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11354Re: [wsjtgroup] Fw: Attempt to explain Split and Dual Mode.

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  • Andrew ZL3CC
    Aug 19, 2013
      I agree with you so far Rudy.

      To complicate the issue more, I have started using split even when working only a single mode, because:

      My FT-857 has a narrow receive and transmit range. By tuning to e.g. 14.076 and using split, my transmit tone is always kept in the more efficient 1500-2000 Hz range. I no longer have to keep increasing the audio input level to get the same output at both ends of the RF frequency range as I get in the centre, as I find I have to when using JT65-HF (or WSJT-X without split).

      At least that is how it seems to me. Please tell me if I am kidding myself here.

      When I want to work JT9 I use the +2 kHz box to move up and continue to use split for the same reason.

      So I am a perhaps rare and misguided user of both split AND +2 for single modes.

      Andrew ZL3CC

      On 19/08/2013, at 15:44, "Rudy Benner" <rudy@...> wrote:


      Yaesu FT450
      Tx response – not more than –6 db 400 to 2600 hz.
      Rx response -  -6 db. 2.2 kHz or better,  –60 db.  4.5 kHz or less

      The above are the specs for my modest HF radio.
      The latest WSJT-X v1.2 r 3556 boasts dual mode and to support it, split operation.
      A typical setup would have the radio VFO A set to 14.076 Mhz.
      I would be able to hear signals from just above 14.076 MHz to roughly 14.078.2 MHz.
      Assuming I am NOT setup for Split operation, my tones would be effective for roughly the same range.
      So far, its all good.
      The way this program is supposed to work, JT65 is assumed to be from 14.076 to about 14.078 and JT9 from
      there up. The default setting for the BLUE LINE is 2500 which would correspond to 14.078.5 Mhz. It can be moved.
      Without split operation, I can hear all the JT65 stations, or all the JT9 stations, or I can straddle both of them by
      setting my dial at 14.077 and setting the Blue Line at about 1500 hz. It works, so far. No need for split.
      If no one had mentioned SPLIT operation, I would have been a happy little camper.
      We all know this is Joe’s fault, he is on holidays, so he can’t banish me for saying so.
      Its his fault.
      Suppose I was the proud father of a radio with a 4 MHz receive bandwidth but with a Tx bandwidth of only 2.6 kHz.
      Lets suppose further than the low frequency response sucks below about 500 hz.
      How can I manage to monitor from 14.076 all the way up to 14.080 MHz in one shot and Tx for the same span too
      without having to touch anything?
      This is where SPLIT comes in.
      VFO A is for receive, VFO B is for transmit.
      You make sure both VFO’s are in the same mode, usually pressing the VFO A=VFO B button will do it. Also press SPLIT.
      In version 1.2 r 3556 the Tx tones vary between 1500 to 2000 hz in split mode. That’s right. Read the manual, connect the output to a speaker to prove it,
      hook it to a scope.
      Suppose the station you want to work is coming in at 610 hz on the waterfall, (14.076Mhz + 610 hz). 14.076610 MHz is the frequency of the sync tone.
      To answer him, your VFO B needs to be 14.075. Add 1610 (the actual tone) to that and you have 14.076610 MHz, which is perfect.
      Likewise for any other segment.
      I use COMMANDER C:\DXLab\Commander\Help\index.htm to do the magical radio control. Some radios are more agile. This works for the FT450.
      Is anyone following this?
      Feel free to stone me.

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