, relatives and friends
  3. Persons who need two-way communications for personal reasons
  4. Persons who are interested in radio technique solely with a personal aim and without pecuniary interest

The correct answer is D–Persons who are interested in radio technique solely with a personal aim and without pecuniary interest.

(Authority: 97.3(a)(4))

This question's presence in the Technician pool acts to ensure that people who are setting out to become hams will understand both what amateur radio is and also what it is not. Amateur radio is not (as is widely believed, if you believe the random noise I hear on Twitter and Backtype) a means by which one can broadcast one's opinions to myriads of rapt listeners. Nor is it intended as a personal communication service (either with your friends and family, or as a general chat service); people looking to do that should consider whether one of the Personal Radio services, or even a cell phone, would better serve their needs. Amateur radio is intended to allow those who have an interest in radio for its own sake a means to explore and develop their interest. If you are hoping to accomplish something useful, and you're just considering using radio as a means to do that, amateur radio may not be what you're looking for. Especially if the thing you're hoping to accomplish involves making money for yourself or someone else: that's specifically prohibited.

As it happens, the foregoing notwithstanding, there's quite a lot of use of amateur frequencies for what amounts to the broadcasting of opinion (as anyone who has listened to 75 meter phone, or to far too many VHF repeaters, can attest), and it's certainly common to see amateur radio used for personal communication between family members, or for general chatting (the latter is often called "ragchewing"). It's just that these are not part of the principle purposes of the amateur radio service, and the FCC offers other services which are explicitly intended for these purposes.

Fundamentally, if you think the whole concept of flinging signals through the air and catching them halfway across the world (or just halfway down the street) is really awesome and want to play with this more, and are willing to take quite a bit of time to learn some pretty complicated stuff, then ham radio is for you. If you just want to talk to people halfway around the world (or, again, halfway down the street), well, may I suggest Twitter? It's a lot easier to get on Twitter than it is to get a ham radio license, after all, and you don't have to buy nearly as much equipment. Fundamentally, ham radio is a geek thing; if you don't have the knack, then it might well not be for you.

Syndicated 2010-08-16 05:39:00 (Updated 2010-08-17 17:27:47) from Kelly Martin

4 Jun 2010 (updated 17 Aug 2010 at 18:12 UTC) »

Electrocution may be hazardous to your health

The first group of new questions from the 2010 Technician pool I'm covering are from subelement T0, which covers safety issues.  The NCVEC has been increasing the amount of safety-related content on the tests in recent years, and the new pool contains 13 new questions in this subelement.  The first of these is T0A02: "How does current flowing through the body cause a health hazard?"  I would think that most people understand that being electrocuted is bad for them, and generally something to be avoided.  However, for whatever reason, the NCVEC has decided that it's at least somewhat important for new hams to be prepared to demonstrate that they understand just why electrocution is bad for you. 

There are three main ways that electric currents within the body are hazardous.  First, any current flowing through any medium which is not a perfect conductor (which is to say, anything whatsoever) generates heat (sometimes called Joule heating).  The body's internal resistance is modest, typically between 300 and 1000 ohms; however, the skin resistance can be much higher, in the 10,000 to 100,000 ohm range depending on conditions.  A current passing through the body will heat and eventually burn tissue, preferentially at points of higher resistance; this will lead initially to burns on the skin and then later (as the skin blisters and its resistance lowers), to burns deeper within the body.  Second, many functions of cells depend on electrical charges, and the moving about of charged ions, to accomplish the purpose of the cells; electrical currents passing through these cells will tend to disrupt these electrical functions.  At very low currents (1 milliamp or less) this manifests itself as a tingling sensation.  At higher currents it will manifest as pain.  Sufficiently high currents (50 to 70 milliamps) may cause the third major effect: involuntary muscle contractions.  At even higher currents, 500 milliamps or more, the muscle of the heart can be disrupted leading to heart fibrillation, cardiac arrest, and death.

