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Reviews Categories | Transceivers: HF Amateur HF+6M+VHF+UHF models - not QRP <5W | FlexRadio FLEX-6400 Help

Reviews Summary for FlexRadio FLEX-6400
FlexRadio FLEX-6400 Reviews: 10 Average rating: 4.7/5 MSRP: $1999
Description: Software Defined Radio Transceiver with 2 Independent
Band/Mode full performance receivers from 100khz to 55MHz
Product is in production.
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W3LI Rating: 4/5 Sep 17, 2019 14:26 Send this review to a friend
Flex-6400M  Time owned: 6 to 12 months
My 6400M has got the best receiver that I have ever used in my 60 yrs in the hobby. The transmitter has many features that are great. The reason that I did not give it a 5 rating is because of the manuals.
In other words the radio by itself is a 9 out of 10, but the manuals I will only give a 4.5 out of 10. not very well written.
KT8DX Rating: 5/5 Sep 16, 2019 23:54 Send this review to a friend
Updated Review  Time owned: 6 to 12 months
Well, I've been using the 6400 for about 7 months now. Honestly, I cannot say one bad thing about the radio. The receiver is absolutely amazing, transverter operation is easy (once you get it set up correctly), support is outstanding, and the selectivity even under tough contest conditions is tight and comfortable to use.

When you update software - READ THE INSTALLATION NOTES. I did not and strange things happen. Tech support bailed me out and everything was back to normal, albeit I was a little red in the face.

Maybe I do have a little knit - the connecters are all on the back. I extended everything to the front and all is good.

73s de KT8DX
KA2ZNI Rating: 5/5 Feb 23, 2019 21:40 Send this review to a friend
Awesome!  Time owned: 0 to 3 months
This SDR is nothing short of phenomenal. It is well built, well designed and runs spot on day after day with heavy use. I wouldn't go back to using anything else after operating this little gem. The audio reports are nothing short of fantastic,and when played thru my stereo system the fidelity of the stations I am listening to is unreal. We will see long term how she holds up, but I can't say enough good about the Flex 6400 Signature Series.. it went way beyond what I expected from an SDR in this price range!
W6OVP Rating: 5/5 Feb 15, 2019 02:45 Send this review to a friend
The best XCVR I have owned  Time owned: 0 to 3 months
The FLEX 6400 is my 5th SDR transceiver and clearly the most capable. This is the best radio I have owned in 64 years on the air.

All hardware needed to get on the air was in the box and the software preset for the factory mike. Went from sealed box to receiving excellent reports in 15 minutes. That included 10 minutes to download and install the computer software.

Unlike the early days of SDR the setup doesn't get any easier than this. The FLEX "out of box experience" has improved dramatically. Installation was as "Beautifully Simple" as with an ordinary knob radio.

Moving from a 6300 with V1 software to a 6400 with V2 yielded a noticeable improvement in local noise control. That justified the upgrade for me. The larger slower fan is also quieter.

I agree with virtually all the comments by prior posters.

But I think FLEX has put too much emphasis on it's elegant and esoteric features and made the 6000 series look terribly complex, with abilities most potential users don't understand or need. This has made it appear aloof and probably hard to use, which is not true. You can tweak settings to your hearts delight but that is not mandatory nor even desirable to just get on the air and have fun. There is room to grow technically, but the optional learning curves are not steep.

I also agree with the prior comment "but they could do so much more with the software". The potential of SDR radio holds so much exciting promise it's easy to become impatient with the software development. I certainly am! EXCELLENT sometimes just doesn't seem good enough.

The software is solid and stable. But IMHO FLEX would do well to take a deep breath and promptly incorporate the many popular FLEX 3000 SDR features and others that were somehow lost in the rush. Happy current users are tomorrows upgrade customers and a lot of seasoned users miss them.
AC3DB Rating: 3/5 Jan 2, 2019 03:08 Send this review to a friend
Great radio, software lacks  Time owned: 3 to 6 months

This is my third flex (previous SDR1000, Flex 1500) and it is a very good radio with 2 receivers which I use both regularly to monitor 2 bands at once. I have compared my 6400 side by side to an IC7300 and IC7610 and the flex receiver is far superior and manages the noise much better than the icoms. Running the flex is an amazing experience, seeing the 2 beautiful waterfalls across my computer screens and clicking on signals that I see. On the second waterfall, I'll monitor another band that doesn't appear to be busy, and I'll be the first one to see a signal calling cq and get to talk to them before there is a pileup.

