megabyte@AMES.ARC.NASA.GOV> (02/08/90)
Well it comes to this: I want to monitor all those buzzes, beeps and chirps I hear on my Icom R71 and I now I need more equipment. I know there are really two routes: 1) Stand alone decoders that can connect to a printer monitor or other RS-232 device 2) Decoders that utilize your IBM computer for the brains. I happens to have a Radio Shack 1000 I don't use much I could utilize in this endever. Here is the question: I see the Universal 'M' series of decoders starting at about $500.00, I se several small RTTY, ASCII, and CW decoeders with little 25 or so element "Times square marqee" displays and then MJF has a RTTY, CW, and ASCII decoder that connects to an IBM PC for about $75.00 What is the best way for a beginer to get into the monitoring of the digital utility stations? How much can I expect to spend? Should I go stand alone, "Marquee Display" type, or units that require an external computer? -- Mark E. Sunderlin: IRS Technocrat in Winchester, VA aka Dr. Megabyte: megabyte@chinet.chi.il.us (703) 667-5203 "We're very kinky, in a Republican sort of way." - Sue Pauloz
mn@BBN.COM> (02/09/90)
In article <1990Feb8.194719.7372@chinet.chi.il.us> megabyte@chinet.chi.il.us (Dr. Megabyte) writes: >Well it comes to this: I want to monitor all those buzzes, beeps and chirps >I hear on my Icom R71 and I now I need more equipment. I know there are >really two routes: > >1) Stand alone decoders that can connect to a printer monitor or >other RS-232 device > >2) Decoders that utilize your IBM computer for the brains. > >I happens to have a Radio Shack 1000 I don't use much I could utilize >in this endever. > >Here is the question: I see the Universal 'M' series of decoders starting >at about $500.00, I se several small RTTY, ASCII, and CW decoeders >with little 25 or so element "Times square marqee" displays and then >MJF has a RTTY, CW, and ASCII decoder that connects to an IBM PC for >about $75.00 > >What is the best way for a beginer to get into the monitoring of >the digital utility stations? How much can I expect to spend? >Should I go stand alone, "Marquee Display" type, or units that >require an external computer? Since you already have a computer, a powerful chunk of hardware, I would suggest getting add-on devices and the software to run them, rather than buying stand alone black boxes that are just very limited computers with limited functions. MFJ makes a radio modem that has just about every commonly used digital mode; CW, FAX, RTTY, AMTOR and few others I forgot. If your RS 1000 is a PC compatable you can choose from a wealth of software, both off-the-shelf and public domain. If you can program you can roll-yer-own shack software, which is what I did. The R71 is a darn good rig to copy digital modes with, and using your computer you'll have a lot of fun making sense of some of those chirps and warbles. There is one gotcha about RTTY on HF. Much of it is encrypted, often using very simple bit inversion techniques that can be easily broken with the right software. Most of the news services that used to be on HF have moved upward to satellites. Even still there is a lot of ham, weather and commercial RTTY being sent in the clear. ------------------------------------------------------------------------------ | Michael Nowicki N6LUU Atari Corp,Sunnyvale CA /TT/UNIX/X team | |............................................................................| | char *disclaimer=" Views expressed are my own, not my employer's"; | | char *good_quote=" 'Wait'll they get a load of me!' - The Joker"; | ------------------------------------------------------------------------------
roskos@BBN.COM> (02/10/90)
megabyte@chinet.chi.il.us (Dr. Megabyte) writes: >Here is the question: I see the Universal 'M' series of decoders starting >at about $500.00, I se several small RTTY, ASCII, and CW decoeders >with little 25 or so element "Times square marqee" displays and then >MJF has a RTTY, CW, and ASCII decoder that connects to an IBM PC for >about $75.00 >What is the best way for a beginer to get into the monitoring of >the digital utility stations? How much can I expect to spend? I looked in great detail at the Universal "M" series about a year ago, including buying the technical manuals, then writing to Universal to ask questions about it. (I was reluctant to spend $1000 on what I found in the technical manual for the M7000, basically, without some more specifications justifying the price.) Actually I also wrote to the manufacturer, but they just forwarded the letter to the Universal salesman. I concluded the Universal devices are overpriced. For best results they require a video monitor. They receive grey-scale fax but the quality is very crude. Internally they are much simpler than some of the other devices that are less expensive; the main thing they have that some of the others (like the PK232) don't is an A/D converter for use with fax. The filters are much simpler than those in the PK232; I