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Showing posts with label Interference. Show all posts
Showing posts with label Interference. Show all posts

2021-09-23

Just what is bentonite?

 and why do I need it?

The ‘OTC Report’ (in the September-October Communicator at https://bit.ly/SARC21SepOctmentions bentonite as an aid to achieve better RF grounding… but what exactly is this stuff?



In geology, the term bentonite is applied to a type of claystone composed mostly of montmorillonite. It forms by devitrification of volcanic ash or tuff, typically in a marine environment. This results in a very soft, porous rock that may contain residual crystals of more resistant minerals, and which feels soapy or greasy to the touch. However, in commerce, the term bentonite is used more generally to refer to any swelling clay composed mostly of smectite clay minerals.

Sodium bentonite expands when wet, absorbing as much as several times its dry mass in water. Because of its excellent colloidal properties, it is often used in drilling mud for oil and gas wells and boreholes for geotechnical and environmental investigations. The property of swelling also makes sodium bentonite useful as a sealant, since it provides a self-sealing, low permeability barrier. It is used to line the base of landfills, for example. bentonite is part of the backfill material used for waste isolation. Various surface modifications to sodium bentonite improve sealing performance in geo-environmental applications, for example, the addition of polymers.

Here in BC, bentonite was installed in slurry walls in North Vancouver, Quesnel and Williams Lake to stop the migration of railway diesel contamination to adjoining properties.  It was also used it to seal up abandoned environmental monitoring wells, and is  used as pond liner to stop the water from seeping away.

Sodium bentonite can be combined with sulfur as fertilizer prills. These permit slow oxidation of the sulfur to sulfate, an important plant nutrient, and maintain sulfate levels in rainfall-leached soil longer than either pure powdered sulfur or gypsum. Sulfur/bentonite pads with added organic fertilizers have been used for organic farming.

The main uses of bentonite are in drilling mud and as a binder, purifier, absorbent, and carrier for fertilizers or pesticides. As of around 1990, almost half of the US production of bentonite was used as drilling mud. Minor uses include filler, sealant, and catalyst in petroleum refining. Calcium bentonite is sometimes marketed as fuller's earth, whose uses overlap with those of other forms of bentonite.

Bentonite is used in a variety of pet care items such as cat litter to absorb pet waste. It is also used to absorb oils and grease.

What you should know when using ground enhancement material

Under almost all soil conditions, the use of a ground enhancement material will improve grounding effectiveness. Some are permanent and require no maintenance. You can use them in areas of poor conductivity, such as rocky ground, mountaintops and sandy soil, where you can't drive ground rods or where limited space makes adequate grounding difficult with conventional methods.

Bentonite is used to lower the resistance to earth by providing ground enhancement effectively reducing the resistance between the soil and earth electrode (such as copper earth rod or earth mats) by retaining moisture. This inherent ability to absorb and retain rainwater increases the electrical conductivity of the earthing compound in positive correlation to local climatic conditions, specifically average rainfall levels. Typically, the compound has a 3 ohms.m resistivity level – Bentonite compound is a cost-efficient material for backfill of earth electrodes and improving performance when it is physically impossible to drive the earth rods deeper and where challenging ground conditions exist such as rock, granite, etc.

Chemical treatment or backfilling of the soil in close proximity to the location of an underground earthing electrode is an established and traditional method of lowering ground resistance for substation earthing on high resistivity ground – such soil backfilling for electrical grounding improvements is commonly used.

There are several kinds of ground enhancement material available. But use care when choosing the material. It should be compatible with the ground rod, conductor, and connection material. Some options include bentonite clay, coke powder, and specially engineered substances.



Conduction in bentonite clay only takes place via the movement of ions. Ionic conduction can only occur in a solution, which means the bentonite clay must be moist to provide the required resistance levels. When bentonite clay loses moisture, its resistivity increases and volume decreases. This shrinkage results in a discontinuity in the contact between the bentonite clay and surrounding soil, which further increases system resistance.

A noncorrosive low-resistance enhancement substance is a conductive cement that you can install wet or dry. Depending on the substance, it will not leach into the soil and meets EPA requirements for landfill. The railroad and utility industries have successfully used this material. When installed dry, it absorbs moisture from surrounding soil and hardens, retaining moisture within its structure. When used dry, no mixing is required, and you achieve maximum efficiency in a matter of days. This is because it absorbs enough water from the surrounding soil. You can also premix it with water to a heavy slurry. You can add this to the trench containing the grounding conductor or use it around a ground rod in an augered hole. The material binds the water into a cement making a permanent, highly conductive mass.

Some products offer a test-proven resistivity of 0.12 ohm-m or lower, compared with 2.5 ohm-m for bentonite clay. Unlike bentonite clay, the cement-like material does not depend on the continuous presence of water; nor does it require periodic charging treatments or replacement.

An ideal ground enhancement material should not require maintenance. When designing or installing a buried grounding system, look for materials that do not dissolve or decompose over time, require periodic charging treatments or replacements, or depend on the continuous presence of water to maintain conductivity.

