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The Hobby Of 49 MHz is getting Old should go digital.

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  • Adam E.
    When did 49 MHz transmission and reception start? When did the FCC implement this. I see that we need to keep this hobby alive with new digital AM
    Message 1 of 19 , Apr 14, 2009
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      When did 49 MHz transmission and reception start? When did the FCC implement this. I see that we need to keep this hobby alive with new digital AM transmission toys and accessories and digital 2 way communications would be the way to go. The voice for digital to
      49 MHz would sound better than the AM quality voice that has been is session for years.

      I know that most radios don't have a digital mode, some have decoders for digital transmission and reception. HDTV is taking over NTSC television and HD Radio is trying to take over FM and AM broadcasting. When is the engineers going to come out with a new form of digital voice technology like the ACPO 25 walkie talkies that police are using? Also when is the owner going to add a new picture up here for his group? I bet the kids will like their new walkie talkies if they sounded better and more fun to play with. Also with digital there is chance for more privacy than analog AM transmission.

      I just wanted to bring this up to the hobbyists and Hams.

      gccengineering Adam E.
    • bruce mallon
      Interesting ......   Now how do you do that and how do you stay within part 15 ? ... From: Adam E. Subject: [49MHz] The Hobby Of 49
      Message 2 of 19 , Apr 14, 2009
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        Interesting ......
         
        Now how do you do that and how do you stay within part 15 ?


        --- On Tue, 4/14/09, Adam E. <gccengineering@...> wrote:

        From: Adam E. <gccengineering@...>
        Subject: [49MHz] The Hobby Of 49 MHz is getting Old should go digital.
        To: 49megahertz@yahoogroups.com
        Date: Tuesday, April 14, 2009, 11:23 AM


        When did 49 MHz transmission and reception start? When did the FCC implement this. I see that we need to keep this hobby alive with new digital AM transmission toys and accessories and digital 2 way communications would be the way to go. The voice for digital to
        49 MHz would sound better than the AM quality voice that has been is session for years.

        I know that most radios don't have a digital mode, some have decoders for digital transmission and reception. HDTV is taking over NTSC television and HD Radio is trying to take over FM and AM broadcasting. When is the engineers going to come out with a new form of digital voice technology like the ACPO 25 walkie talkies that police are using? Also when is the owner going to add a new picture up here for his group? I bet the kids will like their new walkie talkies if they sounded better and more fun to play with. Also with digital there is chance for more privacy than analog AM transmission.

        I just wanted to bring this up to the hobbyists and Hams.

        gccengineering Adam E.


      • Facility 406 DM09
        Don t know the exact year, mid-70 s, I think. 49 MHz equipment is AM, FM, FSK, PWM and so forth, there are radio modems, remote control, voice, telemetry, you
        Message 3 of 19 , Apr 14, 2009
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          Don't know the exact year, mid-70's, I think.

          49 MHz equipment is AM, FM, FSK, PWM and so forth, there are radio modems,
          remote control, voice, telemetry, you name it.

          Would have to check the rules for video, but since there are few if any
          modulation format limitations, I suspect SSTV and the lower frame-rate FSTV
          video modes as used on other Part 15 services could be used since the
          bandwidth is only a couple KHz wide.

          Kurt
        • Facility 406 DM09
          I forgot to mention that both digital an analog encryption has been used on Part 15 49 MHz voice devices for about twenty years too, check out many of the old
          Message 4 of 19 , Apr 15, 2009
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            I forgot to mention that both digital an analog encryption has been used on
            Part 15 49 MHz voice devices for about twenty years too, check out many of
            the old phones and intercoms.

            Kurt
          • Adam E.
            Well, I see that many hams tried to go digital with their home made transceivers, as long as you do not over modulate the signal you should be fine. Digital
            Message 5 of 19 , Apr 18, 2009
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              Well, I see that many hams tried to go digital with their home made transceivers, as long as you do not over modulate the signal you should be fine. Digital is a form of 0's and 1's that are pulses. The FCC should give people the right to build new devices as long they operate within the part 15 rules. Part 15 is considered to be
              experimental, flea powered. One day AM hobby broadcasting will have their own type of format instead of begging the the propertary format from Biequity, which Clear Channel uses for digital broadcasting. Someone will read up on it and come out with a special digital format
              mode. Maybe I could do it if i had the money. Actually Digital Radio Mondiale would be a beginning start in 49 MHz radio broadcasting.

