Antenna Tuner Discussions

The topic of antenna tuner operation and design was popular today. Here are some links that Phil and I have dug up that may be helpful:
How to User Your Antenna Tuner is a fairly long article with several additional web links and many posted comments. Among the included links are:

• Antenna Tuner Operation is a short article by ARRL about how to use a common tuner type.
• A T-Network Simulator is a Java application that lets you practice using a software simulated tuner. You can turn the knobs on the tuner to try your solution and then click the autotune button for comparison. The simulator can be run or the web page or downloaded to run locally on your Java-enabled PC.
  
• Antenna Transmatch Tips provides some details of popular tuner designs that are commercially available along with tips for similar homebrew units. It includes some discussion of common component limitations.
  

Other links provided in Phil's recent email:

• An article about the Ten-Tec Model 238B HF Antenna Tuner describes the circuit and how it operates.
• Getting the Most Out of Your T-Network Antenna Tuner is an article from the January 1995 issue of QST.
  

A subtopic of particular interest is the ability to find more than one group of settings in T-network tuners to provide a match. This property is illustrated in the 1995 QST article cited above. See the article's section labeled Practical T-Network Tips for some recommendations on how to avoid overheating inductors and arcing capacitors.

Many additional articles are available at this DX Zone web page.


Your comments are welcome.

John

Dalton Hamfest 2009 Photos

Photos from this event are available for viewing here. Thanks to N4OLN and W4UOA for their camera work!

Bell Ringers Google Map

View Larger Map

I've created a new Google map showing 34 selected members of our group. Above is a portion of the map, which you can also view in full size. This initial version is based on coordinates available from QRZ.com. I'm updating locations based on corrections sent to me.

If you click on a placemark (push-pin) the member's call sign, name and member number are displayed.

If you are logged in with a free Google account, you can also find a distance measuring tool under the "Featured content" section on the left side. You can also view this map in Google Earth, if you have installed that free program.

Please send me any corrections or additions for the map. I'll be glad to add more members who may want to be included or remove those who don't. Thanks to Jorge ki4SGU for showing us how to use this Google resource. Enjoy!

John

Amateur Radio SDR

I found a recently started blog about this topic. It includes information about the SoftRock radio kits that are promoted as a good way to get started with SDR in amateur radio. A companion web site provides some information about how to set up an amateur radio SDR.

John

Nixa Ice Storm 2009 by N0SAP

Here is a report and photos from Sap N0SAP. Click on any photo below to see it full size.

Here are some pictures of the first ice storm of 2009.  We had about 3/8 inches of ice and four inches of snow.  We have not loss power, so I guess we are lucky for that.  "SAP"

Picture 009 (last) is the permanent building full of radio parts.

PropNET

This morning on 3968 we learned from ki4SGU a little bit about PropNET, a project that uses PSK31 to create an RF-based digital peer-to-peer network. The link in the preceding sentence will take you to the FAQ for some background info.

A fascinating product of this project is an automated communication circuit quality report, a type of propagation map that displays connections made among stations whose locations are marked on the map. The graphical display is frequently updated, giving a snapshot of propagation conditions at the time of viewing. The results can be displayed for all bands or for a single band of interest. Click on any station's location point for info from QRZ.com.

Enjoy!
John WA5MLF

Bell Ringers on a Google Map

Yesterday Jorge ki4SGU assembled, in near real time, a Google map that shows the locations of several stations who participated in our QSO on 75 m. You may view it by clicking here. Click on a blue push-pin either on the map or on the left-side listing to reveal details about that QTH.

The locations are based on the public data that is used by Google maps and similar web applications. Some locations are not quite correct, but can be adjusted in the customized map itself. This will not, however, correct the underlying error in the external database that is accessed by Google and other mapping applications.

Using Jorge's map as inspiration, I hope that we will assemble a similar map that shows more of our members and frequent associates who join with us regularly on 75 or 40 m. Let me know if you wish to help as a collaborator who can edit / update our future map.

73, John