~ Internet sources including:

https://www.powerandcables.com/product/earth-tapes-rods-bars-copper/bentonite/ and https://youtu.be/hHtIYboE8NE

 

2020-10-22

A Look At Modulation



A Back to Basics Column from November 2018

From the Canadian Basic Amateur Radio Question Bank

Back To Basics is a regular column in the SARC Communicator Newsletter, available at:  The Communicator Digital Edition: Amateur Radio Newsletter (ve7sar.blogspot.com)

It is a subject that is important because of the interference overmodulation can cause...

This month we’ll look at percentage of modulation and overmodulation. In all the exams I have administered, this topic is always covered. It’s important because it has the ability to cause significant issues on the air. The impact of this is highlighted by the fact that it is repeated a half-dozen times in the Canadian Basic Question Bank with slightly different wording, for example:.

B-001-019-004

The maximum percentage of modulation permitted in the use of radiotelephony by an amateur station is:

A. 100 percent

B. 50 percent

C. 75 percent

D. 90 percent

When you transmit a signal, you do so over what’s called a carrier frequency. This is a relatively constant oscillation, usually in the radio frequency band, that gets modulated (altered) by the signal. In terms of radio use, the modulation is generally (but not always) a waveform produced by the human voice, music or other audible means.

For example, either the amplitude or the frequency of the carrier gets modified (or “modulated”) by the signal, hence “AM” – (Amplitude Modulation) and “FM” – (Frequency Modulation).

When this modulation is so large that the carrier signal clips (distorts, in the case of AM) or the frequency changes to such a degree that it goes beyond the range that the receiver can pick it up or overlaps other carrier frequencies (in the case of FM), the signal is said to be overmodulated.

Likewise, if the signal is of such small amplitude or frequency variation that it cannot be picked up or adequately amplified by the receiver (because of background noise and/or the strength of the carrier frequency), it is said to be undermodulated.

Overmodulation is the condition that prevails in telecommunication when the instantaneous level of the modulating signal exceeds the value necessary to produce 100% modulation of the carrier. In the sense of this definition, it is almost always considered a fault condition. In layman's terms, the signal is going "off the scale". Overmodulation results in spurious emissions by the modulated carrier, and distortion of the recovered modulating signal. This means that the envelope of the output waveform is distorted.

In the image, an amplitude modulated sine wave:



  • At 0% unmodulated [top left], the sine envelope is not visible at all;
  • Less than 100% modulation [top right] depth is normal AM use;
  • At 100% modulation depth [bottom left], the sine envelope touch at y=0. Maximum modulation that can be retrieved with an envelope detector without distortion;
  • At greater than 100% modulation depth [bottom right], "overmodulation" occurs and  the original sine wave can no longer be detected with an envelope detector.

Therefore, the answer to our sample question at the top of this article is A. 100 percent.


~ John VE7TI

18/11



2020-10-18

Tech Topics: Filters, Diplexer and Triplexer Fundamentals


A Popular Communicator Article from 2018 

Several stimulating discussions around the Saturday morning club breakfast table have taken place recently in connection with our use of bandpass filters, diplexers and triplexers.  This article is designed to remove some of the mystery surrounding these devices, which we use both at the OTC and at Field Day.  Although the discussion relates to HF devices, the same general principles apply to VHF and UHF.

Introduction

As propagation conditions change throughout the day, week and year-to-year, HF stations need to have the flexibility to change to those bands which are open. Typically 20 m is open during the daytime hours with 160, 80 and 40 m opening up in the evening and nighttime hours.  In years when sunspot activity is greater, 15 and 10 m also open up during the day.  Currently we are near the sunspot low with the result that DX contacts are a challenge at any time of the day with only the low bands consistently productive for DX.

 

Ideally, a transceiver will utilize an independent antenna for each band on which it operates.  However this is not always possible, where space does not permit or when several transmitters are operating simultaneously (at Field Day, for example).  So we may deploy a multi-band antenna in conjunction with electronic devices that will allow more than one transmitter to use this single antenna, so long as each transmitter is operating on a different band.

SARC’s first exposure to these electronic devices was ca 2015 when we acquired a set of bandpass filters and triplexer for use with our 10-15-20 m TH7 beam antenna.  This was successful and allowed us to have the one antenna on a high tower serve multiple transmitters without significant mutual interference.   


Then a couple of years ago at Field Day, we began using an off-centre fed long wire for 40 and 80 m.  During the late evening hours these two bands were the only game in town, so the antenna was in demand by two stations simultaneously.  Again, a triplexer and bandpass filters allowed this to happen.  Alas, one of the devices failed at the critical time. 

In 2017, we acquired an identical set of the devices described above for use at the OTC, where we have a tri-band beam for 10-15-20 m plus an OCF dipole for 40 and 80 m.  Once again, the 160-80-40 triplexer failed during use.  

This could not continue as failures in these devices place expensive radios in danger of serious front-end damage (i.e. smoke) due to strong other-band signals not being adequately blocked.  It was time for serious reflection about our physical setup.  

