Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please refer to the product documentation or check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

6400M Internal Tuner

john
john Member ✭✭
edited December 2019 in FLEX-6000 Signature Series
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

Answers

  • KB4OIF
    KB4OIF Member ✭✭
    edited August 2018
    John.  It's 3 to 1.  Tuner works well if your antenna is close to 3 to 1.  I believe it does a little better than 3 to 1.  If it's a trap vertical, it should work.  Others may not work with it.   My 6400M has the tuner but I rarely use it now as I have a amp in line.  I use a KPA 500 and the KAT 500 combo.  
    KB4OIF
  • Ted  VE3TRQ
    Ted VE3TRQ Member ✭✭✭
    edited December 2019
    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 - K3MA Member ✭✭
    edited August 2018
    You can figure out the SWR range.  300/50 = 6:1 50/8.3 = 6:1
    So it is 6:1 range on 80m - 10m

    I will leave you to calculate it on 160m and 6m
  • john
    john Member ✭✭
    edited August 2018
    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
    KL4QG Member ✭✭

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

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    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
    Pat_W5WTH Member ✭✭

    I just checked my 6400 with factory installed ATU.

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

Leave a Comment

Rich Text Editor. To edit a paragraph's style, hit tab to get to the paragraph menu. From there you will be able to pick one style. Nothing defaults to paragraph. An inline formatting menu will show up when you select text. Hit tab to get into that menu. Some elements, such as rich link embeds, images, loading indicators, and error messages may get inserted into the editor. You may navigate to these using the arrow keys inside of the editor and delete them with the delete or backspace key.