Re: [Tlf-devel] Re: Tlf-devel Digest, Vol 42, Issue 2

[Rob Vance]

Hi Lee,

Sorry for the delay; I've been on business travel for the past several days.

My interface is a 1:1 transformer from the audio output of my sound card to 
the microphone input jack of my radio.  I have not included a connection from 
my radio to the microphone input of my computer, which is required for 
digital modes.  The radio is set to VOX so any time the computer talks, the 
radio will transmit.  This can lead to unwanted transmission of beeps and 
bells; however, it also means that you can begin talking as soon as the 
computer finishes without having to push any buttons.  I use a headset with 
boom microphone.  The microphone and the computer connection are made in 
parallel to the input of the radio.  This is handy if you operate as a run 
station frequently as you can respond to calls very quickly.  But if you are 
in a noisy environment (e.g. barking dogs) then it can be problematic.

I have included a potentiometer in the connection which allows me to adjust 
the level from the computer to the radio.  I observe the ALC meter on my 
radio as the audio track is playing to get it close; then I ask a friend on 
the air to give me a report on level, quality, etc.  I turn on the Tx Monitor 
function (refer to the menu list in your rig) so I can hear what the computer 
is saying over the air.  I record my audio tracks using Audacity.

The connections are not complicated, if you are comfortable with soldering, 
cable/connector fabrication, and schematics then you can make a very capable 
interface.  The deluxe commercial units seem very nice and have many features 
but appear to rely on MS Windows drivers to operate (via the USB port).  I 
hesitate to spend the money on the chance that they may, or may not, work 
with Linux.  The more basic units are probably operating system agnostic and 
may be a good choice for simple operations.

This interface I am using is not intended to be a complete solution; it was 
just a hack to get me on the air and try out voice-keying - and for this 
single function it works remarkably well.  However, I cannot send CW with 
this interface.  To do CW I would need to provide a direct connection from 
the computer to the CW key interface of the radio; via either the parallel 
port or the serial port.  Parallel port would be more straight forward as our 
radios require the serial port for rig control.  The schematic for this type 
of interface is in the help file at the TLF webpage.

I may construct the interface by Larry Coyle, K1QW, published in QST April 
2005, page 31, "An Improved Digital Communication Interface".  This article 
is also included in the most recent ARRL Radio Amateur's Handbook.  This 
interface is designed primarily for digital modes and it includes audio 
connections to and from the radio.  The unit has a sort of VOX circuit of 
it's own to derive PTT, which I would not use for voice modes as I suspect it 
would clip the beginning of most of your transmissions.  Therefore if I build 
this interface I would add direct keying connection from computer to radio; 
hence my original post.  This will allow the computer to send CW and do voice 
keying without relying on the VOX setting of the microphone.  In this set up 
you can use a footswitch to activate your mic; this gives you and the 
computer direct control over PTT.  Otherwise I like the design of the 
interface, especially the ability to adjust the level using a meter 
indicator.  I recommend reading the article; it is a good primer on the 
issues associated with rig interfaces (ground loops, etc.).  The other 
benefit of this interface is that it can be used with other digital modes in 
addition to the basic voice keying that I am interested in here.  I would 
like the ability to expand to digital modes some day and this interface seems 
that it would allow me to do that.

Hope this helps you and others on the list.  This is a vast subject and I am 
still learning myself.  If you'd like to chat about it more, send me a direct 
email at n6rob at arrl dot net.

73

Rob, N6ROB

On Wednesday 13 December 2006 12:23 pm, NY6P wrote:
> On 12/13/2006 09:09 am, Rob, N6ROB wrote:
> > Message: 1
> > Date: Tue, 12 Dec 2006 21:35:14 +0000
> > From: address@hidden
> > Subject: [Tlf-devel] Rig and key control
> > To: address@hidden
> > Message-ID:
> >     <address@hidden
> >ne t>
> >
> >
> > Hi,
> >
> > Just had a great time on the ARRL 10M contest using TLF.  I get better
> > with this program every time I use it - even though I am an SSB-only
> > operator ;o)
> >
> > I have been reading about using serial/parallel port for interfacing to
> > radios and I writing to ask for some clarifications.
> >
> > My set-up is fairly conventional; one radio (TS-570D, with RS-232 serial
> > port), and one desktop computer with Kubuntu+TLF+hamlib+cwdaemon.
> > Currently hamlib and my radio are happy together; I can control the radio
> > just like the instructions say.  I am using the voice-keyer with the VOX
> > function on my radio.  This has the usual problems with various beeps,
> > and noises being transmitted unintentionally from the computer to the
> > radio and over the air (though this happens rarely).
> >
> > I am considering a more elaborate rig interface and I would like to add
> > direct PTT and CW control from TLF to the radio, and maybe a footswitch
> > (perhaps I can help you test 0.9.4, Joop).  However, I am using my one
> > and only serial port for hamlib/rig control.  I could add a PCI card with
> > more ttySx ports or the external box that ZL2BSJ reported about on this
> > list (nice, but expensive).  Otherwise I can just use the lp0 since I
> > don't use it for other purposes.
> >
> > If I understand the notes in cwdaemon correctly it will default to use
> > /dev/lp0.  I believe the cwdaemon is working because the sidetone & voice
> > keyer work just fine.  If I want to change the port for cwdaemon from lp0
> > to something else, where can I do this?  If cwdaemon defaults to lp0, the
> > I should be able to see activity on the relevant pin using a oscilloscope
> > or voltmeter when TLF is sending - yes?
> >
> > In summary, hamlib and rig control use ttyS0 (set in the logcfg.dat file)
> > and cwdaemon will use lp0 as default - do I have this correct?  I realize
> > these can be configured to use other ports and I have read about those
> > set-ups on this list; but I am just trying to make sure I understand this
> > set-up properly.
> >
> > The more I learn about this program the more I like it; thank you for
> > such a great contribution.  In the future I would like to contribute my
> > experiences to the help notes and documentation (I recall someone asking
> > for this type of support), but I must gain more experience with the
> > program, first.
> >
> > Rein, I enjoyed your blog on 5A7A, especially the part about getting out
> > - there's no place like home!
> >
> > 73
> >
> > Rob, N6ROB
>
> What if any soundcard interface are you using?  I have the
> TS-480, which also uses a rs-232 cable to access the TTYS0 port of the
> computer.  I have the rig control working, but have not attempted using the
> voice keyer or morse sender since I assume I need a soundcard interface.
> Could you explain?  Thank you.