New 6400M Sometime won't start, distorted terrible transmit audio

Jimw6lg

I received the 6400M from Flex on Saturday. Since that time I have tried to use it without success. Sometimes, when I turn it on, I get the message to wait and nothing happens. i waited 20 minutes. It then says to pull down to restart. When it does start, the transmit audio is distorted with a digital clipping as described by about 20 others. I tried to the stock mic, BM800, Heil, Astatic, Shure SM7B and others. All give the same terrible result. Processing off, Normal, DX and DX+ all result in complaints of terrible audio. With the equalizer on or off, it does not matter. The response is "pinched", "does not sound good", "there's something wrong with that transceiver and send it back. The mics are direct to the back. I've been on the air for almost 60 years and this is by far the worst experience with a transceiver. Also, I did a reset with no change. I have K3 to listen with and the Flex does sound like ****. 73, Jim Heath W6LG

KD0RC

HI Jim, I think that the most common cause is that the mic gain is not set properly. Set the mic gain so that the little peak indicator (circled below) is around -5 dB. At no time should it go into the red. In the screen capture, I had a hard time capturing the screen at exactly the right moment, so my peak is normally just a tad higher. Anything over -10 but less than zero should give a very clean signal.

If you already have this set properly, it might be RF getting in somewhere.

Jimw6lg

I had it much less than that with the processor off and on and off using the stock FHM3 mic. It sounds digital with distortion. I am honestly pretty unhappy so far because of all of the bad reports. Thanks Len, 73, Jim Heath W6LG

KD0RC

Ah OK Jim, Do you have the TX equalizer on? If so, try with it off. If you still have bad audio, I would suspect an RFI problem.

If you are really sure that it is not RF getting in, I would submit a helpdesk ticket.

Jimw6lg

I tried both on and off with the equalizer. I used the same mics and cables that are used with my Elecraft K3 and K3S. I have one inch wide flat strap to the transceiver from a pipe under the desk that is connected to the frame of the desk. The room has rigid foam with foil. There is also 2 flat copper strips that are 3 inches wide and parallel that lead to the grounding system. Mic cables are very good coiled cords. Two the mic are completely metal housings. The distortion does not sound like RF in the audio. It has a odd digital weirdness. Thanks for your help. 73, Jim

Jimw6lg

I ordered one with the antenna tuner. The one I received does not have the ATU. Also, the bias voltage in stand bye is just 2.9 volts and not 5 vdc as indicated in the instructions. I have requested an exchange and asked to get what I had ordered; 6400M with ATU. I suspect I got a defective transceiver by mistake that should not have been sent out. It is not my fault and I should not have to pay for return shipping. I sent the request yesterday and I hope to get an answer today. At this point, I am pretty upset with Flex and hope to get it resolved without causing me a lot of grief. I have the beginning of Leukemia, myeloydisplastic syndrome and do not need stress. 73, Jim W6LG

Arizona Mike

This is my first post here and I am very concerned.

I have read an extreme number of Flex issues dating back to 2018. It seems that the QC of these radios may be lacking. I am very nervous about ordering a 6400 although I have been having a tough time between the 6400 and 6400M I ordered the 6400M two days ago.

That little voice keeps telling me to move on and don’t go down the Flex highway.

So confused.
Mike

Neil D Friedman N3DF

4.5 years with my 6600M and not a speck of trouble. I suspect 95+ percent of Flex owners find the same.

John KB4DU

Mikie, although no product is perfect, the flex radios have a good track record for reliability. I have had only one issue with my 6400 in 4 years, and it ended up being user error. What is seen here is much like reviewers of cars, hotels, and phones. The ones having issues predominate, with vast majority just keep hamming without a squeak. Flex offers a 30 day return if not satisfied, the service department is very good, and the help desk far exceeds any other manufacturer. The radio is very different in design philosophy from other radios and requires some adjustment mentally. For example, most others have features “baked in”, while the flex uses additional external software to add desired features. The 6400M front panel cannot access most of these, but an external windows pc can be used simultaneously to provide them. There is also iOS, iPadOS, and Mac access.

Mike-VA3MW

@Jimw6lg

This is not normal and I have opened a support ticket for you regarding this.

