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@msn.com>
To: "Discussion of Ten-Tec Equipment" <tentec@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@free.fr>
To: Discussion of Ten-Tec Equipment<mailto:tentec@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@verizon.net<mailto:roncasa@verizon.net>>
To: "Discussion of Ten-Tec Equipment"
<tentec@contesting.com<mailto:tentec@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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