[TenTec] Digital (PSK31) Communications

Sat Feb 2 12:41:08 EST 2008

Agreed.  If the ALC light blinks either you have too much mic gain or too 
much signal from the sound card.  There should be NO ALC action for a good 
clean PSK-31 signal.

With Tentec radios, when properly adjusted and with the correct level from 
the sound card, you should receive IMD reports during idle from the other 
station in the order of -25 to -30 dB.  If your IMD is higher than this, 
i.e. -20 to - 10 dB, then you have too much signal from the sound card or 
you are operating the transmitter at too high of power output.

If you are not sure, ask a station that you are in contact with to give you 
an IMD report. To do this you must not transmit data, just let the system 
idle without typing for 10 to 20 secs.  Have the other station let the 
software on the receiving end provide you a signal report.  If your IMD is 
high, then reduce the level from the soundcard or the interface device that 
you are using.

For a 100 watt radio, your power output should be 25 to 35 watts.  It all 
cases it is normal to have the radio set so that it is capable of producing 
100 watts of output.  However, it should be driven with level from the sound 
card so as to produce no more than 25 to 35 watts of actual power.  Do not 
turn radio power down.  Turn sound card level down.

73
Bob, K4TAX

----- Original Message ----- 
From: "KXB" <w7kxb at msn.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Saturday, February 02, 2008 11:28 AM
Subject: Re: [TenTec] Digital (PSK31) Communications

Hello Herve
In psk, "DO NOT BLINK THE LIGHT" period
Carry-on
Bill Harris w7kxb
  ----- Original Message ----- 
  From: F8EHJ<mailto:f8ehj at free.fr>
  To: Discussion of Ten-Tec Equipment<mailto:tentec at contesting.com>
  Sent: Saturday, February 02, 2008 8:49 AM
  Subject: Re: [TenTec] Digital (PSK31) Communications

  Hello,

  I subscribe to this list for this reason :
  What is the adjustement for PSK31 using a Ten tec jupiter.

  I am agree with you that ALC indicator should not be always lighted.
  So I adjust sound card output level to have ALC led blinking with
  modulation.

  But what about MIC GAIN ? I selected in the menu line mic for input.

  There is a relation between MIC GAIN, ALC and RF OUTPUT !

  If I decrease RF POWER I must decrease MIC GAIN to have ALC blinking.
  (or I must decrease sound card OUTPUT LEVEL.

  Thanks for explain.

  best 73's

  Herve F8EHJ

  TENTEC JUPITER 538
  MICROPHONE 706 DESK

  Le 2 févr. 08 à 17:38, Bob McGraw - K4TAX a écrit :

  > A comment to the point of setting vs. controlling the power on the
  > Jupiter.
  >
  > For modes like PSK-31 the Jupiter should be configured to operate
  > at its
  > rated output power or 100 watts.  Then the actual power output
  > should be
  > controlled by the PSK-31 software or the sound card output level or
  > interface output level to the Jupiter so as to cause the Jupiter to
  > produce
  > some 25 to 35 watts of power.  This will prevent the ALC activation
  > and
  > subsequent distortion from being generated and transmitted.  Also,
  > any SP or
  > speech processing should be OFF.
  >
  > It should be noted that the PSK-31 signal will cause the power
  > output to
  > vary slightly depending on if idle or data is being transmitted.
  > This is
  > normal and the amount of variation depends on several factors, such
  > as tone
  > frequency, power meter response and dampening and etc.
  >
  > Here is the basic NO NO.  Reduction of the Jupiter power to 25 to
  > 35 watts
  > and then have the sound card audio drive the Jupiter to 25 to 35
  > watts will
  > activate the ALC and subsequent distortion of the transmitted
  > signal will
  > likely result.  This produces a transmitted signal that is several
  > hundred
  > Hz wide and thus an annoyance or interference to others on the band.
  >
  > In general it is frowned upon to run "high power" on PSK-31.  The
  > issue with
  > this lies in the fact that an exceptionally strong signal adjacent
  > to a weak
  > signal, both within the IF passband,  will cause the strong signal to
  > capture the AGC and thus further suppress the weaker signal.  As a
  > general
  > "rule of thumb" one should always operate with actual PSK-31 power
  > output
  > being no more than 25% to 35% of the rated transmitter power.
  >
  > 73
  > Bob, K4TAX
  >
  >
  >
  >
  > ----- Original Message -----
  > From: "ron" <roncasa at verizon.net<mailto:roncasa at verizon.net>>
  > To: "Discussion of Ten-Tec Equipment" 
<tentec at contesting.com<mailto:tentec at contesting.com>>
  > Sent: Saturday, February 02, 2008 9:42 AM
  > Subject: Re: [TenTec] Digital (PSK31) Communications
  >
  >
  >> Henry Mackey wrote:
  >>>
  >>>   The power setting on the Jupiter was at 100%. However, I would
  >>> reduce
  >>> the power according to the rigs meter to 20-25 watts and avoid
  >>> any ALC.
  >>>
  >>>
  >>
  >>
  >> 25 watts??
  >>
  >> For a mode that only needs minimal wattage??
  >> Try less and be amazed. (the spectrum would also be cleaner if we
  >> all did)
  >> (smile)
  >>
  >> Ron
  >> "the 516 is a keeper"
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  >
  >
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