Metrology is the science of measurement. The International System of Units, also called SI, consists of standards which result from meticulous negotiations among international metrologists. The purpose of the International System of Units is to communicate quantitative information clearly across languages and cultures.

This check-list summarizes the most important elements of those standards. For more detail, you may wish to download the PDF document NIST Special Publication 811, 2008 Edition, by Ambler Thompson and Barry N. Taylor: Guide for the Use of the International System of Units (SI). A relevant Wikipedia article is also useful. The Bureau International des Poids et Mesures (BIPM) also publishes useful information in French and English.

Here is a simple checklist to help you use SI correctly:

• Except for degrees Celsius, SI units like microfarads and millivolts are always written in lower case and are almost always pluralized. (See below for exceptions to the usual pluralizing standard.) Because of their phonetics, some SI units like megahertz are written the same in singular and plural.
• SI symbols like kHz and µV are written in lower case or UPPER CASE Latin or Greek characters or in combinations. SI symbols are the most universal parts of SI, and are never pluralized.
• Be careful with UPPER and lower case: UPPER CASE M is the SI symbol for the mega- prefix; lower case m is the symbol for meters or metres as well as the milli- prefix; lower case Greek µ is the symbol for the micro- prefix. With the advent of computer word processors, using u as a substitute for µ is an obsolete practice. Lower-case italic m represents mass. UPPER CASE K is the SI symbol for thermodynamic temperature in kelvins and lower case k is the SI symbol for the kilo- prefix. One should not be used in place of the other.
• With three exceptions, SI values and SI symbols are always separated with spaces and never with anything else. Those exceptions are the symbols for angular degrees, minutes and seconds. The 100 m dash and a 10 A fuse are correct expressions. It is also correct to write: The summit of 6190 m Denali in Alaska is located at 63°04’08.7”N 151°00’25.5”W.
• When used in an adjectival sense in English, SI values and spelled-out SI units are separated with hyphens and are not pluralized: the 100-meter dash and a 10-ampere fuse are correct expressions. When accompanying values of exactly 1 or -1, SI units are not pluralized.
• Abbreviations do not exist in SI. Instead of abbreviations like amps and secs, use SI symbols like A and s or fully spelled-out SI units like amperes and seconds. Note that the symbol for the time unit minutes is min, which is not an abbreviation, and therefore it is not pluralized and it is not followed by a period.
• Never use SI prefixes in isolation. Avoid using expressions like 10 kilos of flour or 5 K run; use 10 kilograms of flour or 10 kg of flour or 5-kilometer run or 5 km run instead.
• Except at the end of a sentence, an SI symbol is never followed by a dot or period. To avoid confusion, try not to end sentences with SI symbols if possible.
• Fractional SI values are decimalized and preceded with a zero or other integers: 0.529 µm or 0.529 micrometers.
  
• Since either a dot or a comma may be used in SI as a decimal marker, the comma should never be employed as a separator for long integers or long fractions. Segment values with five digits or more utilizing spaces or half spaces. Using a word-processor, create a half space by changing the font size of a regular space to about half the value of the rest of the text. The speed of light, whose symbol is italic c [see footnote 1] is 299 792 458 m/s or 299 792.458 km/s or 299.792 458 Mm/s when written in SI. The speed of light may also be written as 299 792,458 km/s or 299,792 458 Mm/s without any change in meaning.
• SI symbols should never include suffixes. Instead of 115 VAC, write AC 115 V or 115 volts alternating current in correct SI.
• Avoid orphaned values. Instead of 9-15 volts or 9-15 V, write 9 volts to 15 volts or 9 V to 15 V in SI.
• SI dates are rendered with numerals in descending order. The origin of what became the International System of Units began in Paris on 1875-05-20 with an international treaty. SI time is reckoned in the 24-hour system, often with the time zone specified: 1445 UTC or 0657 EST.
• SI standards have changed over time. Avoid obsolete expressions. The old degrees kelvin should be kelvins (symbol K). The obsolete mhos should be siemens (symbol S), which is followed by an s in both singular and plural unit forms. The old cubic centimeters unit is still commonly used in medicine, but milliliters or millilitres (symbol mL) [see footnote 2] should be used instead. The obsolete microns unit is now micrometers or micrometres (symbol µm). Multiple prefixes like µµ or micromicro- are no longer allowed in SI. Use the pico- unit prefix or the p- symbol prefix instead. An acceptable SI substitute for the obsolete parts per million (ppm), parts per billion (ppb) has not yet been developed. If international metrologists eventually agree on an SI unit and symbol for nominal-scale entities, then fractional prefixes combined with that unit or symbol will do a good job of carrying out that proportional function.

