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Re: Hello ALL..

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  • wb9mjn
    Here is my station setup. Drake TR-7, with mods allowing DRM reception (12 KHz IF output), as well as digital HF modes. to indoor 4 foot diameter magnetic loop
    Message 1 of 5 , Apr 3, 2011
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      Here is my station setup. Drake TR-7, with mods allowing DRM reception (12 KHz IF output), as well as digital HF modes. to indoor 4 foot diameter magnetic loop antenna (tunes 6200 to 18500 KHz, plus 60 meter with Tin-Foil hat added). Antenna is at 15 feet agl, in a wood frame building. This station has been successful worldwide on JT-65, as well as local 60 meter NVIS and continental range Digitial Voice (Windrm/FDMDV) .

      73, Don...
    • Harry Britton
      Wow! You need 12kc wide for DRM? Harry
      Message 2 of 5 , Apr 4, 2011
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        Wow! You need 12kc wide for DRM?
        Harry


        --- On Sun, 4/3/11, wb9mjn <donver@...> wrote:

        > From: wb9mjn <donver@...>
        > Subject: [V4Protocol] Re: Hello ALL..
        > To: V4Protocol@yahoogroups.com
        > Date: Sunday, April 3, 2011, 10:00 AM
        >
        >
        >   Here is my station setup. Drake TR-7, with mods
        > allowing DRM reception (12 KHz IF output), as well as
        > digital HF modes. to indoor 4 foot diameter magnetic loop
        > antenna (tunes 6200 to 18500 KHz, plus 60 meter with
        > Tin-Foil hat added). Antenna is at 15 feet agl, in a wood
        > frame building. This station has been successful worldwide
        > on JT-65, as well as local 60 meter NVIS and continental
        > range Digitial Voice (Windrm/FDMDV) .
        >
        >   73, Don...
        >
        >
        >  
        >
        >
        >
        > ------------------------------------
        >
        > Yahoo! Groups Links
        >
        >
        >     V4Protocol-fullfeatured@yahoogroups.com
        >
        >
        >
      • wb9mjn
        ... Hi Harry, The 12 KHz refered to is the center of the LO IF. By downconverting to a IF with a range from 0 to 24 KHz, allot of radio techniques can be
        Message 3 of 5 , Apr 4, 2011
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          --- In V4Protocol@yahoogroups.com, Harry Britton <harryhydro1962@...> wrote:
          >
          > Wow! You need 12kc wide for DRM?
          > Harry
          >
          >

          Hi Harry,

          The 12 KHz refered to is the center of the LO IF. By downconverting to a IF with a range from 0 to 24 KHz, allot of radio techniques can be programmed into the typical PC sound car DSP.

          So, the common way to receive the 10 KHz wide DRM broadcasts, is to convert the last IF to 12 KHz, which makes the signal range from 7 to 17 KHz. And even though its in the audio band, its still an RF/IF signal.

          There are two softwares that can take that and make it audio, that are commonly used - DREAM and SODIRA.

          The DRM voice used on Ham Radio is about 2.5 KHz wide.

          The 10 KHz wide DRM broadcasts have a tremendous capability at overcoming multipath. One can see the delay spread of the received signal in the DREAM software. Almost continuous, triangular shaped delay spreads at 5 msec of length are commonly copied. Vatican Radio in the evening (40 or 31 meter bands depending on season), and Radio New Zealand in the morning (on 40 meter) show this response some times of the year.

          On the Drake TR-7 I added a second crystal to the BFO, and reprogrammed the switches , so that when in AM, the BFO is still on using the 12 KHz hi crystal, and the detector path is still through the product detector. This signal then goes through an OP amp buffer out to the computer. I use the same circuit for Ham Digital signals. I do not have a 10 KHz wide crystal filter, so resistors are used for that IF bandwidth, and the roofing filters have just about the right bandwidth, albeit not great rejection. So far, its not been a problem.

          On Topic,

          I did get on V4 on sunday, but late. I was copying KU2A very well, but was very disappointed it required so much signal to be heard. I probably wont be able to make much use of it. As 60 meters does not allow digital modes, and 40 meters NVIS is shut down again (it had a brief opening the weekend before last). Long range contacts require too much power.

          I think we may need a 100 Hz wide DRM for me to have good keyboarding with my station. A shame, as I have contacts on JT-65 out to 10000 miles, yet cannot even keyboard to New Hamshire on V4 (or so I am told) with my signal....
        • Siegfried Jackstien
          You need 9 or 10 kc bandwidth for receiving commercial drm on short and mediumwave ... with a center of 12kc .... You switch the rig to am or fm (what gives
          Message 4 of 5 , Apr 5, 2011
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            You need 9 or 10 kc bandwidth for receiving commercial drm on short and
            mediumwave ... with a center of 12kc ....

            You switch the rig to am or fm (what gives you the widest filters) ... grab
            the last 455kc if and downmix it with 467kc (or 443) to 12kc .... feed that
            in the soundcard and hear errorfree music *g* (with the right software)
            Dg9bfc
            Sigi


            > -----Ursprüngliche Nachricht-----
            > Von: V4Protocol@yahoogroups.com [mailto:V4Protocol@yahoogroups.com] Im
            > Auftrag von Harry Britton
            > Gesendet: Montag, 4. April 2011 23:35
            > An: V4Protocol@yahoogroups.com
            > Betreff: Re: [V4Protocol] Re: Hello ALL..
            >
            >
            >
            > Wow! You need 12kc wide for DRM?
            > Harry
            >
            > --- On Sun, 4/3/11, wb9mjn <donver@...
            > <mailto:donver%40sbcglobal.net> > wrote:
            >
            > > From: wb9mjn <donver@... <mailto:donver%40sbcglobal.net> >
            > > Subject: [V4Protocol] Re: Hello ALL..
            > > To: V4Protocol@yahoogroups.com <mailto:V4Protocol%40yahoogroups.com>
            > > Date: Sunday, April 3, 2011, 10:00 AM
            > >
            > >
            > > Here is my station setup. Drake TR-7, with mods
            > > allowing DRM reception (12 KHz IF output), as well as
            > > digital HF modes. to indoor 4 foot diameter magnetic loop
            > > antenna (tunes 6200 to 18500 KHz, plus 60 meter with
            > > Tin-Foil hat added). Antenna is at 15 feet agl, in a wood
            > > frame building. This station has been successful worldwide
            > > on JT-65, as well as local 60 meter NVIS and continental
            > > range Digitial Voice (Windrm/FDMDV) .
            > >
            > > 73, Don...
            > >
            > >
            > >
            > >
            > >
            > >
            > > ------------------------------------
            > >
            > > Yahoo! Groups Links
            > >
            > >
            > > V4Protocol-fullfeatured@yahoogroups.com <mailto:V4Protocol-
            > fullfeatured%40yahoogroups.com>
            > >
            > >
            > >
            >
            >
            >
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