Table of Contents
Yaesu FT-991A
The FT-991A is all mode, all band MF/HF/VHF/UHF transceiver with C4FM (System Fusion) Digital capability. The FT-991A includes multi-mode operation on CW, AM, FM, SSB, and Digital Modes (Packet, PSK31, RTTY and C4FM), with 100 Watts of HF/50mhz Capability (50 Watts VHF/UHF).
The has a high-resolution full color 3.5“ TFT touch panel, incorporating a High Speed Spectrum and High Resolution real-time scope.
The FT-991 can be connected to a computer using a USB cable for CAT control and firmware updates, or the use of an integrated SCU-17 Interface Unit to support USB Audio In/Out, TX Control (PTT, Key, Shift).
The FT-991A has an in-built automatic antenna tuner.
TNC cable
(taken from FT-450D manual)
| Pin | Use | NinoTNC / Kantronics pin |
| 1 | TX audio | 1 |
| 2 | Ground | 6 |
| 3 | PTT | 3 |
| 5 | RX audio | 5 |
A suitable cable can be made from a PS/2 extension lead, scrap PS/2 mouse or keyboard. Sometimes with the mouse/keyboard option, not all of the required pins are populated, so may not be suitable. Identify the pins with a multimeter (a croc clip lead is useful here.) Solder a DB9 plug on to the other end as above.
Packet Radio with NinoTNC
Settings on the radio for HF are:
- mode: data-usb
- dial setting of 7.04575 (for GB7IOW)
On the (F) button:
- DT Gain 10 (DT Gain is unique to each setup, monitor ALC - increase until you see ALC kicking in, then back off)
On the Menu button:
- 073 Data Out Level at 80-95
- 062 Data Mode - OTHERS
- Remember to set 108/109 back to DAKY/DATA if you've been using the SCU.
For legacy HF modes with a 1700 CF (Centre Frequency)
- Menu 064 and 065 set at 1700Hz. (F) Width 500hz
For the new beta NinoTNC modes with a 1500 CF (500Hz Bandwidth)
- Menu 064 and 065 set at 1500Hz. (F) Width 800hz (500Hz does work though)
Packet Radio with soundcard modem
The FT-991A’s USB interface can be used for packet radio with soundcard modem software, with the caveat that it cannot be used for 9600 baud. See https://sourceforge.net/p/fldigi/wiki/FT991A_9600/