| |
PA2AGA > HDDIG 21.12.99 08:05l 231 Lines 7203 Bytes #-9642 (0) @ EU
BID : HD_99_322B
Read: DL6KCF GUEST
Subj: HamDigitalDigest 99/322B
Path: DB0AAB<DB0PV<DB0MAK<DB0ERF<DB0BRI<PI8DRS<PI8DAZ<PI8GCB<PI8HGL<PE1NMB<
EA7URC<PE0MAR<PI8VNW
Sent: 991221/0316Z @:PI8VNW.#ZH2.NLD.EU #:36062 [HvHolland] FBB7.00g $:HD_99_32
From: PA2AGA@PI8VNW.#ZH2.NLD.EU
To : HDDIG@EU
Received: from pa2aga by pi1hvh with SMTP
id AA26455 ; Tue, 21 Dec 99 02:24:36 UTC
Received: from pa2aga by pa2aga (NET/Mac 2.3.67/7.5.3) with SMTP
id AA00017291 ; Tue, 21 Dec 99 00:02:25 MET
Date: Mon, 20 Dec 99 23:57:42 MET
Message-Id: <hd_99_322B>
From: pa2aga
To: hd_broadcast@pa2aga
Subject: HamDigitalDigest 99/322B
X-BBS-Msg-Type: B
> complicated.
>
> A schematic for an opto isolator circuit for the PTT can be found
at
> www.qsl.net/wm2u
>
> 73'
>
> Rob
>
> "Jim Haynes" <haynes@alumni.uark.edu> wrote in message
> news:83h9ta$nh3$1@ash.prod.itd.earthlink.net...
> > I have found it necessary in several situations that all happen
to involve
> > Kenwood rigs to use an isolation transformer when feeding audio
from a
> > TNC or computer sound card to the radio. I have used the little
Radio
> Shack
> > output transformer 273-1380 since it also provides a voltage
step-down.
> > In the Kenwood mic connector there are two separate grounds, one
for the
> PTT
> > switch and one for the mic element. I run the transformer
secondary to
> > the mic element pins only. This has cleared up the trouble every
where I
> > have used it.
> >
>
>
>.
------------------------------
Date: Sun, 19 Dec 1999 14:24:58 -0500
From: "Rob" <NoEmail@NoWay.com>
Subject: ground loops and audio isolation transformers
Hi Bob,
I also use short cables (abt 3 feet) between the sound card and rig.
I think the main problem may be related to the fact that I use a laptop.
The laptop has an external power supply with a two prong plug. It is not
grounded well (like most laptops).
The ground loop problem is not that bad but it is there. The solution is to
use audio isolation transformers which SOME radio shack stores keep in
stock.
Many SSTV programs for sound cards now recommend that you use these
transformers just to be on the safe side. Some people just prepare cables
with the transformers in them since the transformers are really small.
But the audio isolation transformers won't be much good for real ground loop
problems unless you also isolate the PTT circuit using opto isolator. Not a
big deal. It will just cost you a dollar or two more in parts.
I don't know why lots of Hams use a simple transistor for PTT switching from
the computer's serial port. Using an opto isolator is just as simple and
provides true ground isolation.
73's
Rob
VA2FB
"Bob Lewis" <aa4pb@erols.com> wrote in message
news:83j8k1$2m4$1@bob.news.rcn.net...
> Just curious. When you have the ground loop problem are the radio and
> computer plugged into the same power outlet? How long is the cable
> run between the rig and the sound card? I've not had any ground loop
> problems but the IC761 and computer are about a foot apart with only
> about 2 feet of cable.
>
> Rob <NoEmail@NoWay.com> wrote in message
> news:VM674.199071$5r2.503727@tor-nn1.netcom.ca...
> > Jim,
> >
> > Yes, those audio isolation transformers do a great job when they
> are used
> > right!
> >
> > Unfortunately, many people connect one lead of the secondary and
> one lead of
> > the primary BOTH to ground usually INDIRECTLY via a chassis. If
> you dos
> > this, the audio isolation transformer is useless (as you know).
