Sunday, February 26, 2017

Amatuer Radio RF Safety Calculator. Post #1055.

Amateur Radio RF Safety Calculator
(http://www.hinklink.com/power_density.htm).
Accessed on 26 February 2017, 23:55 hrs, UTC.
Author:  Paul Evans (VP9KF).
Please click link or enter title URL into your browser search box to read the full article.

Comment:

Here's a handy reference guide from Paul Evans (VP9KF) that will help you determine how much RF exposure you and your family are getting from your amateur radio operations.

All you have to do is fill in the appropriate forms on this calculator to find out the exposure levels from your HF/VHF/UHF antennas.  Paul also provides key links to various FCC and University RF studies concerning RF exposure.

Please bookmark Paul's website so you can refer to it after you build or modify your antennas.

For the latest Amateur Radio news and information, please visit these websites:

http://www.HawaiiARRL.info.
https://oahuarrlnews.wordpress.com.
https://bigislandarrlnews.wordpress.com.
http://www.kh6jrm.info (breaking news for radio amateurs).

Other sites of interest:

http://hawaiisciencedigest.com (sciene and technology news for radio amateurs).
https://hawaiiintelligencedigest.com (trends in geopolitical intelligence, strategic forecasting, terrorism, and cybersecurity).

Be sure to check the blog sidebars for additional antenna and propagation articles.

Opinions expressed in this blog are mine unless otherwise stated.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM0

Saturday, February 25, 2017

Ham Radio - Build your own L network antenna tuner


If you can't view this video, please insert this title URL int your browser search box: https://youtube.com/watch?v=EXD9rAOM_o4. This is post #1054 in a continuing series of Simple Ham Radio Antennas.

Here's a handy device that will increase your enjoyment of amateur radio while protecting your HF transceiver from excessive SWR.  SWR protection is particularly important with end-fed half wavelength wire antennas and random length wires used during portable and emergency operations.

Kevin Loughin (KIB9RLW) shows us how to design, build, and use a simple, inexpensive L network antenna transmatch (i.e. "tuner") that will enable you to use a variety of random length wire antennas without worrying about excessive SWR or RF feedback in the shack.  The video is well-produced and explains in simple terms how to build this valuable accessory to your ham shack.

For the latest Amateur Radio news and information, please visit these websites:

http://www.HawaiiARRL.info.
https://oahuarrlnews.wordpress.com.
https://bigislandarrlnews.wordpress.com.
http://www.kh6jrm.info (breaking news for amateur radio operators).

Other sites of interest:

http://hawaiisciencedigest.com (science and technology news for radio amateurs).
https://hawaiiintelligencedigest.com (trends in geopolitical intelligence, strategic forecasting, terrorism, and cybersecurity).

Be sure to check the blog sidebars for more antenna and propagation articles.

Opinions expressed in this blog are mine unless otherwise stated.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM)

Friday, February 24, 2017

Zepp Antenna Theory. Post #1053.


If you can't view this video, please insert this title URL into your browser search box: https://www.youtube.watch?v=TwYSS335wZw.

Here's another classic amateur radio antenna you may want to try if you're in an experimental frame of mind.  This antenna is patterned after the HF antennas used on Zeppelin airships during the 1920s and 1930s.

Stan Gibilisco (W1GV) does an excellent job of explaining the theory, design, construction, and use of this legacy multiband HF antenna.

For the latest Amateur Radio news and information, please visit these websites:

http://www.HawaiiARRL.info.
https://oahuarrlnews.wordpress.com.
https://bigislandarrlsnews.wordpress.com.
http://www.kh6jrm.com (breaking news for radio amateurs).

Be sure to check out the blog sidebars for additional antenna and propagation articles.

Opinions expressed in this blog are mine unless otherwise stated.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM)

Thursday, February 23, 2017

Three-Wire Dipole Antenna. Post #1052.


If you can't view this video, please enter this title URL into your browser search box: https://www.youtube.com/watch?v=zWWhNBrx4I.

Here's an interesting dipole design for antenna experimenters.  The three-wire folded dipole or T3FD was popular during the 1950s and 1960s, with several companies, including B & W, marketing the antenna to the military, commercial interests, and radio amateurs.  The antenna has a broad bandwidth, high impedance, and exhibits high efficiency.

In this video, Stan Gibilisco (W1GV) explains the theory, design, and operation of this classic antenna.  In Stan's version, the 1/2 wavelength top section consists of three parallel elements, with the center element connected to a balanced feedline, which goes to a transmatch (i.e. "tuner") and then to your HF transceiver.

Although this antenna is a bit of a curiosity, you may want to build one just to see what it can do for your signal.

For the latest Amateur Radio news and information, please visit these websites:

http://www.HawaiiARRL.info.
https://oahuarrlnews.wordpress.com.
https://bigislandarrlnews.wordpress.com.
http://www.kh6jrm.info (breaking news for radio amateurs).

Be sure to check the blog sidebars for additional amateur radio news and propagation forecasts.

Opinions expressed in this blog are mine unless otherwise stated.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM)

Wednesday, February 22, 2017

Converting Radio Shack CB Antenna to 2m. Post #1051.

Converting Radio Shack CB Antenna to 2m
(http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=32533).
Accessed on 22 February 2017, 21:35 hrs, UTC.
Author:  W6OT.
Please click link or enter title URL into your browser search box to read the full article.

Comment:

You never know where antenna materials can be found.  In this article, W6OT converts an old "found" magnetic mount CB antenna into a useful 1/4 wavelength 2 meter antenna.  Although I've converted several Radio Shack 102 inch/259.02 cm steel whips into 10 meter vertical antennas, I have yet to change one of these old shorted CB antennas from 11 meters to 2 meters.

By adding a short length of brass rod to the original whip and attaching a coiled 19 inch/48.26 cm counterpoise wire, W6OT was able to cut and trim the antenna so it resonated in the middle of the 2 meter Amateur Radio Band (around 146.0444 MHz).

Rather than toss that old CB antenna (full-length or "shorty" version), try converting it to some other ham band.  It's like getting an antenna for free, minus your labor and set up time.

For the latest Amateur Radio news and information, please visit these sites:

http://www.HawaiiARRL.info.
https://oahuarrlnews.wordpress.com.
https://bigislandarrlnews.wordpress.com.
http://www.kh6jrm.info (breaking news for radio amateurs).

Be sure to check the blog sidebars for more antenna and propagation articles.

Opinions expressed in this blog are mine unless otherwise stated.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM)