[Elecraft] K2 and Digital Modes

[Fred Jensen]

Gary McKelvie wrote:
> Hi to the List,
> 
> I'm thinking of buying the kit for the K2 with the 100 watt PA. I will 
> mainly be operating on Digital modes such as PSK 31 MFSK 16 RTTY and 
> Hellschreiber. I will be using a Tigertronics SL 1+ interface but was 
> wondering if there are any known problems with the K2 and any or all of 
> these modes before I buy the Kit and start building.

I switched my RTTY contesting to my K2, primarily to take advantage of 
the RX filters.  I have a splitter in the headphone cord that feeds the 
audio input on the computer, and the computer audio output directly 
feeds the mic jack.  I juggled the audio input level in Windoze so I can 
run with the AF gain on the K2 at about half-scale.  I use amplified 
headphones [I'm generally deaf and my hearing aids don't work with 
phones] and that gives me a comfortable listening level.  WriteLog/MMTTY 
keys the TX via the serial CAT port.

It works way better than just great.  I centered my RTTY filters around 
1.1KHz, and set them for about 1.0KHz, 800Hz, 400Hz, and 250Hz 
bandwidth.  I rarely use anything but 400Hz.  The K2 RX and filtering is 
so superior to what I had with the FT-847, there isn't even a reasonable 
way to compare them.

Digital modes are 100% duty cycle when transmitting, and the KPA100 heat 
sink got very hot, even at 50-60W.  I mounted an old 12VDC computer 
muffin fan on top of the HS with a little bit of sticky backed Velcro, 
and now at 100W, the HS stays cool to the touch.

I haven't tried PSK31 or other modes.  Maybe I'll get around to them, 
but don't hold your breath :-)  Oh, in order to get the RTTY filters to 
show up in the K2 menu, you have to turn them on.  Apparently, they are 
off when the K2 comes out of the box.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2007 CQP Oct 6-7
- www.cqp.org