A Review of Some Basics 

Inductors tend to pass lower frequencies and capacitors high frequencies.  In other words inductors have a low impedance to low frequencies and capacitors the reverse, the resultant reactance or impedance depending on the value of the inductance, capacitance and frequency.  

An inductor connected to a capacitor will have a unique frequency at which the pair resonates, called the resonant frequency.   At exact resonance, the inductive reactance equals the capacitive reactance expressed as XL = XC and the impedance will either be very low or very high depending on their parallel or series configuration.  The effect of resistance in any practical circuit does not change the resonant frequency but it does affect the sharpness (or Q) of the tuning.

In other words, an inductor in series with a capacitance has a low impedance at its resonant frequency, but the same pair connected in parallel exhibits a high impedance to the flow of current.  These properties are the basis of many types of radio circuits, used most notably for tuning purposes.  They can also be deployed in various combinations as RF filters and in power supply filters to change pulsating DC to “pure” DC.

A low pass filter will pass low frequencies and block high frequencies.  A high pass filter does the opposite.  Bandpass and bandstop filters allow a band of frequencies to pass or be blocked, respectively. The figures above show the generalized frequency response of the 4 basic filter types. 

Below are some simple examples of L-C circuits used in practice for the various kinds of filter devices.  The presence of R in the circuits represents loads but otherwise does not affect the general type of filter and can be ignored for the sake of this discussion.



Intuitively, it is not difficult to determine which type of filter it is by examination of the circuit, if you think of the way L and C respond to low and high frequencies, whether in isolation, in series or in parallel when presented with a range of different frequencies.  

More complicated circuits have been devised that improve the performance of these basic circuits and make them more useful.  A study of such devices will bring forth variations named for the engineers who studied their properties, such as Butterworth, Chebyshev, Cauer and Bessel.  More complicated circuits are not within the scope of this introductory article, but a comprehensive discussion can be found in any ARRL Handbook.

The complexity of a filter circuit is described in terms of its “order”, a measure of the number of L and C elements.  Here, for example, is a 4th order high pass filter:


Practical Devices

A diplexer allows two transmitters to feed one antenna or, conversely, two antennas to serve one transmitter (don’t confuse a diplexer with a duplexer, which is a different animal).  A diplexer simply consists of a low pass filter and a high pass filter operating in parallel, with the cutoff of each somewhere between the two operating frequencies.  With an HF unit used to separate 40 m (~7.0-7.3 MHz) from 80 m (~3.5-4.0 MHz), the cutoff frequency typically would be 5 MHz.   

A diplexer may be able to discriminate 80m from 40m signals by 20-40 dB.  While 20 dB represents a power suppression of the unwanted signal by a factor of 102  it is insufficient to protect the radio.  

That is why an HF diplexer is seldom used by itself.  A bandpass filter in series with the diplexer might suppress the unwanted frequency an additional 40-60 dB depending on its design.   So the diplexer and bandpass filter, operating together, would typically suppress the adjacent band signal by a total of 60-100 dB or a factor of 106-1010.  

If a triplexer rather than a diplexer, is desired to facilitate a third band, the problem becomes more complex.  The “middle” frequency would necessarily have to be a bandpass filter.

One problem is that the size of components for diplexers and triplexers for 160, 80 and 40m bands will be large.  This size factor and associated high cost generally make high power diplexers, triplexers and bandpass filters quite costly.  

Our Devices

Our Dunestar triplexers appear to be rather simple filter circuitry.  Why do these units fail repeatedly, even with the radios operating at 100 watts?  It can only be inadequate current or voltage ratings on the components or excessive SWR, or both.  This would suggest that the antennas connected to the triplexer should be close to resonant at the desired frequencies.  Operating at extreme ends of the band, especially under Field Day conditions when time does not always permit “tweaking” of their length, height or configuration may produce unacceptably high SWR.  

Here is the lesson we have learned: carefully research the characteristics of the diplexer or triplexer you are considering for purchase.  Not only are the band isolation and insertion loss important, but the need to have conservative voltage and current ratings on components is critical.  Then do not deploy these devices on antennas where a near resonant condition cannot be achieved.  



Conclusion

We will probably replace both our Dunestar 160-80-40 triplexers with more robust devices to ensure another failure does not happen.  Units available from VE6AM (www.va6am.com) and DX Engineering (dxengineering.com) and 4O3A (www.4o3a.com/products/high-power-filters/combiner/) are under consideration to meet this need. [In the end we went with VE6AM's product, which has given excellent service]

More good reading can also be found at: 

https://static.dxengineering.com/global/images/technicalarticles/lbs-pb-tp500_sn.pdf.

~ John VA7XB

18/09



2020-08-23

LADD and RR Frequencies


The SARC Communicator [Excerpt]

Back to Basics – Sept/Oct 2020

From The Canadian Amateur Radio Basic Question Bank

There has been a great deal of discussion, confusion, and misinformation surrounding the legality of the off-road community using so-called LADD and RR frequencies while travelling the backcountry. Many of our SARC Basic class students take the course to become certified and are under the impression that having an amateur radio operator certificate gives them legal access to LADD and RR frequencies with amateur equipment. To shed some light on this oft discussed subject, and perhaps avoid forfeiture of equipment or a fine, this Communicator’s Back to Basics column offers an explanation.

