i'm on rtty and psk31 but hear a 'warbling' mode in the 20 meter area
where these modes are. can anyone clue me in as to what this is?
thanks much

You didn't mention whether you are listening in the phone or cw sections of the band. If you are in the phone section around 14.230, it is probably one of the various types of SSTV. If you are between the PSK31 and the RTTY areas, it could be one of several digital modes. My guess is that you were hearing MFSK16.

One way to familiarize yourself with these modes is to visit one of the web sites that have sample wave files of the various digital modes. Here are a couple you might check out:

http://www.bartg.org.uk/modesamples.asp

http://www.wb8nut.com/digital.html

Hope this helps.

73,
Ken - K4XL