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PA2AGA > HDDIG 21.12.99 04:21l 213 Lines 7071 Bytes #-9643 (0) @ EU
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Date: Mon, 20 Dec 99 23:57:36 MET
Message-Id: <hd_99_321B>
From: pa2aga
To: hd_broadcast@pa2aga
Subject: HamDigitalDigest 99/321B
X-BBS-Msg-Type: B
> > mono in most cases. Is this true most of the time? Cliff K7RR
> >
> > On Sat, 18 Dec 1999, D. Stussy wrote:
> >
> > > On Sat, 18 Dec 1999, Rob wrote:
> > > > I heard that it is NOT a good idea to connect both channels (Left and
Right)
> > > > of the sound card's line output to the Rig's mic input. It might
cause
> > > > distortion. (On the other hand, I heard it doesn't matter whether the
rig's
> > > > speaker output is connected to both channels of the sound card's line
input
> > > > or mic input).
> > > >
> > > > Is this true? Will there be distortion?
> > > >
> > > > I also heard if you just used a mono plug for the sound card's line
output
> > > > (or speaker output), it will short out one of the channels and may
cause
> > > > distortion. It is best to use a stereo plug and only use one of the
> > > > channels. Is this good advice?
> > >
> > > ...If someone were smart, the soundcard driver software could be re-
written so
> > > each audio channel were a different "port" thus creating a dual-port
virtual
> > > TNC. Of course, there would have to be two PTT circuits, two DSP
engines for
> > > RX, etc. Then the above situation would be moot.
>
>
>
>.
------------------------------
Date: Sat, 18 Dec 1999 23:32:04 -0500
From: "Rob" <NoEmail@NoWay.com>
Subject: Connecting sound card to Computer
Hi Cliff,
Yes, both the mic and line input jacks of a sound card are stereo jacks.
The line input accepts a stereo input and uses the tip and ring for separate
channels (e.g. left and right). You can supply a stereo signal to the
computer ONLY using the LINE INPUT. In Ham radio applications, we typically
only supply a mono audio output from the rig to ONE of the channels. (Even
though you could connect to mono signal from the rig to both channels - BUT
I do not recommend this approach -- see below)
The mic jack also uses a stereo jack even though the audio input is mono.
The audio is on the tip. The ring is used to supply a DC voltage from the
sound card to the mic. The DC voltage is used by some computer mics. I
checked my computer, the ring supplies 3.5 mV of DC. Not very much but it
is there.
IF YOU PLAN TO USE THE MIC INPUT JACK TO RECEIVE THE RIG's AUDIO OUTPUT, DO
NOT USE THE RING (since the ring supplies some DC!)
HERE IS THE SAFE APPROACH: Wire the line input jack of the sound card using
a stereo jack and ONLY using the tip. DO NOT CONNECT the ring (which is
used by the other channel)
Why is this the safe approach?? Well Hams like me can easily plug in the
cable to the mic jack by mistake especially considering that the mic jack is
beside the line input jack. Using this approach to wiring the jack, you can
safely connect your cable from the rig's audio output to EITHER the LINE
INPUT or MIC of the sound card.
I think I have it all straight in my mind know. Thanks for all the input.
Does anyone else have any other ideas or comments?
73's
Rob
"Clifford Buttschardt" <cbuttsch@slonet.org> wrote in message
news:Pine.GSO.3.95.991218132227.19452D-100000@oso.slonet.org...
> Good comments these, but I am still confused. Is the line and microphone
> inputs USUALLY stereo plugs? I think the mic input is always stereo but
> does it use the "ring" in any way? I would guess the line input would be
> mono in most cases. Is this true most of the time? Cliff K7RR
>
> On Sat, 18 Dec 1999, D. Stussy wrote:
>
> > On Sat, 18 Dec 1999, Rob wrote:
> > > I heard that it is NOT a good idea to connect both channels (Left and
Right)
> > > of the sound card's line output to the Rig's mic input. It might
cause
> > > distortion. (On the other hand, I heard it doesn't matter whether the
rig's
> > > speaker output is connected to both channels of the sound card's line
input
> > > or mic input).
> > >
> > > Is this true? Will there be distortion?
> > >
> > > I also heard if you just used a mono plug for the sound card's line
output
> > > (or speaker output), it will short out one of the channels and may
cause
> > > distortion. It is best to use a stereo plug and only use one of the
> > > channels. Is this good advice?
> >
> > ...If someone were smart, the soundcard driver software could be
re-written so
> > each audio channel were a different "port" thus creating a dual-port
virtual
> > TNC. Of course, there would have to be two PTT circuits, two DSP
engines for
> > RX, etc. Then the above situation would be moot.
> >
> >
> >
>
>.
------------------------------
Date: Sun, 19 Dec 1999 03:10:37 GMT
From: owner1999@yahoo.com
Subject: Explain freq. settings
I am new to the digital hf scene. I need someone to provide an explanation of
the freq. setups for digital.
Lets say I want to work a station that I pickup calling cq. My tnc locks on
to them at 14.060.60 as read on the dial. Is this where I set my rig? Please
explain this in idiot terms :) I want to call cq. Where should I be setting
my freq. to not only transmitt but to receive an answer.
Any help or advise would be most appreciated.....
thanks...
Don
N0FGK
>.
------------------------------
Date: Sat, 18 Dec 1999 11:32:44 -0500
From: "Bob Lewis" <aa4pb@erols.com>
Subject: ground loops and audio isolation transformers
How about a ceramic capacitor, perhaps 0.01 mfd or so, between the
two grounds in order to provide more complete RFI shielding while
still preventing the 60 Hz ground problem. This is often done in
professional audio systems.
Rob <NoEmail@NoWay.com> wrote in message
news:poO64.198933$5r2.502510@tor-nn1.netcom.ca...
> Thanks George.
>
> Well I am planning to use an opto isolator so my serial port can
key my rig
> using the PTT line.
>
> The opto isolator should break up the ground loop and isolate the
ground of
> the computer from the ground of the rig. A good circuit can be
found at
> www.qsl.net/wm2u/psk31.html
>
> I plan to put the opto isolator circuit, the audio isolation
transformers
> and my resistor network in a metal box with the metal box connected
to the
> rig's ground (via the cables from the box to the rigs mic and the
rigs audio
> output). Of course the shields of the cables from the sound card
will NOT
> be connected in any way to the metal box BUT DIRECTLY to the audio
isolation
> transformers. I think this will work okay.
>
> But I will have to make sure that the RS232 cable from the computer
is not
> somehow grounded to the metal box -- That may be tricky! I assume
that is
> what many HAMs choose to ground the metal box to the computer (via
the
> shields of the cables (including the RS232) cable to the computer)
and
> connect the cables from the metal box directly to the rig (making
To be continued in digest: hd_99_321C
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