[Elecraft] K3 Problem during transmission on SSB

[Luigi Casari]

Tnx Wes and Scott for your replay,

I connect a dummy load and I transmit on different bands.
The problems is on 21,24 and 28 MHz band.

To times when I push the PTT of the microphone the power is low and then gets up.

Don't believe is a problem of return RF as Scott suggests me.
When I have seen the first time the problem were doing DX in 21MHz, I used the PA and I get lots of compliments for the modulation. 
If they had been a RF problems with 1 KW the modulation has been distorted or with strong noises.

Seem more a false contact from some part.

This evening after the work I will try with K3 Utlility and I will check the connectors.

73 to all.

Luigi HB9CXZ
  ----- Original Message ----- 
  From: Wes Stewart 
  To: Luigi Casari 
  Sent: Thursday, October 14, 2010 11:33 PM
  Subject: Re: [Elecraft] K3 Problem during transmission on SSB


        Luigi,

        You might try running into a dummy load and see what happens.  If you still have the issue use the utility program and run the TX power calibration.  If that fails, then you may have an intermittent issue the same as several of us have had.

        One issue seems to be the "2D connector" at the right rear of the radio that connects the output filter board to the chassis.  This is the only ground return for the output connector.  Make sure the screw is tight.  It is the one that runs from the side panel completely though the 2D connector to the circuit board.

        Wes

        --- On Thu, 10/14/10, Luigi Casari <hb9cxz at ticino.com> wrote:


          From: Luigi Casari <hb9cxz at ticino.com>
          Subject: [Elecraft] K3 Problem during transmission on SSB
          To: elecraft at mailman.qth.net
          Date: Thursday, October 14, 2010, 1:37 PM


          Ragards to all,
          I have just discovered a problem, 28 MHz or 21 MHz SSB, during transmission 
          the power drop down to abt. 10/15W.

          This after few second of transmission, the power staies low for some seconds 
          and then increases again. No question of microphone, I have tried with MC85 
          and Pro set, also change the levels of the mic gain and compressor without 
          result.

          I have tried on other frequencies and have not been able to recreate the 
          problem, only in 21 and 28 MHz.
          Don't believe is a problem of SWR and some protection what limits the power, 
          the antenna is the same from the 10m to the 40m, Opti Beam, and the SWR 
          where have done the tests are low. Also the internal SWR meter of the K3 
          give me low SWR.
          Even in 160m, 80m or 6m with others antennas no problem.

          In FM mode I don't notice any decrease of power, 110W constant.

          Some idea?

          73, Luigi HB9CXZ

          hb9cxz at ticino.com
          http://web.ticino.com/hb9cxz/



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