[Elecraft] K3: data modes - bizarre behavior

[Matt Zilmer]

Hi Don,

I've captured the commands sent to the K3 prior to TX on the assigned
frequency:

FA0000FFFFfff;	# FFFFfff is the correct carrier frequency.
FR0;
RT0;
XT0;
MD;
DT0;

I'm still mystified, since the FA command is setting the correct cxr
frequency.

It is also true that RMS Express uses frequencies with the center
frequency shown, however it compensates by subtracing off half the
channel width to set the carrier freq.

Thanks and 73,
matt W6NIA

On Sun, 01 Jan 2012 14:48:58 -0500, you wrote:

>Matt,
>
>I too believe your software does not compensate for how the K3 handles 
>(and displays) the frequency when in DATA A mode.  The K3 indicates the 
>suppressed carrier frequency rather than the Passband center frequency.
>
>It sounds like your software is trying to set the K3 to the channel 
>center frequency.  Just as a guess, that might be SOP for government 
>gear, but not for most ham rigs which refer to the suppressed carrier 
>frequency..
>
>73,
>Don W3FPR
>
>On 1/1/2012 2:25 PM, Matt Zilmer wrote:
>> Thanks for your reply, Bill.
>>
>> I verified that the software is setting the correct carrier freq,
>> based on the center freq cited by the MARS frequency matrix.  I was
>> thinking along the same lines as your suggestion below.
>>
>> If I use program control to set the freq, then I get TX + 1.5 KHz =
>> RX.  This is with split disabled and RIT / XIT turned off.
>>
>> Temporarily, I'm manually setting the carrier freq to 1.5 KHz below
>> center instead of relying on the control program to do this.  That
>> solved the problem, but doesn't explain why the radio has carrier freq
>> centered on the freq only under program control.
>>
>> Mysteries....
>>
>> 73,
>> matt W6NIA / NNN0UET
>>
>>
>>
>> On Sun, 01 Jan 2012 13:21:51 -0500, you wrote:
>>
>>> Well, this is normal for digital mode DATA A.  I'm not familiar with your
>>> particular software, but for PSK31 and similar modes, the K3 VFO A is set to
>>> a frequency for the carrier.  The audio is on the upper sideband, and is
>>> centered in the 3 KHz passband which is 1.5kHz up from the carrier.  Thus
>>> the offset.  Some digital software has an allowance for an offset, but I'm
>>> not sure about yours.  You might check on this.
>>>
>>> Typically if operating on 20 meters with radio set to 14.070MHz, the
>>> waterfall will be full of traces at audio frequencies spread across the
>>> passband of your radio.  So you actual transmission freq is the sum of VFO
>>> plus the audio.
>>>
>>> ...bill  nr4c
>>>
>>> -----Original Message-----
>>> From: Matt Zilmer [mailto:mzilmer at verizon.net]
>>> Sent: Sunday, January 01, 2012 11:31 AM
>>> To: elecraft at mailman.qth.net
>>> Subject: [Elecraft] K3: data modes - bizarre behavior
>>>
>>> In all this time with K3 #24, I've never been stymied by any issue
>>> such as described below.
>>>
>>> I'm a Navy-Marine Corps MARS member.  We use RMS Express in the WL2K
>>> system on HF, running WL2K Winmor mode  The software I have is version
>>> 1.1.3.0.
>>>
>>> I also use LP Bridge to create two COM ports: one used for DTR (PTT)
>>> and the other for control, COM19 and COM20 respectively.  The sound
>>> card is an EMU 0202.
>>>
>>> The problem is this:  When RMS Express takes control of the K3,
>>> calling an RMS node on HF *always* results in the receive frequency
>>> being 1.5 KHz too high.  I've had to rotate the RIT between call-up
>>> transmissions to get the RX on frequency before the initial 5 attempts
>>> time out.  The TX frequency seems dead-on, because the RMS always
>>> answers - but RX is 1.5 KHz high.  And yes, I've tested with multiple
>>> RMS nodes, including my own NMCM RMS here at the shack.  Same problem
>>> occurs with each, so it's a setup issue with software or the K3 here.
>>>
>>> RMS Express sends the following commands after it's set the COM20 comm
>>> parameters:
>>>
>>> 	FR0;	# cancel split
>>> 	RT0;	# RIT OFF
>>> 	XT0;	# XIT OFF
>>> 	MD6;	# TX DATA mode
>>> 	DT0;	# DATA A sub-mode of TX DATA
>>>
>>> The sequence above is sent once at the beginning of an RMS Express
>>> call-up of the remote node.  Only COM19's DTR is used to assert PTT
>>> for transmissions.
>>>
>>> Just for grins, I checked the various meta-modes the K3 is in.  I
>>> discovered that even though AI is set to ZERO, I'm still getting IF
>>> annunciations back from the K3.  Odd, that.
>>>
>>> 	K31;	# K3 extended commands enabled
>>> 	K22;	# K2 extended " "
>>> 	AI0;	# AUTOINF OFF
>>>
>>> Since split and the incremental controls are off and ZEROed, I'm
>>> totally blind to what's going on.  VFO A is on the correct frequency
>>> in each case (for each RMS Node), which means to me that RX and TX
>>> actual frequencies should be the same.
>>>
>>> Any ideas what's causing this?
>>>
>>> 73 and HNY,
>>> matt W6NIA, NNN0UET
>>>
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:Elecraft at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>