I have made several thousand RTTY Contest QSOs using the K2/100. It is
AFSK only. My TX power out is about 90 watts usually into a low
Diamond verticle antenna rated for 200 watts. Receive works OK for me
considering the limitations of the antenna. Transmit works well for me
on search and pounce. I leave the fan speed set high during contests.
The limitation of my antenna have kept my rate at 100 - 200 QSOs per
contest. If I had better antennas, a higher S&P QSO rate might result
in over heating.
I have tried running mode but find that the rig starts to get
unacceptably hot after several minutes of CQing. During very good band
conditions, my hourly S&P rate was high enough to damage the 40M and
20M matching components in the Diamond antenna. I now must restrict
the Diamond antenna to 80M and 15M use and use a low Alpha Delta DX-CC
fan dipole for 40M and 20M.
I set the K2 AGC off and control RX signal strength into the computer
sound card using RF gain. AGC off prevents pumping that can depress
weak signals when a strong signal comes onto the passband. Under
crowded conditions, I use AFil to narrow bandwidth with 1000 Hz being
used as my center frequency. RTTY AFil is set to opt1 with the strong
right third of the filter passband aligned with 1000 HZ. I always try
to TX at 1000 HZ to keep the TX signal strength consistent. I use
narrowed CW filters centered on 1000 Hz when needed.
Reducing RF gain is more beneficial for copying weak signals that using
narrow DSP filters. Problems copying weak signals appear to be more
related to the background noise level than adjacent signal
interference. The narrow DSP filters work FB to eliminate unwanted
signals within a wider passband with the AGC off to prevent signal
strength depression by the AGC. I avoid XFil because I find the small
frequency shift annoying on digital modes when switching between the
XFil used on RX and the Opt1 fil always used on TX.
I hope to make the following future changes:
-higher and better antennas to improve my QSO rate,
-an external amplifier so that I can use lower power on the K2/100 to
enable run mode without significant heating,
-an external muffin fan to improve K2 cooling efficiency.
I have never had a heating problem using typically lower power PSK31.
AGC pumping can be challenging on PSK 31 because of the narrow signal
and closeness of adjacent signals.
HTH 73 de KB1IKD
Lee Buller wrote:
> > Well, I am getting back into RTTY and PSK31 after a couple of
years away from the modes. I have my IC756PROII set up for AFSK and
going to FSK using MMTTY on RTTY (only)
> What I "hate" about the PROII is when you are using RTTY I have to
use AFSK Keying and the receiver's bandpass is less that ideal. This is
why I am going to FSK so I can used the great filters on the PROII.
> Well, I never thought about using the K2/100 as an RTTY rig. I know
it has RTTY filters...but I am sure it does not use FSK, but uses AFSK
through the RTTY Filters? Right?
> Could somebody who has used the K2 on RTTY and PSK31 eludicate me
on their experience with the rig and the mode?
> Lee - K0WA
>
In our day and age it seems that Common Sense is in short supply. If
you don't have any Common Sense - get some Common Sense and use it. If
you can't find any Common Sense, ask for help from somebody who has
some Common Sense. Is Common Sense devine?
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