FCC Issues $10,000 Fine to Missouri Man for Unlicensed Operation on 14.312 MHz


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On February 25, the FCC issued a Notice of Apparent Liability for Forfeiture (NAL) in the amount of $10,000 to Jared A. Bruegman, ex-KC0IQN, of Bolivar, Missouri.

Russ Roberts‘s insight:

Some people never learn.  Aloha de KH6JRM.

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STRaND-1 Amateur Radio Smartphone CubeSat


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Recorded at the 2012 AMSAT-UK International Space Colloquium CubeSat / Microsat event in Guildford, UK. Chris Bridges talks about the Smartphone (NEXUS-1) Cu…

Russ Roberts‘s insight:

STRaND-1 smartphone CubeSat is operational.  Check out this youtube video.  Aloha de KH6JRM.

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Amateur radio experiences DIY renaissance | View from the Top


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David Sumner By David Sumner When amateurs began experimenting with radio more than a century ago, they had no choice but to build everything they needed.

Russ Roberts‘s insight:

Nice article from the CEO of the ARRL.  I started my amateur radio "career" during the Heathkit era and remember well the thrill of making something with my own hands and solder-burned fingers.  Kit making is coming back, from antennas to full-blown transceivers.  Build a kit–you’ll enjoy the experience.  Aloha de KH6JRM.

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FCC Proposes More Spectrum at 5 GHz for Unlicensed Broadband


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On February 20, the FCC released a Notice of Proposed Rulemaking in ET Docket No. (FCC Proposes More Spectrum at 5 GHz for Unlicensed Broadband: On February 20, the FCC released a Notice of Pro…

Russ Roberts‘s insight:

Keep your eye on this one.  Perhaps this is a case of "use it or lose it."  Aloha de KH6JRM.

See on www.topix.com

Simple Ham Radio Antennas–a short, ground-mounted vertical antenna for 40 meters, post #341


A SHORT, GROUND-MOUNTED VERTICAL ANTENNA FOR 40 METERS.

One of the frustrations of operating an amateur radio station from a deed or space restricted environment is the shortage of space (vertical or horizontal) to erect 1/4 or 1/2 wavelength antennas such as flat top dipoles, verticals, and, even in some cases, inverted vees.  In my military and civilian careers, I moved around a lot and lived in areas most unfriendly to ham radio operations.

Although I’ve had some success with attic and ceiling mounted antennas, I really prefer having my antennas outside.  One of the antennas I used several years ago was a vertical helix on a ten-foot (3.04 meters) pvc pole.  This antenna was centered on a radial field of 16 evenly spaced AWG #16 wires.  Because of space limitations, each radial was cut to the length of the pvc pole in use, i.e. each radial wire was approximately 10-feet (3.04 meters).  The vertical helix was fed with 450-ohm ladder line and topped off with an attached 10-inch (25.4 cm) aluminum pie pan.  The pie pan served as a capacitance hat and prevented high voltage from setting the top of the pvc pole on fire.  Yes, I actually “blew” the top off of an earlier design when I ran a little over 100 watts from my old Kenwood TS-520.  That was quite a sight!  Scared the heck out of me.

With the balanced feed line, an old W9INN balun, and the trusty Drake transmatch (MN-4), I was able to work stations from 40 to 10 meters.  The bandwidth was very small and the process of lowering the SWR below 1:5 to 1 often presented a challenge, but I was able to work stations without the neighbors knowing what I was doing.  Of course, I ran mostly cw after 10 p.m., so problems with rfi were very few.

My inspiration for this handy, small, and workable antenna was original research done by the late Professor Jerry Sevick, W2FMI, who researched and built ground-mounted short verticals in the early 1970s.  Reading his reports and articles gave me hope that I, too, could achieve decent dx contacts without spending a fortune or irritating nosey neighbors.  I cite several articles by him in the reference section of this post.

What got me started with this antenna was a quote from Sevick’s article in the “ARRL Antenna Anthology”, p. 25, entitled “The W2FMI Ground-Mounted Vertical.”  Sevick states:  “A short vertical antenna properly designed and installed approaches the efficiency of a full-size resonant quarterwave antenna.  Even a  six-foot (1.83 m) vertical on 40 meters can produce an exceptional signal.”  Of course, he says, “the practical achievement of such a result requires an understanding of ground losses, loading, and impedance matching.”

Those considerations inspired him to create a series of 80 and 40 meter antennas which employed both top loading using aluminum tubing and an extensive radial field of 115 wires.  Using these steps, “practically no earth loss was measured, and hence, any radiation resistance above a few ohms assured good operation and an opportunity to verify the theoretical predictions for very short vertical antennas.”  Sevicks test results, graphs, and various measurements are impressive.

So much for theory, a decent antenna test range, and sufficient space to lay down an effective ground system.  With Sevick’s results and cautions about narrow bandwidth, high voltages at the top of the antenna, and the establishment of a proper radial field, I set out to use as much of the professor’s guidance as I could.  Those first efforts years ago were interesting, to say the least.

And now, with some time on my hands, I decided to refine and improve my 40 meter helical vertical without going too far astray from Sevick’s design.

MATERIALS AND ASSEMBLY:

I had a 10-foot (3.04 meters), 2-inch diameter (5.08 cm) piece of schedule 40 pvc pipe under the house for the antenna support.

