DES Rotating Dipole |
Now, neat though this is, I question whether it is really worth the expense. At this stage I have no idea of price but I would expect somewhere between £50-100? My simple Homebase-10 wire halo is MUCH smaller because the 10m dipole is arranged in a square. A 6m halo can be nested inside very easily and fed with the same coax. To add a 15m halo would only increase the size by 50%. Unlike the Cobweb antenna, my simple design could be assembled as a 3 band version for less than £15 with all new parts.
Homebase-10 10m halo |
A dipole, if rotated, does have the advantage of being able to null out interference but I am not sure this is such a benefit. For me, it is either something like a horizontal halo which tends to be a "quiet" antenna picking up little local (vertically polarised) man-made interference or a small beam which would have some gain and directivity. However, the latter will only add about 0.5-1 S-point in signal level and, time you buy a decent rotator and the beam, you will have paid 10-15 times more for the privilege. A beam does add directivity and interference rejection, but is much larger. For me it is a "no brainer". My simple little halo has allowed me to get QRP reports on SSB, CW and WSPR from all over the world. It is simple and works well.
3 comments:
Do you have schematics or point references on how do you feed the double (would be triple) halo with a single coaxial feed? TU de Pedro LU7HZ
Pedro, The coax is connected to the centre of the folded dipole section of each of the 3 dipoles. In effect, all 3 dipoles are in parallel. You will have to trim the lengths of each dipole to get best match across all 3 bands.
So you think this new antenna will cost GBP 50-100? The way ham gear is priced these days you're probably off by a factor of five.
If you're going to go through the hassle of putting up a rotator, at least get some front-back directivity out of it. A two or three element Yagi at-least.
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