              Here is a demo version of digital radio monodiale on a cassette or
              radio. The audio quality is going to be like this if you are going to use 5 kHz of a channel. That's how best its going to get for 49 MHz and narrow bandwidth AM transmissions.

              http://www.youtube.com/watch?v=2mseiBwPKvk


              --- In 49megahertz@yahoogroups.com, bruce mallon <wa4gch@...> wrote:
              >
              > Interesting ......
              >  
              > Now how do you do that and how do you stay within part 15 ?
              >
              >
              > --- On Tue, 4/14/09, Adam E. <gccengineering@...> wrote:
              >
              >
              > From: Adam E. <gccengineering@...>
              > Subject: [49MHz] The Hobby Of 49 MHz is getting Old should go digital.
              > To: 49megahertz@yahoogroups.com
              > Date: Tuesday, April 14, 2009, 11:23 AM
              >
              >
              >
              >
              >
              >
              >
              >
              >
              > When did 49 MHz transmission and reception start? When did the FCC implement this. I see that we need to keep this hobby alive with new digital AM transmission toys and accessories and digital 2 way communications would be the way to go. The voice for digital to
              > 49 MHz would sound better than the AM quality voice that has been is session for years.
              >
              > I know that most radios don't have a digital mode, some have decoders for digital transmission and reception. HDTV is taking over NTSC television and HD Radio is trying to take over FM and AM broadcasting. When is the engineers going to come out with a new form of digital voice technology like the ACPO 25 walkie talkies that police are using? Also when is the owner going to add a new picture up here for his group? I bet the kids will like their new walkie talkies if they sounded better and more fun to play with. Also with digital there is chance for more privacy than analog AM transmission.
              >
              > I just wanted to bring this up to the hobbyists and Hams.
              >
              > gccengineering Adam E.
              >
            • Facility 406 DM09
              Bypass the input filter and go straight to the modulator, you should be able to get 50 - 100 KHz bandwidth. Kurt ... From: Adam E.
              Message 6 of 19 , Apr 18, 2009
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                Bypass the input filter and go straight to the modulator, you should be able
                to get 50 - 100 KHz bandwidth.

                Kurt

                ----- Original Message -----
                From: "Adam E." <gccengineering@...>

                radio. The audio quality is going to be like this if you are going to use 5
                kHz of a channel. That's how best its going to get for 49 MHz and narrow
                bandwidth AM transmissions.
              • Dave
                ... The problem, though, is that digital transmission media require a much better signal to noise ratio than an analog signal. A bit of noise in an analog
                Message 7 of 19 , Apr 20, 2009
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                  --- In 49megahertz@yahoogroups.com, "Adam E." <gccengineering@...> wrote:
                  >
                  >
                  > When did 49 MHz transmission and reception start? When did the FCC implement this. I see that we need to keep this hobby alive with new digital AM transmission toys and accessories and digital 2 way communications would be the way to go. The voice for digital to
                  > 49 MHz would sound better than the AM quality voice that has been is session for years.


                  The problem, though, is that digital transmission media require a
                  much better signal to noise ratio than an analog signal. A bit of
                  noise in an analog channel can be filtered out by the operator. But,
                  a bit of noise in a digital channel causes the system to lose sync,
                  resulting in either no output, or garbled output.

                  Signal to noise ratio is basically dependent upon the signal
                  strength, which is limited by the Part 15 rules, there's not much
                  that can be done to improve this. Signal to noise ratio is also
                  dependent upon the bandwidth, but digital usually loses here, too,
                  since it usually takes a wider bandwidth to send audio data than
                  an analog voice signal (Yes, there can be some compression used,
                  which helps a bit, but there is usually control information, which
                  negates that savings.).

                  Thus, while a digital Part 15 device can (and do) work, the range
                  is usually inferior to analog systems.

