Re: No 2m but still an APRS igate?
"John D. Hays" <john@...>
Hi Sander,toggle quoted messageShow quoted text
Maybe I can clarify this a little bit. If you look at the wiki information in the link you included, 144.39 nor 1200 baud is universally used for APRS or igates. You will find there are UHF networks and 9600 baud networks, including 9600 baud UHF networks.
Obviously, anyone using a UDR56K for an APRS tracker is only going to be able to report to 70cm igates.
The UDR56K was designed to be both a user radio and an infrastructure (igate, D-STAR gateway, AMPRNET, RMS, etc.) radio. If you are using it in infrastructure, say as an igate, it can do that. A frequency, modulation (FSK, GMSK, 4FSK) and baud rate (4800-56000) would be selected and the proper application loaded and run. Any trackers would need to match the same combination.
A lot of thought went into the selection of the band and the modes under which the radio would operate.
The concept of "Universal" Digital Radio means it can be used for more than one application. So while one user might want to use it for 9600 baud APRS, another might want to run it at 56Kbps for file transfers in an RMS function, or to pass AMPRNET or D-STAR DATA traffic. Yet another user might want to run D-STAR Voice or Codec-2.
2 meters, suffers from being "too popular" -- in many countries it is only 2 mHz wide, with FM repeaters, weak signal, APRS, satellites, etc. all trying to squeeze into the band. A 56Kbps signal is not permitted in the US FCC regulations on 2 meters and would not be friendly to other spectrum users if it were.
The 219 and 222 band is interesting and may lend itself to a UDR type radio (the band is only available in a limited area such as US/Canada), so the thought is that it is better to use 70cm as a good place to start:
Here's the good news though. If you have a current igate on 2m, you can replace the computer with a UDR56K, attach a USB-to-Serial cable to the TNC and radio to continue to service the 144.39 net, while offering 9600 baud or better APRS on the UDR56K's 70cm radio. Then you would have a dual band igate with less power requirement (by loosing the computer) and a much smaller package. Attach a diplexer and dual band antenna and you are ready to go.
On Tue, May 22, 2012 at 10:27 AM, Sander Pool <sander_pool@...> wrote: