Inverted-L Experiences
March 2021

  My first inverted-L was built in the backyard when I lived in Stone Mountain GA. The vertical section was ~50 feet. The length of horizontal section has been long forgotten. The distance between the trees supporting the antenna were over 100 feet apart. The wire was intentionally cut long and its length was adjusted using wire thimbles and clamps to get the best SWR. The antenna was fed with coax and no other attempts were made to further tune the antenna. A make-shift ground round took the place of radials.  
  The first antenna raised in Stone Mountain was a 160M full-wave loop hung in the front yard of the 3+ acre property. With various balanced tuners the antenna worked FB from 160M all the way up to 2M. Comparing the antennas revealed no noticeable difference between the loop and the inverted-L. The loop stayed and the inverted-L went away to be replaced with other experimental antennas. With loop 30 countries and 47 states were worked over several years.  
  After retiring to the current QTH a new antenna farm was needed. One of the first temporary antennas was an inverted-L for 160M with three radials. Using a thimble and wire clamps to tune for the best SWR was not completely successful. The rig managed to tolerate the SWR and had trial runs in the December 2019 ARRL 160M and Stew Perry tests. The results were acceptable.  
  An L-C circuit was added at the feed point and an antenna analyzer was used to adjust the variable capacitor to get the least reactance. The SWR seemed reasonable although the point closest to resonance was ~1925 Khz. A non-scientific comparison of the results from the 2019/2020 December Stew Perry and ARRL 160M tests suggests the changes were most beneficial. In the 2020 tests 41 and 43 states respectfully were worked. In 16 months of using the inverted-L 48 states (missing AK & WY) have been worked along with 39 DXCC entities. The best DX to the east has been the Ukraine (~4580 miles) while to the west is Hawaii (~4450 miles). Not bad for 100 watts and a hunk of wire.  
  Even so the antenna's performance could theoretically be improved. The feed point was at the end of the driveway near the house and the antenna ran down the driveway parallel to the property line. This location limited the radial field to a quadrant rather than a full 360 degrees. The resonant frequency could be lowered by extending the antenna further down the driveway. Unfortunately with all the trees overhanging the driveway, not a one was suitable for a skyhook.  
  From the beginning this was a temporary 160M antenna. A decision was made to convert the antenna into an 80M vertical. The vertical is fed directly with coax and tuned empirically to 3550 kHz.  
  to be continued ...  
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