This particular question appears in the pool with an "All of the above" option.  Any experienced test-taker knows that "all of the above" is often the correct answer to any question that has such an option, and this question is no exception to that rule.  In any case, what really matters is that hams must understand that electrical voltages, even relatively low ones, are potentially dangerous, and must take precautions to avoid finding out about these effects first-hand.

Syndicated 2010-06-04 06:24:00 (Updated 2010-08-17 17:27:47) from Kelly Martin

3 Jun 2010 (updated 17 Aug 2010 at 18:12 UTC) »

New Technician Pool, coming soon to a VE team near you

The NCVEC announced a new Technician pool back in February; it's now June and that new pool goes into effect July 1.  I've been blogging about the old Technician pool (an activity which, of late, I have been kinda lax at), and I've decided to abandon that effort in favor of blogging about the new pool, on the grounds that that might be more useful.

The new pool has 396 questions, 5 more than the old one; there are 67 questions carried across unchanged, 142 carried across with some changes (either minor or, in some cases, major), and 187 questions that are entirely new.  182 questions were dropped.  I would say that this new pool is somewhat harder than the old one; the new pool has significantly more electronics on it as well as content related to ionospheric propagation and SSB and CW operations (reflecting the fact that all Technicians now get limited HF privileges, not just those few who pass a code test).  There's even a few basic antenna theory questions.  Overall I think this is a better pool, in that it will force candidates to learn more of what they should know as beginning amateur radio operators.

Future posts will discuss specific topics that are new or newly handled on the new pool.

Syndicated 2010-06-03 07:49:00 (Updated 2010-08-17 17:27:47) from Kelly Martin

28 May 2010 (updated 28 May 2010 at 18:09 UTC) »

Don't drive in Northlake this weekend

I guess Northlake is short on money or something: I just got a $50 "seatbelt violation" (given to me by NLPD Officer Carpenter, badge #128) for driving while wearing a seatbelt. Yes, you heard me. For driving while wearing a seatbelt.

The incident occurred near the intersection of Fullerton and Roy, around 11:15 am today. This is a common place for Northlake to set speed traps, and I know this, so I was being careful to watch my speed through here. I noticed the cop (in his tiny little Northlake compact cop car, they don't drive Crown Vics there) as I drove by, and even nodded to him. I'm driving my GMC Sierra, which means I'm probably 4 feet above his eye level: there is no way he can tell if I'm wearing my seat belt or not. I always wear my seatbelt. Always. No exceptions.

After I clear the intersection he lights up and chases me down a half block down the road. I pull over, of course, and go to get the insurance card out of the glove box while waiting for him to walk up. In order to do this, of course, I have to take off my seat belt: the glovebox on a Sierra is a LONG reach and it's really hard to do without removing the seat belt, so when he gets to me I have already taken my seat belt off. He gets to me and tells me that he pulled me over for not wearing a seat belt. I tell him that that's ridiculous, and he gets all hot and huffy at me (including the classic "You got a problem with that?" line that dumbass powerfreak cops use all the time). He takes a brief look at my license and insurance (probably just to verify that I don't live in Northlake: I don't, and my license still has my Niles address on it) and decides at that point that he's going to write me a citation.

The fine is $50, and I'm not going to fight it because the only way I can win is to hope that Officer Carpenter doesn't show up. Basically this is the Northlake Mafia, tagging me for $50 for being in the wrong place at the wrong time. I actually figure I'm better off having taken my seat belt off before he got up there; otherwise he'd have to come up with some other bogus violation to charge me with that would have cost me more and maybe even put points on my license. But this certainly is a huge discouragement for me to do any business in Northlake, especially this weekend.

Quick note to Mayor Jeffrey Sherwin: antagonizing your neighbors is not a good business practice. I can easily take my business in Northlake to Melrose Park, Stone Park, or Franklin Park.

Syndicated 2010-05-28 16:50:00 (Updated 2010-05-28 17:16:08) from Kelly Martin

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