28Mhz Delta loop Antenna;

In order for shrinking my luggage size, I would like to bring wire antenna on this DXpedition. However I want to make QSO as much as possible due to high possibility of this new entity. For the low bands, a beam antenna even or a full-sized antenna would force my luggage fat. I should study high band antenna deeply to begin with anyway.

Delta loop, vertical, or dipole would become promising candidates for this DXpedition, because these antennas are easy to be configured with copper wire. To make a proto type is one way to study antenna but most effective solution to check the antenna is simulation. As many of hams may know, EZNEC is well applied antenna simulation. EZNEC demo, even some useful function was restricted, really works enough for these simple antennas.

I took the elevation angle and gain into account as my priority. The band width is second priority for me. Comparing the gain, the delta loop and the dipole are same, but the vertical gave approx -3dB less than these two. Comparing the elevation angle, the delta loop gave 20deg, but the dipole and the vertical gave 7degree higher than the delta loop. 7degree difference might impacts the traveling distance significantly. Flat surface model shows 40% longer traveling distance in delta loop case. Regarding the band width, these three are comparable each other for me. Finally I figured out the delta loop gave suitable result according to my concept based on the simulation. As the result of proto type test, I observed excellent capability on antenna analyzer measurement.

Please see the data I referred this study in below;

 Calculated data EZNEC demo Measured data Azimuth Beam Elevation Beam SWR SWR [Measured] 28Mhz Delta loop Gain= 8.67dBi Elevation Angle=20deg f0=28.15Mhz f0=28.4Mhz |Z|=46+0.8j SWR=1.15 28Mhz Vertical Gain=5.12dBi Elevation Angle=27deg f0=28.2Mhz 28Mhz V-Dipole Gain=8.19dBi Elevation Angle=27deg f0=28.15Mhz

Traveling distance/ Flat surface model

28Mhz delta loop dimension

Delta loop in test;

18Mhz Dipole Antenna;

Dipole for 17M is well adjusted with no problem at all.

Buddistick for 80M and WARC;

Buddistick with extra grounding wires, 10ft 6pcs, shows good SWR quality.

 3.5Mhz 3.8Mhz 10Mhz 18Mhz