johnmichaelwelton wrote: > Any recommendations for a 1.2GHz antenna to be used in a DSTAR DD/DV > application at a commercial site (hospital)? > > John/N4SJW > Charleston, SC
For a repeater or base station (ID-1)? The options are somewhat limited out there. Sadly it seems the Comet/Diamond type antennas are some that a lot of people are using, and commercial quality options are few. For our repeater, which is on a mountain on the West side of the city, we used a custom-built 120 degree panel reflector. Sending the extra RF of an omnidirectional antenna back into the mountains, turned out to be a problem for our analog 1.2 machine years ago, so we avoided it and went straight to something with some gain toward town on the D-STAR system. DV (voice) on D-STAR 1.2 acts similar to any other analog 1.2 GHz repeater. DD (high speed data) being 100 KHz wide, requires more gain to go the same distance. Gain antennas are often necessary for good links on DD... a 10W radio, 100 KHz wide, isn't much signal left to work with a the far end. There is at least one ham running around saying he's bumped his ID-1 to 20W with no ill effects by finding the power setting pot inside and cranking it wide open. Not sure I'd do that, but just relaying the info. I'd want to look at it on a spectrum analyzer and also keep a very close eye on it for heat load if I were going to mess with the power setting in the rig. But his reports are that his ID-1 is surviving the abuse, just fine so far. Nate WY0X