I hammered a 5-foot (1.52 meters) wooden stake into the ground to support the mast.  The pvc pipe would be slipped over the mast when I completed the helical winding of the antenna element.

I cut 16, 10-foot (3.04) pieces of #16 AWG wire for the radials.  I used a pizza cutter to dig a groove in the lawn for each radial.  In a few days, the grass-covered the radial system.  Lawn mowers didn’t seem to bother the radials once the earth and grass covered them.  The radials were buried approximately 1-inch (2.54 cm) below the lawn.

According to the “ARRL Antenna Book, 14th edition”, “no strict rule has been established concerning how short a helically wound vertical can be before a significant drop in performance is experienced…a guideline might be to maintain an element length of 0.05 wavelength or more for antennas which are electrically a quarter wavelength long…thus, use 13 feet or more of stock for an 80 meter antenna, 7 feet for 40 meters, and so on.”  I chose a length of 10-feet (3.04 meters) for the mast.

The same antenna reference noted that “there is no hard-and-fast formula for determining the amount of wire needed to establish resonance in a helical antenna.  Experience has indicated that a section of wire approximately one half wavelength long, wound on the insulating form with a linear pitch…will come close to yielding a resonant quarter wavelength.”  With that in mind, I wound 66-feet (20.12 meters) of #16 AWG wire on the pvc pipe.  To prevent the top portion of the antenna from catching on fire (I had that experience earlier), I provided some capacitance top loading with a 10-inch (25.4 cm) aluminum pie plate attached to the top of the pvc pole and connected to the end of the helix.

I attached one leg of the ladder line to the vertical helix and connected the other lead to the radial system.  I soldered all joints and wrapped them with several layers of vinyl electrical tape.

I ran the 450-ohm ladder line to a W9INN balun.  I ran a ground wire from the balun to an 8-foot (2.43 meters) copper ground rod beneath the shack window.  A short piece of RG-8X coaxial cable connected the balun to the Drake transmatch (MN-4).  A short patch cord connected the transmatch to the Swan 100 MX and the dummy load.

PRELIMINARY RESULTS:

Considering the compromises I made in Sevicks’s design, the antenna performs rather well.  The bandwidth is quite narrow and minimizing SWR can be a bit touchy with a manual transmatch.  Nonetheless, I’m able to get a 1.7 to 1 or less SWR with careful tuning on 40, 20, 15, and 10 meters.  I can crank the old Swan 100 MX up to 50 watts cw and SSB without any problems.  Everything runs cool.  Unlike my earlier efforts at short helically wound verticals, the current edition doesn’t lose its top half to extreme voltage.  The small capacitance hat seems to keep things under control.  The radial system can be improved, but the 16, 10-foot (3.04 meters) buried radials appear adequate for now.

Despite the obvious bandwidth and tuning issues, there are several advantages to using a shortened vertical antenna:  it is easy to build, erect, and take down; it is invisible from the street facing my qth; it can be used with either 50-ohm coaxial cable for single band, 40 meter use or with 450-ohm ladder line/300-ohm tv twinlead for multiband use.  In the multiband category, a 4:1 balun and a transmatch will be necessary to minimize the wide range of SWR readings found with this antenna.  And finally, this shortened vertical can serve as a compact emergency or portable antenna.

If you’re pressed for space, try making a vertical helix antenna.  It could be the antenna you’re looking for.

REFERENCES:

Anderson, Marian S. (WB1FSB), editor.  “The ARRL Antenna Anthology”.  Copyright 1978.   pp. 25-29.  ARRL, Newington, CT, 06111.

Hall, Gerald L. (K1TD), editor.  “The ARRL Antenna Book, Fourteenth Edition, Copyright 1982.  pp. 10-11 to 10-12.  ARRL, Newington, CT, 06111.

Sevick, Jerry (W2FMI).  “The Ground-Image Vertical Antenna,” “QST”, July 1971.

Sevick, Jerry (W2FMI).  “The W2FMI 20-Meter Vertical Beam,” “QST”, June 1972.

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Until next time,

Aloha es 73 de Russ, KH6JRM–BK29jx15–along the beautiful Hamakua Coast of Hawaii Island.

I

Amateur Radio Kit Roundup – Updated 2/26/2013 | AmateurRadio.com


See on Scoop.itKH6JRM’s Amateur Radio Blog

Splinter Transceiver from BreadboardRadio.com Kit building appears to be on the rise again.  With so many people talking about it lately I attempted to

Russ Roberts‘s insight:

Neil, W2NDG, has compiled an extensive list of Ham Radio kits for the amateur radio community.  Kit building appears to be catching on again, and Neil offers a good source for radio kits, from Hendricks QRP to Ten Tec.  Aloha de KH6JRM.

See on www.amateurradio.com

Youth@HamRadio.Fun: New Mexico — Land of Hamchantment


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In a typical engineering discipline, one spends four (or more commonly, five) years in classes learning more math, science, circuit analysis and classroom topics than you could ever fathom to understand.

Russ Roberts‘s insight:

Excellent article on how amateur radio can sometimes get you the job of your dreams.  Thanks to his hard work and knowledge of amateur radio, Sterling Coffey (N0SSC), the ARRL Youth Editor, was able to secure an internship at the Very Large Array (VLA) in New Mexico.  Coffey says the job really isn’t work–it’s fun.  Imagine using all of that state of the art test equipment and those large deep space parabolic dishes.  I’m jealous.  Aloha de KH6JRM.

See on www.arrl.org

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