The software setup of the 6400 is very easy compared to the older flexes and the icoms. I remote the radio from my warehouse and also from my office, and it always connects and operates trouble free.

The reason I give the flex only a 3 out of 5 is it lacks great features that the icoms have.
-The icom 7610 has cool VU meters or the bargraph meter to choose from. The flex could have different style meters to choose from, but it doesn't.
-The IC7300 and 7610 have a fully automatic antenna tuner that will retune any time the radio sends rf out. The flex 6400 has memory tuning, but if something in your antenna changes, the flex is dumb and doesn't automatically retune. I experiment with antennas often, and with the flex I have to always click tune every single time.
-The icoms have 8 recordable tx audio slots (awesome for contesting) and the flex has only 1 that doesn't work right with the latest firmware.
-The icoms have bands labeled in frequencies instead of meters, as in if you press 7, it goes to 7mhz, and if I click 10, it goes to 10mhz. The flex is labeled in meters instead of mhz, and this is confusing. I have to click 40 to go to 7mhz, and click 30 to go to 10mhz and so on.

The flex is a really good radio, but they could do so much more with the software. If you read the reviews for the 7300 and the 7610s, everyone raves about how awesome those radios are for they money. If you read the flex reviews, they are good but not the most amazing thing they spent money on.
W5BE Rating: 5/5 Nov 14, 2018 02:00 Send this review to a friend
Fantastic HF radio  Time owned: 6 to 12 months
If you're considering the purchase of an SDR based transceiver that has a lot of features you'll be well served to purchase this radio.

Having owned and operated several conventional HF rigs in the past, I was a little apprehensive about buying a rig that didn't have knobs and wouldn't even work without a computer associated with it! I reasoned however, these days I'm never setting at my operating position without a computer on so why not try it?

Long story short... after coming up to speed on the various controls available via the software, I like the Flex 6400 extremely well. I've heard it said, "you can't miss what you've never had"... with that in mind I can't imagine what it would be like to go back to using a "regular ole HF rig" on an exclusive basis.

W7RU Rating: 5/5 Nov 3, 2018 09:05 Send this review to a friend
Works Great  Time owned: 6 to 12 months
The filter separation is great with this radio. Like others say you can see many capable spots using FT8 mode. You can slide beside another station and not have adjacent interference. Depending on your situation. In Audio I find the NR (noise reduction) and sometime with the ANF Filter use open up a given receive better in a noisy environment. The radio is very Flexable.
N7DK Rating: 5/5 Aug 14, 2018 23:42 Send this review to a friend
Superb SDR   Time owned: 3 to 6 months
I've owned a 6400 since early April, using it mostly for FT8 contacts. It's been terrific.

I've logged (LOTW) over 2000 QSOs, and I've worked DX that I've never worked before in over 50 years of hamming -- and I did it under today's low-sunspot, poor band conditions and modest HOA-friendly antennas. That's a credit to both the radio and the amazing FT8/WSJT-X weak-signal software.

It was a bit difficult to get the radio working at first, but that's mostly because I'm the type that only reads directions as a last resort(!)

I had been using a TenTec Omni VII, which is a great radio, especially on CW. With an external SDRPlay radio, COM-port sharing software, USB-RS232 adapters, a SignaLink device and other kloodgey stuff, I managed to get waterfall tuning working on my Omni. But it was always "buggy" with that COM-port sharing software failing from time to time. I was spending too much time chasing software bugs.

One day it dawned on me that I had effectively synthesized a clumsy version of a FLEX radio, so I broke down and got the 6400! No regrets - it's the most fun I've had hamming since the 1960's.

I have had only one issue with the radio - ironically it was the computer-style box fan. The motor started started getting noisy and periodically the radio would shut down when the fan RPM dropped too low. Flex Repair service generously offered a fast turnaround repair, but I found an exact replacement fan on Amazon for $15, so I simply installed it myself and have had no problem since. I was having so much fun I couldn't bear to send the radio back! If I must send it back to Flex it will be for something more serious (heaven forbid).