¹ Quantities to be measured and their symbols are written in italics: current and inductance are examples. Think of e=mc² and I=E/R.

² Although lower-case l may be used as a symbol for liters of litres, that character may be mistaken for the numeral 1, so most writers prefer the upper case L for that symbol.

Stories you’ll find in our December, 2017 issue:

The Beginning of Sports Broadcasting and Radio’s First Sportscasters
By John Schneider W9FGH

Despite its great advantage of immediacy, radio did not become a dominant news medium until the start of World War II. Throughout the 1920s and 30s, newspaper owners were successful in keeping the press news agencies from selling their services to broadcasters, and radio remained a secondary source for news. But, the reporting of sporting events was another story. Sports and radio were a made for each other like ball in glove, and the country’s broadcasters were quick to capitalize on that advantage from the industry’s earliest years. John charts the rise of sports on American radio.

The Brief and Colorful History of Private US Shortwave Giants
By Richard Fisher KI6SN

In AM radio’s ever-evolving place in broadcasting history, there was a time when U.S.-based AM stations took to the shortwaves, either as standalone broadcasters or as an extension of their AM broadcast band partners. While their popularity soared in the 1970s and ’80s, many have vanished as others carry on.

Powerhouse American shortwave stations, including WRNO, WNYW, WBCQ, KUSW and KNLS, profiled here, had (or have) a substantial worldwide following on the high frequencies. In this 21st Century, many are gone or have changed formats from, say, popular music and news to Christian oratory or other programming. Richard looks back at some of these stations.

Meter Matters: Modern vs. Vintage Meters in Radio Restoration
By Rich Post KB8TAD

What happens when you calibrate that Hickok tube tester at those 150 and 130 voltage specifications or the bias voltages ignoring the line that calls for that ancient 1000 ohms-per-volt meter and just use a digital meter like my very-expensive-when-new Fluke 87 or that bargain Harbor Freight CenTech P37772 instead? Well, the calibration for your Hickok will be off. Those modern meters have a specified sensitivity of 10 megohms. Rich warns that not all that will be off as he examines the use of various meters in vintage radio technology.

TSM Reviews: Yaesu FT-70DR
By Cory GB Sickles WA3UVV

When an item is released that offers breakthrough technology or more features and benefits than previous models, the price is typically higher. When the price of an item is higher, many tend to hesitate in buying it. Further, economy of scale eventually kicks in, allowing a manufacturer to lower prices a bit, or produce and release additional models with many of the features of the premier version. The FT-70DR (FT-70DE in Europe) is the latest dual-band portable and takes its place in the market with a substantial entry-level feature set, as well as being the most inexpensive portable produced by the “traditional” amateur radio manufacturers—all for a street price of just under $200.

Scanning America
By Dan Veeneman
Interoperability Update; Orange County, Virginia

Federal Wavelengths
By Chris Parris
Urban Area Security Initiative (UASI)

Milcom
By Larry Van Horn N5FPW
Introduction to Military Monitoring: VHF Low Band—the Forgotten Military Band

Utility Planet
By Hugh Stegman NV6H
North Korea Resumes HF “Numbers” Broadcasts

Shortwave Utility Logs
Compiled by Hugh Stegman and Mike Chace-Ortiz

VHF and Above
By Joe Lynch N6CL
The Geminids and Ursids Meteor Showers

Digitally Speaking
Cory GB Sickles WA3UVV
System Fusion II

Amateur Radio Insights
By Kirk Kleinschmidt NT0Z
A Vertical in Hospice!

