[TenTec] Omni VI first impressions

[Steve Hunt]

Ken,

I only just spotted your question about shield covers over the optional filter slots.

There aren't any - just holes! Should there be? I don't recall seeing any obvious fixing holes for covers or I might have been suspicious.

73,
Steve G3TXQ


  ----- Original Message ----- 
  From: Ken Brown 
  To: Discussion of Ten-Tec Equipment 
  Sent: Sunday, November 26, 2006 8:03 PM
  Subject: Re: [TenTec] Omni VI first impressions


  Hi Steve,


  >
  > There was a consensus of replies that the variation of display brightness, and the "key up thump", seem to be "features" that other Omni VIs exhibit.
  >   
  The variation in display brightness is a feature. Key up thump? Not in 
  my Omni VI.
  >  At warm-up several heterodynes, one after the other, drift quickly through the pass band - all of them are non-tunable. Once the rig is stable, if I'm left with a heterodyne in the pass band it can be tuned out with PBT control. I don't mean "filtered out" with PBT; just a few degrees rotation of the PBT control around its mid position and the heterodyne rapidly moves in audio tone and out of the passband. If the PBT control is more than about 5 degrees away from its central position I never hear a heterodyne at all. I guess this must be some funny mixing product involving the15.3 MHz PBT oscillator.
  >   
  A very interesting problem. Since it happens on all bands, I would guess 
  that the 15.3 MHz PBT oscillator is generating a spurious signal that is 
  getting right into the 9MHz IF, or even the 6.3 MHz IF. Come to think of 
  it, suppose that the 15.3 MHz PBT oscillator is mixing with the 9 MHz 
  BFO, and generating a signal at 6.3 MHz. Changing from USB to LSB would 
  move the 9 MHz BFO, and the setting of the PBT required to hear the 
  unwanted mix would also move. Does that happen?

  So then why would your 9 MHz BFO oscillator or 15.3 MHz PBT oscillator 
  radiate, or conduct through undesired paths, more than most other 
  peoples? I would look for loose connectors and board mounting screws 
  around the TX Audio Board (which includes the BFO) and the Passband 
  Tuning Board. What about the shield covers over the optional crystal 
  filter access? Are the shields there, with all the screws in place?

  DE N6KB


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