> >
> > I have also found that sometimes it is necessary TO COMPLETELY
> isolate the
> > ground of the computer from the ground of the rig. To do this, you
> MUST
> > also isolate the ground used by the PTT. Instead of using a simple
> > transistor to key the rig's PTT line from the serial port. It is
> necessary
> > to use an opto isolator circuit.. It is really not that much more
> > complicated.
> >
> > A schematic for an opto isolator circuit for the PTT can be found
> at
> > www.qsl.net/wm2u
> >
> > 73'
> >
> > Rob
> >
> > "Jim Haynes" <haynes@alumni.uark.edu> wrote in message
> > news:83h9ta$nh3$1@ash.prod.itd.earthlink.net...
> > > I have found it necessary in several situations that all happen
> to involve
> > > Kenwood rigs to use an isolation transformer when feeding audio
> from a
> > > TNC or computer sound card to the radio. I have used the little
> Radio
> > Shack
> > > output transformer 273-1380 since it also provides a voltage
> step-down.
> > > In the Kenwood mic connector there are two separate grounds, one
> for the
> > PTT
> > > switch and one for the mic element. I run the transformer
> secondary to
> > > the mic element pins only. This has cleared up the trouble every
> where I
> > > have used it.
> > >
> >
> >
>
>
>.
------------------------------
Date: Sun, 19 Dec 1999 22:55:31 -0500
From: James Wilson <jameswade@mindspring.com>
Subject: Is there a way to get WWW access over packet?
Hi!
I'm going to be spending a lot of time out my property where I don't
have phone service or even cellular service. I'd still like to have
full Internet access. I can't tell in the FAQs if this can be done with
packet. If not, is there another way to do this? If so, what kind of
speeds can be expected?
Thanks!
-James Wilson
jameswade@mindspring.com
>.
------------------------------
Date: Sun, 19 Dec 1999 22:04:58 -0600
From: "Steve Sampson" <ssampson@usa-site.net>
Subject: Is there a way to get WWW access over packet?
Depends on what you can afford, and what you build. Bandwidth costs money.
Who's going to provide the Internet gateway? Are you going to set this up
somewhere, or are you expecting someone else to do it?
Figure on $300 per mile for Spread Spectrum at 2.4 GHz.
I have a system in Oklahoma City that people out in the Pan-Handle
use to get mail. It operates over 1200 baud nodes, and they can read
at the rate of about 30 characters per second on a good day. Zero
on a bad day.
James Wilson wrote
> Hi!
> I'm going to be spending a lot of time out my property where I don't
>have phone service or even cellular service. I'd still like to have
>full Internet access. I can't tell in the FAQs if this can be done with
>packet. If not, is there another way to do this? If so, what kind of
>speeds can be expected?
>.
------------------------------
Date: Sat, 18 Dec 1999 21:27:16 GMT
From: 106255.1565@compuserve.com (Richard C. Ferryman)
Subject: jnos - what versions for linux?
I downloaded lxjn111d.gz and ran it through gunzip. This produced
lxjn111d executable. I created a directory structure and a script to
run jnos and it runs ok insofar as it connects to the local hub and
runs a pop3 session. Pings go well via both attached asy ports (tncs)
to local ip stations. However jnos just drops out after a while. The
last entry in the log is a refernce to closing the pop3 session. No
error messages, no core dumps, zilch. It may be related to the
directory structure or entries which I simply mcopied from my working
dos version. I removed all the dos executabes, reconfigured
autoexec.nos and left the spool directories intact with old mail
files. I suspect there is more to it but have no idea how to use gdb
as that may have been a good diagnostic tool.
Richard G4BBH (G-4-Best British Ham)
nielsen@primenet.com (Bob Nielsen) wrote:
>
>The "x" versions of JNOS are preliminary versions prior to a version
To be continued in digest: hd_99_322C
Read previous mail | Read next mail
| |