Radio 101
By Ken Reitz KS4ZR
AM Band DXing Circa 1964 and Now

Radio Propagation
By Tomas Hood NW7US
Heliophysics Research Reveals More About Substorm Mysteries

World of Shortwave Listening
By Rob Wagner VK3BVW
Making Shortwave Audio More Listenable

The Shortwave Listener
By Fred Waterer
2017 SW Review and New Programming

Amateur Radio Satellites
By Keith Baker KB1SF/VA3KSF
A Wealth of New Amateur Radio Satellites

The Longwave Zone
By Kevin O’Hern Carey WB2QMY
Primetime Arrives!

Adventures is Radio Restoration
By Rich Post KB8TAD
What’s an “Acoustic Labyrinth?” The Stromberg Carlson 240M

The Spectrum Monitor is available in PDF format which can be read on any desktop, laptop, iPad®, Kindle® Fire, or other device capable of opening a PDF file. Annual subscription is $24. Individual monthly issues are available for $3 each.

Some HF digital modes were designed for long-distance (DX) radio-wave propagation via the ionosphere. One such keyboard-to-keyboard digital mode is Olivia.

Friday evening, 8 December 2017, at 0200 UTC {9-DEC}, Larry, N7ZDR, called an Olivia-mode 80-Meter digital roundtable net. The following video is a snapshot of about nine minutes of on-air net operations as received at my location in Omaha, Nebraska.  My antenna is a wire run from an SEA marine autotuner mounted under the three-story-high roof’s eaves.  I live in a high-RF environment within two miles of eight high-powered broadcast antenna facilities–TV, FM, AM–as well as business and public-service transmitters.   All that RF desensitizes my receiver.  The noise floor is also affected by industrial-level man-made RF noise.

No, Olivia is not lightening-fast keyboard-to-keyboard chatting, but it can get the job done. This following video shows some real-world operation in which the very weakest signals did not decode well. However, even with the 80-Meter band (center frequency is 3585 kHz) really difficult to work with, it did well in terms of what was available for the Ham Radio Deluxe DM780 software to decode.

Example QSO in Olivia Video:

[embedyt]https://www.youtube.com/watch?v=G7TlGEuStx4[/embedyt]

In 2005, SP9VRC, Pawel Jalocha, released to the world a mode that he developed starting in 2003 to overcome difficult radio signal propagation conditions on the shortwave (high-frequency, or HF) bands. By difficult, we are talking significant phase distortions and low signal-to-noise ratios (SNR) plus multipath propagation effects. The Olivia-modulated radio signals are decoded even when it is ten to fourteen dB below the noise floor. That means that Olivia is decoded when the amplitude of the noise is slightly over three times that of the digital signal!

Olivia decodes well under other conditions that are a complex mix of atmospheric noise, signal fading (QSB), interference (QRM), polar flutter caused by a radio signal traversing a polar path. Olivia is even capable when the signal is affected by auroral conditions (including the Sporadic-E Auroral Mode, where signals are refracted off of the highly-energized E-region in which the Aurora is active).

Currently, the only other digital modes that match or exceed Olivia in their sensitivity are some of the modes designed by Joe Taylor as implemented in the WSJT programs, including FT8, JT65A, and JT65-HF–each of which are certainly limited in usage and definitely not able to provide true conversation capabilities.  Olivia is useful for emergency communications, unlike JT65A or the newly popular FT8. One other mode is better than Olivia for keyboard-to-keyboard comms under difficult conditions: MT63. Yet, Olivia is a good compromise that delivers a lot.

