April 24, 2012
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Magnetic Loop Design
~George N2APB and Joe N2CX
Audio Recording ... (Listen to MP3 recording)
Text Log ...
<20:08:28>"George - N2APB": Be sure to subscribe to the new Yahoo Group called "CWTD" (Chat With The Designers) at CWTDemail@example.com
<20:09:07>"George - N2APB": (The link is alo on our main CWTD webpage for tonight's session, located at http://www.njqrp.org/teamspeak/Apr24.html
<20:14:38>"Armand WA1UQO": Marty Feldman with the crossed eyes !
<20:19:57>"Alan W2AEW": ...and it's directional too, so you can reject signals "off of the sides"
<20:23:30>"Rick K3IND": panadapter/waterfall would be useful to see where the loop is tuned?
<20:29:10>"George - N2APB": Regarding use of waterfall displays ... Absolutely! As you'll see in the coming slide or two.
<20:34:13>"Rick K3IND": what happens to your capacitor when it rains ?
<20:34:26>"George - N2APB": BrzzzzzzzZAPPPP!
<20:38:06>"Alan W2AEW": if you open the PDF in the web browser, you don't have page numbers
<20:44:29>"Paul - wa0rse": so, the transmitted frequency and received frequency are always the same but the amplitude moves up and down as the resonance is shifted by the stepper?
<20:44:48>"Alan W2AEW": I'm interested in hearing about the details of the feedpiont - how to connect feedline to the loop?
<20:45:30>"Paul - wa0rse": the user sets the transmitter frequency and then the feedback loop seeks the capacitance for maximum rf sampling measurement, yes?
<20:46:01>"Paul - wa0rse": nice blizzard, btw -- looks like typical MN in winter, but warmer...
<20:49:33>"John - KJ6CVB": Comment on K8NDS: http://www.hlmagneticloopantennas.com/
<20:59:19>"Alan W2AEW": I wonder how well it would work using a metal mesh instead of the flashing - to cut down on wind loading.
<21:06:31>"Paul - wa0rse": I missed the beginning ... why is a narrow BW desirable?
<21:07:38>"John - KJ6CVB": Can SDR-Cube be made to auto-tune mag loop?
<21:09:03>"Alan W2AEW": Paul - narrow BW desirable because it acts as a pre-selection filter (for busy band conditions). Not desireable due to touchy tuning.
<21:09:07>"George - N2APB": Yes it can! (That was some of the "SDR advances in the last 2 years" that I was alluding to.
<21:09:54>"Rick K3IND": what was the gain vs a dipole?
<21:11:43>"Joe N2CX": John I saw the helically loaded loop. I want to try to model it to see how well it might compare.
<21:12:40>"Joe N2CX": Gain will be less than a dipole since it radiates over a wider surface.
<21:12:44>"John - KJ6CVB": Joe: I am building 2 helically loaded loops now. Lots of opportunities!
<21:12:52>"Paul - wa0rse": How did you arrive at the 100ft clearance and how could I evaluate a smaller space?
<21:15:45>"John - KJ6CVB": Loop currents are 5 to 7 amps.
<21:17:52>"Frank N3PUU": good presentation, thanks guys! 73
<21:18:50>"John k4kqz": good stuff. my first time to attend one of these, tnanks and 73!
<21:19:08>"Carlos - PY1EGG": 73 to all...
Click the Session Notes link below to see the slides for tonight's presentation ...
SESSION NOTES ... in PDF format
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