The focus in this issue has two questions that apply. One has to do with the equipment, the other with the licencing or certification requirement:

Question B-001-006-006  
Some VHF and UHF FM radios purchased for use in the amateur service can also be programmed  to communicate on frequencies used for land mobile service. Under what conditions is this permissible? 

A. The equipment has an RF output of 2 watts or less 
B. The equipment is used in remote areas north of 60 degrees latitude 
C. The radio is certified under the proper Radio Standards Specification for use in Canada and is licenced by Industry Canada on the specified frequencies 
D. The radio operator has Restricted Operator’s Certificate 

And the second question:

B-001-006-005  
Which of the following statements is NOT correct? A person may operate radio apparatus, authorized in the amateur service: 

A. only where the person complies with the Standards for the Operation of Radio Stations in the Amateur Radio Service 
B. only where the apparatus is maintained within the performance standards set by Industry Canada regulations and policies 
C. except for the amplification of the output power of licence-exempt radio apparatus outside authorized amateur radio service allocations 
D. on aeronautical, marine or land mobile frequencies

I will be quoting frequently from Innovation, Science and Economic Development Canada regulations and policies and will refer to them hereafter as ‘ISED’.   

First some definitions… 

Amateur Radio Service


Amateur radio service means a radiocommunication service in which radio apparatus are used for the purpose of self-training, intercommunication or technical investigation by individuals who are interested in radio technique solely with a personal aim and without pecuniary [monetary] interest.

An Applicable Basic Amateur Radio Certificate Restriction

According to Radio Information Circular (RIC) 3

4.4.1 Basic Qualification

The following privileges and restrictions are applicable to the Basic Qualification:

  • re-programming of radio equipment to operate in the Amateur Bands if this can be done by a computer program

    Note: No physical modifications to the circuitry of the radio are permitted.

Land Mobile Service


Radiocommunications Regulations state:

Land mobile service means a radiocommunication service that provides for communications between mobile stations and

(a) fixed stations,
(b) space stations, or
(c) other mobile stations

Mobile Station 


A Mobile Station is also defined on the ISED website as: “a radio station intended to be used while in motion and during stops.”

Commercial Licence Radiocommunication Services and Stations



Per the Canada Radiocommunications Regulations:

s.3 It is a term of a radio licence that the holder of the licence may

(a) install, operate or possess radio apparatus to perform any of the following services, as authorized by the radio licence, namely,

(i)  aeronautical service,
(ii) amateur radio service,
(iii) public information service,
(iv) developmental service,
(v) fixed service,
(vi) intersatellite service,
(vii) land mobile service,
(viii) maritime service, and
(ix) radiodetermination service; and

(b) install, operate, or possess radio apparatus at a fixed station, mobile station or space station as authorized by the radio licence.


Mobile Stations s.60 (4)


The radio licence fee payable in respect of radio apparatus installed in a mobile station that operates in the land mobile service is the applicable fee set out in item 5 of Part I of Schedule III for all authorized transmit and receive frequencies.

s.63  The fee, for the applicable metropolitan or other area, set out in Part IV of Schedule III for each assigned transmit or receive frequency (Sections 56 and 60) Fee Schedule Applicable for a Mobile Station in any Service other than the Amateur Radio Service

  • Mobile station in the land mobile service – monthly $3.40 - annually  $41.00


Licences, Certificates and Callsigns


The Amateur Radio Service requires the operator to hold an amateur radio operator's certificate. Traditionally, amateur radio operators were issued two separate authorizations: An Amateur Radio Operator Certificate and a radio station licence. The Amateur Radio Operator Certificate was issued for life and had no fee associated with it, while the radio station licence was issued on a yearly basis and a licence renewal fee was charged.

Effective April 1, 2000, ISED combined these documents into one authorization, the Amateur Radio Operator Certificate. This certificate is the sole authorization required to operate amateur radio apparatus in the amateur radio service. (It is no longer called a licence - Amateurs have a certificate to operate)

A callsign is assigned when you receive your amateur certificate. This is required for the purpose of station identification. For a fee, additional callsigns can be requested by contacting the Amateur Radio Service Centre. Your callsign covers all your base, mobile, and portable radios at that location, and allows you to operate within any of the amateur bands (frequency ranges) for your certification class. Fixed stations at separate locations require a separate callsign for station identification.

A radio operator certificate is required only in the aeronautical service, maritime service, and the amateur radio service. (per s.33 of the Radiocommunications Regulations). A radio operator certificate is not required in the Land Mobile Service but each radio requires a separate licence (callsign); this is different than your Amateur certificate. So, if you own a mobile and a portable used on a commercial band, you would require two licences. You pay per radio, not per frequency in the radio, but each frequency in the radio must be listed on that radio's licence.

