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.
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
ReplyDeletePedro, 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.
ReplyDeleteSo 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.
ReplyDeleteIf 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.