[RTTY] Some basic RTTY questions

[Joe Subich, W4TV]

> I'm wondering if I can dispense with the switching all together. I
> don't have an electronics background so sometimes simple things elude
> me.

Yes, you can dispense with the switching.

> Would there be a problem with the PTT line from the Signalink and the
> PTT line from the W3YY box being connected to the PTT pin on the
> FT-950 at the same time? They obviously wouldn't be keyed/carry a
> signal at the same time.

Signalink USB uses a relay for PTT, W3YY uses an optical isolator both
are high impedance in receive and low impedance in transmit - they can
be connected in parallel without any problem as long as you do not
generate audio in the Signalink when transmitting RTTY.

Of course, most digital programs include the option to generate PTT
using the RTS line of a serial port.  You could disable the Signalink
PTT completely and use the W3YY board/serial port for PTT with all the
modes.

73,

    ... Joe, W4TV


On 2014-05-31 1:37 PM, Michael Rapp wrote:
> Hi all,
>
> I did some experimenting last night to work on my RTTY receive and it was
> an exercise in enlightening frustration clearly in the unintended
> consequences/too-good-to-be-true category.  :)
>
> I tried three different sound cards -- two Audigy 2 models (PCIe) and one
> $15 basic one (PCI) -- and none of them worked.  Either the jacks acted
> erratically or the cards caused blue screens (in Windows 7, not an easy
> thing to do).  After much research, I found out what is going on.  My shack
> PC is an old Dell PowerEdge SC1430, which is from their server line.  It's
> a very robust computer as you'd expect being a former server....but has a
> little problem for shack use.
>
> As low-end servers and desktop PCs are almost indistinguishable these days,
> Dell intentionally crippled the PCI bus in the server so that you could not
> buy a cheap server and then load it up with nice after-market video or
> sound cards.  The only solution to get an internal sound card to work is to
> buy a new PC, something I'd rather not do for the cost and the fact that I
> just recently reformatted the thing from XP to Win7.
>
> Of course, while the PCI bus is crippled, the USB bus is not.   That's why
> the Signalink works just fine.
>
> To recap my problem.  My Yaesu FT-950 has a single DATA/RTTY mini-din plug
> on the back.  I can either have my Signalink USB plugged in or my W3YY FSK
> box plugged in.  Indeed, right now, I use a switchbox to switch between
> them.  So for RTTY, I can have either receive audio or FSK keying.
>   Obviously not optimal.  :)
>
> So my current idea is to devise a breakout box by which I can switch
> between these two setups:
>
> Full Signalink (for non-RTTY digital modes):
> -- To Signalink:  Data Out from radio (receive audio), Data In to radio
> (transmit audio), PTT
> -- Nothing to W3YY box
>
> RTTY Mode
> -- To Signalink:  Data Out from radio (receive audio)
> -- To W3YY box:  PTT, FSK
>
> I'm wondering if I can dispense with the switching all together.  I don't
> have an electronics background so sometimes simple things elude me.
>
> Would there be a problem with the PTT line from the Signalink and the PTT
> line from the W3YY box being connected to the PTT pin on the FT-950 at the
> same time?  They obviously wouldn't be keyed/carry a signal at the same
> time.
>