6400M Internal Tuner

john

Thinking of purchasing the 6400M with the internal tuner. Is the tuner wide range 10:1 or is it 3:1? Will be using the radio with a multiband vertical antenna. I am new to this group and my first post. 73 John W9QP

KB4OIF

Ted VE3TRQ

The tuner in Flex radios are not designed for wide range. Although they do not mention an actual VSWR that is the limit, I recall 3:1 being mentioned, definitely not 10:1. From the hardware manual for the 6400/6600: "VSWR Range: 8.3 - 300 Ohms (80m – 10m) 6.7 - 150 Ohms (160m and 6m) It is not recommended to attempt repeated tuning of antennas with the ATU connected to antenna systems that exceed the maximum VSWR on a frequency of interest. Some antenna systems, such as physically short multiband antennas may exhibit a very narrow range of resonance (a high Q antenna) in addition to being very reactive. The FLEX-6400/FLEX-6600 ATU is not designed to tune these types of antenna systems. An external antenna tuner that is designed to handle a wider VSWR range is recommended for these types of antennas."

John - K3MA

john

Thank you all for the information concerning the internal tuner. I will order the 6400M with internal tuner, if that doesn’t work on some bands will use my MFJ tuner. Hope to order the radio in a few weeks.

KL4QG

How can I tell my used flex 6400M has a built in ant tuner

Mike-VA3MW

I 'think' it says Tuner or ATU on the back, but if you try to Tune and it works, you have a Tuner installed.

Pat_W5WTH

I just checked my 6400 with factory installed ATU.

Yes, there is a small sticker next to the S/N that says "ATU".