I hope the group will pardon me while I engage in a bit of RTTY heresy.....
When you use a PC sound card for decoding RTTY, the center frequency is no longer important, just the tone spacings. With MTTY, I can pick any center frequency I want to use (typically 1000 Hz so I stay away from the roll-off) and tune until I see it in the MTTY spectrum window. I make any fine adjustments with the cursor to pick the signal I want if there are multiple signals shown. If I want a bandpass filter, I use the bandpass function in MTTY. MTTY uses the same audio frequency for encode as it used for decode so the signal is inherently locked to the received signal. It even has an AFC function to track any drift. Using just the SSB filter for receive and transmit avoids the problem of center frequency tracking between the SSB filter that is always used on transmit and whatever receive filter has been selected. It also has the advantage of allowing you to hear what is happening across the audio bandwidth so you know whether to go higher or lower for the next signal. Very useful in a contest. I use Writelog with the MTTY decoder for contests and the whole setup works very well. Using the mouse wheel for tuning and macros for the exchange, I rarely touch the K2 at all. Hope this helps. 73 Logan, KZ6O -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Clark Macaulay KE4RQ Sent: Thursday, September 04, 2008 7:39 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K2 RTTY 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 <snip> _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
