K3 Data Modes
From Zerobeat
- New K3 Firmware Release -- Major Improvements to DATA Modes - December 28, 2007.
PSK31
Matt Zilmer mzilmer at verizon.net Sat Dec 1 19:39:22 EST 2007
I have reached the conclusion that the K3 may be the best data radio I've ever owned or operated. Got plenty of compliments on the audio quality (no IMD or wide-bandwidth products). The folks I worked - most of them had heard of or seen the K3 [hamfests], and two of the guys wanted their own after hearing this one.
My set up here is pretty plain so far, but I had a whale of a good time operating low power PSK on 20m today.
Did some experimentation before going live, and set up things as follows. The MON and TEST functions really help with getting levels right.
Data MD: Data A
TX line in setting: 20% of full scale. The output is a laptop's speaker jack and the setting reflects the playback volume set on the laptop.
RX line out setting: 55% of full scale. The input is the mic jack of the laptop.
RX Filter: shift it to 1 KHz Fc, and 200 to 400 Hz bandwidth.
K3 Line In Gain: set at 5 to 10. This range seems fine, but it won't help to go any higher than 8 or so.
K3 Line Out Gain: leave this at the default 30 setting. It works fine.
K3 Mic Source: Select Line In. Don't forget to put it back when you return to voice modes.
PTT-Key: I ran it DTR-Off, but you could also use RTS for keying.
K3/10 MFJ-941 tuner Long wire antenna - 130' long at 35' above ground. Two stereo cables - 3.5mm to 3.5mm, both male USB: Keyspan USA-19HS serial port adapter @ 38400 bps. SW: Digipan 2.0 running on XP Pro, SP2.
I had a power setting of between 3 and 5 Watts. With PSK31, that's enough.
If you are having a problem check:
1. That in addition to being in Data Mode A you are in transmission mode Data, NOT Reverse Data.
2. That you do not have CWT on. This will prevent transmission.
3. Apparently there is still a problem with setting Mic Sel to Line In. Results are inconsistent.
4. Dual PB filter does not appear to work in DATA A and AFSK. (can not receive in DATA A, can not transmit in AFSK)
RTTY
[Elecraft] K3 operating tip: RTTY operation without a computer
wayne burdick n6kr at elecraft.com
Fri Dec 28 13:24:37 EST 2007
If you're a CW operator but would like to dabble a bit in RTTY (especially easy during a contest), you're in luck: You can use the K3's internal keyer to directly transmit RTTY. You can also copy RTTY on the K3's text display, making it a self-contained RTTY station -- no need to set up computer cables or software.
Just follow the procedure below (all parameters are saved, so you'll only need to do the setup one time).
1. Tap either end of MODE to get to DATA, then hold DATA MD and select FSK D.
2. Hold PITCH and select a mark tone; I use 915 Hz.
NOTE: No matter what pitch you select for FSK D mode, the K3's VFO will always show you your mark frequency. Thus there's no need to do any math to convert from an SSB suppressed-carrier frequency to the actual data carrier frequency. This makes RTTY operation very similar to CW: just tune in a signal and call them using the keyer paddle.
3. Hold TEXT DEC and turn the text decoder. You'll start seeing random noise characters on the VFO B display.
4. Tap CWT; the upper half of the S-meter will become an RTTY tuning aid. When tuning in signals, try to get the mark and space tones balanced in their number of bars on either side of the CWT pointer.
5. Set power to the desired level. The K3 can transmit at full power in RTTY mode.
6. Plug in a keyer paddle. Adjust the sidetone volume in CW mode (if necessary), then switch back to DATA mode.
7. Send a few characters with the paddle. If you don't hear the FSK signal, adjust the MONitor level (hold the CMP/PWR knob in to select MON level adjust). Note that you can adjust the levels in TX TEST mode, too, without putting out any power. This is a good way to practice with CW-to-RTTY.
8. If you pause, the K3 will remain in a data idle state for about 4 seconds before automatically returning to receive mode. To cut the 4 second timeout to about 1 second, you can send "..--" (IM prosign, for "IMmediately exit").
For further details, see the Owner's Manual, page 32 (revision C).
Wayne Burdick n6kr
