View Single Post
  #11   Report Post  
Old May 29th 09, 04:31 PM posted to rec.radio.amateur.antenna
John KD5YI[_3_] John KD5YI[_3_] is offline
external usenet poster
 
First recorded activity by RadioBanter: Jun 2008
Posts: 24
Default Loop antenna matching question


"Owen Duffy" wrote in message
...
Michael Coslo wrote in news:gvhhkj$do4m$1
@tr22n12.aset.psu.edu:

I'm starting up an old project that I never quite finished - my loop
antenna.

When I first put it together, I tried a simple loop of coax to couple
the radio to the loop. Was never really satisfied with that though.

I'm wanting to try a gamma match, possibly something a little like what
Owen Duffy posted a nice version of.

The Gamma match is fairly understandable to me, and I expect it to work
well.

What I am wondering about is in the coax loop coupling system, how is
the best match obtained? Loop size? orientation? Luck?


Mike, you haven't given much information about the loop (size,
frequency). Is loop balance / symmetry important?

If it was a small loop, I would not be thinking about a gamma match
because of the impedance ratios for just one reason.

Owen



Owen -

I've had this nagging idea for a couple of years: What if the (single-turn?)
loop passes through a toroid which already has, say, 10 or so turns on it?
That should give an impedance step-up of 100 or so. Would that not be a good
way to at least get the matching closer? In fact, the tuning capacitor could
be connected to the high impedance side to reduce the capacitor's value.

Your comments will be appreciated.

John