|
The hat used in these tests was the
DX
Engineering Hot Rodz system.
| Type |
Height Base |
Top Length |
Hat dia |
Field Strength |
Frequency |
Relative FS |
|
| Reference |
|
|
-18.5 |
|
|
best tested antenna |
| Large
air |
36" |
84" |
0 |
-18.50 |
7.2 |
0.00 |
3"dia #12 |
| Large Air |
36' |
27" |
47" |
-18.70 |
7.2 |
-0.20 |
3" dia #12 47" hat |
| Small air |
36" |
27" |
47" |
-19.90 |
7.2 |
-1.40 |
1.5"dia #16 47" hat |
| TarHeel |
42" |
27" |
47" |
-21.00 |
7.2 |
-2.50 |
Tar with 47" dia |
| TarHeel |
43" |
84" |
0 |
-21.10 |
7.2 |
-2.60 |
Tar with 7' whip |
| RM-20 |
36" |
27" |
52" |
-21.20 |
7.2 |
-2.70 |
Hustler RM-20 on 40m |
| TarHeel |
43" |
27" |
23" |
-22.00 |
7.2 |
-3.50 |
Tar with 23" dia |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| TarHeel |
61" |
84" |
0 |
-19.80 |
3.5 |
|
|
| TarHeel |
59" |
27" |
47" |
-19.70 |
3.5 |
|
47" DXE |
The most striking things are:
- The range between the best and worse system was
only 3.5dB
- A large hat at the TOP of the antenna allows
considerable shortening with no loss in efficiency
- For a given height antenna, efficiency is
increased with a hat at the top
Mobile and Loaded Antenna
|