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Author Topic: Would an antenna analyzer be very useful w/ a mag loop antenna?  (Read 988 times)

jackson_r

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I'm still struggling a bit trying to maintain a low SWR on my recently built mag loop antenna.  Could be the feedline, the coupling loop, connection points to the cap...I'm not sure at this point but I continue to troubleshoot.  In any case, I've been starting to consider buying a dedicated antenna analyzer to see if that makes it easier to pinpoint the problem, but I'm not certain it would be of much use with my setup.  From my research, it seems like the way you'd use an analyzer with a mag loop is simply making tweaks (either by rotating your cap or making adjustments to your coupling loop) while watching for the lowest SWR dip.  But this is what I'm already doing from the comfort of my shack via remote control.  I watch the SWR on my meter while making fine tuning adjustments to the vacuum capacitor via DC motor control.  The only thing I have to walk 15 feet outside to do is make positioning adjustments to the coupling loop.  

I know some people swear by antenna analyzers and feel it's nearly impossible to design or properly tune a mag loop without one.  I'm not opposed to buying one if it'll help ferret out my problem, but I want to make sure it's going to do something more than what I'm already able to do.  Because from what I have managed to read so far, it seems all the analyzer would do is enable me to stand outside in the cold weather making adjustments I could be making from inside the warm house.   :D
« Last Edit: March 21, 2016, 1741 UTC by jackson_r »

Offline Josh

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Re: Would an antenna analyzer be very useful w/ a mag loop antenna?
« Reply #1 on: March 21, 2016, 2140 UTC »
A decent ant analyser can be of great help in understanding reactances and so on, if you want one get one! They're not just useful for analysing ants, they make for a decent sig gen and can be used to perform other tests as well.
Also, some of the modeling programs may be of help, as well as looking over other people's work to make sure you're not reinventing the wheel or creating losses inadvertently that others have already overcome.
Conveniently located near Vincennes Indiana.

Offline pendulous

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Re: Would an antenna analyzer be very useful w/ a mag loop antenna?
« Reply #2 on: March 26, 2016, 0111 UTC »
I'm still struggling a bit trying to maintain a low SWR on my recently built mag loop antenna.  Could be the feedline, the coupling loop, connection points to the cap...I'm not sure at this point but I continue to troubleshoot.  In any case, I've been starting to consider buying a dedicated antenna analyzer to see if that makes it easier to pinpoint the problem, but I'm not certain it would be of much use with my setup.  From my research, it seems like the way you'd use an analyzer with a mag loop is simply making tweaks (either by rotating your cap or making adjustments to your coupling loop) while watching for the lowest SWR dip.  But this is what I'm already doing from the comfort of my shack via remote control.  I watch the SWR on my meter while making fine tuning adjustments to the vacuum capacitor via DC motor control.  The only thing I have to walk 15 feet outside to do is make positioning adjustments to the coupling loop.  

I know some people swear by antenna analyzers and feel it's nearly impossible to design or properly tune a mag loop without one.  I'm not opposed to buying one if it'll help ferret out my problem, but I want to make sure it's going to do something more than what I'm already able to do.  Because from what I have managed to read so far, it seems all the analyzer would do is enable me to stand outside in the cold weather making adjustments I could be making from inside the warm house.   :D

I think having an antenna analyzer is helpful for troubleshooting issues. I have the mfj. i have used it to find resonance, reactances, shorts and opens on coax. They make it easier. your problem with the loop sounds very interesting. I have a mag loop. the bandwidth is very, very narrow. Move of frequency just a little and swr will change. Are you retuning after you move frequencies? is your transceiver frequency output stable, no drift?