American Association of Variable Star Observers (AAVSO)
Sun, 05/26/2019 - 04:11


I am planning on setting up a SuperSID monitor and have some questions regarding the antenna.

First is the size of the antenna. On the solar observing section it states that the antenna needs only to be a little larger than a dinner plate. The Stanford Solar Center states that a larger antenna, maybe 2 meters on a side would be more sensitive. How important is the size of the antenna for monitoring SIDs?

Next, how critical is the orientation? The pictures I’ve seen all have the antenna mounted upright. With a 2 meter antenna mounted upright, I am most likely limited to having the normal to the plane pointing north.

I was considering mounting a circular antenna on the ceiling of a room so that the normal would point up. Would this work?

I live in Springfield Oregon in case the location of the transmitters are an issue.

After I get this cleared up I’m sure I will have a whole lot of other questions.  

I appreciate any help I can get.

Duane Dedrickson

SID antenna

Hi Duane,

Many different designs for these loop antennas.  I prefer the smaller loop with 75 cm cross bars using # 28 gage magnetic wire.  To resonate at aournd 30 kHz it takes about 145 turns of wire (approximately 1000 feet).  See the image attached.  The SARA folks, where you got the SuperSID, suggest a larger loop with less turns and larger gage wire.  

The orientation (pointing) the loop is very important, it needs to be somewhat vertical. To pick up NPM, NLK, NML and NAA from your location, it probably needs to be pointing east - west. But only by moving it around some can you be sure.  

Make sure your sound card is set at high definition (96 kHz). When you run the SuperSID software you can watch the plot window as you rotate the loop.  Notice the spectrum in this screen shot, with the 4 stations, from 19 - 25 kHz.  Here in Fort Collins, CO, the loop is pointing east - west.