USB Cable Experiment

Given all of the electronic gadgets in my life, I end up carrying quite a few cables and power adapters around with me. Somehow these things always end up in a tangled mess inside by backpack/computer bag. It often takes me days to untangle them after a trip. Although annoying, I didn’t really give it too much thought as it just seemed part of having all these gadgets.

This weekend, I decided to apply the scientific method to aid in my understanding of how these cords get tangled. I did a controlled experiment using two USB cables carefully laid on a flat surface a few centimeters apart:

I left the cables in a locked room, with windows closed so that wind or other outside forces could influence the outcome. The above photograph was recorded at 9 PM on Day 1.

The next morning, I returned to the room and verified that the door was still locked and that nothing had been disturbed. To my surprise, I found the two cables in this condition, recorded by photograph at 9 AM on Day 2:

Apparently, the cables are able to move on their own and create a tangled mess without human intervention. There must be some physical force present that causes this movement, perhaps the triboelectric effect? I will need to repeat this experiment, perhaps with a video camera capturing any movement.

Has anyone else produced similar results?

– 73, Bob K0NR

This Spewed Out of the Internet #15

It’s time to do one of those miscellaneous collections of drivel that spews forth from the interwebnet pipes. Some of this might even be important!

Some upcoming events: ARRL June VHF QSO Party and the Colorado FM Sprint, on the weekend of June 12th. The FM Sprint runs concurrently with the ARRL contest but only on Sunday afternoon. This is a good chance to get on the air with very basic equipment and have some fun.

The ARRL Field Day is coming up on June 26th and 27th. This is arguably the biggest on-the-air amateur radio event in North America.

I was playing around with setting up an SMS text messaging system for callsign lookup. The idea is that you send a text message (containing an amateur call sign) with your mobile phone and get the FCC or QRZ info back. In the meantime, I found that this problem has been solved by Callsign By Text. Very nice, check it out.

Female radio amateurs should check out Chick Factor International. It looks like a fun group.

I picked up a DV Access Point (DVAP) for D-STAR. This is a neat little device that provides flea-powered D-STAR access on 2 Meters by plugging it into a PC with internet connection. The South Yorkshire Repeater Group has a good description of the product. So far, this thing works really well.

By the way, the South Yorkshire group has a really good web site…interesting and timely information. Although they are in the UK, I find it relevant to US ham radio activity, too.

The Technician Class License question pool will be updated as of July 1, 2010. Our next Tech Class in Monument will be in October, so we’ll be updating the classroom material before teaching that class. It is clear that more technical content is being added to the question pool, which I think is a good thing. See KB6NU’s posting on the topic.

From The Complete Waste of Time Department, the FCC once again dismissed a petition from K9STH to change the amateur radio station identification requirements. Look, the FCC doesn’t see a problem here (and neither do I) so save yourself the trouble.

The FCC is seeking comments on the proposed new rules concerning emergency communications.  I took the time to file a short comment, basically saying that the FCC is on the right track but they should remove the reference to “government-sponsored drills”. Any legitimate emergency communications drill should be included, regardless of who sponsors it. The ARRL made similar but more detailed comments.

– 73, Bob K0NR

Update on the IC-9100

Ham radio VHF enthusiasts have been patiently waiting for the ICOM IC-9100. This HF/VHF/UHF/Satellites covers most or all of the popular amateur bands. Recently, ICOM has posted the specs and brochure on its web site.

The rig has dual receivers that allow monitoring two bands at once and it is set up for full-duplex on satellites. The built-in antenna tuner covers HF and 50 MHz. Operating on 1.2 GHz requires an optional module.

There is an optional DV (D-STAR) option that works on 10M, 6M, 2M, 70 cm and 1.2 GHz. This is the first combo HF+VHF+UHF rig that has DV available.

The 100 Watt output power all the way up to 50 MHz and 144 MHz is a real plus and 75 Watts on 430 MHz is not bad either. The 1.2 GHz option would be nice, too. This would be a great radio for portable VHF contesting. Oh, and I guess it works HF, too. 🙂

So everyone was expecting a big ICOM announcement at the Dayton Hamvention. Based on the reports I heard via the D-STAR system in Dayton, one unit was shown “under glass” so attendees could look but not touch. Also, a number of people have reported that the ICOM booth staff are saying that the 9100 will be available later this year (fall timeframe?) at a price of ~$US 4000.

Ouch. Most observers see that as a bit too expensive. I’ll withhold judgment until it is really in stock at a dealer with a real price.

–   73, Bob K0NR

SWR and Return Loss – There’s an Ap for That

For the RF/microwave enthusiasts out there, you may recall the old HP Reflectometer Calculator that does conversions between SWR, Return Loss and calculated mismatch uncertainty.

Well, fast forward to the 21st century and this same functionality can be found in an iPhone ap. Agilent Technologies has a free ap available on iTunes that does these calculations and some other things like decibel conversions.

Check it out at here or just search for microwave calculator on iTunes.

– 73, Bob K0NR

Announcing the Colorado FM Sprint

The Colorado FM Sprint is a short and simple VHF contest that runs in parallel with the ARRL June VHF QSO Party. Basically, it’s a chance to have some fun on the VHF bands for not-so-serious contesters.

