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The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. For a thorough treatment of the topic, take a look at the National Institute of Standards and Technology (NIST) publication: Guide for the Use of the International System of Units (SI). A shorter and easier-to-read document was written by Charles Poynton: Writing SI units and symbols.

But more to the point, here are three common mistakes I often see occurring in ham radio literature:

1. Using mHz instead of MHz to indicate megahertz (one million hertz). Upper case M indicates mega, while lower case m indicates milli (one thousandth). In ham radio usage, we rarely speak of frequencies in mHz.  Note that I wrote mega with a lower case m even though the abbreviation has a upper case M. The unit of hertz is with a lower case h but when abbreviated as Hz, it should be upper case.
2. Using KHz or khz instead of kHz to indicate kilohertz (one thousand hertz). Lower case k should be used for kilo but upper case H is used for hertz. It is common to see upper case K used to indicate 1024 in digital systems.
3. Using M instead of m to indicate the unit of meter. The proper way to refer to the wavelength of the 144 MHz ham band is 2m, not 2M. Similarly, the abbreviation for kilometers is km, not kM or KM. The abbreviation for centimeter is cm.

Units that are based on a person’s name use an upper case letter in the abbreviation. For example, ampere, volt, watt and hertz are abbreviated as A, V, W and Hz respectively. When the unit is spelled out, it is left lower case (go figure).

While the world does keep on turning when we make these mistakes, accuracy and understanding is improved by proper usage. Did I miss any other common SI errors?

73, Bob K0NR

The post Three Common Mistakes When Using Metric Units appeared first on The KØNR Radio Site.

When we teach the Technician License Class, we provide a simple explanation of Standing Wave Ratio (SWR) that emphasizes the concept of impedance matching. An SWR of 1:1 is a perfect match; anything higher is less than perfect.

SWR is an important amateur radio concept, one that is not that easy to explain so I am always on the lookout for training materials. HamRadioNow just republished this video of excellent standing wave demonstration by Bill Hays, AE4QL. Bill actually goes well beyond just standing waves and shows some antenna and transmission line theory as well.

If you just want to learn about standing waves and basic antenna radiation, view the first 35 minutes. After that, it starts to get a little deep.

Grab a cup of your favorite beverage, settle in and get ready to learn from this video.

73, Bob K0NR

The post Explaining Standing Waves appeared first on The KØNR Radio Site.

I am often disappointed by the crummy microphone hanger clips supplied with mobile ham transceivers. Typically, they are cheap metal clips with sharp edges waiting to impale your hand, that look like this:

I recently came across these microphone clips that are awesome! Available from Amazon for $7.49.

73, Bob K0NR

The post World’s Best Microphone Hanger appeared first on The KØNR Radio Site.

Last weekend, I had a fun time working the CQ WPX contest on SSB. I’ve always liked the format of the contest with the callsign prefix as the score multiplier (e.g., K1, K2, W1, W2, VE1, VE2 are all multipliers). Its like every new contact is a multiplier. This contest attracts plenty of DX but unlike some DX contests, everyone works everyone.

Consistent with the contest, the CQ WPX Awards Program issues operating awards based on callsign prefixes. The initial mixed mode (CW, SSB, digital) award requires confirmed contacts with 400 different prefixes. Back in the 20th century, I kept track of my confirmed contacts for WPX but lost interest along the way. I am sure I’ve worked more than 400 prefixes but the challenge was getting them all confirmed. More recently, the ARRL Logbook of the World (LoTW) added support for the CQ WPX Awards, so I started paying attention again, watching my CQ WPX total grow. I am not a big awards chaser but I have found value in using them as a specific goal to motivate me to get on the air.

Right before the CQ WPX contest, I had 380 prefixes confirmed via LoTW, so I figured that if I worked a few new ones during the contest, I could punch through 400 without too much trouble. I used my signature HF slacker approach at the cabin, using the Yaesu FT-950 to push 100 watts of RF power to wire antennas in the trees. For 40m, 20m and 15m, I used a trap-dipole antenna and for 10m I used a newly built ladder-line j-pole mounted vertically.

On Saturday, the propagation on the 10m band was smokin’ hot, strong signals from all continents. The 10m j-pole performed well. It was an absolute blast to easily work into Africa, Europe, South America, Australia, New Zealand and Asia.  The 15m and 20m bands were also very productive. My approach was to tune around, looking for new prefixes to add to my confirmed total. Propagation was not as good on Sunday but still respectable but I only operated a few hours.

