We have moved…Post #4754


Effective 30 December 2014, “KH6JRM’s Amateur Radio Blog” has moved to a new URL.

The blog title remains the same.

The new URL is http://kh6jrm.net.

Thanks for your patience and understanding.  Reconstructing a blog after a mysterious hacking incident is never pleasant.  But, with the new blog running successfully, things are returning to “normal.”

Happy Holidays from my family to yours!

I’ll see you on the new site (http://kh6jrm.net).

Aloha es 73 de Russ (KH6JRM).

Free antenna tutorial – KB6NU’s Ham Radio Blog


Free antenna tutorial

november 7, 2014 by dan kb6nu leave a comment

For a limited time, Rohde & Schwartz and the IEEE Communications Society are offering a free tutorial on Antenna Basics. Here’s a description of the tutorial:

In this tutorial the basic functionality of an antenna is explained. Starting with Hertz’s antenna model and a short introduction to the fundamentals of wave propagation, the important general characteristics of an antenna and its associated parameters (e.g. antenna gain, radiation pattern, bandwidth or VSWR) are explained. A more detailed explanation of the functionality of some selected antenna types (e.g. dipole or monopole) is also given.

Speaking will be Maik Reckeweg, Product Manager Antennas, Rohde & Schwarz GmbH, Munich, Germany, responsible for all the company’s monitoring, measurement and communications antennas.

The video is kind of dry, but I think Reckeweg does a pretty good job of discussing antenna basics. The video is also accompanied by a white paper that delves into these topics a little more completely. Overall, there’s a bit more math than in most amateur radio discussions of antennas, but this makes the discussion a little more comprehensive.

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filed under: antennas

via Free antenna tutorial – KB6NU’s Ham Radio Blog.

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Thanks to Dan Romanchik (KB6NU) for this tip.  For a limited time, you can download an excellent video tutorial and white paper on “Antenna Basics” from the IEEE Communications Society and Rohde & Schwartz.  Although there’s some sophisticated math in the presentation, the information is easily digestible.  Download a copy of this well-organized tutorial for your reference library.

For the latest Amateur Radio news and events, please check out the blog sidebars. These news feeds are updated daily.

Aloha es 73 de Russ (KH6JRM).

SARL 5 MHz propagation research project


Page last updated on: Saturday, November 1, 2014

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SARL 5 MHz propagation research project

The 5 MHz propagation research project show unexpected results.

One of the most interesting findings is the inconsistency in the results of Near-vertical-incidence sky wave propagation (NVIS).

Comparing a communications path between two amateur stations, ZS6KN and ZS6KTS (a distance of 51 km) it is interesting to note that in June 2014 there was a good communications path from just after 05:00 until approximately 16:30 after which the signals disappeared. The pattern for July was the same, but signals were considerably stronger than during August and September.

During September, a strong dip in signal strength can be seen. The other interesting observation from the graph is that propagation “opens” earlier and closes later as we go into summer which indicates variations in the ionisation of the D layer of the ionosphere as the sun rises earlier and sets later.

Not enough data has been collected to make any meaning full conclusions. If the path was a pure ground wave, the signals would have been more or less constant throughout the day and night.

The article will be published in the November/December edition of EngineerIT and is already available on the web. You can find the link on http://www.sarl.org.za, click on propagation research. You will find links to the article as well as a report of the first six months.

The South African Radio League

via SARL 5 MHz propagation research project.

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The South African Radio League (SARL) has found some unusual results from its recent test cycle of the 5 MHz band.  According to SARL officials, there was much inconsistency in Near Vertical-Incident Skywave Propagation (NVIS) and the discovery that 5 MHz “opens earlier and closes later as we go into summer…, indicating a variation in the ionization of the D Layer of the atmosphere.”  The SARL notes that is hasn’t collected enough data “to make meaning full conclusions.”

For the latest Amateur Radio news and events, please check out the blog sidebars.  These news feeds are update daily.

Aloha es 73 de Russ (KH6JRM).

Weird antenna behavior – KB6NU’s Ham Radio Blog


Weird antenna behavior

november 1, 2014 by dan kb6nu leave a comment

Two years ago, I put up a 20m, end-fed half-wave antenna. It wasn’t a terrific performer, but it worked OK, and I was able to make contacts on 20m.

