FLEXRADIO ACC USBSERIAL and KPA500/KAT500

DM2DZM

I used to operate my KPA 500 on a K4D, which worked without any problems. Now I have had a FLEX 8400M for a few days and want to control it with the cable, but it works, hopefully I have made the settings correctly, or do you need other cables for control, it does not switch QRG and no control or PTT. Do I perhaps have to make other settings in the KPA menu?

tnx 73 de Peter DM2DZM

KD0RC

Hi Peter, see my response to your other post.

Rich M5RIC

Elecraft has a guide on interfacing with the Flex,

https://ftp.elecraft.com/KPA500%20%26%20KAT500%20Power%20Combo/Manuals%20Downloads/E740349%20Rev%20B%20Interfacing%20PwrCombo%20to%20Flex%206000-series.pdf

DM2DZM

Hello Len and Rich, tnx info but

As I can see from this, I need a different cable than just the ACC-USBSerial, but I have not yet been able to find where the RS 232 (xcvR) should be plugged into the FLEX, sri.

Or is it better to do this control via DDUTIL to avoid always having to change the KPA in the menu when switching from K4 to Flex?

vy 73 de Peter

Rich M5RIC

I think you could just use a FTDI USB to Serial Cable DB9F cable, USB plugged in to the Flex and then DB9F in to the KPA500.

I don't own a KPA500 so just looking at whats in the manuals. I have configured CAT control for other amps using this method though with my 6600 and it's worked fine.

https://www.flexradio.com/documentation/usb-cable-interface-guide-pdf/ for more general info.

KD0RC

Hi Peter, the KPA 500 RS 232 (XCVR) gets plugged directly into either one of the USB ports on the back of the Flex. The USB ports are adjacent to the Ethernet port.

DM2DZM

ok Len tnx i think in picture this?

KD0RC

Yes, the bottom one plugs into one of the USB ports on the Flex. You need an FTDI cable that converts RS 232 to USB.

DM2DZM

tnx, ok Len unfortunately I only have an FTDI cable for upper

I still have to buy, the Wimo salesman told me I only need the upper hi

73 de Peter DM2DZM

DM2DZM

oh wonderful i have now found an adapter hi,
but the PA does not switch to the new band during qsy

all tnx 73 de Peter DM2DZM

David Decoons, wo2x

set auto report to enable in Flex USB menu for that cable.

73 Dave wo2x

DM2DZM

ok I have that but I think you need both cables on the KPA500 so that the presets for PWR control and tape change are also transferred from FLEX

73 de Peter

Craig_KØCF

There are two documents linked above, one from Elecraft and one from FlexRadio. Please download both of them. Between the two, they completely explain how to connect and configure the KPA500. I had the KPA500 for a time, and only ONE USB cable is required, plus an RCA-RCA audio cable for TX switching. (I am now using the KPA1500 and it also works flawlessly with the Flex.)

73, Craig KØCF

DM2DZM

ok tnx Craig must now looking hi

73 de Peter DM2DZM

DM2DZM

ok https://www.flexradio.com/documentation/usb-cable-interface-guide-pdf/ but I could only find the link to ELECRAFT,

I have now connected both RS232 PC + RS 232 XCVR and the USB from the FLEX to the KPA500 with an FTDI and the settings on the KPA menu as described in the document.
It can be sent, but it does not take over the QRG into the KPA 500 when changing the band, but only when sending a cw character the correct qrg is shown in the display of the KPA.
What is even worse is that it does not take over the preset TX band settings PWR for control, but it is controlled with the PWR that was just set on the band, which can then be 100W and then the KPA is at fault and possibly not good for the electronics in the KPA. With the K4, the control of the KPA was always immediately automatic as preset. I'm at a loss and don't want to destroy my KPA500 hi

73 de Peter

KD0RC

Hi Peter, I am away from my shack right now. When I get home, I will post screenshots of everything that I have set up to use my Flex 6400 with my KPA500/KAT500 combo.

Mike-VA3MW

I used to run a KPA500 with my FLEX-6600.

A simple 9 Pin cable will work, but you need a NULL modem adapter so that pins 3 and 2 are swapped. You can easily make your own. Or even a Null Modem Gender Bender. You can find those on Amazon.