                  > I know that most radios don't have a digital mode, some have decoders for digital transmission and reception. HDTV is taking over NTSC television and HD Radio is trying to take over FM and AM broadcasting. When is the engineers going to come out with a new form of digital voice technology like the ACPO 25 walkie talkies that police are using? Also when is the owner going to add a new picture up here for his group? I bet the kids will like their new walkie talkies if they sounded better and more fun to play with. Also with digital there is chance for more privacy than analog AM transmission.

                  Be ware of tossing out the digital TV analogy, since many people
                  are finding that digital TV is vastly inferior to analog TV.
                  Digital TV is fine for people on cable, or in the local broadcast
                  area. But, for anyone in the fringe area, the usual result is that
                  they lose several of the channels that they are used to seeing in
                  analog. Plus, even for those stations that they can still receive,
                  any noise tends to cause audio drop-outs and pixelation of the
                  display, which is much more annoying that just a spec of black in
                  the image [1].

                  [1] The designers of the analog TV system really knew what they
                  were doing in using negative modulation for the video signal.
                  That means that a noise spike results in a black pixel, rather than
                  the white pixel which would have resulted if a positive modulation
                  format were to have been used.

                  > I just wanted to bring this up to the hobbyists and Hams.

                  There are quite a few digital modes being used by hobbyists and
                  hams. AX.25 is the first one that comes to mind, but there is also
                  PSK-31, RTTY, and even CW (The reason that CW often punches through
                  when voice doesn't, despite being a digital mode, is that the
                  data-rate/bandwidth is significantly smaller than for voice modes.).

                  > gccengineering Adam E.

                  Dave
                  WA4QAL
                • bruce mallon
                  49 mhz has been around for at least 40 years ..... To be leagal you would have to design a system that put out under 10,000 uv per meter  at 3 meters and i
                  Message 8 of 19 , Apr 20, 2009
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                    49 mhz has been around for at least 40 years .....
                    To be leagal you would have to design a system that put out under 10,000 uv per meter  at 3 meters and i dont see how you could measure digital based on this very old part 15 requirement. ALSO how would you keep everything within the 15 khz ch spacing????
                     

                    > When did 49 MHz transmission and reception start? When did the FCC implement this. I see that we need to keep this hobby alive with new digital AM transmission toys and accessories and digital 2 way communications would be the way to go. The voice for digital to
                    > 49 MHz would sound better than the AM quality voice that has been is session for years.

                  • Facility 406 DM09
                    ALSO how would you keep everything within the 15 khz ch spacing???? Narrow digital. Kurt
                    Message 9 of 19 , Apr 20, 2009
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                      ALSO how would you keep everything within the 15 khz ch spacing????

                      Narrow digital.

                      Kurt
                    • bruce mallon
                      This is fine but how do you comply with part 15 ? ... From: Facility 406 DM09 Subject: Re: [49MHz] The Hobby Of 49 MHz is getting
                      Message 10 of 19 , Apr 20, 2009
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                        This is fine but how do you comply with part 15 ?

                        --- On Wed, 4/15/09, Facility 406 DM09 <facility_406@...> wrote:

                        From: Facility 406 DM09 <facility_406@...>
                        Subject: Re: [49MHz] The Hobby Of 49 MHz is getting Old should go digital.
                        To: 49megahertz@yahoogroups.com
                        Date: Wednesday, April 15, 2009, 1:32 PM

                        I forgot to mention that both digital an analog encryption has been used on
                        Part 15 49 MHz voice devices for about twenty years too, check out many of
                        the old phones and intercoms.

                        Kurt


                      • Facility 406 DM09
                        Yes, I used to have a beacon in the 90 s that transmitted Commodore and similar tapes. My first transmission used the boot cassette from an old Wang at work
                        Message 11 of 19 , Apr 20, 2009
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                          Yes, I used to have a beacon in the 90's that transmitted Commodore and
                          similar tapes. My first transmission used the boot cassette from an old
                          Wang at work around 1992. I still have many bankers boxes of the data
                          cassettes, both micro and standard transport, I think about doing it again
                          from time to time.

                          Interesting idea... I could play the data cassettes into my computer and
                          record it as a .wav file, then you could play it, connect the headphones
                          jack of your computer to your 49 MHz device audio input or modulator.

