Re: Fw: [cwops] ZoomT Recording of N4XL's excellent presentation available now
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Thank you, thank you, *thank you!* I just finished watching this antenna presentation by Kevan Nason N4XL and it is terrific for helping to understand and optimize vertical antenna system performance. While he illustrates using vertical antennas built for the lower bands (80m and 160m), the principles are applicable to higher bands that many of us have (40-10m).
Kevan uses many charts and graphs excerpted from other references to illustrate his points … But N4XL provides great added value by telling viewers what the ‘takeaway’ is for each diagram.
The discussion points are:
Antenna lengths, radials (#, length, elevated, buried, diameter, folded v. straight), ATUs (at base v. in shack), feedlines, baluns, near-field vs far-field efficiency, SWR, phasing, and overall ‘system’ performance. And again, each of these discussion points is illustrated by his use of charts and annotations showing ‘what this chart means’.
Many of us merely put up a given vertical antenna (e.g., a Hustler BTV6 or just a wire up into the trees as N4XL uses, but Kevan is an avid DXer and a contester, which tells me that he looks for ways to improve and/or optimize all parts of his station.
A great takeaway for me was his illustrating the antenna system as a series circuit of three resistors being fed by the RF power delivered by the transmitter:
This mental image of the antenna illustrates how/why you want to maximize your radiation resistance (radiated power) and minimize the losses. Kevan points out that one can have a ‘good’ SWR while having most of the power merely being sent into the ground! … Hence a good SWR is not a good indicator of antenna efficiency, and he describes why.
The presentation started out a little slow during introduction, but it really picked up steam around the 10-minute mark, which was the point at which I was hooked and started taking notes like crazy! The presentation portion ends at the 1-hour mark, and there is another 45 minutes of (good)
To all: Be sure to watch this presentation. I guarantee you’ll also find some good takeaways!
73, George N2APB
From: TLARC@groups.io <TLARC@groups.io> On Behalf Of Juan Lopez
Sent: Thursday, October 15, 2020 9:28 AM
Subject: [TLARC] Fw: [cwops] Zoom™ Recording of N4XL's excellent presentation available now
For anyone that missed it, this was a great program.
Courtesy of the Deep Dixie Contest Club.
The you tube link of the recording is available in the message below.
From: firstname.lastname@example.org <email@example.com> on behalf of Dr. Larry S. Anderson <nn5olarry@...>
Deep Dixie CC family (and others)—
I am pleased to announce that the recording of Kevan Nason’s excellent presentation last night is now available for viewing via our DDCC YouTube channel.
Presentation title: Low Band Vertical Antenna Decisions at N4XL
The URL is https://youtu.be/dNznZ64aY-4?t=3
I’m interested to get your feedback on what you think about the presentation, as well as suggestions for how we might improve what we deliver.
Thanks to all the various contest clubs represented last night. If you are a member of any of these clubs, please make sure your members know how to find this valuable information. Share widely among your ham radio friends, please.
Other contest clubs with members present were:
• Dallas-Fort Worth Contest Group (DFWCG)
• 599 DX Association
• Tennessee Contest Group
• Florida Contest Group
• Potomac Valley Radio Club (PVRC)
• Society of Midwest Contesters (SMC)
• Yankee Clipper Contest Club (YCCC)
• Maritime Contest Club
• North Texas Contest Club
(I believe I included them all. If I omitted your club, I apologize)
—Larry NN5O (ex-WB5EIN)
President, Deep Dixie Contest Club
visit our Deep Dixie Contest Club web site
Dr. Larry S. Anderson, Founder/CEO
National Center for Technology Planning
P. O. Box 2393 -- Tupelo, MS 38803
**APPLE DISTINGUISHED EDUCATOR * CLASS OF 2000 **
Assoc. Prof. (Ret.), Mississippi State University