How do I connect a Flex 6600M to an Ameritron ALS 1306 amp so its auto bandswitching works?

Hi Jim
Welcome to thw 6600M, I love mine!
You should download and read two great manuals:
1. The 6600 User Guide
http://www.flexradio.com/downloads/flex-6400m-and-flex-6600m-user-guide-pdf/
2. SmartSDR Users Guide
http://www.flexradio.com/downloads/smartsdr-software-user-guide-pdf/

Up front, let me say I have never seen nor used this amp. While it looks nice and very reasonably priced, I am using the Flex PG XL which integrates usage of the amp with SmartSDR. Very slick and powerful!

The USB ports on the back of your radio can be used to send radio control data from the  radio to peripherals. You can see how to define this in the SmartSDR user guide above. You will need to buy an FTDI-based USB to Serial cable to plug in the back of the radio, and configure it via SmartSDR's USB Cables section in its Settings menu.

One option is to define usage of the serial port as a BCD port. I see that Ameritron sells a radio interface cable that implies its used for BCD. No idea if it will work or not but, at least, on paper, it looks like it might.

You would also need a RCA-RCA audio cable to go from the TX1-TX3 port on your radio to the Relay port of the amp. In SmartSDR, you also need to go in the Settings->Radio Settings->TX section and enable these ports so they ground when applying PTT.

You can also use another RCA-RCA audio cable to go from the ALC port on the back of the radio to the ALC port on the amp. The amp's manual has a calibration routine which you definitely need to do if you use this. You will also need to enable the ALC port, again in SmartSDR v1a the Settings->Radio Settings. You can read all about it in the manuals I listed above.

I would strongly recommend that you download and read the two manuals I listed above before going much further. It is not very complex but when using amps its better to fully understand what the settings are doing before getting an email from an OO!

Hi Neal,
Thank you for your reply.  I have only had my 6600M for 2 days, but used it briefly in the CQ CW contest this weekend and it was AWSOME!!  The receiver, filters etc are unbelievable.

I have downloaded every document that is downloadable and have the Flex USB to DB9 serial cable.  I see that there is a table showing the databits (band selection byte) for each band.  Since my interest currently ends at 6m, I need only the first four bits to select the band.

My first attempt was to simply connect the Flex BCD cable to the amp via a F-F gender bender.  I set the USB menu to BCD,  It didn't work.

I have a Yaesu FT950 transceiver that currently drives the amp properly via an Ameritron transceiver specific cable..  I made a bitmap of all the pins on its cable for each band.  Since four of the pins match the values in the Flex documentation, I figured the pinouts of the Flex cable must be different from the Ameritron cable. So, I mapped the status of every pin of the Flex cable on every band.

What a surprise, no pin or combination of pins matches the Yaesu cable on any band.  That is where I am now.

I have concluded (perhaps erroneously) that the Yaesu cable is providing a static,parallel 4 bit byte to the amp via four pins on its DB-9 connector.  But the Flex is providing that same information in serial form.  I am assuming this because I can't read serial data with a voltmeter.

Apparently to resolve this problem, some posts refer to the use of an Ameritron provided Kenwood specific cable as an interface between the DB-9 end of the Flex BCD cable and the amp. However, there are two different Kenwood cables and the posts don't say which to use. Also, the Kenwood cables both have three connectors, weird.  Some posts refer to the need for a null modem cable and others say it's not needed. 

In the end, I'm unclear how to hook everything up.  I am willing to buy whatever cables are needed, but I don't want to damage anything by accidentally shorting pins or applying the wrong voltages.

Incidentally, the TX1 port keys the amp correctly.  I am not using the ALC at all.  The amp does not rely on ALC for protection and I set drive power manually by watching input and output waveforms.

Thanks again for guidance,
Jim Charlton  AD0AB