Re: DB212-3 (Low-Band Antenna Systems)
Hi Norm, > "NORM KNAPP" <nkn...@...> wrote: > Took down a set of DB212-3 dipoles in good shape with harness. > I want to use them on 6m for a repeater antenna. I also want > to add one additional dipole. I guess I will need to modify > the harness and the dipoles as they are marked for 35.960 mhz.... If the loops are assembled with dimples in the metal, it's a bit of a pain to disassemble them for size reduction to 6 meters. I've also seen the same antenna assembled with rivets. 35.960 MHz up to 52 MHz is quite a distance... If you have a chance, please record the measurements of the original loops at 35.960 MHz... and the length of the coax phasing harness. > I will be mounting all four (or 3) on one leg of a tower > that is 4 feet on a face. Is it worth my while to go for > the 4th dippole? The loops are 155 inches from tip to > tip now. Looks like they need to be about 105 inches. > Anyone with any tips, pointers or advise? > Thanks.... As Kevin would say... the only "free lunch" regarding system gain is at or starting with the antenna. So an assumption would be to go for all the antenna gain you can muster. And there's something (often positive) to be said for the shear amount of antenna surface area. However, interference, noise and the site effective sensitivity are a side dish often served cold (often not very helpful to the system performance). Some juggling of the antenna system can be used to deal with really serious problems. You might first drag a single 52MHz dipole up to the repeater site and measure the effective sensitivity. cheers, s.
