1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice

Mirage 2950

Discussion in 'Amateur Radio Modifications' started by n4dxx, Sep 24, 2018.

  1. n4dxx

    n4dxx Member

    Joined:
    Jan 27, 2010
    Messages:
    81
    Likes Received:
    5
    I traded for a like new old school rci 2950 with mirage on the faceplate..Radio has never been touched other than the 11m expansion..It has about 5 lights on the s meter on usb receive even with rf gain all the way down all others modes are fine.I have seen this same issue with some hr2510's.Alignment seems spot on ..Sounds great on usb and lsb on tx..Just has that crazy carrier..Any ideas?Thanks


     
    #1 n4dxx, Sep 24, 2018
    Last edited: Sep 25, 2018
  2. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    1,869
    Likes Received:
    1,293
    So, it doesn't do this on LSB, does it?

    A carrier on only one sideband points to the 10.695 MHz (nominal) carrier oscillator.

    One quick way to tell is to listen to the, ah, "pitch" of the noise in each SSB mode.

    Ideally, the hiss you get on an empty channel should sound the same on upper as it does on lower sideband.

    The pitch of the 'hiss' you hear in SSB mode is a hint. If it sounds a lot lower on one sideband, the carrier-frequency setting for that mode has been set too close to the SSB filter's frequency. Allows too much carrier to leak through. Also tends to give the receiver's empty-channel "hiss" sound a low pitch.

    There is also a trimpot that serves to balance out the carrier in SSB modes. VR7 is set for minimum carrier in sideband transmit, with the mike gain set at zero.

    If this fixes your problem, that was simple.

    If you can hear a big difference in the pitch of the empty-channel hiss between USB and LSB, that points to the carrier oscillator. Has a trimmer coil for AM, USB, and LSB.

    The last 3 steps in this alignment page cover the carrier crystal. http://www.cbtricks.com/radios/rci/rci_2950/rci2950_pll_adj.htm

    But you need a way to measure the frequency of the carrier-crystal's oscillator to set those.

    73
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!