Tag Archives: Double Bazooka

Rich re-activates Santa Fe Prairie State Park with QRM-busting in mind

Many thanks to Rich (KQ9L) for sharing the following field report:

Field Report: Testing a horizontally-polarized antenna at a high QRM POTA site

by Rich (KQ9L)

I wanted to give a quick follow up report from Santa Fe Prairie State Park (K-7839).

As you may recall I wrote up my POTA activation from this park on Oct 23, 2022. I made 15 Q’s that day but deep down felt I could do better. The setting of the park is quite industrial and consequently the man made noise is bad. Reflecting back on this activation, I feel that the limited the number of QSO’s I made that day was due to this QRM.

I resolved to try again but this time my objective was to figure out a solution to mitigate the effects of the QRM on my QSO count. Thinking about the problem, I recalled than manmade noise typically is vertically polarized and therefore for my second attempt, I decided to test this and use a horizontal antenna.

As luck may have it, here in Chicago we continue to experiencing unseasonably warm weather and my work schedule wasn’t too busy on Thursday, November 3, 2022, so it seemed like a great chance to put my theory to the test.

For the antenna, I decided to use one which I have owned for awhile, but have never used. I had purchased a RadioWaves Double bazooka from an online retailer some time back when they were on sale and planned to set up it a flattop dipole.

If you recall from my description of the Santa Fe Prairie State Park, there is a scenic overlook which has a tree mounted pulley system perfectly spaced to mount a 20m dipole. Although this would be the first time I used the system, it turned out to be a well designed and intuitive hoisting solution to use.

The “pulley” is actually an eyelet with paracord running through the eyelet. The paracord is in a continuous loop just like rope on a flag pole. By employing a simple overhand knot I secured the end of the antenna to the paracord and hoisted the antenna up into the tree about 20ft. It literally took a few minutes and I was ready to go.

Antenna was fed with my RG-316 feedline with built in common mode choke. Since a dipole is a balanced antenna system, it really doesn’t need the choke, but it was the coax that I had packed with me and I figured it wouldn’t cause any harm or negatively affect my test. I was QRV by 3:20pm, and anxious to get on the air. Continue reading Rich re-activates Santa Fe Prairie State Park with QRM-busting in mind