Last updated: December 23, 1999
I live in an apartment, no roof, no backyard and no tower (of course). I face the problems which most ham face in Hong Kong when setting up their HF antenna. The only things available for me is window mount type. I do not want to use antenna tuner as I do not have space for it. So, the elements are all 1/4 wavelength long.
| elements length = 0.25 * c/f * vf
c = velocity of light ( 299,792,458 m/s ) f = centre frequency of the antenna in Hz vf = velocity factor of coated wire (I use 0.95) |
The set up is only temporary as I do not expect the PVC tube I use will be strong enough to stand tough weather. Most important is that I do not want to get too much attention from my neighbour and the estate management company. Basically, I set it up only when I want to have QSO.
Sketch
Caution
Special attention should be paid to securing the PVC tube (I used a 9 feet long one). It will really kill someone if it drop from my 32 floor apartment. The performance of the antenna will improve if the tube is longer. However, we have to judge our ability to SECURE IT FIRST !!!
Advantages
It is cheap, easy, fast to set up and most important is "It Works!!". I have been having lots of funs by DXing with this antenna (10 to 20 meters). Quite some hams in Hong Kong setting up their antenna similiarly. Of course, there are always much better antenna, but it is my only choice at this moment.
Disadvantages
Attention must be paid in securing the PVC tube each time I set it up. Also, a pair of elements must be made for each ham band. Although the set up is fast, I need 4 to 5 minutes to change band. Please wait for me if you ask me to change band for testing.
References