Well as you know, one is never satisfied with their own repeater. Always wanting to have better!
Yes, the Dstar system is great. I am changing the fiberglass vertical to the Anitron-150 which is a set of folded dipoles. I'm running a TE Systems PA and a Chip Angle preamp. Yes, 50 feet sucks but, it's the law here in Laredo. Nothing over 50' I have not purchased Heliax in years and was a little afraid to even ask due to the copper costs have risen over the last few years. Hope to hear you on Dstar? --- In Repeater-Builder@yahoogroups.com, Ron Wright <[EMAIL PROTECTED]> wrote: > > > Shame you can only get up to 50 ft. D-Star is exciting mode and the > telewave 4 can duplexer is good. I would consider something other than > the LMR400 for with their dis-similar double shields it can cause noise. > I would seriously consider 1/2" heliax and 80 ft will not be big > investment. > > I am not familar with the Anitron-150, but since similar to the 220 it > will play well. One problem with fiberglass antennas is that they are > made of coaxial lines that are often soldered together. Lightning tends > to melt the solder when hit and being top mounted can be a concern. > > I think all ICOM D-Star gear is lower power than the 120+ Watts. Wonder > what PA you are using. > > As so many Ham repeaters start they begin at a low site. Then they get > going and others find them and someone comes up with a better site often > a broadcast engineer with an inside tie or commercial guy that has > access to a higher site. You just need to be ready to jump on it when > it comes, and if you hang in there it will come...not a question of if, > but just when. > > Good luck with your system. You've gone this far so might seriously > consider replacing the feedline. I am sure there are others that agree. > > 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 6:49 PM, atms169 wrote: > > It's the KE5KAF Dstar system in Laredo. > 2 Meters > 120 watts after duplexers > Telawave 4 cans 600 Split > Coax LMR-400 80feet > Antenna I want to put up is a Commercial Anitron-150 Similar to a DB220 > > --- In Repeater-Builder@ yahoogroups. com > <mailto:Repeater-Builder@yahoogroups.com> , Nate Duehr <nate@> 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> >