I know I am biased, but our radios do get glowing audio reports. I was even surprised this morning when I was using SmartSDR for iOS to my remote 6600 that someone on 80M said it was my best audio ever. Go figure. :)

The support guys will work with you on this to ensure that it isn't something that isn't right on the user configuration side first and then, if it has a hardware issue, they will take care of it for you. Starting with the handmic is a great first step as that actually sounds not bad.

I never depend on anyone else to tell me how they want me to sound. I used the FDX feature of the radio so I can listen to myself.

Here is a video describing it:

https://youtu.be/p79V9Nn8l0U

Bikermaninphx

I have the same type scratchy audio which is intelligible but very unpleasant to hear. I’ve tried every possible suggestion both here and from the manual but to no avail. I’ve listened on duplex, from my recordings and from KK7CPL down the street. I’m beginning to wonder if the mic is bad. Very frustrated in Phoenix! Steve W7DJ

Mike-VA3MW

@Bikermaninphx

I opened a support ticket for you.

Bikermaninphx

Thank you Mike. Enjoy your videos!

FrankAD9BI

New flex owner, and I have had terrible audio reports using the fhm-3, iPhone 13 Pro, AirPod pro’s, and iPad Air 2. I actually went back to the 7300 and received great reports. Looking for any help.

Frank
AD9BI

Mike-VA3MW

There are many things that can affect your TX audio.

You may want to consider how the audio gets from the Microphone to the radio. You can't really compare the IC-7300 operation to a Flex-6000 series being used remotely other than you might be using the same antenna.

When you use an iPhone, you need to consider the following:

• Bluetooth Mic (AirPod's). The Mic is not noise canceling and they will pick up a lot of background noise and they will not sound as good as your hand mic on your IC-7300 (which is hard-wired, no BlueTooth and no WiFi)
• What was your MIC gain set to on SmartSDR for iOS? Did you make sure you were not over driving things? Make sure that the Mic Level does not exceed -5db on the Level meter. Having it set too high can cause audio distortion.
• Turn of the TX EQ on SmartSDR EQ
• It is possible that streaming Audio on your WiFi network could be fragmented. Next time someone gives you a bad audio report, you will need to ask them to what they are hearing. Is it the fidelity? Or broken audio.
• Or, what if you listen to yourself on your IC-7300 and maybe record it?

Without specifics other than 'bad' it is a bit hard to provide any more guidance.

73

FrankAD9BI

I included the hard wired hand mic in that post. I used the flex provided hand mic and received even worse audio reports than when using iOS. The hand mic would sound ok then would go to ****, changing nothing. Hand mic audio was very inconsistent. Need help, I’m ready kick things to the curb.

Mike-VA3MW

@FrankAD9BI

In order to help narrow this down to the root cause (this is not normal BTW), we need to get some more details, so I would recommend opening a support ticket to make sure no stone is left unturned.

The support guys are very good about this. They will help narrow it down of course. The first step is to make sure it isn't a configuration issue and then move on from there (most audio problems are configuration issues).

They will want to start with (like you did) the hand mic. If you can recreate the problem into a dummy load at 5 watts while listening to yourself in Full Duplex on a 2nd slice, then we might have a hardware issue.

Doing so eliminates any RFI issues. Full Duplex is about having a 2nd slice actually receiving, via RF, your transmitted RF signal. No other HF radio can do this and it is very very handy.

If you don't have a Dummy load, then try transmitting at 1 or 2 watts while using the radio in Full Duplex mode. Put on some headphones and listen to yourself and use only connections from the back of the radio.

We want to start with a very simple configuration and then add more stuff, such as full power, etc.

This will really help narrow it down.

https://www.flexradio.com/videos/using-full-duplex-in-smartsdr/

John KB4DU

Another point to check is the EQ settings along with the mike level. The flex EQ settings are after the level meter, so a lot of boost can overdrive the radio even though the meter ,looks ok.

FrankAD9BI

Any recommendations for eq settings, or how to adjust them optimally? I just use the preset eq settings for the iOS default mic profile.

John KB4DU

I have very little confidence in the pre-set eq settings because Flex does not describe how they were determined (criteria, measurement techniques, etc). In setting eq, first rule is to cut before boost. Can’t boost what isn’t there, and boost can result in overdriving. I set the eq to level and set the tx bandwidth to 300-2900 where most of the voice intelligibility is.

Mike-VA3MW

@John KB4DU

The Mic presets were provided by Alpha team members, Employees who are operators and customers.

They are considered a starting point to but are by no means set in stone. What works for one person often does not work for another.

73