Basically, it’s a 33-ft. piece of wire connected to a matching network, made up of a toroid and a capacitor, as shown in the figure at below. The inductor is a toroidal inductor, and the capacitor is made from a length of RG-174 coax, as shown in the figure below.

A month or so ago, the antenna started acting funny. While transmitting, the power would fluctuate, not wildly, but noticeably. Thinking it might be the coax, I took my dummy load outside and connected it to the coax, but that checked out OK.

The next step was to check the matching unit. I had built the matching network in a waterproof box, or so I thought. When I opened the box, there was water inside it. Water had apparently gotten in around the screws holding the SO-239 to the box. I dried it out, replaced a rusty nut and bolt, and when I put it back together, sealed up the SO-239 with silicone.

That still didn’t do it, though. I was still getting the erratic behavior. Today, I practically rebuilt the entire antenna, aside from rewinding the toroid and making a new coax capacitor, but it’s still acting weird.

I guess my next step is to make a new capacitor. I suppose some water could have wicked up into the braid, compromising it. That seems kind of far-fetched though. At this point, I’m open to any other ideas you guys might have.

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filed under: antennas

via Weird antenna behavior – KB6NU’s Ham Radio Blog.

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Dan is asking for your help in diagnosing the weird behavior in his end-fed half-wave antenna.  Somehow, his antenna is radiating fluctuating amounts of power, despite Dan’s efforts at replacing parts of the matching network and checking to see if his coaxial feedline was alright (it checked out fine).  The source of the problem could be a failed capacitor in his matching network, but I’m not certain of that. Perhaps the RG-174 coax he used in the capacitor has a short or some water “wicked up” inside the coax shield.  If you have a solution to Dan’s problem, drop him an e-mail.

For the latest Amateur Radio News and Events, please check out the blog sidebars. These news feeds are updated daily.

Aloha es 73 de Russ (KH6JRM).

TC2M Broadband HF Antenna


Page last updated on: Tuesday, October 28, 2014 Share on facebookShare on twitterShare on emailShare on printMore Sharing Services3. TC2M Broadband HF Antenna. Martin Ehrenfried G8JNJ has developed an omni-directional antenna with a claimed bandwidth of 2-30 MHz at less than 2.5:1 SWR.  View the TC2M site at http://www.tc2m.info/Read the construction article at http://www.tc2m.info/TC2M%20HF%20Vertical%20G8JNJ.pdf 

via TC2M Broadband HF Antenna.

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This antenna appears to be a kind of “cage” antenna (minus the other half) often seen in broadband 80 meter dipoles.  There are a few AM broadcast antennas that employ a variant of this antenna, such as the folded monopole antenna.  At one time Barker & Williamson made something called a TFTD antenna that closely resembled a folded dipole. This antenna was used by the U.S. military to give broadband HF coverage. Martin’s (G8JNJ) TC2M looks fairly simple to make and gives a reported 2.5:1 SWR from 2 to 30 MHz.  This antenna looks interesting.  It might be worth the time to make one.

For the latest Amateur Radio news and events, please check out the blog sidebars.  These news feeds are updated daily.

Aloha es 73 de Russ (KH6JRM).

HamTV reception with a low gain antenna | Southgate Amateur Radio News


Page last updated on: Friday, October 17, 2014

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HamTV reception with a low gain antenna

Tonino Giagnacovo IZ8YRR conducted an experiment with a low gain antenna during the commissioning of the Ham Video system on the International Space Station (ISS) earlier this year

He has written a 10-page article on his experiment which can be read at

Click to access HAMTV_IZ8YRR_1.pdf

Read more about the ISS Ham Video system on the ARISS-EU site at

http://www.ariss-eu.org/

via HamTV reception with a low gain antenna | Southgate Amateur Radio News.

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Great article by Tonino Giagnacovo (IZ8YRR) on low gain HamTV antennas on board the International Space Station (ISS).  Sometimes, simple is best.  This post also connects you to a more extensive article about the ISS Ham Video system.

For the latest developments in Amateur Radio news and events, please refer to the blog sidebars.  These news feeds are updated daily.

Aloha es 73 de Russ (KH6JRM).

Why radio hams should consider 3D printing | Southgate Amateur Radio News


Page last updated on: Thursday, October 16, 2014

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Why radio hams should consider 3D printing

Mike Grauer, Jr, KE7DBX, asks radio amateurs to think about how 3D printers can be used in home construction

He says:

As a member of the ham radio community, I have always been fascinated by the maker mindset which has existed since the early days of radio. From making radio equipment from scratch, to kits and even modifying commercially available equipment, the maker movement and radio go hand in hand.

