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Author Topic: Snap Shot of a Couple Different Antennas  (Read 5134 times)
W8BYA
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« on: April 07, 2013, 06:47:29 PM »

Over the weekend I installed a full wave length, single element delta loop antenna for 40m between two self supporting towers.  The antenna is in a triangle configuration with the horizontal side at the top at ~70' with the feedpoint down at the bottom at about the 20' level.  The loop favors E/W on 40m and has a TOA of around 30 degrees and a gain of almost 8 dBi. The loop is matched to 50 ohms through a series section line transformer. My goal is to use the loop as a general purpose SWL antenna on the different bands.

Using the two receivers of the flex 5000A I thought it would be interesting if I fed one receiver with the new loop antenna and fed the 2nd receiver with a CC R8 reference vertical that is ground mounted with the feedpoint at about 10'. Both antennas are in the clear.

Along those lines, I thought some members might find it interesting to see the relative responses of both antennas for several HF bands like I did.  I took a snap shot of the 16m, 19m, and 40m bands during the daytime at about 14:30 UTC.  Below are the URL's for those 3 snap shots with the loop being the top trace in all 3 cases:

http://gedas.cc/v/Misc/HAM-1/16m+band+2-ants.jpg.html

http://gedas.cc/v/Misc/HAM-1/19m+band+2-ants.jpg.html

http://gedas.cc/v/Misc/HAM-1/40m+band+2-ants.jpg.html

I guess the thing that struck me the most was how little difference there was between the two antennas, overall.  For some reason I was just expecting the loop to clobber the small vertical every where.  In general, it seems on 40m, most of this signals were arriving at a higher angle of arrival and the loop provided a slight advantage, but not huge.  On the other bands, the R8 seems to have provided slightly higher levels on some signals, but again, nothing huge.  If there is interest I can run more tests on more bands and at different times.  One test I will be doing soon is to repeat the 40m tests at night when lower angle DX signals will be present.

73 Gedas, W8BYA
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