                          I still have full-blown Vic 20, Commodore SX-64 and 128 systems as well as
                          Timex Sinclair 1000's, a beacon image or data string could be programmed,
                          sent to the recorder port and recorded on a new computer for current data in
                          a current format.

                          I've also thought about beacons of the data output of some of my old TelStar
                          video game consoles.

                          Kurt

                          ----- Original Message -----
                          From: "eamoniski" <eamoniski@...>

                          bell) would broadcast computer programs over the air for hobbyists to record
                          and use on their cassette driven computers. Has anyone ever tried that on
                          49 MHz? Back in the day when I had a Color Computer 3 I was going to try it
                          with a friend over using my Part 15 AM Broadcast band transmitter, but we
                          never got around to it. Now (to be honest) I wouldn't even know how to try
                          that experiment with my Toshiba Satellite notebook.
                        • Facility 406 DM09
                          What part of Part 15? Kurt ... From: bruce mallon
                          Message 12 of 19 , Apr 20, 2009
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                            What part of Part 15?

                            Kurt

                            ----- Original Message -----
                            From: "bruce mallon" <wa4gch@...>

                            : This is fine but how do you comply with part 15 ?
                          • wa4gch@yahoo.com
                              FCC rules....   http://edocket.access.gpo.gov/cfr_2008/octqtr/pdf/47cfr15.231.pdf   Now this should at least give all of us a starting point as to fcc
                            Message 13 of 19 , Apr 21, 2009
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                              FCC rules....
                               
                               
                              Now this should at least give all of us a starting point as to fcc rules ....
                              For 49 mhz the following would apply ..... this is from coardless phone rules ...
                               
                               
                               
                               17                      46.630                    49.845
                                 18                      46.670                    49.860
                                 19                      46.710                    49.770
                                 20                      46.730                    49.875
                                 21                      46.770                    49.830
                                 22                      46.830                    49.890
                                 23                      46.870                    49.930
                                 24                      46.930                    49.990
                                 25                      46.970                    49.970

                                 (c) The field strength of the fundamental emission shall not exceed
                                 10,000 microvolts/meter at 3 meters. The emission limit in this
                                 paragraph is based on measurement instrumentation employing an average
                                 detector. The provisions in § 15.35 for limiting peak emissions apply.

                                 (d) The fundamental emission shall be confined within a 20 kHz band and
                                 shall be centered on a carrier frequency shown above, as adjusted by
                                 the frequency tolerance of the transmitter at the time testing is
                                 performed. Modulation products outside of this 20 kHz band shall be
                                 attenuated at least 26 dB below the level of the unmodulated carrier or
                                 to the general limits in § 15.209, whichever permits the higher
                                 emission levels. Emissions on any frequency more than 20 kHz removed
                                 from the center frequency shall consist solely of unwanted emissions
                                 and shall not exceed the general radiated emission limits in § 15.209.
                                 Tests to determine compliance with these requirements shall be
                                 performed using an appropriate input signal as prescribed in § 2.989 of
                                 this chapter.
                               
                              Part 15 bands are as follows
                               
                               
                               
                               
                               
                               
                               
                              Band
                              Typical Use
                              160 - 190 kHz
                              Hobbyist
                              510 - 1705 kHz
                              Hobbyist
                              1.705 - 10 MHz
                              General
                              13.553 - 13.567 MHz
                              General
                              26.96 - 27.28 MHz
                              Hobbyist, walkie-talkie, baby monitor, etc.
                              40.66 - 40.70 MHz
                              Perimeter protection systems, control systems
                              43.71 - 44.49 MHz
                              Cordless telephones
                              46.60 - 46.98 MHz
                              Cordless telephones
                              48.75 - 49.51 MHz
                              Cordless telephones
                              49.66 - 50.0 MHz
                              Cordless telephones, walkie-talkie, baby monitor, etc.
                              72.0 - 73.0 MHz
                              Auditory assistance devices
                              74.6 - 74.8 MHz
                              "
                              75.2 - 76.0 MHz
                              "
                              88.0 - 108.0 MHz
                              Hobbyist, miscellaneous
                              174.0 - 216.0 MHz
                              Biomedical telemetry on unused TV channels
                              890.0 - 940.0 MHz
                              Measurement systems, Amateur
                              902.0 - 928.0 MHz
                              Multiple Part 15 uses, Amateur