The 3D printing community shares many traits with the ham radio movement. At the heart of it all is making, creating and inventing.

And just like ham radio operators, those involved with 3D printing are constantly learning new technical skills that can be used in other areas of our lives.

Read the full story at

http://www.inside3dp.com/ham-operators-consider-3d-printing/

 

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via Why radio hams should consider 3D printing | Southgate Amateur Radio News.

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Nice essay on the traits shared by amateur radio operators and those following the “maker mindset.”  Mike Grauer, Jr. (KE7DBX) makes an excellent case for having these two groups of “makers” share more ideas and common interests.  At the very least, 3D printing can duplicate hard to find parts for classic radios, such as dial pointers, cabinets, knobs, and toggle switches.  3D printing can also be used for experimental projects by both groups of enthusiasts.  Aloha de Russ (KH6JRM).

For the latest Amateur Radio news and events, please check out the blog sidebars.  These news feeds are updated daily.

Aloha es 73 de Russ (KH6JRM).

New Challenge Coin Premium for AMSAT Fox Donations


New Challenge Coin Premium for AMSAT Fox Donations

AMSAT is excited to announce that a new premium collectable is now available for qualifying donations to the Fox satellite program. AMSAT has commissioned a unique challenge coin for donors who have contributed at the $100 level or higher. This challenge coin is shaped as an isometric view of a Fox-1 CubeSat, complete with details such as the stowed UHF antenna, solar cells, and camera lens viewport. Struck in 3mm thick brass, plated with antique silver, and finished in bright enamel, the coin is scaled to be approximately 1:4 scale, or 1 inch along each of the six sides. The reverse has the AMSAT Fox logo.

The coins are scheduled for delivery just prior to the 2014 AMSAT Space Symposium, and will be first distributed to donors attending the Symposium. Coins will also be made available to qualifying donors that have contributed since the Fox-1C announcement on July 18, 2014 upon request. Donations may be made via the AMSAT website at http://www.amsat.org, via the FundRazr crowdsourcing app at fnd.us/c/6pz92, or via the AMSAT office at (888) 322-6728.

The Fox program is designed to provide a platform for university experiments in space, as well as provide FM repeater capability for radio amateurs worldwide. Fox-1A and 1C are set to launch in 2015, and Fox-1B (also known as RadFXSat) is awaiting NASA ELANA launch assignment. Further information on the Fox project can be found at http://www.amsat.org.

via New Challenge Coin Premium for AMSAT Fox Donations.

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Thanks to Drew (K04MA) and QRZ.com for this article on the AMSAT Fox 1-A and Fox 1-C satellites which are scheduled to launch in 2015.  Drew says some of the links cited in his article may be broken, so here are some alternate links concerning the program:

http://www.amsat.org

http://www.amsta.org/?p=2957.

For the latest Amateur Radio News and Events, please check out the blog sidebars.  These news feeds are updated daily.

Aloha es 73 de Russ (KH6JRM).

 

 

 

 

 

 

 

Propagation Forecast Bulletin #39 de K7RA:


Propagation Forecast Bulletin #39 de K7RA:

from W1AW Bulletin via the ARRL on September 26, 2014

Website: http://www.arrl.org/

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Propagation Forecast Bulletin #39 de K7RA:

SB PROP @ ARL $ARLP039

ARLP039 Propagation de K7RA

ZCZC AP39

QST de W1AW

Propagation Forecast Bulletin 39 ARLP039

>From Tad Cook, K7RA

Seattle, WA September 26, 2014

To all radio amateurs

SB PROP ARL ARLP039

ARLP039 Propagation de K7RA

Solar activity was down this week (September 18-24) when compared with a week earlier, but solar flux is on a rising trend.

Average daily sunspot numbers dropped from 124.9 (for September 11-17) to 80.9, and average daily solar flux slipped from 139.8 to 128.3.

The latest predicted solar flux and planetary A index has flux values at 165 on September 26-28, 170 on September 29-30, 165 and 160 on October 1-2, 155 on October 3-4, 150 on October 5-7, 145 on October 8-9, 140 on October 10-11, then 135 and 130 on October 12-13, 125 on October 14-15, and 120 on October 16-18. Flux values are then expected to rise to 155 on October 30-31.

