Modern radios

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

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  1. N2DTS

    N2DTS Ham Member QRZ Page

    Old gear is fun and looks great, but it can be big, heavy and trouble prone.
    In the past I spent a lot of time and money on getting old gear and improving it, sometimes till it did not work at all, but that's another thread....
    Been there, done that when old AM gear was cheap as dirt.

    What about modern rigs?
    What is the best (for AM) modern radio today?
    Say made in the last 10 years.

    Is there anything that works well on RX and TX with good fidelity both ways?

    Most of the major SDR's work very well, Flex, Anan, even the Elad.
    The K7DYY works well as a transmitter.

    Besides those, is anything any good at all?
    My little R928 plus works fantastic on RX and the TX is poor and very low power.
    The Elecraft KX2 and KX3 work ok but are hardly hifi on RX or TX and are very low power.

    Is there anything out there among the all mode all band rigs that works well on AM?
    Ten Tec?
    The icom 7300 works ok on TX but has no audio on RX below 200 Hz or maybe higher, that makes it sound thin on RX. I hear the 7610 is the same.

    The Icom 756pro series were very bad as were the modern Yaesu radios I have had.

    Is there nothing?
    Will there ever be anything that is any good on AM?

    (slow day at work)
     
  2. KA4KOE

    KA4KOE Ham Member QRZ Page

    Probably not. It's called inertia. It's easy to keep doing what you are doing. Catering to a small interest group with questionable financial payback is a non-starter.
     
  3. G0GSR

    G0GSR Ham Member QRZ Page

    It's the same on TX too, sounds too thin.
    My TS-590 is also not so good on AM. Can't exceed 80% mod. but at least the LF response is not deliberately crippled like the Icoms.

    Frank
     
  4. KB8VUL

    KB8VUL Ham Member QRZ Page

    THe bigger issue with modern rigs is the DSP that exists in most of them.
    Historically if a radios audio band pass was a bit lacking, it was due to the audio filter consisting of some caps and inductors that set the audio pass limits.
    You break out the schematic and find it, and modify it to your liking.

    Now DSP chips are common place and they are programmed for a band pass and there is no going around it unless the rig will allow you direct access to the chip and not to rely on the firmware commanding the chip.
    Which oddly is why the SDR radios are better on AM, you have more access to configure them.
     
    AC0OB likes this.
  5. N2DTS

    N2DTS Ham Member QRZ Page

    Some of them, the ones using computers.
    None of the standalone ones except for the Elad allow much bandwidth.
    And many have very poor modulation.
    With a good microphone, I can get my mcHF rigs to sound good and modulate well, but only to 3000 cycles and 2 or 3 watts carrier.
    The Elad went out to 4500 or more, modulated well, but was only 2 watts or less.

    The old FT101 and 102 you could get to sound like a broadcast station, 25 or 35 watts out.
    A better on AM icom 7300 would be nice, audio down to 50 Hz both ways and out to 4000 on TX, and an antenna tuna that actually does something useful.
     
  6. W8EJO

    W8EJO Ham Member QRZ Page

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  7. W1NB

    W1NB XML Subscriber QRZ Page

    I would not dismiss the K3 quite so quickly. It actually can be set up to sound pretty good on AM. I run mine on AM quite often. I use a Heil Classic mic, run it in enhanced transmit and have set up the TX EQ. On receive, I run a decent amplified speaker which improves the audio response. I also have the FM filter in it so I can widen out the receive passband. Fidelity is respectable.

    It is only 25-30 watts out on AM. I use mine to drive a THP 1.5 KFX solid state amp and set it to about 150W carrier. The THP and my auto tuner track band and frequency so I can generally just change frequency and key up.
     
  8. N2DTS

    N2DTS Ham Member QRZ Page

    So what does the passband go out to on TX?
    The Elecraft stuff is expensive and I dislike the compressed control setup, on a portable rig its expected, on a base rig, not so much.
     
  9. W1NB

    W1NB XML Subscriber QRZ Page

    The operator selects which filter is active in the transmitter for each mode. I have the 6KHz filter on for transmit and the FM filter (15 KHz, I think) in receive. I then use the variable passband tuning to narrow it based on receive conditions.

    I’ve not swept it to see what the response looks like. I set the transmit equalizer at the Heil recommended settings for ESSB then got on the air with Tim (HLR) and tweaked the mic gain an compression. In my opinion, Tim has a very good ear and doesn’t soft-pedal his opinion. He told me it sounded pretty respectable.

    Price wise, I’ve seen several used but well-kept K3s selling for pretty good prices lately. I think the introduction of the K4 has driven the prices of the K3s’ down a bit.
     
  10. KF5LJW

    KF5LJW Ham Member QRZ Page

    SDR radios a will take over because they are superior in every aspect. Right now they are a bit expensive just like VHS was once upon a time. Amateur radio products are behind in technology for the most part, but commercial radios are becoming predominately SDR. Example every cellular carrier has been using SDR for a decade now, and every cell phone is SDR. The various modes is just a detail in the firmware, whatever you want from CW to Spread Spectrum to QAM. No problem, push a button and instantly tuned and ready to go. Once IC manufactures work out the details on A/D converters, Het RX and TX will be antiquated.
     

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