Sponsored by:  Colorado ARES and the Colorado VHF Group (KØYB)
Direct any questions to

This contest is held concurrently with the ARRL June VHF QSO Party, with compatible rules and operating procedures. The purpose of this contest is to:

·        Promote the use of FM VHF/UHF simplex

·        Provide an opportunity for radio amateurs to test the limits of their stations using FM VHF/UHF and to experiment with ways to improve their stations

·        Practice deploying portable and mobile operation as a means of identifying effective locations for temporary relay stations

·        Provide a simple and enjoyable radio contest experience (“Have fun!”)


Sunday, June 13, 2010; 1200 to 1600 Mountain Time (1800 to 2200 UTC)


To work as many stations as possible using FM simplex on the 146 MHz, 222 MHz and 440 MHz bands in as many different VHF grids as possible.


Operate on FM simplex frequencies consistent with the Colorado Council of Amateur Radio Clubs (CCARC) band plans with special emphasis on using ARES designated frequencies.

(Consistent with the ARRL Rules, 146.52 MHz is not allowed to be used in the contest.)

Suggested Frequencies:

2 Meters: 146.58, 146.55, 146.49 MHz

222 MHz: 223.5 MHz

440 MHz: 446.0, 446.025, 446.100 MHz

Do not operate on repeater frequencies or 146.52 MHz, the National Simplex Calling Frequency.

Remember to be a considerate operator and share the frequency with other operators.

Contest Exchange

To complete a contest QSO, you and the other station must copy each other’s callsign and 4-digit Grid Locator. You may optionally exchange Name and ARES District.

Note: These are an abbreviated set of rules…the complete rules and FAQ are at

73, Bob K0NR

Bob’s Rules for A Fun Radio Club

The other night, I attended one of those unfortunate, but all too common dysfunctional radio club meetings. (The name of the club will remain confidential.) You have probably been to one of these sessions where the leadership of the club is frustrated because they feel like only a few of the members are doing all of the work. The other folks may come to the meeting but are reluctant to sign up for anything.

The topic of discussion happened to be Field Day. The plans in place were not coming together and the leadership was getting frustrated. My point of view was quite simple: if no one wants to help with Field Day, then let’s not have Field Day. Heck, this radio club stuff is supposed to be fun. If we are trying to make activities happen that people don’t want to support, then we are probably off in the weeds.

This caused some of the folks to raise their hands and say “yes, of course we should do Field Day and this is how I can help.” So things are probably on track for now. Maybe.

This situation is not unique…most clubs (of any kind) have the core group that does most of the work and the secondary group that does much less. Sometimes the players change depending on changing circumstances such as family and work obligations, but the structure tends to remain.

I came up with a couple of simple rules to avoid frustration in this kind of situation:

  1. Don’t volunteer to do anything that you aren’t personally motivated to take on. If you aren’t doing it because you truly want do, then you’ll end up resentful if other folks aren’t “doing their fair share.” It’s a volunteer organization, after all.
  2. Don’t expect others to sign up for volunteer work because you think it is important. Their priorities might be different and it is totally their decision (see Rule 1).
  3. Lead, Follow or Get Out of the Way. If you want to make something happen, get out in front and lead. If you don’t want to lead, then follow. Commit your own time to making it happen (see Rule #2). If you can’t lead or follow, then stay out of the way.

I get enough of this “gotta do it” stuff at work. Ham radio should be fun.

What do you think?

73, Bob K0NR

AM, FM, WX and 2-Way Radio

A few weeks ago, I woke up to find that the power was off at my house. It so happens that most of the fun electronic stuff in the house doesn’t actually work when the power is out. The most critical thing is that the freaking internet didn’t work. Huh?

I remembered that I had purchased one of those whizzy emergency radios that has a hand-crank generator built into it. After I fumbled around and found it stuffed away in a closet, I gave it a crank and the radio receiver came alive! Wow, instant communications without batteries or AC power.

I got to thinking that we should have one of these radios at the cabin up in the mountains. After all, the power goes out there even more often.

Searching around and a few other sites, I discovered that the Midland XT-511 Base Camp radio has a hand-crank radio that includes AM broadcast, FM broadcast, Weather receive and, yes, a GMRS 2-way radio. OK, it doesn’t work on the ham bands but the FRS and GMRS frequencies might be useful when things go dark.

It arrived the other day and, so far, I am very pleased with it. It is a consumer grade piece of radio gear but it seems to perform well. I tuned around the AM, FM and Weather bands, clearly receiving the stations that I would expect to hear. The GMRS radio seems to work OK but the transmit audio was a little mushy.

The radio can operate off of the internal rechargeable batteries or standard AA alkaline batteries…quite flexible, I’d say.

The radio costs around $56 from

73, Bob K0NR

Results from the Second Technician Class

We completed our second attempt at the Technician License Class. The format we are using is two all day Saturday sessions, supplemented by self-study using the Gordon West book. We had 14 people take the Technician exam (Element 2), with 13 passing (93% pass rate).  We had 4 Boy Scouts in the group and they all passed. (Their troop is getting quite a few Scouts with licenses and they are having a blast with it on camp outs.)

The 2-day formula seems to be working, so we’ll do it again in the fall. Summer seems like a good time to lay low and we will need to rework the material due to the new question pool for the Tech exam. At first glance, it looks like the new question pool is a little more difficult as it includes more advanced technical topics.

The next Technician Class will be held in the fall, tentatively scheduled for October 16 and 23.

73, Bob K0NR