There is really a lot of good information in this thread. It's going to help me a lot.
I think I might be going the less-preferred route in setting one of these up. Being not so patient :-), I'd like to get something up and running as soon as possible and then tweak it to a better system. Therefore, I will probably just get these at first. 1) ID-PR2C - The controller 2) ID-RP4000V - Voice Module 3) A duplexer (yet to be decided; suggestions) 4) Gateway server (with software) I will use my existing antenna, even though it might not be the best one for this purpose. But I have it already. And if I'm going to buy a new antenna I would probably have to have different mast structure and such and that's something I can improve later. That should give me the essential part of the system and allow me to check out the interconnectivity, software and a gateway. I'm a bit concerned about setting up the gateway computer. I'm thinking that might be my technically most difficult task. Mike --- In dstar_digital@yahoogroups.com, Nate Duehr <n...@...> wrote: > > On Aug 25, 2009, at 8:06 AM, ipscone wrote: > > > I have been thinking about setting up a D-Star repeater. I don't > > have access in much of the area where I live. So, I'm thinking about > > setting up my own. > > > > But I want to scope this thing out, before I start purchasing. Mine > > would be limited to 70cm and 23cm. I would likely start out with a > > bare bones 70cm system and build. I would also like to add a > > gateway. So what all is required, is my question. > > > > I already have the antenna, that I use for analog station. > > > > > Let's talk about the RF side of things, since you have an > understanding already of what "boxes" to buy from Icom. > > Starting off, let's re-iterate my old elmer's rule: "The antenna makes > the radio." > > What he means by that is... you can hook a $4000 radio to a crappy > antenna system, and it will underperform a $100 radio hooked to a good > antenna system, every day of the year. > > Many good repeater folks would recommend against most of the usual > fixed station antennas that are usable for home use because they > exhibit odd problems when operated in duplex service. You might want > to consider as one of your first upgrades, purchasing a DC-grounded > (since you won't be unplugging antennas when storms come through -- > you might do that for your home station, but repeaters stay on the air > during thunderstorms), high-quality, commercial antenna. Personally, > my repeater club uses Sinclair brand antennas, but there are others. > > > I know I will need: > > > > 1) ID-PR2C - The controller > > 2) ID-RP4000V - Voice Module > > > > Does this get me a basic system? Am I missing anything? > > > > The PC/server for the Gateway, and a router capable of NAT'ing a full > Class C (the 10.x.x.x network), plus assorted Ethernet cabling, etc. > John covered the Gateway specifications in his reply. > > > Then, to add the 23cm, I would need: > > > > 3) ID-RP2D - 23cm Data > > 4) ID-RP2V - 23cm Voice > > > > Yes. > > > Is that all that's needed additionally to add the 23cm capability? > > Are either of these two required for my basic setup? The reason I > > ask is that the ICOM brochure shows these 2 modules in the path > > between the 4000V and the controller. > > > > You'll also need an antenna on 23cm. Since 23cm is a frequency most > hams haven't used, many are surprised that finding low-loss coax is > really their first lesson in learning to use hardline. Look up > feedline loss for your chosen cable and calculate how much signal is > lost from the antenna to where you'll install the radio, and you'll > start to see pretty fast that hardline is the way to go. Foil over > braid cables like LMR-400, LMR-600, etc... are not recommended by many > for duplex service. Some get away with it for a while, but eventually > you'll have noise on a duplexed system. Smarter to spend the money > once, and avoid the problem. > > Same really goes for the UHF side as well. When all is said and done, > not only does the antenna need to perform, you need low-loss feedline > between the antenna and the duplexer, and then again (even though it > might be something different and more flexible), between the duplexer > and the radios. > > Also as mentioned above, the repeater will be on the air in all > weather. Consider that you need a proper grounding entrance panel and > lightning protection capable of handling just about anything other > than a direct strike (nothing properly handles direct strikes, but you > can minimize the damage). Most home setups are NOT properly set up > for lightning and you might find that putting in a proper entrance > panel, bringing all antennas through it, and adding Polyphasers or > similar lightning protection runs into many hundreds of dollars. > > Final comments: In a later message you mention you need a duplexer. > The requirements for the duplexer in terms of isolation match any > other analog repeater system. A brand new duplexer for 1.2 GHz is > about the only way to go, you won't find those in the used market very > often. TX-RX makes a duplexer and combiner system specifically > designed to share a 23cm antenna between the voice and data modules, > otherwise you need two antennas and feedlines. Many folks have > reported that their setup for this works well. > > Pre-amps: Someone else mentioned preamplifiers. The D-STAR modules do > tend to be a little "deaf". Depending on your noise floor/noise > temperature at your desired installation location, most of the time I > would agree. You may want HIGH quality low-noise pre-amplifiers on > the receive sides on both UHF and 1.2 GHz. The hard part is measuring > performance increase. In an analog system, you can measure the usable > sensitivity fairly easily with standard RF test gear for repeaters. > In D-STAR, not so simple. > > > Now the gateway server questions: > > > > 5) I assume I can add this to either my basic setup or the full > > setup, right? > > > > You can add anything on at any time. No rush. Might as well get a > UHF running as best as it possibly can, before tackling the Gateway. > Then add the Gateway. Then go back and add 23cm. > > John covered your other questions. > > > Looks like a basic setup for 70cm only might be in the are of $3000- > > $4000 and a full system under $7+/- a bit. Have I missed anything > > that I need to know about? > > > > Better look into the pricing of the antennas, feedline, and duplexers > and make sure you have those right. But starting with a budget of $7K > and planning to build in stages, is smart. I've seen people THINK all > they need is a chunk of RG-8X, a cheap $100 "mobile" duplexer flat > pack from eBay, an old junk antenna from the garage rafters, and the > Icom modules. Those folks have never (usually) built an analog > repeater before, so they're in for a nasty surprise when it doesn't > work right, or at all. > > You're on the right path. Build it like the BEST performing analog > repeater in your area, and it'll perform well. > > Also not sure where you live, but don't forget to investigate the > frequency coordination situation in your area, and be prepared to > follow your local coordinator's process for finding an appropriate > frequency for the UHF and 1.2 modules. I've seen at least one person > in a densely populated area buy a VHF module, and then find out there > is a long waiting list for VHF pairs in their area. > > -- > Nate Duehr, WY0X > n...@... >