Predicted planetary A index is 15 on September 26, 12 on September 27, 15 on September 28-29, 10 on September 30, 8 on October 1-2, 5 on October 3-14, then 8, 15 and 8 on October 15-17, 5 on October 18-19, 8 on October 20-21, 12 on October 22, and 15 on October 23-24.

Petr Kolman, OK1MGW makes geomagnetic predictions, and believes the geomagnetic field will be quiet to active September 26-27, quiet to active September 28 through October 3, mostly quiet October 4-7, quiet to unsettled October 8-9, quiet October 10-12, mostly quiet October 13, quiet to active October 14-15, mostly quiet October 16-17, quiet to unsettled October 18-20, and quiet to active on October 21-22.

Earth’s geomagnetic field has been unsettled recently, with planetary A index at 25 on September 24 and College A index (high latitude) at 57. Spaceweather.com reports this is not due to a CME or solar flare, but a crack in the Earth’s magnetosphere, opening a spot for the solar wind to pour in.

John Campbell, K4NFE of Huntsville, Alabama sent in an article and video explaining the difference between solar flares and Coronal Mass Ejections.

Read it at, http://www.universetoday.com/114729/nasa-explains-the-difference-between-cmes-and-solar-flares/ .

If you would like to make a comment or have a tip for our readers, email the author at, k7ra@arrl.net.

For more information concerning radio propagation, see the ARRL Technical Information Service web page at http://arrl.org/propagation-of-rf-signals. For an explanation of the numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us/.

Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation.

Sunspot numbers for September 18 through 24 were 75, 91, 75, 72, 87, 90, and 76, with a mean of 80.9. 10.7 cm flux was 120, 122, 119, 124, 130, 138, and 145, with a mean of 128.3. Estimated planetary A indices were 8, 22, 6, 7, 9, 11, and 25, with a mean of 12.6. Estimated mid-latitude A indices were 7, 23, 4, 7, 9, 9, and 19, with a mean of 11.1.

NNNN

/EX

Source: W1AW Bulletin via the ARRL.

There are no comments on this article: Post One

via Propagation Forecast Bulletin #39 de K7RA

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Another excellent article from Tad Cook (K7RA) and his cast of propagation experts. Tad provides plenty of tips, forecasts, and links to make your operating more productive and efficient.

For the latest Amateur Radio News and Events, please check out the blog sidebars.  These news feeds are updated daily.

Aloha es 73 de Russ (KH6JRM).

International Space Station Fast Facts – CNN.com


(CNN) — Here’s a look at what you need to know about the International Space Station (ISS), a spacecraft built by a partnership of 16 nations.

The 16 nations are the United States, Canada, Japan, Russia, Brazil, Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland and the United Kingdom.

At full capacity, the almost one-million-pound space station will include six laboratories and provide more research space than any spacecraft ever built. There will be enough living space for a crew of seven.

Information on ISS crews and expeditions can be found here.

Statistics (as of June 2014) Source: NASA

The ISS includes three main modules connected by nodes: the U.S. Laboratory Module Destiny, the European Research Laboratory Columbus, and the Japanese Experiment Module Kibo (Hope). Each was launched separately and connected in space by astronauts.

The ISS weighs 924,739 lbs (419,456 kilograms)

Habitable Volume: 13,696 cubic feet (388 cubic meters)

Solar Array Length: 239.4 feet (73 meters)

There have been 180 spacewalks conducted in support of space station assembly, totaling almost 1,130 hours.

The space station has been visited by 214 individuals.

According to Johnson Space Center, as of August 2014, there have been 151 launches to the space station: 98 Russian vehicles, 37 space shuttles, seven U.S. commercial vehicles, five European vehicles and four Japanese vehicles.

On its tenth anniversary (November 2, 2010), the ISS is estimated to have made 57,361 orbits around the earth.

via International Space Station Fast Facts – CNN.com.

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Since the International Space Station has been in the news recently and is the host of several successful ISS to school programs, I thought it appropriate to list some of the basic facts and figures associated with this space platform orbiting above us.  Thanks to CNN and NASA for the  article.

For the latest in Amateur Radio News and Events, be sure to check the blog sidebars.  These news feeds are updated daily.

Until next time,

Aloha es 73 de Russ (KH6JRM).

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