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  • 14 Jun 2015 22:44 | Bill Laakkonen (Administrator)

    Crystals


    Quartz crystals are a natural structure. When plates of Quartz are cut in certain relationships to the crystalline axes, the plates will show the piezoelectric effect.  


    The crystals have mechanical resonance and will vibrate at a very high natural frequency due to the stiffness with the natural period depending upon the dimensions of the crystal. 


    Quartz Crystals may be rotated at specific angles for grinding to yield a particular coefficient of frequency. Figure 5 shows the coefficients of frequencies for given angles of cut. 


    The AT (+35 deg 15') and BT (-49 deg cuts) are used at HF. AT is most used for 500 KHz to 6 MHz. The BT cut is widely used over the same lower range and up to 12 MHz, though the AT cuts is more stable at the lower range than the BT. 


    For Lower Frequencies, say a 100 KHz standard oscillator, the GT cut is recommended, the the CT and DT cuts are also commonly used. The CT, GT, and DT cut plates are called contour cuts. They oscillate along the long dimension of the plate and are much smaller than a AT or BT plate cut for the same frequency.

  • 24 Mar 2015 21:13 | Bill Laakkonen (Administrator)

    Our thanks to ALL for supporting the Stuart Hamfest again this year. We had an overwhelming turnout and a busy- albeit short- hamfest. This year we sold out of inside vendor space and had several new commercial vendors as well. We had more tailgaters than we could count (literally). The bargains on the club donation table and consignments were flying off the tables... (not literally). :-) 


    So with no further adieu - here are the winners of the prizes, all purchased by Martin County Amateur Radio Association thanks to a near cost deal from our pals at Gigaparts.com (thanks!)


    Grand Prize: Barry Mathison KC8CCH
    Second prize: Jack Moyer K4KDI
    Third prize: Donald Hartlein N4NOD


    Grand Prize Winner
  • 24 Mar 2015 09:45 | Bill Laakkonen (Administrator)

    The Portable Software Defined Radio, or PSDR, is an Open Source, Fully stand-alone HF/Shortwave Software Defined Transceiver which includes a Vector Network Analyzer (VNA) and Antenna Analyzer as well as a GPS receiver. A rugged portable transceiver designed to be a flexible platform for development, learning aid, and a useful test kit in it's own right.

    Check out the video embedded below.

    The project is now fully funded on Kickstarter- you can learn more at the Portable SDR Kickstarter pages.

  • 09 Mar 2015 14:29 | Bill Laakkonen (Administrator)
    At a recent meeting we were asked about logic gates AND OR how they work. Here is a simple treatise via Computerphile. http://youtu.be/UvI-AMAtrvE


  • 02 Mar 2015 09:50 | Bill Laakkonen (Administrator)

    MCARA are pleased to announce our February Meeting Annual Election results as follows:


    New President: Ron Schoner K4OIL 

    VP: Gary Webster K4GMW 

    Treasurer: Dick Langbert K4MMZ 

    Secretary: Amy Laakkonen KI4RHM

     

    Board of Directors: 

    Joe Sawyer KI4OXP, 

    Eric Boyd W4ELB, 

    Arnie Dykes KH7GZ, 

    Lee Pennington II K4LJP,

    Bob Kagel KM4DS


    We wish to thank our outgoing 2014 staff for their service to the club- Thank You All. Meeting minutes for the Feb 2015 meeting are available in the Members Area under "Meeting Minutes".


    Dues and Renewals Changes


    Also taken under motion and approved was a call to raise annual dues from 15 dollars to 20 for Regular membership, and 22.50 to 30 dollars for Family Membership levels. This modest increase is our first ever dues increase since 1974. Thanks to all our members for your continued support. 


    Please be aware if your membership is in renewal status, you may renew at the old rate listed on your invoice. If your membership is now expired, you must renew at the new rates. All new members are using the new rates, this change, along with the change to anniversary renewals for memberships approved in 2014, should make it easier for folks to join us during the busiest parts of the year. 


    We look forward to seeing you all at the Stuart Hamfest on 21 March, 2015. If you would like to volunteer, please contact the Hamfest Chairman, Doug Shields - you do not need to be a member to volunteer to help with the event. We appreciate all our friends pitching in to support our event and keep it free of cost to attendees.


    73



  • 10 Nov 2014 14:34 | Bill Laakkonen (Administrator)

    Oct 30 K4ZK at the Stuart Airshow
    K4ZK 2-14 Oct 30 Stuart Airshow
    https://plus.google.com/photos/109062455654311685610/albums/6080152628975494385?authkey=CJbWsNiP4JWSygE

    K4ZK 10-31 2014

    https://plus.google.com/photos/109062455654311685610/albums/6080155971489101905

    K4ZK Sunday Nov -02 2014 Stuart Airshow

    https://plus.google.com/photos/109062455654311685610/albums/6080157799357692977

    From Kevin Jackson W4JKJ

    Thanks for putting up the special event station!
    Had a great time as always with you guys.
    I uploaded my pics to shutterfly. There are a few pics of some of the folks working the radio that you may want to grab.

    Best of 73,
    de Kevin-W4JKJ

    https://2014airshow.shutterfly.com/


  • 10 Nov 2014 13:19 | Bill Laakkonen (Administrator)

    2014 Airshow Video

    2014 Airshow Stuart Florida from MCARA on Vimeo.

    Find the video to share on Facebook

    Find the video to share on YouTube - 1280 HD

  • 31 Oct 2014 07:50 | Bill Laakkonen (Administrator)

    Please Join us as our club celebrates a 40 year anniversary at the 2014 Stuart Air Show in Stuart Florida - you may join us on air with  our special event station operating on 10, 15 and 20 meters or come out to the Airshow and join the fun!  

  • 19 Jun 2014 09:28 | Bill Laakkonen (Administrator)
    So on occasion we are asked "Where is the best place to start learning how to build electronic projects?"


    Fritzing


    Fritzing - from University of Potsdam, is a nice representation of the real-world process from schematic to breadboard to PCB. Would you be interested in learning the Fritzing way? Have a look and let us know: http://fritzing.org/home/
  • 12 Mar 2014 08:17 | Bill Laakkonen (Administrator)
    Explaining how radio beams bend around the Earth for HF communications has always been a bit of a task to convey for me. Radio waves, which are in the same domain as light waves, don't "reflect" - they actually refract, or bend.

    Refection makes the pencil appear to bend
    One way to see the bending is to place a pencil in a clear measure cup-- you will notice it appear to bend at the water line. Rays of light, and indeed radio waves-- do the same.

    Refracted arrow appears to reverse direction
    What you see is not always what actually happens. The arrow appears to reverse direction- and radio waves can do the same when traversing a medium such as the ether.

    This video shows an even more dramatic demonstration of refraction:
    )

    These visual cues may help you to understand how our ionosphere shapes and bends signals around the globe.  Here is some more info on the effect including a better explanation.  So the next time you hear a person stating signals reflect off the ionosphere- you have a couple quick and easy ways to show that they refract-- not reflect. The ionosphere is not a mirror. If you would like to learn more about ham radio and how we communicate around the world-- and how you can get a license to do the same. Please feel free to contact our club to find out about a ham radio license class near you.   
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