Not sure how good or bad these antennas are, but even if these antennas are crap, it is a good source of 3 meters of coax with sma male connector for $4 , and we can always cut the whip to 1/4 wavelength or replace the whip by thin wire of 1/4 wavelength, or a V-stub design.
I have ordered 4 of above antennas.
Today I received these. I compared them with the good one I have purchased 3 years ago. None of above Whip antennas are as good as the one I already had.
Since the Old Good one had 1m RG174 cable, while new ones have 3m RG174 cable, to keep comarision realistic, I did not change the whole antenna assembly. Instead I kept base and 1m coax of Old Good One in place, and only changed Whips, which is very easy as the whips are screwed to the base, and all have identical thread.
| Antenna Description | Length & Number of Coils | Number of aircraft received |
|---|---|---|
| Old Good One | 20.4 cm, 1 coil 9.5 turns | 35 |
| New # 1 | 20 cm, 1 coil 10 turns | 18 |
| New #2 | 25 cm, 1 coil, 10 turns | 25 |
| New #3 | 29 cm, 1 coil 8 turns | 15 |
| New #4 | 31 cm, 2 coils 10 turn each | 7 |
|
Repeate: Old Good One |
20.4 cm, 1 coil 9.5 turns | 34 |
CLICK ON IMAGE TO SEE LARGER SIZE
CLICK ON IMAGE TO SEE LARGER SIZE
Maybe they simply want to tell us that it can be used for Flightaware 
