Hi David,
Thanks for the input. I am bound and determined to get FSK working and
plan to try a switching transistor as you suggest. However, I was not
aware that AFSK could provide a better and narrower signal than FSK. I
will have to learn a bit about that and consider switching! My previous
forays into RTTY were in the '70s when AFSK was shunned by most
operators. I imagine improvements in producing clean audio signals has
changed that.
73,
Tim WS4V
On 2/23/2018 3:47 PM, David G3YYD wrote:
Tim
Use a switching transistor as per N1MM wiki on interfaces see
http://n1mm.hamdocs.com/tiki-index.php?page=Serial+Parallel+and+Sound+Card+Interfacing&highlight=interface+cw#Interfacing_for_PTT_and_CW_Keying
Opto-Isolators are not needed.
Even better would be to use AFSK as that will have narrower transmission width
than rig based FSK. It will also be jitter free unlike MMTTY FSK making copy at
the far end better. If you use MMTTY AFSK then configure it for the TX filter
on with tap set at 51, the default setting for this is not very good.
73 David G3YYD
-----Original Message-----
From: RTTY [mailto:rtty-bounces@contesting.com] On Behalf Of
groupsrichart@gmail.com
Sent: 23 February 2018 19:49
To: KenwoodTS-590@yahoogroups.com; rtty@contesting.com; TS-590@groups.io;
TS-590S@yahoogroups.com
Subject: [RTTY] FSK Keying of TS-590SG
I would like to hear from anyone who is successfully keying the FSK and PTT
lines via the ACC2 connector on the rear panel of the TS-590SG. What serial
adapter and what hardware interface are you using to do so?
I have tried two different interfaces using optoisolators to attempt FSK and
PTT keying from a serial card to the rear panel ACC2 connector. Both attempts
have failed. I am using MMTTY software for keying and I do get the requisite
signal change on TXD pin 3 (FSK) and RTS pin 7 (PTT) lines. I have also
verified proper setup of the '590 by manually grounding the inputs PKS pin 9
(PTT) and RTTY pin 2 (FSK) on the ACC2 connector.
However, I *think* the problem lies with the serial card not providing enough
voltage/current for the optoisolators to completely turn on and provide a hard
ground to the ACC2 inputs. I have tried two different serial cards and one
swings from -4.9 to +5.0 VDC on the data lines and the other card swings from
-3.8 to +3.9 VDC. The cards I am using are a two port generic PCI Express
SI-PEX15037 and a four port Perle Fast 4 PCI card. Does anyone know of a serial
card that has a full -12 to +12 VDC swing?
One of the hardware interfaces has 4N25 optoisolators and the other uses
Fairchild FOD852 optoisolators. There are 1K series resistors in the input line
to the optoisolators and I have tried various values (100,
220 & 470Ω) with limited success but nothing consistent.
While my objective was to keep the rig isolated from the computer, I am
thinking about building an interface that uses NPN transistors for keying. Is
anyone using NPN transistors to key their '590? Are you tying the ground from
pin 5 of the RS-232 port to the pin 4, 8 or 12 ground of the ACC2?
Any input is appreciated...I have been off RTTY since purchasing this rig in
November and I want to get back on the bands.
Thanks,
Tim WS4V
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