Yes, I have spent a lot. It's a Dstar repeater.
--- In Repeater-Builder@yahoogroups.com, Ron Wright <[EMAIL PROTECTED]> wrote: > > > At 50 ft HAAT, which looks as what you have, 10 mi ideal situation > coverage (dist=(sq root (2 x 50)). > > A good DB224 or fiberglass like the RFS 220 or Telewave ANT150F6-2 (I am > assuming 2 m) would give good coverage of what you have. Feed line 1/2" > heliax a min. At this run going to larger would gain little. I like > the fiberglass, but for top mount DB224 would better stand the > lightning. > > However, you seem to have put lots in a PA and little in anything else. > The PA except for suppurious emission specs, is the last to worry about. > Good antenna and receiver should be what you are talking about. > > All of what Nate said is good advice. Mainly height and antenna is the > name of the game. > > I hope you did not spend much on this repeater, but guess is a start. > > 73, ron, n9ee/r > > > > > > Ron Wright, N9EE > > 727-376-6575 > > MICRO COMPUTER CONCEPTS > > Owner 146.64 repeater Tampa Bay, FL > > No tone, all are welcome. > > > > > On Sat, May 31, 2008 at 4:15 AM, Nate Duehr wrote: > > atms169 wrote: > > Hey guys, I'm trying to find radiation patterns or a calculator to see > > what would be the best possible coverage for our repeater. > > There's a number of calculators on the web, and some good links in the > RB website for Excel spreadsheets where you can see the math if you > like. > > > We are in the very flat lands of Texas and our repeater is only up 50 > > feet (total of 530 above sea level). With 120 watt output. > > 120 watts after the duplexer loss, or before? What kind of duplexer, > feedline, etc. > > Assuming 50' for the transmitter and 8' (I'm being generous) for a > mobile rig, the radio horizon between those two is approximately 14 > miles, according to the popular calculators. > > Anything else isn't line of sight propagation. > > > Which do you think would work better? A dual folded dipole antenna > > with low angle of radiation or a fiberglass vertical at 6db? > > Let's assume power doesn't matter for a moment, and just break it down > into comparison of the antennas. > > Remember, altitude trumps all, antenna gain and feedline losses next, > and the PA is *last* place you want to make up for a weak antenna > system. The antenna is gain both directions, transmit and receive. The > PA only helps people hear the repeater... it doesn't help them get into > it. > > So... the important info is missing in your question... > > What band? Can't answer the antenna question without knowing what band > you're looking at to compare different sized antennas. Makes a big > difference. I will assume VHF for these answers for the moment. > > You say 6dB. Is that 6 dBd or 6 dBi? That also makes a big difference, > since we're going from your numbers for the one antenna, and don't know > which other antenna you're comparing to. > > What specific antennas are you looking at? Spec sheet on the web > somewhere to reference? For both... the dipole array and the stick. > > Most dual-dipole- array antennas claim about 6 dBd gain when set up in > an > elliptical pattern. That assumes a 1/2 wave spaced (from the mast) > dipole array, like this Sinclair: > > http://www.sinclair technologies. com/catalog/ product.aspx? id=1680 > <http://www.sinclairtechnologies.com/catalog/product.aspx?id=1680> > > There are different configurations for 1/4 wave spaced (from the mast) > dipole arrays, the lowest gain being the purely omni-directional setup. > The "offset" setup where you pick a direction to "push" your RF one > way more than the others, gives you a little more gain that direction at > the expense of the other side. > > http://www.sinclair technologies. com/catalog/ product.aspx? id=326 > <http://www.sinclairtechnologies.com/catalog/product.aspx?id=326> > > Generically, there's no free lunch. The same sized antennas exhibit > much the same gain, but you can do tricks with the dipoles a stick can't > do... like offset the pattern a bit. > > You could always go for an enormous VHF corner-reflector! > > (Yep, they make 'em...) > > http://www.sinclair technologies. com/catalog/ product.aspx? id=1403 > <http://www.sinclairtechnologies.com/catalog/product.aspx?id=1403> > > It's ONLY 10' wide... hahaha... > > More info needed... the devil is in the details. > > Nate WY0X > <http://www.sinclairtechnologies.com/catalog/product.aspx?id=1403> >
