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Yaesu ftdx 3000

Discussion in 'Amplitude Modulation' started by N2DTS, Aug 21, 2019.

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  1. K5UJ

    K5UJ Ham Member QRZ Page

    I have a FT1000MP I have been running on 160 m. driving a leenyar for the past 10 years. On AM it used a dinky little Murata ceramic filter in the 455 kc IF stage to limit AM bandwidth on tx and rx so it would transmit space shuttle audio rolling off at 3 kc. I yanked that sucker out and put in a wire. That gave me an AM exciter that could be run like a broadcash rig (i.e. no audio filtering in the rig at RF) with any audio roll off imposed where it ought to be at the processing gear. On AM rx it meant the plastic radio was barn door wide but I didn't care because I used my separate receivers anyway. Maybe this is an option for this FT3000 box?

    My experience with my 1000MP if it is anything to go by, is that running a plastic radio on AM pretty much sucks compared to a regular plate modulated rig. It's a lot easier to mess around with the audio in a Ranger for example. you can get it out of its cabinet and bolt it to a wood plank and then arrange out board parts like decent mod. transformer and driver transformer and have a 40 watt rig if that's the power level you want but build up the modulator, maybe even use a small reactor. The plastic radio here has an RF carrier that is constantly drifting up and down. I'm told it is a design flaw. The rig was clearly intended for slopbucket.
     
    K4KYV likes this.
  2. W2VW

    W2VW Ham Member QRZ Page

    A rice burner done right on AM can produce low unwanted distortion and any frequency response one might want.

    None of them are up to spec without some work. This filtered out non-technical persons.

    Specification would be 125% positive modulation and a flat audio passband. Desired bandpass shape to be determined by the audio chain.

    Low level modulation workes fine with a dubious limiter where plate modulation right up to 100% negative requires repeatable, low artifact hard limiting before the transmitter.

    On the air today we find several operators who are working hard to make their 1950s AM transmitters work as well as their Phlexx xcvr.

    I used plastic radios on AM for the better part of 20 years and worked the civilized world with them especially on 10 meters.

    Going back to an ancient transmitter in the last 5 years actually required much more attention to audio chain details and it's still not quite where I want it.
     
  3. N2DTS

    N2DTS Ham Member QRZ Page

    Well, its easy and fun to run qrp on a modern radio, some can sound great to me, others sound quite poor.
    There are a number of reasons some sound bad, most old Icoms hammered the alc and pumped the carrier down along with restricted audio passband.
    The Flex rigs can sound quite bad if not set up correctly, the TenTec I had would not modulate past 70% positive, the Elecraft turned the power down randomly, the Elad sounded great and the new Icom 7300 sounded quite good on TX even using the hand mic.
    It was hard to get that rig to sound bad.

    The FTdx 3000 modulates just fine but its restricted to about 50 to 3000 Hz audio.
    That can sound ok if eq'd right (just ok).
    You can open it up to 4k on ssb but not AM.
    Its all done in dsp (software), no filters other then roofing filters and it uses the 15 KHz one for AM.
    Yes, they COULD give you up to 7.5 Khz of audio if they wanted to....
    Even though the modern radios do not sound like broadcast stations, they sound much better on AM then the Collins S line and kwm2 radios do,
    and even better then a stock drake, dx60b and other stock older radios....

    For a modern radio, the Flex 5000 can sound the best stock, 10 to 10,000 Hz audio or wider if you want, flat response, and whatever you want the
    modulation to look like, 150% positive, etc.
    You can actually transmit a 10Hz square wave and it will be a square wave...
    The newer radios (software mostly) restricts the bandwidth I think.
     
  4. K5UJ

    K5UJ Ham Member QRZ Page

    Another part of the Yaesu rig where they get you is in the front panel accessed mic to line level preamp. That circuit had passives that further restricted the audio. What used to be done with the older analog transceivers like mine was to mount a rear panel jack for an audio phono plug, put a 0.1 100 v. or more polypropylene cap in series with the hot center to the audio in pin on the balanced modulator and run the line level audio in via an isolation transformer direct to the bal. modulator. I'm not sure if this is possible now with all this firmware etc.

    I get the impression that with the plastic radios coming out over the past 15 years, the ability of the owner to make modifications has been continually reduced to the point that the manufacturer may as well pot the interior of the cabinet and make the transceiver just one solid block of epoxy or plastic. Then it would be truly a plastic radio but that won't happen because it isn't necessary, it would add to the cost and hams would complain about the weight.:D
     
  5. N2DTS

    N2DTS Ham Member QRZ Page

    No, you can repair them and modify them, I have enabled general coverage TX on most of the new radios I have got.
    The parts are smaller, lots smaller, but there is no reason things can not be done.

    Software is another thing, some people can build new software/ios/firmware but its a rare talent.
     
  6. K4KYV

    K4KYV Subscriber QRZ Page

    Amateur radio has evolved into two distinct pursuits. First, there is what might be called the traditional hobby, which largely includes AM, interest in tube type and through-hole solid state equipment, experimentation, homebrewing/modifying/maintaining one's own gear, vintage equipment, on-air technical discussions, etc., but this element is rapidly becoming a fringe minority. The other facet, which now includes the vast majority of the amateur community, could be called the plastic radio hobby whose interest is predominantly purchasing and operating (often expensive) state-of-the-art consumer electronics, with little knowledge or interest in what's inside or how it works; most on-air discussion is about topics other than radio. Radio-related conversations tend to be about the manufacturers' latest products, prices, warranties, professional repair service and one manufacturer's products vs another.

    There is some overlap; some AMers are strictly plastic radio operators (AM is just another mode button on the radio), some SSB-only operators are more technically oriented and would fall into the first group, while a few others experiment with digital circuitry and write or re-write software, or open up and attempt to repair their own plastic radios, but the divide described above is clearly the general trend.
     
  7. N2DTS

    N2DTS Ham Member QRZ Page

    Well, there is quite a bit of know how needed to run all the digital modes, leo satellite work, the software that is out now and do on.
     
  8. W2VW

    W2VW Ham Member QRZ Page

    Things aren't all that black and white.

    Fun watching ssb guys who want to sound like humans.

    They are forced to learn about compression and audio techniques.

    They also need to use antennas that aren't a joke because they are ragchewers. Anybody can get a 5N report with a wet noodle on a fake DX net.

    Also fun seeing folks who have been on the air for 50 years plus trying new things.

    The AM commun-it-ay has been lucky to have had several examples of real ham radio over the years. W3DUQ comes to mind.

    Bill was not put off in the slightest, experimenting with multi-layer circus board riceburners.

    There's still a good amount of really interesting AM activity if one looks in the right places.
     
  9. AC0OB

    AC0OB Subscriber QRZ Page

    I looked at the schematics and the DSP board is where they are analog limiting your transmit audio to 3.6kHz with a 9 dB roll-off circuit. I could tell you how to modify it for a wider passband but the DSP firmware probably would probably cough on a wider passband.

    Pheel
     
  10. W2VW

    W2VW Ham Member QRZ Page

    A neighbor has purchased and used every new radio made except for the really expensive models.

    He likes AM in spite of some of he current stupidity heard in this area.

    The Phlexx 6300 has produced the finest sounding effective audio of all the models I have been able to record.
     

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