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6600 Setup for CQ160 CW

ChrisVE3FU Member
edited January 2022 in Contesting
I have an idea of how I'd like to use my 6600 in the CQ160 CW contest this weekend, but first a description of the setup:

- Flex 6600
- SmartSDR v3.2.39
- TX Ant: Inverted-L connected to ANT1
- RX Ant: TX Ant plus two reversible Beverages, switchable in 4 directions, connected to RX A
- FlexControl knob (button 3 configured to "Change Active Slice")
- 1500W Amp

My idea is to run on Slice A (locked so as not to accidently change frequency) and use a second Slice to look for mults / other stations to work. Both Slices will be configured to only TX on ANT1 and RX on either ANT1 or RX A. FDX (Full Duplex) will not be enabled. DIV (Diversity) will likely be enabled on Slice A.

I assume the switching will be fast enough that I won't **** out the front end / damage the radio by doing this? i.e. Both slices on the same band but only ever one of them TXing at a time. Even at 1500W?

Am I better off setting up the second slice in the same panadapter, or in a separate panadapter?


Chris VE3FU


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


    First, set up your station as an SO2R station. All Flex 6000 radios should be set up this way.

    Follow this to the letter. https://www.flexradio.com/documentation/flex-6700-so2r-configuration-n1mm/

    Next, review the SO2R settings in N1MM and the hotkeys so you can make use of OTRSP which is the correct handling of the audio from both receivers. https://n1mmwp.hamdocs.com/manual-operating/single-operator-contesting/

    N1MM won't let you put both bands on 160M from within N1MM but you can do this from SmartSDR.

    You can also run the radio in full duplex (FDX) if you like.

    If you are overloading the front of the 2nd receiver, the radio will tell you so. Unlike other HF radios, you don't need to worry about the front end.

    (BTW, RF still comes down antenna feedlines while you are on some other frequency/band - very very few radio ground antenna inputs when not in use. Even with the radio off, RF makes it to the front end of the radio).

    It is best if you use 2 slices/panadapters.

    I have used this setup many times with great success with the PGXL.

    Don't wait until the last minute to test this out.


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

    Oh, I wanted to add one more point.

    Since this is a single band contest, even a 6300, 6400 or a 6500 can leverage 2 receivers running at the same time in band, essentially just like an SO2R setup.

  • Thanks for the quick reply Mike.

    I have SO2R profiles configured for CW, SSB, and RTTY, having previously followed the link you provided. (I went through the document again, just to make sure).

    I've used those profiles before in other contests, such as the CWTs, at low power. (I don't have an amp here and have borrowed a non-SO2R amp for the CQ160 CW contest). I was pleasantly surprised at how easy it was to configure and slick to use!

    I'm surprised you mentioned that I could enable FDX. Doesn't that allow you to listen on the second slice / panadapter when the you're TXing on the first slice? I've done that before using the 6600 barefoot. I thought you'd need BPFs to do that running high power, even in a multiband contest, let alone a single band contest. (I know some of the big multi-ops have Run and Mult stations on the same band, which I assume they do using narrow BPFs).


    Chris VE3FU
  • Dan-N7HQ
    Dan-N7HQ FlexRadio Employee, Community Manager admin

    Hi Chris,

    You're not going to see benefits running with FDX for a contest like CQ160 CW where all the action is in one band segment, and you won't be transmitting on the beverages. The RX slice(s) will be impacted when you transmit. Mike's main point is that the radio will warn when overloaded and don't need to worry about the front end. However, it is possible to damage the "front end" of a Flex 6000 series radio; you just have to try really, really, really hard to do it.

    Any reason you don't plan running in diversity RX with your kit, especially on 160m CW?


    Dan, N7HQ

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

    (I bet this sounds confusing).

    However, the short story is that you can have 2 slices active on the same band at the same time on the same or different antennas. Of course, you won't be able to 'hear' while transmitting.

    The band pass filters will not have any affect when on the same band.

    Here is the part that is hard to comprehend. Imagine you have a tribander and an 80/40 meter dipole on the tower below it. This is a pretty common setup.

    When you transmit on the tribander, RF energy will be picked up by the dipole below, which is to be expected, and the RF energy will run down to your radio (any radio). The radio VFO does not have to be tuned to the frequency or even on for that matter for RF energy to bombard the front end of the radio. (There is a common misconception that the radio has to be on and tuned to the operation frequency).

    This is why all HF radios have front end protection (sometimes as simple as a couple of back to back diodes or a Neon 'fuse' to short when required and dump all that energy to ground even if the radio is off but still directly connected to your antenna.

    Just to put your mind at ease, I did a test with about 1400 watts on my 160M Inverted L with elevated radials, the radio is in FDX and a 2nd Panadapter open. I'm transmitting on 1860Khz and you can see the lower slice sees the transmitted signal just fine and the radio isn't complaining one bit.

    The noise you see is from a switching power supply that I don't even hear at night. I have a bit of a spur at bit up the band, but it is pretty low at -120dbm.

    I am using a DX Engineering active antenna on RX A. It is also vertical and about 1/2 wavelength away.

    tldr; use both slices and antennas at the same time and you'll be good to go

  • Hi Dan,

    Thanks for the extra info!

    I plan on running in diversity mode. I've played around with DIV in a couple of other 160m contests, or even just listening on the band: TX ant in the left ear and one of the Beverages in the right ear. It was pretty neat to hear signals jumping from ear to ear. I was impressed!

    I've run some of the CWTs using N1MM with dueling CQs (Ctrl-B) enabled but without DIV enabled, and have used the tilde (~) button to mute the other Slice when I needed to concentrate on pulling out a signal. In my setup for the CQ160 CW this weekend, I've noticed that if I have DIV enabled, the tilde button only mutes the main slice and not the diversity slice. I'm not sure if I'm not understanding how it's supposed to work or if there's a bug in N1MM.


    Chris VE3FU
  • Hi Mike,

    Not confusing at all! Thanks for the extra explanation and photo.

    I tried it last night barefoot and this evening with the amp. It worked exactly as you explained.

    Hope to hear you this weekend!


  • Ignacy
    Ignacy Member ✭✭

    I tried SO2R in the current CQ 160 contest. My RX antenna is a Wellbrook loop oriented to null the transmit antenna.

    Things are easy with the 6600 if the first radio uses ANT1/ANT1 and the second ANT2/ANT2. With the use of beverages and diversity, things get complicated and often the second radio is muted.

    I tried the first setup with an Expert amp and the loop connected to its SO2R input. I made a few contacts this way. But with beverages or diversity I had to switch the second radio off.

    Ignacy NO9E

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

    I used RX Assistant during the 160M test. It worked wondefully.

  • Ignacy
    Ignacy Member ✭✭

    FRStack allows to automate antenna operations. Keystrokes for selecting RXA, RXB, ANT1 and ANT2. Keystrokes to toggle DIV, APF and A/B switch. Etc. All instant without a need to take the hand for a mouse click. With Green Heron switching, also hotkeys for beverage selection.

    Ignacy NO9E

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