After the contest, I submitted my log to the contest web site and loaded my contacts into LoTW (188 QSOs and 157 prefixes). Immediately, I received two new confirmed prefixes. Over the next few hours, I checked back to watch my CQ WPX confirmed total climb on LoTW. It did not take long before it passed through 400 (and the total is still climbing). I will admit that I really liked the instant gratification of seeing my QSOs immediately confirmed.

That’s when it hit me: I am done with paper QSL cards. The amount of time and effort it takes to get 400 paper cards in my hand is just not worth it. It is soooooo 20th century.

Disclaimer: Actually, I still enjoy and use paper QSL cards…they are now just a secondary activity for me.

The post CQ WPX, LoTW and the End of QSL Cards appeared first on The KØNR Radio Site.

My site has been down for a few days due to a “security problem” that I encountered. it seems that some malware showed up on the server and my host disabled the site. It took a bit of ftp’ing to get the offending files removed but we are back on the air.

I can’t say for certain how the bad guys got into the site but it would appear they were specifically targeting sites using WordPress. I was already running a security plugin for WordPress but since the attack I’ve tightened up the parameters considerably. If I inadvertently locked you out, my apologies.

It is interested to watch how many attacks are reported by the security plugin, mostly from locations outside of the US. If you are using WordPress and don’t have a security plugin installed, I highly recommend installing one and locking things down tight.

73, Bob K0NR

The post WordPress Security appeared first on The KØNR Radio Site.

I’ve written before about the flexibility of Field Day and the need to season to taste to make it your own. I have always thought that one of the great things about Field Day is that it can be tuned to whatever interests you or your club. It can be a serious radio contest (well, almost); it can be an emcomm drill. It can be a radio campout; it can be a foodfest, it can be a beer-drinking party. Insert your idea here.

This year, our local club, the Tri-Lakes Monument Radio Association is going to try a new approach that we call Tech Field Day. We previously have held a one-day educational event that we call Tech Day, that featured a series of presentations and hands-on demonstrations. The main theme of Tech Day was to help the Technician level hams gain more knowledge and help them move on up to General class operating.

We are taking the basic idea of Tech Day and combining with a shortened one-day version of Field Day. So on Saturday June 27th, we’ll offer a series of educational presentations along with some classic Field Day radio operating. The operating emphasis will be on giving newer hams a chance to get on the air, probably on both HF and VHF. (Our plans are still coming together.) We will also promote the theme of emergency communications, operating off a emergency power source, etc.

There are a number of things that we are intentionally leaving out. We won’t operate the entire 24 hour period…in fact, we’ll probably just be on the air Saturday afternoon. We won’t worry about making a lot of contacts or running up the score. Our stations will be relatively simple (no towers, no amplifiers).

So that’s our idea of a fun Field Day. What are you planning to do?

73, Bob K0NR

The post ARRL Field Day: Season To Taste appeared first on The KØNR Radio Site.

On the topic of operating events for Summits On The Air (SOTA) activations, Guy N7UN suggested focusing on six major events for 2015. Most of these are VHF-oriented but HF activity can also occur on these days.

• Jan 24-26: ARRL Jan VHF Contest + NA SOTA Winter Activity Weekend
  (oops, I guess we already missed that one)
• Apr 18-19: North America SOTA Spring Activity Weekend
• Jun 13-15: ARRL June VHF Contest + NA SOTA Summer Activity Weekend
• Jul 18-19: CQ WW VHF Contest + optional for SOTA
• Aug 1-2:  Colorado 14er Event + NA SOTA Rocky Mtn Rendezvous + W7 SOTA Activity Weekend + ARRL UHF Contest
• Sept 12-14: ARRL Sept VHF Contest + NA SOTA Fall Activity Weekend

Of course, any day is a good day for SOTA activity. I also think six weekends are a great way to focus our operating activity and create S2S (summit to summit) radio contacts. The August 1-2 weekend looks to be the alignment of the planets with four events happening on that weekend. Early August usually offers excellent conditions for hiking the highest peaks in Colorado, so come on out and play.

For more info on VHF SOTA, see How To Do a VHF SOTA Activation.

Get off the couch, put on your hiking boots, grab your backpack, grab your radio but most important: get on the air!

73, Bob K0NR

The post 2015 SOTA VHF Activity Days appeared first on The KØNR Radio Site.