Join us — not just on the HF waterfall, but by joining our email-based group at:

–> https://Groups.Io/g/olivia

or, on Facebook at:

–> https://www.facebook.com/groups/olivia.hf

Thanks for spreading the Olivia love!  See you on the waterfall.

Addendum: 

Current CENTER Frequencies With 8/250 (eight tones, 250-Hz bandwidth): 

1.8269 MHz
3.5729 MHz
7.0729 MHz
10.1429 MHz
14.0729 MHz
18.1029 MHz
21.0729 MHz
24.9229 MHz
28.1229 MHz

See the pattern?

The current suggested CENTER frequency with 16/1000 or 32/1000 on 20 meters is 14.1059.

(Why the xxx…9 frequencies? Experts say that ending in a non-zero odd number is easier to remember!)

Q: What’s a ‘CENTER’ Frequency? Is That Where I Set My Radio’s Dial?

For those new to waterfalls: the CENTER frequency is the CENTER of the cursor shown by common software. The cursor is what you use to set the transceiver’s frequency on the waterfall. If your software’s waterfall shows the frequency, then you simply place the cursor so that its center is right on the center frequency listed, above. If your software is set to show OFFSET, then you might, for example, set your radio’s dial frequency to 14.0714, and place the center of your waterfall cursor to 1500 (1500 Hz). That would translate to the 14.0729 CENTER frequency.

The standard Olivia formats (shown as the number of tones/bandwidth in Hz) are 8/250, 8/500, 16/500, 8/1000, 16/1000, and 32/1000. Some even use 16/2000 for series emergency communication. The most commonly-used formats are 16/500, 8/500, and 8/250. However, the 32/1000 and 16/1000 configurations are popular in some areas of the world (Europe) and on certain bands.

These different choices in bandwidth and tone settings can cause some confusion and problems–so many formats and so many other digital modes can make it difficult to figure out which mode you are seeing and hearing. After getting used to the sound and look of Olivia in the waterfall, though, it becomes easier to identify the format when you encounter it. To aid in your detection of what mode is being used, there is a feature of many digital-mode software implementation suites: the RSID. The next video, below, is a demonstration on how to set the Reed-Solomon Identification (RSID) feature in Ham Radio Deluxe’s Digital Master 780 module (HRD DM780).

I encourage ALL operators, using any digital mode such as Olivia, to TURN ON the RSID feature as shown in this example. In Fldigi, the RSID is the TXID and RXID; make sure to Check (turn on) each, the TXID and RXID.

Please, make sure you are using the RSID (Reed Solomon Identification – RSID or TXID, RXID) option in your software. RSID transmits a short burst at the start of your transmission which identifies the mode you are using. When it does that, those amateur radio operators also using RSID while listening will be alerted by their software that you are transmitting in the specific mode (Olivia, hopefully), the settings (like 8/250), and where on the waterfall your transmission is located. This might be a popup window and/or text on the receive text panel. When the operator clicks on that, the software moves the waterfall cursor right on top of the signal and changes the mode in the software. This will help you make more contacts!

RSID Setting:

[embedyt]https://www.youtube.com/watch?v=lBIacwD9nNM[/embedyt]

+ NOTE 1: The MixW software doesn’t have RSID features. Request it!

+ NOTE 2: A problem exists in the current paid version of HRD’s DM780: the DM780 RSID popup box that lists the frequency, mode, and configuration with a link to click, does not work. HRD support is aware of the problem. You can still use the textual version that shows up in the DECODED TEXT window, a feature of RSID that you can select in the HRD DM780 program settings. This setting ensures that the detected RSID details appear in the receive text area. If you click the RSID link that comes across the text area, DM780 will tune to the reported signal, and change to the correct settings.

