[Elecraft] K2 RTTY

[Clark Macaulay KE4RQ]

I've decided to take the plunge into digital modes and 'found' the RTTY mode
(and extra set of filters) in the SEC menu.  There is still much about my 1
year old K2 that I'm still finding out.  What a radio!

When I went in to set the filters in RTTY mode and decided to check the SSB
filters as well.  Using Spectogram, I cannot ajust anything to make the 300
cycle point at -60 db down.  I CAN adjust it such that it is -60 db down at
2500 hz.  There appears to be no low frequency roll-off at all.  Adusting
the BFO moves the high frequency point; it does not move the low frequency
point.  My setup:   

K2# 6110.  AF option is OFF and switched out of the circuit.  I'm using the
External Speaker Output to drive the sound card.  

I don't see this porblem with the CW filters.  Is this normal?  Received SSB
signals sound fine. 

73, Clark KE4RQ 




Don Wilhelm-3 wrote:
> 
> JT,
> 
> There is nothing wrong with AFSK - in fact, if the carrier balance on 
> the KSB2 board is adjusted correctly, AFSK is indistinguishable from FSK.
> 
> The only 'problem' with the K2 is that the BFO range is limited, with 
> the result that narrow filters cannot be set with a center frequency 
> equal to the 'true RTTY' tones.  MTTY and other soundcard RTTY programs 
> offer a selection of tone frequencies - so if you align your narrow RTTY 
> filters to at 800 or 1000 Hz, MTTY can accommodate that center 
> frequency.  When I set up RTTY filters on a K2, I set the FL1 filter the 
> same as the SSB filter and then set FL2 at 1.00 kHz, FL3 at 0.70 and FL4 
> at 0.400.  The narrow filters are centered at either 1000 Hz (or 800 Hz 
> if the BFO range will not accommodate 1000 Hz for the 0.40 filter on 
> both sidebands).  In operation, the RTTY signal is tuned to center on 
> 1000 Hz (or 800 Hz) and the program will decode the signal - 
> transmission will occur at the same offset and noone on the receiving 
> end will know whether you are using real FSK or AFSK.
> 
> So the short answer is: the K2 will operate just fine on RTTY, and yes, 
> you can use narrow RTTY filters to minimize the QRM.
> 
> 73,
> Don W3FPR
> 
> John Tobias Croteau wrote:
>> How well does the K2 work in RTTY mode?  I presume it is AFSK only?  I
>> seem to recall that some do not recommend the K2 for serious RTTY
>> operating but I don't remember the reasoning behind this.  I vaguely
>> recall reading this about 2 years ago from somewhere.
>> 
>> I'm a RTTY operator first then SSB.  I've never been good with CW and
>> probably never will so I focus on these two modes.  I know it's a poor
>> attitude but let's just not go there, at least I am honest about it.
>> Most of my RTTY operation is centered around contest weekends simply
>> because I can only operate portable due to antenna limitations at the
>> home QTH.  However, I am not a hardcore contester.  I merely operate
>> during the contests to maximize QSO numbers although getting a good
>> score never hurts.
>> 
>> Around August, I'm finally going to be able to upgrade to something in
>> the K2 price range.  Will the K2 be acceptable for the way I operate
>> RTTY or should I hold out for a K3?  I know the K3 will be a much
>> better data rig.  I can't really afford a K3 but I could probably make
>> it happen.
>> 
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