locked low freq tones problem with Icom 706 #decode #transmit #txaudio #bluetooth


 

I am using WSJTX with an Icom IC-706. It works great except for one thing. If my tx tone frequency is below about 375 Hz, it apparently gets rolled off by the radio and little or no power gets transmitted. From about 400 to 2400 HZ works great. Anyone else seen this? Any suggestions for a setting in the radio, a mod, or a workaround?


Michael Black
 

Use "Fake It" or "Rig Split".  That's what those are for...keeps your audio in the 1500-2000Hz offset from the split frequency.
Mike W9MDB

On Tuesday, January 25, 2022, 05:23:28 PM CST, Rik Rasmussen <rikrasmussen@...> wrote:

I am using WSJTX with an Icom IC-706. It works great except for one thing. If my tx tone frequency is below about 375 Hz, it apparently gets rolled off by the radio and little or no power gets transmitted. From about 400 to 2400 HZ works great. Anyone else seen this? Any suggestions for a setting in the radio, a mod, or a workaround?


Jim Brown
 

On 1/25/2022 2:33 PM, Rik Rasmussen wrote:
It works great except for one thing. If my tx tone frequency is below about 375 Hz, it apparently gets rolled off by the radio and little or no power gets transmitted. From about 400 to 2400 HZ works great. Anyone else seen this? Any suggestions for a setting in the radio, a mod, or a workaround?
WSJT-X generates audio-frequency tones that are transmitted and received in SSB mode, and SSB radios include very steep bandpass filters typically set to pass modulation resulting from 300 Hz - 2.8 kHz audio. The same filters are generally in place for receive. In other words, what you are observing is how radios work. The ARRL Handbook and equivalent RSGB publications have lots of tutorial information. AND questions about how they work are on the exams for our ham licenses.

73, Jim K9YC


 

Using the Hold Tx Freq feature and picking a freq above 400 Hz in a quiet area has solved my problem. Also seems to help me in pileup situations. Thanks for the replies. I apparently can't use split or fake it because I am not controlling the radio with WSJT-X. I will be attempting to set up control when a cable on order arrives.