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De: Psk31 Digest <owner-psk31@aintel.bi.ehu.es>
Para: <psk31-digest@aintel.bi.ehu.es>
Asunto: Psk31 Digest V1 #117
Fecha: martes 20 de julio de 1999 4:34
Psk31 Digest Tuesday, July 20 1999 Volume 01 : Number 117
In this issue:
[psk31] PSK Overdrive
Re: [psk31] PSK Overdrive
[psk31] PSK 1.12.B22 observations
RE: [psk31] PSK Overdrive
Re: [psk31] Dual Soundcards
[psk31] Overdrive
See the end of the digest for information about psk31-digest
----------------------------------------------------------------------
Date: Mon, 19 Jul 1999 06:46:00 -0500
From: "Pete Francescon" <PFrancescon@worldnet.att.net>
Subject: [psk31] PSK Overdrive
Hello Everyone,
With the help of several people, I have made a few PSK contacts - thank you.
Each station reports that I have a very wide signal, like I am overdriving
the xmtr. I am running a TS-570D, with the sound card wired to the rear aux.
mic input through an isolation xfmr. I tried to use an attenuator but
couldn't get enough audio to drive the rig. Everything is well sheilded and
grounded, and RF chokes on input and output lines. I have adjusted PC audio
level, wave level, and rig mic level to the point where I am getting no ALC
reading, and only 20 watts out. I still have the problem! Any ideas? Thank
you for your help.
73,
Pete WB4YDY
------------------------------
Date: Mon, 19 Jul 1999 10:29:58 -0500
From: "George T. Baker" <w5yr@swbell.net>
Subject: Re: [psk31] PSK Overdrive
Pete, many if not most soundcards will heavily clip and distort their
output signals if the mixer level controls are run much above 50%. This
distortion will cause your PSK31 signal to be broad even though you are
not overdriving your transmitter. Depending upon your card, there may be
several controls that affect your output signal level.
The only way I know of to make sure about this is to look at the card
output to the transmitter with a scope. Even if you have to rent or
borrow one, that is about the only sure-fire way of ensuring that you are
coming into the rig with a clean signal. Use the PSK31 IDLE signal
(two-tone) and you will see a very easily identified waveform. Handbooks
have presented and described this way of testing SSB transmitters for
years.
If you have a Heathkit or other brand of Monitor Scope that will do as
well, but there you will be seeing the output envelope of the transmitter
and any distortion could be coming from the transmitter as well as from
the card. I recommend examining the audio waveform from the card.
In any event, run your mixer controls at the lowest possible settings to
guard against possible distortion.
Another possibility that I have uncovered with my Icom IC-765 is the
presence of a very low-level 120 Hz components on the output signal. When
modulated by the PSK31 IDLE signal, the two-tone spectral components are
present not only at the virtual carrier frequency (usually 1000 Hz) but
also at + and - 120 Hz. This effect causes your transmitted spectrum to
be over 240 Hz wide, which is about half the width of the waterfall. Note
that this does not result from overdriving the transmitter.
72/73, George AMA 98452 R/C since 1964
Amateur Radio W5YR, in the 53rd year and it just keeps getting better!
AutoPOWER Systems, Fairview, TX (30 mi NE Dallas) Collin County
QRP-L QRP-ARCI FISTS NORCAL ZOMBIE ARS 10-X 33.2 N 96.6 W EM13RE
------------------------------
Date: Mon, 19 Jul 1999 11:20:07 -0500
From: "hasan schiers" <schiers@netins.net>
Subject: [psk31] PSK 1.12.B22 observations
Bugs:
1. When transitioning from TX to RX, it seems that it takes several missed
or garbled characters before MIxW can "synch-up" properly. I never
experienced this with psk31 by Peter.
2. ALT-P which brings up the log entry screen, doesn't default to the first
field so the callsign can be entered...you have to click on the portion of
the window where you want to enter data. The entry screen box is not even
highlighted, so it isn't the focus of the keyboard yet. That would not seem
to be "rational", so it is probably a bug.