Voluntary Olivia Channelization 

Since Olivia signals can be decoded even when received signals are extremely weak, (signal to noise ratio of -14db), signals strong enough to be decoded are sometimes below the noise floor and therefore impossible to search for manually. As a result, amateur radio operators have voluntarily decided upon channelization for this mode. This channelization allows even imperceptibly weak signals to be properly tuned for reception and decoding. By common convention amateur stations initiate contacts utilizing 8/250, 16/500, or 32/1000 configuration of the Olivia mode. After negotiating the initial exchange, sometimes one of the operators will suggest switching to other configurations to continue the conversation at more reliable settings, or faster when conditions allow. The following table lists the common center frequencies used in the amateur radio bands.

Olivia (CENTER) Frequencies (kHz) for Calling, Initiating QSOs

It is often best to get on standard calling frequencies with this mode because you can miss a lot of weak signals if you don’t. However, with Olivia activity on the rise AND all the other modes vying for space, a good deal of the time you can operate wherever you can find a clear spot–as close as you can to a standard calling frequency.

Note: some websites publish frequencies in this band, that are right on top of weak-signal JT65, JT9, and FT8 segments. DO NOT QRM weak-signal QSOs!

We (active Olivia community members) suggest 8/250 as the starting settings when calling CQ on the USB frequencies designated as ‘Calling Frequencies.’ A Calling Frequency is a center frequency on which you initially call, ‘CQ CQ CQ. . .’ and then, with the agreement of the answering operator, move to a new nearby frequency, changing the number of tones and bandwidth at your discretion. Even though 8/250 is slow, the CQ call is short. But, it is narrow, to allow room for other QSOs nearby. It is also one of the best possible Olivia configurations for weak-signal decoding.

– End of Addendum –

73

For those of you who have dived into the crowded but fun pool of FT8 operation or one of the other Joe Taylor modes (such as JT65 or JT9) and are excited now about digital modes, here’s something you might enjoy, too.  Unlike those modes that allow you to make quick work of getting DX stations into your logbook, simply by exchanging callsigns, a signal report, and a grid square, there are other modes that offer keyboard-to-keyboard conversational QSO opportunities.

One such mode is known as Olivia and this mode offers keyboard-to-keyboard chatting for when you want to relax, and maybe make a friend.  Ham radio is the oldest electronic social networking infrastructure.

In 2005, SP9VRC, Pawel Jalocha, released to the world a mode that he developed starting in 2003 to overcome difficult radio signal propagation conditions on the shortwave (high-frequency, or HF) bands. By difficult, we are talking significant phase distortions and low signal-to-noise ratios (SNR) plus multipath propagation effects. The Olivia-modulated radio signals are decoded even when it is ten to fourteen dB below the noise floor.  That means that Olivia is decoded when the amplitude of the noise is slightly over three times that of the digital signal!

Olivia decodes well under other conditions that are a complex mix of atmospheric noise, signal fading (QSB), interference (QRM), polar flutter caused by a radio signal traversing a polar path. Olivia is even capable when the signal is affected by auroral conditions (including the Sporadic-E Auroral Mode, where signals are refracted off of the highly-energized E-region in which the Aurora is active).

Currently, the only other digital modes that match or exceed Olivia in their sensitivity are some of the modes designed by Joe Taylor as implemented in the WSJT programs, including FT8, JT65A, and JT65-HF–each of which are certainly limited in usage and definitely not able to provide true conversation capabilities.  Olivia is useful for emergency communications, unlike JT65A or the newly popular FT8.

Here is a demonstration of a two-way transmission using the Olivia digital mode on shortwave. I am in QSO (conversation) with KA5TPJ. There are two other Olivia QSOs just below our frequency. Just above us is a lot of FT8 activity. Below the two other Olivia QSOs are PSK31 QSOs. The band is active. Olivia is not dead!

The standard Olivia formats (shown as the number of tones/bandwidth in Hz) are 8/250, 8/500, 16/500, 8/1000, 16/1000, and 32/1000. Some even use 16/2000 for series emergency communication. The most commonly-used formats are 16/500, 8/500, and 8/250.  However, the  32/1000 and 16/1000 are popular in some areas of the world and on certain bands.