could never get Universal to give me any specifications to use to compare the M7000 performance-wise with the other models (though they did give me a nice sales pitch with an analogy to sportscars), so I could never find out whether some magic software in the M7000 made up for the lower-order filters (which should not have as sharp rejection of adjacent signals and noise as the higher-order filters in the other manufacturers' equipment, unless I'm missing something). Eventually I bought a PK-232, and am quite pleased with it. It's rumored that AEA is about to come out with an all-new replacement for the PK232 based on a digital signal processor, though; so it might be a good idea to wait and see if this rumor turns out to be true. But the PK232 works remarkably well, across a wide range of shift widths (the difference between the "mark" and "space" frequencies in RTTY). HOWEVER... there is not much out there to receive. Remember that most of the people who send by the digital methods, other than amateur radio and a few weather stations, don't want their communications monitored, and so they encrypt them. Using real, genuine encryption schemes. Most of those really strong stations you can hear with an SSB receiver are military encrypted communications. Here in Washington DC (which is also where the person asking the question lives), I can receive only the USIA's "Wireless File", the Canadian Forces' Halifax weather broadcasts, and a strong Spanish-Language station from Argentina, with regularity. Also occasional telegrams from Cuba to people in the US. Generally there is a good bit of garbling of the data in all of these, though, since RTTY is more susceptible to minor interference and fading than voice stations. I can also receive the coded (for compactness, not for purposes of encryption) weather broadcasts from the Air Force's weather station in Nebraska. There are other things... for example, ship-to-shore communications via SITOR. But there is nothing one would really want to read regularly, in my opinion, since other than the weather broadcasts, most of it is point-to-point communications, not broadcast news or similar information. My personal interest is in weather facsimile. It is generally intended for wider reception; and there are a lot of different types of weather facsimile to experiment with. If you have a good SSB receiver, you can get a demodulator to go with a PC for around $100 or so. (It produces 4-bit parallel data; you can input it through the game port, for example.) For about $200, you can get a VHF receiver to receive the satellites directly when they go over head, although this takes some serious interest since they only go by at specific times which you have to calculate (via software) from the bulletins TS Kelso publishes in rec.ham-radio or a similar source, and it takes some work to get the receiving station set up. You need the above demodulator for those too, so the cost is closer to $300, plus you need a good EGA or (preferably) VGA display. You can buy display software to use with the above for about $50, so that part's easy. In my opinion, having started out with the PK232 because I hoped there would be AP news, weather, etc. out there, and then found that there wasn't much, and then gotten eventually into WEFAX, it's better to skip the intermediate, somewhat disappointing steps and start out with WEFAX. Of course, your interests, and thus relative enjoyment, may differ. -- Eric Roskos (roskos@IDA.ORG or Roskos@DOCKMASTER.NCSC.MIL) "Some countries maintain `fast time' throughout the year, in which case it becomes `standard time'." -- DMA World Map 1150 (USGS)
pfluegerm@BBN.COM> (02/13/90)
In article <1990Feb8.194719.7372@chinet.chi.il.us>, megabyte@chinet.chi.il.us (Dr. Megabyte) writes: > Well it comes to this: I want to monitor all those buzzes, beeps and chirps > I hear on my Icom R71 and I now I need more equipment. I know there are > really two routes: Try the AEA PK-232. It'll copy basically everything except SSTV. Copies RTTY (baudot, ASCII) TOR (e.g. AMTOR, SITOR), CW, FAX (yes, weather fax and other photos), multiplex, NAV STX, and packet. IMHO the best. A very complete package for around $300. Audio in, RS-232 out. Needs a terminal emulation program. Needs their program (~$60) to display FAX onscreen (Mac or PC, I think its available for Amiga & Commodore also). They are rumored to be near completion of a DSP (digital signal processing rather than analog modems) unit - which should be more flexible for upgrades, etc. Any ham store should be familiar with this, and all the ham mags have ads for it. FYI, most non-amateur RTTY is encrypted. What isn't is mostly weather information, although a few wire services can be heard. -- Mike Pflueger @ AG Communication Systems (formerly GTE Comm. Sys.), Phoenix, AZ UUCP: {...!ames!ncar!noao!asuvax | uunet!hrc | att}!gtephx!pfluegerm Work: 602-582-7049 FAX: 602-581-4850 Packet: WD8KPZ @ W1FJI Internet: PLEASE USE UUCP PATH (NOT INTERNET)!