Considering joining in on some AM tips needed

Discussion in 'Amplitude Modulation' started by W9RAC, Oct 17, 2019.

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  1. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Use what you have if it puts out a reasonably good signal on AM. But if it's one of those rigs with "AM" mode that consists of one sideband plus carrier, that's not really AM; just SSB with poor carrier suppression, which doesn't demodulate well with a conventional AM detector, so it would be better to use something else. Fortunately, most of to-day's multi-mode transceivers transmit true DSB AM when in "AM" mode, but some modulate better than others.

    It doesn't matter whether it's tube or solid state, plate modulated or low-level modulation, leen-yar, etc. I have heard some solid state transceivers that transmitted AM well enough that I would have believed it if the op had told me he was running a modified broadcast transmitter. Some rigs are finicky to tune up and adjust on AM, so make sure you are doing it properly before trying to get on the air, or have someone help you get it adjusted right. Requesting help OTA is all right, as long as you don't impose on an ongoing QSO in the middle of some in-depth discussion. A dummy load can be very useful for tuning up, or practising tune-up procedure.

    If you plan to run AM with any regularity I would strongly suggest acquiring a monitor (oscillo)scope capable of displaying the envelope pattern. To me, transmitting without a monitor scope is like driving a car at night with the headlights turned off.
     
    W9RAC likes this.
  2. W9RAC

    W9RAC Platinum Subscriber Platinum Subscriber QRZ Page

    I'm sorry Clark, somehow I overlooked your question. Was not ignoring it, just missed it. I'm glad you ask so perhaps I can get some feedback regarding them. My current radios are, TS 990, FT 101d, FT 2000, FT 450d, TS 850/dsp100. I should mention the Yaesu radios have been dedicated strictly for CW. I prefer Kenwood for SSB maybe AM? The 990 does have a audio scope, the TS 850s/dps100 is a eSSB set up which may work great for AM also. Amps are, Alpha 8410, Acom A2100, Ameritron 811H which I have been using for CW and I doubt its up to the task of AM. Mic, RE 27, RE 320, Shure SM7b which is my mic of choice. I do run a audio rack which would work fine with AM also. Bellari RP520 pre, 2496, Aphex exciter, Virtualizer Pro. With this information what's your thoughts? I have not gotten on air yet, still on the side experimenting. 73 Rich
    rack 001.JPG
     
    Last edited: Nov 18, 2019
  3. N2DTS

    N2DTS Ham Member QRZ Page

    Many Kenwoods sound VERY good on AM.
     
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  4. W9RAC

    W9RAC Platinum Subscriber Platinum Subscriber QRZ Page

    I have this morning been doing some testing with the 990, shure mic, audio rack into dummy load and headphones to monitor. I sounds fair. I'm not certain about the band width. I have the TX set at 4kc. that seems a bit narrow for AM? Ill wait for some more comments before I waste a lot of time working on stuff that may be incorrect. tnx, Rich
     
  5. N1BCG

    N1BCG Ham Member QRZ Page

    Ooof. That's not total bandwidth, right?

    If that's 4kc of frequency response (8kc bandwidth) then that would be very effective for later hours when the bands get crowded, but widening things up makes for more pleasant listening when there's plenty of room.
     
  6. W9RAC

    W9RAC Platinum Subscriber Platinum Subscriber QRZ Page

    Yes, scope shows 8 KC bandwidth.
     
  7. N2DTS

    N2DTS Ham Member QRZ Page

    Plenty of old folks cant hear over 4000 Hz anyway.

    From looking at signals, 8000 Hz total bandwidth seems very common.
     
  8. WA4SIX

    WA4SIX Ham Member QRZ Page

    Since you like the ESSB & should be good at setting it up, I would suggest to go for 10 KHz & wow the fellers for a Newbie.

    Ed
     
  9. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    I normally set my transmit audio for 4̶ ̶k̶c̶/̶s 6 kc/s frequency response. Not many receivers are set at bandwidths greater than 8 kc/s. When the band is congested, I usually switch to the 3400~ filter. Even with no filter, the response of my unamplified D-104 is not much above 5000~.

    Yep, my ears have developed their own built-in low-pass filter as well.
     
    Last edited: Nov 21, 2019
  10. N2DTS

    N2DTS Ham Member QRZ Page

    Your signal is always clean, punchy and easy to copy Don.
    Phonetics are my friend!
     

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