[Elecraft] K3 and RTTY

Fred Jensen k6dgw at foothill.net
Fri Jan 30 18:29:02 EST 2015


Ummmm ... I've never understood the infatuation with FSK over AFSK, 
especially for someone just trying RTTY out for the first time.  If the 
sound card produces clean audio [pure sine wave sans noise], and most 
newer ones do these days, the result at RF is essentially the same, with 
less equipment.  The K3 also has a shaping filter when running AFSK that 
makes AFSK cleaner than FSK, or so I've read.

My "radio laptop" is a fairly new [1 yr] quad-core Acer running Windows 
7.  On the spectrum analyzer, any undesirable products other than the 
single tones are lost in the minuscule noise on the baseline.

There can be other reasons for running FSK with the extra interface 
equipment which usually offers other features beside FSK, but for 
someone just trying out RTTY, "less is definitely more."  There is a 
steady stream of traffic on this list from people trying to get 
MicroHam, SignalLink, or other interfaces working, so it's definitely 
not a piece of cake.  MMTTY is tough enough for a newbie.

The K3 does have a potential "gotcha" which is easy to avoid if you know 
about it.  The RF Power is controlled by a closed-loop ALC system.  The 
power knob sets the "requested" power, the loop then adjusts the drive 
to make that power.  Consequently, you cannot adjust the output power 
with the MIC/LINE IN front panel gain control.  Adjust the MIC/LINE IN 
control for 4 solid ALC bars with the 5th just flickering when sending 
idles [diddles].  Then set the desired power with the PWR knob.

There's almost no conversational RTTY anymore, it's pretty much all 
contesting.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org

On 1/29/2015 5:15 PM, RIchard Williams wrote:
> Though AFSK will work, I think you will be a lot happier with using FSK.



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