                              --- On Tue, 4/21/09, Facility 406 DM09 <facility_406@...> wrote:

                              From: Facility 406 DM09 <facility_406@...>
                              Subject: Re: [49MHz] The Hobby Of 49 MHz is getting Old should go digital.
                              To: 49megahertz@yahoogroups.com
                              Date: Tuesday, April 21, 2009, 12:44 AM

                              What part of Part 15?

                              Kurt

                              ----- Original Message -----
                              From: "bruce mallon" <wa4gch@yahoo. com>

                              : This is fine but how do you comply with part 15 ?


                            • Facility 406 DM09
                              From what I recall, cordless phones have their own set of rules with references to Part 15. Use Part 15 direct, everything applying to walkie-talkies-baby
                              Message 14 of 19 , Apr 21, 2009
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                                From what I recall, cordless phones have their own set of rules with
                                references to Part 15. Use Part 15 direct, everything applying to
                                walkie-talkies-baby monitors, intercoms, remotes, radio controls, radio
                                modems and so forth is there. I don't have it handy at the moment, but the
                                rules are VERY basic. So many uV per meter, maximum antenna length and
                                bandwidth. AM, FM, voice, data, it's all been used over the past
                                twenty-five years that I personally know of and probably longer.

                                I'm wondering if a few services and bands are missing from the chart you
                                sent or maybe I am confusing it with Part 15 type operations under Part 95?
                                Kurt
                              • James Alexander
                                I too still have my retro computers, mainly Commodore 64 (& C16), Atari 8bits, even a TI99/4a and TS1000. I too would be interested in trying this out with
                                Message 15 of 19 , Apr 21, 2009
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                                  I too still have my retro computers, mainly Commodore 64 (& C16), Atari 8bits, even a TI99/4a and TS1000.  I too would be interested in trying this out with someone within range.

                                  On Tue, Apr 21, 2009 at 12:38 AM, Facility 406 DM09 <facility_406@...> wrote:


                                  Yes, I used to have a beacon in the 90's that transmitted Commodore and
                                  similar tapes. My first transmission used the boot cassette from an old
                                  Wang at work around 1992. I still have many bankers boxes of the data
                                  cassettes, both micro and standard transport, I think about doing it again
                                  from time to time.

                                  Interesting idea... I could play the data cassettes into my computer and
                                  record it as a .wav file, then you could play it, connect the headphones
                                  jack of your computer to your 49 MHz device audio input or modulator.

                                  I still have full-blown Vic 20, Commodore SX-64 and 128 systems as well as
                                  Timex Sinclair 1000's, a beacon image or data string could be programmed,
                                  sent to the recorder port and recorded on a new computer for current data in
                                  a current format.

                                  I've also thought about beacons of the data output of some of my old TelStar
                                  video game consoles.

                                  Kurt



                                  ----- Original Message -----
                                  From: "eamoniski" <eamoniski@...>

                                  bell) would broadcast computer programs over the air for hobbyists to record
                                  and use on their cassette driven computers. Has anyone ever tried that on
                                  49 MHz? Back in the day when I had a Color Computer 3 I was going to try it
                                  with a friend over using my Part 15 AM Broadcast band transmitter, but we
                                  never got around to it. Now (to be honest) I wouldn't even know how to try
                                  that experiment with my Toshiba Satellite notebook.


                                • Facility 406 DM09
                                  Glad to see I m not the only crazy one. My oldest computer is a Magnavox from 1969. It s built into a suitcase, the programs are some sort of chip on a
                                  Message 16 of 19 , Apr 21, 2009
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                                    Glad to see I'm not the only crazy one. My oldest computer is a Magnavox
                                    from 1969. It's built into a suitcase, the "programs" are some sort of chip
                                    on a porcelain substrate card about 3x5" with a black plastic handle on one
                                    end and edge contacts on the other.

