How to connect MFJ-998 tuner and ALS-1306 amp to a Flex 6400 ?

Larry

I am a new FlexRadio owner and need some help getting my amplifier and external antenna tuner talking with the Flex 6400.

The hardware is:

Radio: Flex 6400

Amp: Ameritron ALS-1306

ATU: MFJ-998

I purchased the Ameritron cable to go from the Flex USB to the Ameritron serial connection for Band Control Data. This cable is specific for this model amp to a Flex radio, part# DB-USB6000. So I think this will take care of the amp following the band selection on the Flex radio. 

What I am not clear on is how to get the Flex 6400 talking to the MFJ-998 antenna tuner.

With my old radio (Icom) I am able to push the tune button on the tuner and the tuner puts the radio in low power, transmits to find a tune solution, then sets the radio back to the setting before the tune started.

I want to achieve the same functionality with the Flex 6400.

Does anyone have this configuration successfully working?

M0GVZ

Hi Larry.

Not used a Flex for a while but it used to have a CW Tune option similar to the Kenwood radios and you could set the power level for that. You'd then have a single button press option that'd change the TX power, put the radio into CW mode and transmit.

K2KXK

Hi Larry,
I have the same setup (Flex 6500).  Yes, the cable you have will handle the band switching.  There is no equivalent interface between the Flex and the 998 as you have with the Icom.  Therefore, you can not use the Tune button on the tuner.  However, this is not a problem.  You use the Tune button in SSDR to initiate a match on the 998.  All you have to do is make sure that the Tune Pwr is set very low, say about 3-5 watts.  Otherwise, the amp will send too much power to the tuner and it will error out.  I am not using any ALC connection between the Flex and the AMP but I have been thinking about doing so.  The problem comes if I have been running barefoot at 100 watts and then turn on the AMP forgetting to lower the Flex power.

The one feature that this doesn't provide is to take the 1306 off line during the tuning process as it would with the Icom setup.  However, the reduced power makes sure the AMP is protected.  Hope this helps.  Let me know if you have any questions.

Tim - W4TME

I do not recommend using hardware ALC for exciter control.  The power level setting in SmartSDR is granular enough to prevent overdriving the amp and the max power can be set for each band and saved as a TX profile. 

Also, the amp should have sufficient protection circuitry to shut down in the event of a fault.  For the ALS-1306 this is optional, as per the manual, as it has it's own internal ALC.

In addition, Hardware ALC used with a digital radio can be too slow to make corrections fast enough to protect the amp because of the necessity of sampling an analog signal (negative voltage) and the subsequent decrease in RF power based on threshold settings.  

K2KXK

Right Tim, that's why I haven't used the hardware ALC connection.  As I mentioned, I do occasionally leave the Flex power at 100 W (accidentally) but the AMP seems to tolerate this OK in SSB.  However, I once inadvertently put 100W of FT8 into the AMP and blew one of the final transistors.  It wasn't able to protect itself against this.  I have since changed the settings in my FT8 profiles to limit the power.  I suppose I could have separate profiles for running barefoot at full power and running the AMP at reduced power but I haven't taken the time to do that.  One advantage to this approach would be that you can disable the AMP switching in the barefoot profiles.  However, I use profiles mostly to group different bands together and I'd have to double the number of profiles to take this approach.  Other comments and suggestions would be welcome.

Brian Denley KB1VBF

I use ALC to protect my amp.  I do not use it to control exciter power (nor should anyone), but as a layer of protection in case I **** up.  Are you and Tim advocating not using ALC to prevent overdriving a linear?

Tim - W4TME

Yes.  You said you are not using ALC to control exciter power but that is exactly what it does.

For a more detailed explanation, please see the HelpDesk article Hardware ALC for amplifier protection is not recommended with FlexRadio SDRs

Larry

Thanks Ken, for the detailed reply.  
I am going to try the setup you described.  I don't plan to use ALC, 
I'll post my results when I get it set up.

Thanks,
Larry

Brian Denley KB1VBF

Tim:
that link doesn’t work: asks me to sign in,  I did, says it doesn’t know me (?), I signed up again, now says OOPS...

Larry:
I am using that same usb cable and it works perfectly.

Alan

Same here when trying to access the ALC article......says I am not authorized.

Alan
WA9WUD

Tim - W4TME

@Larry - try it now.

Brian Denley KB1VBF

That worked for me.  Thanks a Tim.

Dawg Fan

I have 1306, 998 tuner and I simply switch my amp to standby to tune.  Not good for amp to tune with amp in line. I find my tuner takes about 10W to trigger tune, 5 watt is advertised minimum.

KI4P

Interesting! I have noticed though with my RF power set to 24 watts and mic set at 50% and level indicator not going into the red that I routinely get drive as high as 35 or so watts according to FRStack and my Alpha software readings, and that doesn't seem to be bothering the Alpha any. when i run barefoot and have power slide to max i see it spike as high as 130 or higher, just trying to understand the Flex a little better. Thanks
PS link worked for me
Richard 

Larry

I am having a problem getting the amp to follow the Flex.
After connecting the interface cable,
The amp would change correctly on some bands i.e. 20m, 15m
Other bands would it would change to the wrong band or error out.

I measured the BCD voltages coming out of the Amertron DB-USB6000 cable going to the amp and found that Bits 0 and 2 are reversed!

Is this a setting in the SmartSDR software that can be change?
Or did I get a bad interface cable?

Thanks,
Larry

Larry

Found the problem.
It is a bad Ameritron cable. It's DB-9 connector was the type that disassemble.
I opened it up and found they had reversed the wires for pins 2 & 9, (Bits 0 & 2).
Too small for me to want to re-solder the wires, I'll put together a brake out box to use until I talk to Ameritron..

Larry - KB5WWW

Ned K1NJ

  You might try opening up the cable itself and exchanging the two wires rather
than dealing with the connector pins.  Proceed with caution.
     Ned,  K1NJ

                

Brian Denley KB1VBF

They sell reversing adaptors for that.  It swaps pins and 3.

 https://www.l-com.com/d-sub-slimline-reversing-adapter-pins-2-and-3-db9-male-female

Brian Denley KB1VBF

They sell reversing adaptors for that.  It swaps pins and 3.

 https://www.l-com.com/d-sub-slimline-reversing-adapter-pins-2-and-3-db9-male-female
 

About $6 on EBay with free shipping.

Buddy Spiegel

i have the same configuration with a flex 6500. i set the parameters for the usb cable per the specs which came with the cable. auto band switching in REM mode does not work. any suggestions, please.

KD0RC

Hi Buddy, does the cable contain the FTDI chip? It will not work with the clones - it needs to be genuine FTDI.