‘Type-Approved’ Radio Equipment 


Contrary to Amateur Radio, commercial radio is pre-programmed to operate on specific frequencies and cannot be user programmable. So, you cannot actually "attempt" to transmit on an amateur frequency if it does not already exist in the radio. Commercial radio equipment must pass testing to ensure it does not create interference and is compliant with both ITU and Canadian regulations. This is referred to as being “type-approved”. Radio equipment is approved according to the bands and purpose for which it is marketed, and a lower standard exists for amateur equipment than commercial. Unlike Amateur Radio, where we can choose our own frequency to operate (if it is within an Amateur band), commercial radios are not permitted to be frequency-agile. For example, a trucker cannot one day decide to set up a talk channel on a frequency that is not already designated and licenced by ISED for trucking. Commercial radios modified to be programmed by the operator in the field are not type-approved and can not legally be used on commercial frequencies.

A commercial VHF radio’s frequency range will typically be capable of covering all or a portion of the amateur VHF band. The amateur VHF band is 144-148 MHz; you will find commercial radios with ranges of 136-174 MHz, 146-174 MHz, 136-152 MHz, or similar. So amateur frequencies CAN exist in a commercial radio, but they would have to be programmed in and the operator licenced to use them in a specific band.

Surplus and new commercial radios are readily available and may be programmed and used by amateur radio operators within the amateur bands for which YOU are certified. If you are an amateur radio operator and have a licence for your commercial radio, you can have your commercial frequencies and your amateur frequencies in the same commercial VHF radio, but they must be professionally programmed to avoid errors.

VHF and UHF commercial gear is better quality because they have more stringent specifications than amateur radios and have minimal operator controls for ease of use, typically only an on/off and volume control, squelch, and a channel selector. 

One more caveat.  Since 1997 narrow band equipment has been implemented in North America for VHF commercial radio equipment. This means that twice as many channels can be assigned as each channel takes up only half the bandwidth. Channels are now specified narrowband (11 kHz) with a maximum transmitter power of 30 watts, or as otherwise indicated. Amateur radio equipment is not narrow-band and causes interference on narrow-band channels. This is one of the reasons Amateur radio equipment is not permitted on commercial frequencies. If you buy an older commercial radio it may not be narrow band and would no longer be type-approved for certain commercial frequencies.

So, amateur radios cannot be used to transmit on commercial frequencies, in part because they do not necessarily meet the specifications required for use in the commercial (land mobile) radio service, and in part because ISED does not want commercial users to be able to program frequencies on the fly, generally assuming that the commercial users are not radio hobbyists and therefore would not have the knowledge to correctly program a radio.

Lastly, it is not illegal to program an amateur radio to receive outside of the amateur band, or possess such a radio if you have a licence, but it's illegal to use it to transmit outside of the amateur band.  Some amateur radios come from the factory able to transmit outside of the amateur bands, but this is not ISED approved.

LADD Frequencies


In Canada, the LADD (or LAD) VHF channels (Logging ADministration Dispatch) were originally intended for commercial trucking, general communications in forestry & logging, heavy mining, and exploration and petroleum. These are also known in Western Canada as the "Opens". Their use is governed by Industry Canada and require a licence and compliant, type-approved radio equipment. Click here for info about ISED licencing.

Due to the wider availability of low cost amateur VHF FM radios and the decline of CB Radio, recreational users have adopted them for back country communications and, for those who do not have reliable cellular service, especially survivalists and preppers, they are marketed as an essential communication resource. Users of LADD channels require commercial type-approved equipment and require a corresponding licence for the radio – NOT AN AMATEUR RADIO LICENCE (or certificate) to comply with the regulations. Also, in keeping with Spectrum Canada regulations, it is important to note that there are geographic restrictions where LADD channels can be used to prevent interference to adjacent users.  

ISED has approved four LADD channel frequencies for radio licencing. Companies or individuals with only one or two radios no longer have to wait for a letter of permission from an existing radio channel holder in order to licence their radios. Their radio supplier can apply with ISED on their behalf for the use of 154,100Mhz (Ladd-1), 158.940Mhz (Ladd-2), 154.325Mhz (Ladd-3) and 173.370Mhz (Ladd-4) in their ISED approved commercial VHF radios. Larger companies may apply for a commercial (shared) channel frequency if they have many mobile vehicles needing to be dispatched from an office base station.

For legacy compatibility, LADD1-LADD4 channels use normal FM (FM is +/-5 kHz deviation, bandwidth 16 kHz, max bandwidth 20 kHz), while most of the other channels increasingly use Narrow NFM (NBFM is +/-2.5 kHz deviation, bandwidth 11 kHz, max bandwidth 11.25 kHz). Normal FM has slightly longer range than Narrow FM (see the RadioMaster article FM versus NFM for Best Radio Communications). If you are using NFM and reception is loud and distorted, try FM instead.

Resource Roads


Background


Mobile radio communication on resource roads had been historically highly variable across the Province of British Columbia (BC) for a multitude of reasons:

  • Road users were required to know unwritten local protocols
  • Heavy radio traffic caused overlapping calls and interference
  • Radios had to be reprogrammed to local channels with each location change
  • Road signage was inconsistent and unclear

A standard mobile radio communications protocol was developed to standardize and simplify, and thus make travel on resource roads safer.