                                    Kurt
                                  • kevin asato
                                    I still use my TRS-80 Model 102 laptop. It s outlasted anything with an 80x86 architecture. Just can t handle the bloated apps! kevin kc6pob ... From: Facility
                                    Message 17 of 19 , Apr 21, 2009
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                                      I still use my TRS-80 Model 102 laptop. It's outlasted anything with an 80x86 architecture. Just can't handle the bloated apps!

                                      kevin
                                      kc6pob

                                      --- On Tue, 4/21/09, Facility 406 DM09 <facility_406@...> wrote:
                                      From: Facility 406 DM09 <facility_406@...>
                                      Subject: Re: [49MHz] Re: The Hobby Of 49 MHz is getting Old should go digital.
                                      To: 49megahertz@yahoogroups.com
                                      Date: Tuesday, April 21, 2009, 8:16 PM

                                      Glad to see I'm not the only crazy one. My oldest computer is a Magnavox
                                      from 1969. It's built into a suitcase, the "programs" are some sort of chip
                                      on a porcelain substrate card about 3x5" with a black plastic handle on one
                                      end and edge contacts on the other.

                                      Kurt


                                    • bruce mallon
                                      It was ment to be basic however these rules apply to HTs as well as any form of base station.....   NOW the problem is how to you apply DIGITAL to these old
                                      Message 18 of 19 , Apr 22, 2009
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                                        It was ment to be basic however these rules apply to HTs as well as any form of base station.....
                                         
                                        NOW the problem is how to you apply DIGITAL to these old RMS measurements ?

                                        --- On Tue, 4/21/09, Facility 406 DM09 <facility_406@...> wrote:

                                        From: Facility 406 DM09 <facility_406@...>
                                        Subject: Re: [49MHz] The Hobby Of 49 MHz is getting Old should go digital.
                                        To: 49megahertz@yahoogroups.com
                                        Date: Tuesday, April 21, 2009, 7:49 PM

                                        From what I recall, cordless phones have their own set of rules with
                                        references to Part 15. Use Part 15 direct, everything applying to
                                        walkie-talkies- baby monitors, intercoms, remotes, radio controls, radio
                                        modems and so forth is there. I don't have it handy at the moment, but the
                                        rules are VERY basic. So many uV per meter, maximum antenna length and
                                        bandwidth. AM, FM, voice, data, it's all been used over the past
                                        twenty-five years that I personally know of and probably longer.

                                        I'm wondering if a few services and bands are missing from the chart you
                                        sent or maybe I am confusing it with Part 15 type operations under Part 95?
                                        Kurt


                                      • bruce mallon
                                        I still have a C-64 with 5.25in drive .... the good old days ...... ... From: kevin asato Subject: Re: [49MHz] Re: The Hobby Of 49 MHz is
                                        Message 19 of 19 , Apr 22, 2009
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                                          I still have a C-64 with 5.25in drive .... the good old days ......

                                          --- On Wed, 4/22/09, kevin asato <kc6pob@...> wrote:

                                          From: kevin asato <kc6pob@...>
                                          Subject: Re: [49MHz] Re: The Hobby Of 49 MHz is getting Old should go digital.
                                          To: 49megahertz@yahoogroups.com
                                          Date: Wednesday, April 22, 2009, 2:19 AM

                                          I still use my TRS-80 Model 102 laptop. It's outlasted anything with an 80x86 architecture. Just can't handle the bloated apps!

                                          kevin
                                          kc6pob

                                          --- On Tue, 4/21/09, Facility 406 DM09 <facility_406@ earthlink. net> wrote:
                                          From: Facility 406 DM09 <facility_406@ earthlink. net>
                                          Subject: Re: [49MHz] Re: The Hobby Of 49 MHz is getting Old should go digital.
                                          To: 49megahertz@ yahoogroups. com
                                          Date: Tuesday, April 21, 2009, 8:16 PM

                                          Glad to see I'm not the only crazy one. My oldest computer is a Magnavox
                                          from 1969. It's built into a suitcase, the "programs" are some sort of chip
                                          on a porcelain substrate card about 3x5" with a black plastic handle on one
                                          end and edge contacts on the other.

                                          Kurt



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