You might also try a slower speed just in case that is the issue. 9600 baud is plenty fast enough.

https://www.amazon.com/female-slimline-transfer-serial-adapter/dp/B075XHWVSJ/ref%3Dsr_1_1_sspa?crid=LL6YMIY9RD72&dib=eyJ2IjoiMSJ9.LTtmyp5m-0Edz7kE21iqFIbqBuE6k3ikYWnGa8PeQ-3bUAZaZaRpG-Lbmdh419dbZ4yGF33wOIAoZ6AYRzy2roc8jKZe1Ak6vXazC2Xihkr-KOKBJeN4M_6Y1BXBOHqveH48MCJJSKnnjvShc8bUpm2PfLt-O0-cjmLYW1zqT7Z12WqPd4vDItnU6JYRvz8y5iKCnE979G2qQUnel_gl48MStwQduCGDfVxpwLDlqDY.fuSr5HF_qqy5WOgz8wkjPME-eNp650QW726uO47-2jw&dib_tag=se&keywords=9pin%2Bnull%2Bmodem%2Badapter&qid=1742224329&sprefix=9%2Bpin%2Bnull%2Bmodem%2Badapte%2Caps%2C108&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

DM2DZM

@ Len ok zhis is very nice

@ Mike i have also a Gender used

but I still want to buy a new FTDI cable, may be it is defective

Thanks for all your help

73 de Peter DM2DZM

KD0RC

Hi Peter, I just reviewed your original posting and see that you have AutoReport disabled. I don't think that it matters, but I do have mine set to Enabled (as suggested by Elecraft).

I don't have a Maestro, but here is how mine looks in SmartSDR:

I did set my KPA 500 RS232 x parameter to 38400 baud. I also set the RS232 P parameter to 38400 baud.

If you have set the amplifier serial rate to match the rate in your Flex, then it is a cable problem that needs to be addressed.

Here is a link to the cables that I use between my KPA500 and my Flex and also between my KPA500 and my PC:

Amazon.com: StarTech.com 6ft (1.8m) 1-Port USB to Serial RS232 Adapter, FTDI DB9 Serial DCE Adapter Cable, Null Modem, USB 2.0 - TAA : Electronics

These cables do not need a null modem converter, as they are already configured properly for the Flex.

Also, make very sure that you have the RS232(XCVR) port on the amp connected to the Flex, and not the PC.

DM2DZM

ok Len tnx

I got the original cable from FLEX for it, but I have already ordered a new one and will test it

73 de Peter

Mike-VA3MW

You 100% require the Null Modem Adapter to ensure the data being sent by the radio is being heard by the Amplifier. Without it, you are sending data (TxD) to another TXD when it should be on the Pin that is RxD.

I would be really surprised if the USB cable was bad.

Required Cables:
● FTDI USB to Serial Cable
● Null Modem Cable (Pins 2 and 3 crossed, pin 5 straight through)

Device Setup:

● Connect the FTDI USB to Serial Cable to the Null Modem cable, and connect the Null Modem cable to the “RS232 (XVCR)” port on the back panel of the KPA500
● Set the baud rate in the “RS232 X” menu entry. All speeds (4800-38400) should work. Set this value to 9600 to match the default value of the FLEX-6000.
● Go to the "RADIO" menu and set the option to "SERIAL"
● Go to the “SER POLL” menu and set polling to “ON”

SmartSDR Setup:
● Set the Cable Type to “CAT”

DM2DZM

ok Mike thanks, that's how I did it with the original cables supplied by WIMO, bar I'm now waiting and have ordered a new one.

However, only 1 cable (FTD18UT6) is displayed on my FLEX and not 2 cables as with LEN in picture.

73 de Peter DM2DZM

Mike-VA3MW

Len might have had 2 devices connected. You get 1 entry for 1 device.

KD0RC

Mike is right, I had the KAT 500 connected to the Flex at one time. I later wrote the FlexiCraft Utility and moved the KAT 500 connection to the PC. Note that in the picture, the first cable (KAT 500) is greyed out, indicating that I set it up, but do not have it plugged in to the radio.

DM2DZM

Hello, the new FTDI cable is now here.

I have connected it to the FLEX cat usb flex.

Now almost everything works wonderfully. My KPA500 also switches to the correct band immediately when qsy is received. Previously this was only done with an HF signal.

I now have the following connections:

KPA500 - KAT 500 cable AUX to AMP - KAT500 XCVR cable open
KPA - FLEX 8400 cable PA KEY to CINCH FLEX TX1

KPA - FLEX 8400Cable RS 232 PC (acc rs232 pc kpa) - USB FLEX
and
RS 232 xvr (cat usb flex kpa rs232 xcvr) to USB FLEX

It also takes over the setting from the FLEX for the PWR control of the respective band of the KPA500.
Unfortunately, what does not work yet is the immediate switching of the KAT500 to the previously stored ant for the respective band (e.g. ant3 for 20M). This only happens when I put an RF signal on the tuner again and the KPA is in OPER, then the KAT500 also switches immediately to ant3 if it was on ant2, for example.
But I think I can live with that, I hope it won't cause any damage to the tuner.
It's probably because the cable in KTA500 XCVR can't be connected to FLEX (previously it went to K4)

Or do I still have an error in the wiring?

vy tnx all help 73 de Peter DM2DZM