[RTTY] [TS-590] UPDATE Re: FSK Keying of TS-590SG

Tue Feb 27 00:06:23 EST 2018

Well, tonight I tried Jim's suggestion of putting +12V directly on the 
input to the optoisolator through a 1k current limiting resistor. I was 
able to do this by unplugging the serial cable from my FSK interface and 
injecting the voltage directly into the pins of the DB9 connector. When 
I did this each output from the optoisolator was able to pull fully low 
(less than 0.05V) and activate the RTTY and PTT inputs on the ACC2 
connector.

So connecting +12V into pin 7 of the DB9 and ground to pin 5 turns on 
the optoisolator and activates the PTT line. Checking the voltage from 
pin 7 to 5 still shows 12V. Checking the output at the optoisolator 
shows 0.05V.

Now, if I go back to the serial cable connected to my computer's serial 
expansion card, I measure +11.5V from pin 7 to ground pin 5 when it is 
not connected. When I connect the cable to the FSK interface card, the 
voltage from pin 7 to 5 drops to 7V. The voltage at the output of the 
optoisolator drops from 2.3V to 0.54V...not low enough to activate the 
PTT line.

So, this is starting to look to me as if the serial adapter card is not 
sourcing enough current to operate the optoisolators. Or the cable has a 
high resistance connection somewhere...11.5V with no current draw but 
drops to 7V with a load.

Hmmm, I will have to think about this one for a while. Time to get some 
sleep! Any thoughts or suggestions appreciated.

73,
Tim WS4V

On 2/25/2018 11:54 PM, groupsrichart at gmail.com wrote:
> Jim,
>
> ..Did you try shorting the lines directly to ground? YES
> ..Did the radio transmit? YES
> ..Did you manually key the radio with it's microphone and ground the 
> FSK line? YES
> ..Did it shift? YES
> ..Did you try putting +12 volts directly on the input to your opt 
> isolator with it hooked to the radio? NO...good idea...I will try it 
> tomorrow.
>
> Thanks and 73,
>
> Tim WS4V
>
> On 2/25/2018 11:18 PM, Jim W7RY wrote:
>> Should be more than low enough.
>>
>> Did you try shorting the lines directly to ground? Did the radio 
>> transmit? Did you manually key the radio with it's microphone and 
>> ground the FSK line? Did it shift?
>>
>>
>> Did you try putting +12 volts directly on the input to your opt 
>> isolator with it hooked to the radio?
>>
>> 73
>>
>> Jim W7RY
>>
>>
>> -----Original Message----- From: Tim Richardson
>> Sent: Sunday, February 25, 2018 9:29 PM
>> To: TS-590 at groups.io
>> Subject: [TS-590] UPDATE Re: FSK Keying of TS-590SG
>>
>> Just to give everyone who has commented a little update:
>>
>> 1. I located another serial card and installed it in my computer. It
>> gives me a full -/+12VDC swing on the data lines.
>> 2. The optoisolators in my interface are not pulling the PTT and FSK
>> inputs of the rig low enough to work. When the optoisolator is turned
>> on, I am still seeing +0.54VDC on the ACC2 inputs to the rig.
>> 3. I tried different values of current limiting resistors from 100Ω to
>> 1.5KΩ on the inputs to the optoisolators with no change.
>> 4. I checked my junk box for some NPN transistors and found none (I
>> could have sworn I had some 2N2222s), so I have a few on order for the
>> coming week. I plan to build the simple resistor/transistor interface
>> that many have suggested.
>> 5. After I get FSK working, I do plan to also try AFSK. There seems to
>> be a spirited debate among many as to which is best. I have no doubt
>> that either method properly used can give good results so I want to find
>> out operationally which method I prefer.
>>
>> My thanks to everyone who has taken the time to respond with your
>> comments and suggestions. I found them all very helpful.
>>
>> 73,
>> Tim WS4V
>>
>> On 2/23/2018 2:49 PM, groupsrichart at gmail.com wrote:
>>>
>>> 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
>>>
>>
>>
>>
>>
>>
>> -=-=-=-=-=-=-=-=-=-=-=-
>> Groups.io Links:
>>
>> You receive all messages sent to this group.
>>
>> View/Reply Online (#71): https://groups.io/g/TS-590/message/71
>> View All Messages In Topic (2): 
>> https://groups.io/g/TS-590/topic/12898158
>> Mute This Topic: https://groups.io/mt/12898158/514165
>> New Topic: https://groups.io/g/TS-590/post
>>
>> Change Your Subscription: https://groups.io/g/TS-590/editsub/514165
>> Group Home: https://groups.io/g/TS-590
>> Contact Group Owner: TS-590+owner at groups.io
>> Terms of Service: https://groups.io/static/tos
>> Unsubscribe: https://groups.io/g/TS-590/leave/1184261/1002795861/xyzzy
>> -=-=-=-=-=-=-=-=-=-=-=-
>>
>