Simply put, the FT-991a is the upgraded version of the older FT-991 from Yaesu.
The FT-991 was created to be an all-band transceiver (MF/HF/VHF/UHF bands) with a digital screen. The FT-991a retains all of this capability as well as the same multi-mode operation and digital modes.
They also come with a beautiful and easy-to-read high-resolution full color touch screen display that measures 3.5”. It doesn’t matter which you choose, you will be offered with outstanding performance.
For two products that are extremely similar, which one is the clear winner?
Features of Both Radar Detectors
Now we are going to take a deeper look and compare these two ham radios and see the difference between the original and the upgraded model. Is it really worth it?
Both devices have a full color touch screen 3.5” screen display. A large screen offers more visibility and ease of use. View the data clearly on the full-color screen that isn’t often seen on a ham radio. There is even a multi-colored waterfall display to help you easily identify signals.
Since we are used to touchscreens thanks to our smartphone devices, the handy LCD display is a great feature to have that both devices offer. It provides intuitive programming and usability.
Both devices offer a 100 watt operating power with 50 watts on the VHF/UHF bands. This ensures solid and reliable performance.
Automatic Cooling Fan
Luckily, with such operating power, both devices are equipped with a large heat sink. This is paired with an automatic cooling fan that prevents the device from overheating, thus prolonging operation time.
Not only does a cooling fan help with operation time, it also ensures the device will be protected and last longer.
Digital Signal Processing
A digital signal processor  is responsible for converting currents that are otherwise in analog form into a digital one. The DSP (digital signal processing) will ensure interference rejection in both devices on HF and VHF and UHF bands as well.
Both the FT-991 and the FT-991a are the same size, measuring at 8.8”x3”x9.9”. They are sturdy and easily portable for mobile use or to set up base. They are also lightweight, not adding to all the bulky equipment you may have.
Real-Time Spectrum Scope
They also both possess a spectrum scope with an automatic scope control that’s built right into the device. However, the only difference between these two devices is the real-time spectrum scope offered by the FT-991a.
This allows you to view the location of the incoming signal on the band graphically.
On the contrary, the FT-991 does not have this in real-time, but it’s more of a “snapshot” version that makes it tougher for you to listen and tune at the same time.
You can tune and move quickly to the right signal as you listen with the real-time option on the FT-991A.
You will also be able to distinguish stronger and weaker signals based on the color differentiation. The automatic spectrum scope control gives you all the information right under the LCD screen.
This also plays into the multi-color waterfall display that will allow you to easily and very quickly identify signal strengths at a glance.
If you want a more dynamic spectrum scope that gives you all the information you need live and in real-time, we would suggest the FT-991a.
As you know, the FT-991a is pricier than the product it was designed to replace. However, is it really worth the big jump in pricing? Since the only major difference is the real-time spectrum scope, this is debatable.
For those who want easier tuning and distinguishing of single strengths, it could be worth the extra cost.
Both of the ham radios are all-band transceivers that include MF,HF,VHF and UHF bands.
Both the FT-991 and the FT-991A from Yaesu, offer the variety of AM, FM, SSB, CW and the digital modes (RTTY, C4FM, PSK21 and Packet). They are both referred to as multi-mode operational devices.
Automatic Antenna Tuner
The two amateur ham radios also have an internal high speed automatic antenna tuner included. This allows a 100 channel memory. All your tuning data will be memorized by this smart device to reduce time when tuning in the future.
Conclusion: Yaesu FT-991 VS FT991a?
These are two very similar devices with two main differences, one of them being the pricing.
They are both measured at the exact same size with the same large LCD touchscreen. So if portability is a major consideration, they both offer the same in this department.
Both machines also have the same output power of 100 watts, to provide enough strength to offer unsurpassed reception.
The internal automatic antenna tuner can memorize 100 channels and significantly decrease tuning time as it automatically memorizes the tuning data.
The only thing to keep in mind when you are choosing between the Yaesu FT-991 and the Yaesu FT-991a is the spectrum scope.
The Yaesu FT-991 doesn’t have this feature in real-time, they just offer stills of the information that makes it a bit more difficult to filter out the weaker signals.
If you find yourself able to work the radio without the graphical views of the real-time spectrum scope, then you could save yourself a lot of cash by opting for the FT-991.
If this is of importance to you, then we would go for the improved Yaesu FT-991a option.
The FT-991a offers a real-time spectrum scope that helps you seek out weaker and stronger signals while viewing it on the waterfall display.
We also assessed how this model stacks up with a radio from another brand, so check out this Yaesu FT-991a VS Icom IC-7300 comparison/review.