Refer to the ISED page RR — British Columbia Resource Road Channels

ISED RR channels are specified narrowband (11 kHz) with a maximum transmitter power of 30 watts, or as otherwise indicated. These channels must only be used in locations where it is specifically posted for usage. Improper usage, for example "chit chat", will result in harmful interference to other resource road and loading usages or to other priority radio spectrum users. All channels are designated such that they cause no interference to other users and must accept interference from other priority users.

Mobile Radio Station Licence Application


In the Province of British Columbia, Resource Roads are typically one or two-lane gravel roads built for industrial purposes to access natural resources in remote areas. Over 620,000 kilometers of roads on the British Columbia landbase are considered resource roads.

Two-way radios using these channels require a mobile radio licence. The use of amateur, marine or user programmable radios is not permitted.




The BC Forest and Range Practices Act regulates the use of these roads and radio communications. Outside BC check your applicable legislation. 

FOREST SERVICE ROAD USE REGULATION [current to 2020-07-28]


Use of 2-way radio

s.5 (1) A driver on a forest service road who uses a 2-way radio to communicate with other drivers on the road must announce, in accordance with any road markers posted at intervals along the road,

(a) his or her position, and
(b) the branch of the road being travelled if the radio's signal can be received on more than one adjacent branch of the road.

(2) Subsection (1) applies to a driver only if

(a) the driver uses a radio frequency provided by the holder of a private commercial radio station licence, or other licence under the Radiocommunication Act (Canada) and the regulations under that Act, to communicate with the other drivers, and
(b) the forest service road is posted with a sign that indicates the radio frequency that is to be used.

[Editor’s note: This legislation says ‘MUST announce, in accordance with any road markers’ and appears to make it illegal for anyone without proper communications – i.e. a licenced commercial type-approved radio with programmed RR channels, to drive on a Forest Service Road if marked with RR signage.]

Liability insurance


s.12 (1) A person must not operate or cause to be operated a motor vehicle or trailer, other than a motor vehicle or trailer described by section 2 (5) of the Motor Vehicle Act, on a forest service road unless

(a) the driver, motor vehicle and trailer are insured under a valid and subsisting contract of accident insurance providing insurance against liability to third parties in the amount of at least $200 000, and

(b) the driver carries written evidence, supplied by the insurer, of the insurance referred to in paragraph (a), or a copy of that written evidence, and produces it, on demand, to a peace officer or an official.

(2) Motor vehicles operated by the government that are subject to a government self-indemnification plan are exempt from the requirements of subsection (1).
[am. B.C. Reg. 354/2004, Sch. B, s. 2.]

[Editor’s notes: For clarity, the insurance exemption under section 2 (5) of the Motor Vehicle Act referred to above is for farm implements.  

If travelling on a Resource Road the vehicle or trailer must have third-party liability insurance of minimum $200,000 and proof must be carried and shown if requested by a peace officer or official.

A reminder also that anyone operating two-way radio equipment is subject to any applicable distracted driving legislation that may be in force.]

Offence


s.13 (1) A person who contravenes section 3 (3), 5 (1), 6 (5), 10 (1) or 11 (1) or (3) commits an offence and is liable on conviction to a fine not exceeding $5 000 or to imprisonment for not more than 6 months or to both.

 (2) A person who contravenes section 4, 6 (3) or (4), 7, 8 or 12 (1) commits an offence.


Resource Road User Safety Recommendations

http://www.bcforestsafe.org/files/tk_pdfs/gde_resrd.pdf and Resource Road Radio Communications

Government in collaboration with industrial and other stakeholders has moved forward with implementation of standard radio communication protocols on Forest Service Roads (FSR) and other natural resource roads across the province.  FSRs with industrial activity and many other resource roads have adopted and are using the standard protocols which consist of:

  • standard call protocols - call content and order
  • standardized signage
  • dedicated, standardized bank of resource road radio channels

The standard bank of resource road mobile radio channels is available, to those with applicable [NOT Amateur] mobile radio licences, for programming at local commercial mobile radio shops.

It is important to note that not all resource roads have adopted the protocols and standard bank of resource road radio channels. It is recommended that road users retain current radio frequencies until such time that they are sure they are no longer required.
Most resource roads are "radio assist" and use of mobile radios for communicating location and direction is not mandatory.  Always drive safely according to road and weather conditions and if using a mobile radio, do not solely rely on mobile radio communications recognizing that not everyone has or is using a mobile radio.

In the transition to new resource road radio channels and communications protocols, resource road users are advised to exercise additional caution when traveling on resource roads. Drive safely according to the road conditions and weather at all times. This should be communicated by employers to all their affected employees and contractors.

Most Forest Service Roads and natural resource roads are radio-assisted, but not all roads are radio-controlled. Road users are reminded not to drive exclusively according to the radio. Where posted, road users using mobile radios must use the posted channels and call protocols.