This can cause some confusion and problems with so many formats and so many other digital modes. After getting used to the sound and look of Olivia in the waterfall, though, it becomes easier to identify the format when you encounter it.  To aid in your detection of what mode is being used, there is a feature of many digital-mode software implementation suites: the RSID. The video, below, is a demonstration on how to set the Reed-Solomon Identification (RSID) feature in Ham Radio Deluxe’s Digital Master 780 module (HRD DM780).

I encourage ALL operators in any digital mode such as Olivia, set the RSID feature on as shown in this example.  In Fldigi, the RSID is the TXID and RXID (I believe).

Please make sure you are using the RSID (Reed Solomon Identification – RSID or TXID, RXID) option in your software.  RSID transmits a short burst at the start of your transmission which identifies the mode you are using.  When it does that, those amateur radio operators also using RSID while listening will be alerted by their software that you are transmitting in the specific mode (Olivia, hopefully), the settings (like 8/250), and where on the waterfall your transmission is located.  This might be a popup window and/or text on the receive text panel. When the operator clicks on that, the software moves the waterfall cursor right on top of the signal and changes the mode in the software. This will help you make more contacts!

+ NOTE 1:  MixW doesn’t have RSID features. Request it!

+ NOTE 2: A problem exists in the current paid version of HRD’s DM780: the DM780 RSID popup box to click does not work. HRD support is aware of the problem. You can still use the textual version that you can select in the settings so that it appears in the receive text areas. If you click the RSID link that comes across the text area, DM780 will tune to the reported signal, and change to the correct settings.

+ NOTE 3: some websites publish frequencies that are right on top of weak-signal FT8, JT65 and JT9 segments. Even if that is a matter of contention, follow the regulations and be kind: DO NOT QRM weak-signal QSOs! AGAIN: make sure that your signal does not cross into other sub-bands where weak-signal modes are active. For instance, do not have any part of your signal at x.074 or higher, as this is the sub-band for FT8, JT65A, and JT9.

Quick Reference: we in the active Olivia group suggest 8/250 as the starting settings when calling CQ on the USB dial frequency of 14.072 MHz with an offset of 700 Hz, on 20m–that translates to a CENTER frequency of 14.0729 MHz. On 40m, 7.072 MHz on the dial with an offset of 700 Hz (and again 8/250) which translates to a center frequency of 7.0729 MHz.

An example of the calling frequency on 20 meters with a center frequency of 14.0729 MHz, 8 tones, and a bandwidth of 250 Hz.

Also, do not quickly switch to other modes without calling CQ for at least a five-minute window. It is really horrid when people call CQ and change settings, modes, bandwidths, tones, every time they call CQ during the same session!

There are several key resources that we in the Olivia community are developing, to make it easier for you to enter into the great world of Olivia.  One is an active support e-mail group to which you can subscribe at https://groups.io/g/Olivia — a group containing topical areas of interest which can be filtered so that you are not flooded by email containing topics of which you are not interested.  It has a files section, as well, in which we will add helpful how-to instructions and so on.

Another resource is our Facebook group, at https://www.Facebook.com/groups/olivia.hf — also with a files area containing help files.  This group is a great resource for getting help from like-minded Olivia digital mode enthusiasts.

Some more eavesdropping on an Olivia QSO:

And, two more:

One last note: Olivia is NOT a weak-signal mode. There are no points won by barely making a contact. In the USA FCC regulations, you are directed to use only the power necessary to make the QSO.  Typically, with poor propagation, using Olivia with an output power of 100w is the minimum to establish a reliable circuit. You just cannot go beyond your rig’s duty cycle (don’t burn out the finals in your radio!). You also must be sure that you do not overdrive the audio chain into your radio. Be sure that you do not have RF coming back into your audio chain. Yes, 100 watts is acceptable. Don’t let anyone convince you otherwise. After all, think about RTTY.

Welcome to Olivia!  See you on the waterfall.

73 de NW7US