K3 - MicroKeyer 2 - mmtty transmit issues on RTTY using FSK-D mode

[Jim Spears]

I am trying to get my K3 operational on rtty and have run aground.  Receive
works fine.  Transmit using FSK-D mode in the K3 keys the transmitter but
the FSK signal does not trigger the K3 to transmit both tones.  I hear a
single tone in the monitor and the P3 also shows the same thing.  

 

Using the K3 utility to send rtty works fine but this is a different
interface, bypassing the MicroKeyer 2.

 

So the big question is "what am I doing wrong?"   I have posted this to the
MicroHam Yahoo group, it will be interesting to see where the best advice
comes from.

 

Details of the hardware and software configuration are available on request.

 

Jim/N1NK

 

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[Don Wilhelm-4]

  Jim,

I do not have enough information for a good answer, but I can ask a
question --
What are the voltage levels you are applying to the ACC pin 1?  It must
be 0 volts and +5 volts - there is a pullup resistor in the K3, so you
only need an open collector transistor to accomplish the keying from an
RS-232 signal.
The TTL voltage must be referenced to ground (ACC pin 5 or pin 12).

What do you mean by "bypassing the MicroKeyer 2" - what is driving the
ACC connector pin 1 (and K3 ground).
I am not familiar enough with the Microkeyer 2 to understand its
connection options.

If you are applying raw RS-232 levels to ACC pin 1, you may have damaged
the TTL input and/or the pullup resistor.

The K3 Utility uses an entirely different path to create RTTY (or PSK31)
from ASCII input through the RS-232 connector, so there is not a 1 to 1
correlation between the K3 Utility method and the FSK input to the ACC
connector.

73,
Don W3FPR

On 10/24/2010 7:57 PM, Jim Spears wrote:

> I am trying to get my K3 operational on rtty and have run aground.  Receive
> works fine.  Transmit using FSK-D mode in the K3 keys the transmitter but
> the FSK signal does not trigger the K3 to transmit both tones.  I hear a
> single tone in the monitor and the P3 also shows the same thing.
>
>
>
> Using the K3 utility to send rtty works fine but this is a different
> interface, bypassing the MicroKeyer 2.
>
>
>
> So the big question is "what am I doing wrong?"   I have posted this to the
> MicroHam Yahoo group, it will be interesting to see where the best advice
> comes from.
>
>
>
> Details of the hardware and software configuration are available on request.
>
>

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[Kok Chen]

On Oct 24, 2010, at 4:57 PM, Jim Spears wrote:

> I hear a single tone in the monitor and the P3 also shows the same thing.  

A microKeyer does not modulate the FSK keying signal unless the keyer is commanded to do so by the software that is controlling it.  If nothing is sent to the keyer from the controlling software, the keying pin from the microKeyer to the K3 will be in a constant Mark state (a single fixed carrier).

A standard convention in Amateur RTTY is to insert the Baudot <LTRS> character when nothing is typed.  This produces the familiar two tone "diddle" signal that you hear from RTTY stations when they are idling.   Among other things, the diddle provides a reference for the automatic threshold control function in the demodulator to work on in case selective fading causes the two tones to have unequal energy.

However, the microKeyer by itself does not automatically insert these characters for you.  The software that is driving the microKeyer is the one that is responsible for inserting the Baudot <LTRS> characters when the "input buffer" is empty (i.e., when you are not typing).

If the software is doing the proper thing, you should see the green front panel LED on the microKeyer II flashing.  If the FSK LED on the microKeyer II is fixed in the on or off state, you might check if there is a "diddle" option in the software that needs to be turned on.

73
Chen, W7AY

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[Joe Subich, W4TV-4]

>> Transmit using FSK-D mode in the K3 keys the transmitter but
>> the FSK signal does not trigger the K3 to transmit both tones.
 >> I hear a single tone in the monitor and the P3 also shows the
 >> same thing.

Which monitor?  Is your software generating shift?  Do you see
the FSK LED flickering on MK II?  Have you checked the cable to
see if the FSK line is correct and connected to the FSK output
pin on the MK II?

73,

    ... Joe, W4TV


On 10/24/2010 7:57 PM, Jim Spears wrote:

> I am trying to get my K3 operational on rtty and have run aground.  Receive
> works fine.  Transmit using FSK-D mode in the K3 keys the transmitter but
> the FSK signal does not trigger the K3 to transmit both tones.  I hear a
> single tone in the monitor and the P3 also shows the same thing.
>
>
>
> Using the K3 utility to send rtty works fine but this is a different
> interface, bypassing the MicroKeyer 2.
>
>
>
> So the big question is "what am I doing wrong?"   I have posted this to the
> MicroHam Yahoo group, it will be interesting to see where the best advice
> comes from.
>
>
>
> Details of the hardware and software configuration are available on request.
>
>
>
> Jim/N1NK
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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