The novelty of the FlexSDR and FT8 is only beginning to wear off. If I wake up early, I have to run out to the radio and run DX on 40m, which still opens up nicely to Japan, Indonesia, Australia, New Zealand, China, etc. I've also worked a lot of DX on 30m, which is a fine band for FT8. I've even worked some FT8 on 6 meters, a band I'd never used for anything ever before!

I highly recommend the radio (and FT8) to anyone who wants to rekindle enthusiasm for hamming, especially DX ... I guess I'm old enough that distance still holds some charm! And I can run the radio from my office study computer, hunting QSOs and DX in parallel with writing, investing, etc.

Hat tip to FlexRadio and the WSJT-X team!
K3WR Rating: 5/5 May 20, 2018 01:35 Send this review to a friend
Great SDR Rig  Time owned: 0 to 3 months
New to SDR radios from many years of Icom radios. Although I still have an Icom 756 Pro III, which is a very nice radio, I am very impressed with the Flex 6400. The $2,k price point compares favorably with other SDR radios on the market. Look at the Icom IC-7610 and IC-7300 for pricing comparisons.

Getting the Flex 6400 on the air is an easy experience. Connect your power supply and antenna to the radio. I used the included cat 5 cable and connected the radio to my laptop running Windows 10. Turn on the radio and voila! I can hear and now also see the radio spectrum on my laptop screen. The panadapter and waterfall provide the mechanism to visualize the radio spectrum, which is a game changer.

SmartSDR, the software application used to manage the 6400, is feature-laden and offers a wide array of controls that significantly improve the user experience. An easy mouse click on the radio control software controls changes bands, modes, antennas, frequencies, ALC, power output, transmit and receive EQ, and much more. Changing frequencies is as simple as clicking the mouse on an observable signal on the panadapter. Bam, you are there is milliseconds! With the 6400's panadapter and waterall, I can see the strength of a signal before I QSY to the frequency.

A very cool feature is the ability to have 2 bands simultaneously displayed on the laptop monitor. Routinely, while working 20 meters, I'll visually observe for any signals on 17 meters or 15 meters for activity. Often, 17 meters appears dead until a signal is displayed on the panadapter, which often is a DX station calling CQ. A quick mouse click and I am on the calling station's frequency in seconds. This feature has enabled me to work DX stations well before the call is spotted and the pile-ups begin.

Guys, this radio offers such a significant delta from the traditional knob equipped radios, that you will be amazed. At first, I was skeptical about needing a PC or laptop to control the rig, but I always have one running for logging and a quick lookup anyway. With my Flex 6400 set-up, I use my laptop monitor to control the rig and have another monitor running N1MM for logging.

If you are considering a new rig, you would be well advised to check out the Flex Radio line.

Very 73,

Jim - K3WR

KG0AQ Rating: 5/5 Feb 8, 2018 09:07 Send this review to a friend
Better receiver and transmitter than Flex-5000  Time owned: 0 to 3 months
I was a very early adopter of the SDR technology. I have used the Flex products from the original SDR-1000 to the 5000 and now the 6400. With each Flex product release the receivers and transmitters get better. I have other Icoms, Kenwood and Yaesu transceivers in my shack. I will not compare those radios to the 6400 because of the age and technology. However, in my shack the Flex is always on.

The Good: Receiver and transmitter performance is the best I have used to date. The panadapter is smooth, accurate and pleasing to the eyes. CW operation is wonderful. SSB is clean and the new compression algorithm is great. 100+ watts out on all bands. The replacement for VAC called DAX is great.

Waiting for: I have to admit that KE9NS spoiled me with his enhancements of the Flex-5000. Useable Band stacking on the 6400 requires a third party program called FRStack. Using CW Skimmer requires a third party program called SDR-Bridge. There is a workaround to get WSJT to work but it is not a Flex issue. The real issue I have is using Fldigi RTTY in split mode. For the time being you must use XIT which is kludgy at best. Again, not necessarily a Flex issue but needs work.

Conclusion: You must be a patient person to use Flex products. Software is ever changing and requires time to develop. This radio is an absolute keeper! To me the bottom line of any transceiver is the receiver and transmitter performance...The 6400 is TOP NOTCH! I can wait for the enhancements and remember the key to Flex products...they keep getting better with each software release.

73 to all de KG0AQ ..

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