Channel Maps


A standard bank of resource radio channels has been provided by Innovation, Science and Economic Development Canada (ISED) for dedicated use for mobile radio communications on resource roads in BC.  By agreement, the Ministry of Forests, Lands and Natural Resource Operations is responsible for administering the use of the standard bank of resource road radio channels in BC.

The standard bank of resource road radio channels has been distributed across the B.C. landscape to minimize the likelihood of interference. Channel assignment maps have been developed, and periodically are changed, to reflect channel assignments as planning tools. The maps should not be relied upon for appropriate channel selection in the field as in some cases, the channel assignments have not been implemented on the ground.  The radio channel signage in the field will always govern over the maps. See the mobile resource road radio planning maps:

Resource Road Radio Channel Planning Maps

Best management practices for mobile 2-way radio use on resource roads in BC, installation and maintenance

Radio requirements on BC resource roads (and elsewhere) will be for narrow-band communications. Radios manufactured after 1997 have this capability but older radios may only communicate with wideband transmissions. Wideband transmissions sound overly loud when received by narrowband radios and narrowband calls received by these radios may sound too quiet. Wideband radios should be replaced with newer, narrowband capable radios.

FRS, GMRS and Other Common Non-Amateur Frequencies


It should be no surprise to you that the licence exempt radios marketed for these bands are very low power and have narrow channel spacing. Licence exempt devices include cordless telephones, baby monitors, family radio service (FRS) walkie-talkies, remote garage door openers, or wireless local area networks. Although licence-exempt radio devices generally transmit signals at low-power levels, the power level alone does not determine if a licence from Industry Canada is required. By law, licence exemptions only apply to radio equipment that has been tested and certified to comply with specific technical standards and operates in specially designated frequency bands.

For the General Mobile Radio Service (GMRS) in Canada transmit power is capped at 2 watts by law, while the units sold in US can operate at 5 watts. Everything else is the same - frequencies and the communication standard. One needs a BS licence to operate a GMRS radio in the States (easily obtainable by anyone and does not require any test), but no licence is needed in Canada.

These devices may not be modified or fitted with different antennas. It is NOT permissible for you to transmit on any of these channels with your amateur equipment as you will exceed power and/or bandwidth limits. As with other frequencies, you may monitor them as receive only.

The answers to our original questions


Some VHF and UHF FM radios purchased for use in the amateur service can also be programmed to communicate on frequencies used for land mobile service. Under what conditions is this permissible? 

C. The radio is certified under the proper Radio Standards Specification for use in Canada and is licenced by Industry Canada on the specified frequencies

You can wade through RSS-119 — Radio Transmitters and Receivers Operating in the Land Mobile and Fixed Services, but it all boils down to: “The radio is certified under the proper Radio Standards Specification for use in Canada and is licenced by Industry Canada on the specified frequencies.”

And the answer to the second question

Which of the following statements is NOT correct? A person may operate radio apparatus, authorized in the amateur service

D. on aeronautical, marine or land mobile frequencies 
You are certified to operate ONLY on the frequencies assigned to the Amateur Service. This means “on aeronautical, marine or land mobile frequencies” is incorrect.

So there it is. I’m not preaching but, as a Basic Amateur Radio course instructor,  simply passing along the existing regulations and policy to answer the question that come up in every class. These rules exist for a purpose. Do with it as you will but be aware that there is enforcement and you are subject to the penalties if you are caught.

~ John VE7TI

Thanks to Kasun Somaratne (ISED) for the review of this article to confirm it reflects current ISED policy and regulation.  






2020-02-20

LED Street Light Replacement

 

Will we soon have more RFI noise to deal with?


Our local electrical supplier, BC Hydro, says it may begin installing thousands of light emitting diode (LED) street lights across the province this summer.

The utility currently owns and maintains approximately 95,000 streetlights around the province, roughly 30 per cent of all streetlights in British Columbia. Most of the ones attached to BC Hydro's electricity poles are high pressure sodium (HPS) lights.

Hydro says: "LED lights are known to last longer, are brighter and render colours significantly better than HPS lights."

The transition to the energy-saving technology could lead to cost savings of 50 to 70 per cent for the smaller communities who rely on the utility's public lighting, according to the Union of B.C. Municipalities (UBCM).

As taxpayers we're certainly in favour of lower costs but, you have only to run a Google search to learn that, in other areas, Amateurs have expressed concern that these lights may contribute to an  increase in RF interference across the spectrum., specifically in the HF bands (below 30 MHz).

In some cases this is apparently due to inadequate shielding, poor quality, or lack of components to reduce noise, but it is generally agreed that the electronic power supplies in LED street lights can be the culprit.
Here are some of the story links:

CBC News 

ABC News Toledo, OH 

NBC Philadelphia

RAC, are you monitoring this?

________________________________

Shortly after this story appeared on our blog page, Keith Whitney VE7KW, RAC Director BC & Yukon, responded. It shows that RAC has taken notice:

I appreciate your concern, but would like to make a couple of points.

