A good source for Heliax is: <http://www.surpluscoax.com/index.html> Reasonable prices at this time. As I recall, 1/2" Heliax for about $1.45 per foot, and they have the needed connectors as well. Prices on the Heliax are less than 1/2, or almost that,compared to what HRO shows for the same types. I would tend to want to go with the 7/8" for even lower loss. I did buy 100' of the 7/8" Heliax, and connectors, for use on my 440 repeater. remember, the lower loss works for receive as well as TX., and can effectivley increase your range a bit more. YMMV
Wayne WA2YNE Imperial, Tejas 441.950TX 446.950RX 167.9 tone On Sat, 31 May 2008 18:07:46 -0500, 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:[email protected]> , Nate Duehr <[EMAIL PROTECTED]> > 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> > -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! 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