Loading ...
Sorry, an error occurred while loading the content.

Re: Giant spike at the center frequency

Expand Messages
  • sv1eia
    I got the same problem too. Although I use 600:600 ohm isolation audio trasformers, the spike is there. When I induce the transformer the spike is not becoming
    Message 1 of 155 , Jan 2, 2008
    • 0 Attachment
      I got the same problem too.
      Although I use 600:600 ohm isolation audio trasformers, the spike is
      there. When I induce the transformer the spike is not becoming smaller.
      So it seems that has something to do with the audio card (integrated
      24/96) or the I/Q SDR software.

      73
      SV1EIA

      --- In softrock40@yahoogroups.com, Bill Dumke <billd@...> wrote:
      >
      > Todd,
      >
      > It depends a lot on AC ground loops. Use a 1:1 RF transformer to
      > eliminate the loop from the antenna ground to your rig, and eliminate
      > the ground on the RX/TX line from the serial port. It is a redundant
      > ground, since the RXTX rig will be grounded to the PC through the sound
      > card inputs anyway.
      >
      > The sound card also has a lot to do with it. Some are worse than
      > others. On my Delta 44 using the above I don't see any hump at all at
      > the center on 40 meters using a 40 meter ground mounted antenna. In
      > fact all I see is a very small dip at the center frequency where the
      > audio passband falls off.
      >
      > Bill wa9pwr
      >
      > Todd Mondragon wrote:
      > > Hi all, happy new year!
      > >
      > > I just finished my first Softrock, the 6.2 RXTX 40/30 and I am
      utterly
      > > amazed that it works right away! CW and RTTY on 30 as soon as I
      fired it up.
      > >
      > > But there is this GIANT central spike right at the center frequency.
      > > It is huge, 20 over.
      > >
      > > Is this normal? I have been searching and I see a couple of posts
      around
      > > about I/Q balance and sound card, would either of these produce that
      > > ugly signal?
      > > If not, how do I banish that to the land of bad memories?
      > >
      > > Thanks and 73!
      > >
      > > Todd KV1M
      > >
      > >
      > >
      > > Yahoo! Groups Links
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      >
    • km5h
      Hi all, All Si570 orders have been shipped (or will be in the next couple of hours). I have 4 CMOS left that can be shipped quickly. New orders will collect
      Message 155 of 155 , Jul 2 6:36 AM
      • 0 Attachment
        Hi all,

        All Si570 orders have been shipped (or will be in the next couple of
        hours).
        I have 4 CMOS left that can be shipped quickly.

        New orders will "collect" until I have close to 25 for a new order.

        Thanks and 73, Tom KM5H
      Your message has been successfully submitted and would be delivered to recipients shortly.