  • RAC monitors this through the RABC (Radio Advisory Board of Canada) EMC Committee.
  • The relevant regulation is ICES-005 Lighting Equipment last updated in December 2018 which sets limits on conducted (HF) and radiated (VHF) emissions. Note the LED limits are lower than the Gas Discharge (Sodium light) limits.
  • Section 4(3) of the Radio Communications Act states that

"No person shall manufacture, import, distribute, lease, offer for sale or sell any radio apparatus, interference-causing equipment or radio-sensitive equipment for which technical standards have been established under paragraph 6(1)(a), unless the apparatus or equipment complies with those standards."

It is to be assumed that a public utility would be compliant.

My personal experience indicates this is not a major problem. 

  • I follow the RSGB EMC reports and am not aware that approved LED lighting has been identified as a problem.
  • I do a lot of contesting from VE7SCC which uses LED lighting almost exclusively in the shack and monitors for noise with an SDR. The site (Riverview Hospital) changed over to LED street lights about 18 months ago with no noticeable noise increase.
  • I have just come from V3T (Belize) where the 80 through 15m noise levels were some of the lowest I have seen despite the entire resort using LED lighting as well as the Town we overlooked using LED street lamps. 

Nothing in the field of EMC is guaranteed and this will merit ongoing monitoring. I would encourage people with access to an SDR to take a wide band “reference noise spectrum” now for comparison later. It would be particularly useful if they turn off their house power to prove that the noise source(s) are external.

~ 73 Keith VE7KW
   RAC Director BC and Yukon

_______________________________________


March 11, 2020 - More Good News:


Here’s my experience with LED street lights. 

While working in my front yard last week, I noticed a contractor’s vehicle with lift crane parked in the street, while some work was being undertaken at the street lamp fixture.  When the contractor moved up to my QTH, I spoke with him and asked him what he was doing.  He was very friendly and advised that he was changing out the sodium mercury lamps for LEDs.  When I expressed my concern about this because I had been hearing stories of RFI from LEDs affecting HF reception, he asked me what I knew about it.  I told him briefly that I was no expert, but would welcome the opportunity to do some testing before and after turning the LEDs on.  He agreed readily.  I am very fortunate to be in a low RFI neighbourhood, with virtually S-0 noise on 20m and up, and only S5 noise on 40m, and I hope to keep it that way.

So I did 2 things: 
1) Turned my beam to point directly at the installation with the receiver on 20 m; and 
2) I brought out my 80 m “Tocko” foxhunt receiver.  

I was pleasantly surprised to find no change on the receiver noise level, and no response when pointing the foxhunt sense antenna at the lamp, either before or after the LEDs were turned on.  I will continue to monitor to see if anything changes but at least at this time, I find no reason to complain about the LEDs on our street.  Both the contractor and I went away happy.

~ JB VA7XB





2020-01-05

Back To Basics: Overmodulation


Overmodulation Leads To Interference!


Question B-001-019-003 (A) - From the Canadian Basic Question Bank:

An amateur station using radiotelephony must install a device for indicating or preventing:

a. overmodulation 
b. resonance 
c. antenna power
d. plate voltage

The  key word here is must. All four of the above can be measured in a transmitting station but not all are required to be indicated or prevented. Only one is harmful to the extent that it can seriously affect enjoyment of the airwaves and cause interference to other Amateurs.

Overmodulation is the condition that prevails in telecommunication when the level of the modulating signal [the intelligible portion holding information— such as spoken audio from a mic] exceeds the value necessary to produce 100% modulation of the carrier. A carrier signal is one with a steady waveform, constant height (amplitude) and frequency shown in the diagram as the envelope. Modulation is superimposed on the carrier at the transmitter and recovered at the receiver.

In layman's terms, the signal is going "off the scale". Overmodulation results in spurious emissions by the modulated carrier, and distortion of the recovered modulating signal. This means that the envelope of the output waveform is distorted. The usual way of ensuring you are not over-modulating is to use the ALC on your HF radio, which will tell you if the audio level is too high.  It is also good practice to monitor your own audio while transmitting to ensure you are not too close to the mic or speaking too loudly, as the presence of distortion will be a sure sign that your audio is driving the transmitter too hard.




In the diagrams above, A indicates an Amplitude Modulated (AM) signal that is modulated to a low percentage. When modulation is increased to 100%, as in B, we are on the threshold of overmodulation. When increased above 100% as in C, the signal is said to be overmodulated resulting in distortion and spurious emissions.

See a demonstration here on YouTube.

There are several questions on overmodulation in the question bank and one is always on the Basic exam.

Resonance is a desirable state when tuning to a specific frequency but does not have to be measured.  Antenna power and plate voltage may be measured but that is also not mandatory.

The correct answer to this question therefore is ‘A’ Overmodulation.


More information on overmodulation? 



~ John VE7TI




2019-12-15

Earth At Night!


A Free NASA eBook 

Earth at Night, NASA’s free new 200-page eBook in three formats, is now available online showing our planet in darkness as captured from space by Earth-observing satellites and astronauts on the International Space Station over the past 25 years.

Aside from the fascinating photos, there are explanations of Earth's weather as well as the Aurora and other phenomena of interest to the Amateur Radio Community




CQ CQ CQ

Five-band HF Linked Dipole [updated January 2025]

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