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 [email protected]
