Hello,
I discovered something last night while working AO-51 and wanted to share it with the group. Thanks for the many short QSOs on AO-51 last night, BTW.
I use two Icom 706Mk2g radios as my satellite station. Although I've read through the manual for my radio many times, I wasn't aware that Icom included a wide and narrow FM capability in this radio. This is not to be confused with WFM receive (which this radio can also do), for commercial radio and TV audio reception.
After checking out page 23 of the manual, I can better understand this, but honestly, it might have been a good idea for Icom to spell this out a little better!
When selected, the narrow filter is active in both transmit and receive. According to Google, the wide FM setting has a maximum of 4.8 KHz deviation, and the narrow FM setting has a maximum of 2.4 KHz deviation.
The standard AM/FM filter (FL-23) is 15 KHz wide, and the narrow filter (FL-94) is 8 KHz wide.
Armed with this new piece of information, I experimented with using the narrow filter on my receive radio last night on AO-51 with very noticeable results! The filter eliminated much of the background noise, and I also noted that the S meter reading displayed typically 2 S-units higher with the narrow filter enabled, FWIW.
If you use a 706 on the birds, you might want to check out menu M3, and select FIL while in FM mode.
73,
Kyle Yoksh K0KN Olathe, Kansas