3. ALT-T which is supposed to insert TIMESTAMP into the program, still
brings up the signal report portion of the logging screen, instead. With the
introduction of newer, more powerful insert macros like <LOCALTIME>, this
may not be an issue, but the ALT-T function should be renamed in the docs as
it doesn't work right.
4. The <CWID> should include "de" instead of just sending the callsign.
See my prior post for many of the things that it does "right" or "especially
well". I am VERY glad I registered the program.
I received an update from Nick, UT2UZ by email attachment on Saturday. I
requested it Saturday morning and had it back by Saturday mid-afternoon.
Note: While Jim, WA2VOS is handling the registration and initial sending of
the program, ALL UPDATES come directly from Nick. You have to REQUEST
updates from Nick, he doesn't just bulk email them out.
The process as I understand it is this:
1. Watch WA2VOS website for announcements of new versions.
2. Click on the email link at this site to send Nick a request.
3. Watch your email.
It works rather nicely. The world has certainly become smaller. I find
myself doing business with someone half-way around the world in a fashion
that is more convenient than running down to the Quik-Shop!
73
hasan schiers, N0AN
schiers@netins.net
------------------------------
Date: Mon, 19 Jul 1999 14:10:19 -0400
From: "Russ Pillsbury" <k2txb@dxcc.com>
Subject: RE: [psk31] PSK Overdrive
Record your voice into a wave file, or use some other wave file with speech
on it. Play it into your rig while using a dummy load and low power.
Listen on a second receiver. You will be able to hear how your signal
sounds. When you get it so that you cannot tell by listening if it is from
the computer, or a signal off the air, you have it right.
I used this technique, and everyone says my signals are perfect.
73, Russ K2TXB
PS: By the way, I used an level pot from the SoundBlaster, then fed an
isolation transformer which then goes through a relay to switch the mike
audio input to the computer or to the microphone. The relay also keys the
ptt line to the mike, and operates automatically when the computer starts
sending, so that there is no conflict from the mike. There is also a
disable switch which disables the relay in case you want to make sure the
computer cannot key the rig.
The whole thing is mounted in a small minibox which has connectors for the
audio and key line from the computer, for the microphone, for the mike line
to the rig, and for 12vdc and ground for the relay. Of course I use
shielded leads for everything, but one of the tricks I found was that I had
to disconnect the shield on the audio lead from the sound board, at the
input to the minibox. This eliminated a serious ground loop and completely
eliminated hum problems. Your mileage may vary.
------------------------------
Date: Sun, 18 Jul 1999 19:56:25 +0000
From: Peter Martinez <Peter.Martinez@btinternet.com>
Subject: Re: [psk31] Dual Soundcards
From Peter Martinez G3PLX
When writing PSK31SBW, I noted from the windows "mmsystem" API that
when your application requests a soundcard, you can specify which one
you want by giving it's number. However there's no documentation I
that I could find which gives any clue as to how WINDOWS numbers the
soundcards. I couldn't explore this as I only have one soundcard. It
may be that they are always assigned in some order based on the
hardware addresses, or, if one soundcard is in use, then Windows
might assign the second one to PSK31.
I simply made PSK31SBW open the "first" soundcard (The one WINDOWS
numbers "zero"). I reasoned that this would always work in a system
with only one soundcard, and this seems to be correct. If Barry or
anyone else can explore what happens with two cards, and feed this
back to me, I can see if there is anything to be gained by building
this new knowledge into the program.
73
Peter
------------------------------
Date: Mon, 19 Jul 1999 15:55:02 -0400
From: "John C. Baird" <KB2GCH@email.msn.com>
Subject: [psk31] Overdrive
Testing overdrive: Another way. . .
Before I went on the air I direct fed my ancient 486/66 the PSK signal and
found that a very low signal level is all you need. I keep all the audio
levels threshold low to create a SSB RF output. However, I did back up the
observations with a scope looking at my radios RF and sound card output.
Please have a nice day, John
------------------------------
End of Psk31 Digest V1 #117
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