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Change RF power output setting so all bands are set to transmit at the same power?

I often use an amplifier and would like to have the RF power set so each band is the same.

Best Answers

  • Dan Trainor
    Dan Trainor Member ✭✭✭
    edited April 2023 Answer ✓

    Hello Mike,

    "I want the RF power on each band to be set the same value when I control the RF power on the Flex.I want the RF power on each band to be set the same value when I control the RF power on the Flex."

    I see. Not sure you can do that with Flex exactly. Power levels are set on a per band in "TX Band Settings". But when you adjust the RF Power slider it resets the value in "TX Band Settings to the last one used on that band. So for example, if you had set Power Level to 100W on say 20 meters, the last time you were on 20 meters, it will be 100W the next time your on that band.. Which means you would have to remember to change it back to 15W to use amplifier on that band as it has changed it in the "TX Band Settings".. Yes, that's a problem. I would prefer it behave differently. The only other thing I can think of is to set global "Max Power" setting to 15W, but then you would have to change that to 100W each time you want to operate without the Amp on any band. So, not sure what the best answer is. Maybe others have an idea.

    Dan de WA1QZX.

  • Craig_KØCF
    Craig_KØCF Member ✭✭✭
    Answer ✓

    Profiles will do what you want. I also use the KPA1500, and have transmit profiles set up for 1500 W out, 750 W out and barefoot. You can go through the bands, set the power output on each, then save the profile with a name that identifies the power output level. Do this for each power level. Now you will have named transmit profiles for each power output you wish to use and can see at a glance which one is in use.

    For more details, download the Profiles manual from the FlexRadio Support page.

    73, Craig KØCF

  • Tim K9WX
    Tim K9WX Member ✭✭✭
    Answer ✓

    Whether or not profiles should autosave is a very old topic on this board. See https://community.flexradio.com/discussion/7887668/profile-auto-save-discussion/p1

    If you read through all of the postings you will see what I thought was a commitment from Flex to make the profile autosave feature an option, but perhaps I read something into it that was not there because I wanted the option. I asked a Flex official in the Flex booth at Dayton last year what happened to that and he recalled the issue but could only offer that they never got around to implementing the option.

    Without the option, the power output per band reverts to the last used power out, even if you thought you had saved a specific power out in a profile. Which is why many have come to rely on third party mechanisms such as FRStack to be really sure they don't overdrive their amp,

    Tim K9WX


  • Dan Trainor
    Dan Trainor Member ✭✭✭

    In "TX Band Settings", there is a list of each of the bands. You can enter a value for "RF Power" and also "Tune Power" for each specific band. Also for bands you never want to transmit on check "PTT Inhibit". Also if you have an RCA PPT cable between Radio and Amp, check the appropriate "RCA TX1", "TX2" or "TX3" you're using for each band.

  • Dan Trainor
    Dan Trainor Member ✭✭✭
    edited April 2023

    Also in the "Settings/Transmit" dialog box you can enter a value for "Max Power (W)" by adjusting the slider. This effect all bands at a global level regardless of the "TX Band Settings" mentioned above and regardless of Transmit Profiles. Set a value of slightly less than the Max drive power your Amp can handle without tripping. This is meant to be a "back stop" for Amp protection, if you choose to be totally safe. Also, in this same dialog box you can check off "RCA TX1, TX2, TX2" lines you're using and the delay time. I set mine at 10 ms. Also set "TX Delay" to 20ms. This prevents "hot switching" your Amp. The radio will wait 30ms before applying RF to the ANT1 or ANT2 connected to Amp. This is important to make sure the Amp has time to switch into a state where it is ready to accept RF Power. de Dan WA1QZX.

    PS. I use SmartSDR for Mac software, so where you find these menus may be slightly difference on other client types such as Win, Maestro, M Front Panel, or iOS. But, you will find them easily. de Dan WA1QZX

  • Mike-N1VE
    Mike-N1VE Member ✭✭

    Thanks for the information Dan. However my situations is this. For instance, when I switch from one band after I've been using the amplifier, I might have the RF power set on that band to 15 watts on the Flex. Then if I switch to another band to operate with the amplifier, I might not notice that the last time I used that band I was operating at 100 watts. I don't want to mistakenly run 100 watts from the Flex into the amplifier. My amplifier senses the operating band and automatically tunes to whatever frequency the radio is set to. My other HF radios to not remember the previous RF power output for each band (whatever the radio is set for RF power all bands are the same). I find that more convenient for my operating needs. In other words, I want the RF power on each band to be set the same value when I control the RF power on the Flex.

  • Larry _ NY8T
    Larry _ NY8T Member ✭✭✭
    edited April 2023

    You don't say what amplifier you use but if its a PGXL, I use FRSTACK for this, you can set it for a power (drive) level when amp is in operate and it will go back to 100 watt or what ever power level you specify when amp is in standby.

  • Mike-N1VE
    Mike-N1VE Member ✭✭

    Larry, Dan, I am using an Elecraft KPA1500. I don't know what "PGXL" is. I use the Maestro not a computer with the Flex 6400. I would prefer to have total control of the RF output on the Flex. I think it's very odd that Flex sets the power level on all bands based on the last power level chosen for any band.

    Though the Flex radio has many wonderful features, there are many aspects of the radio that I am not comfortable with. I am very thankful for the Flex Radio Community participants and their willingness to help.

  • Ken Wells
    Ken Wells Community Manager admin

    That is what having different Transmit Profiles is for.

    You can set different "power profiles" for different antenna outputs so that the power is different on ANT1 and it is on ANT2 on different bands.

    Each TX Antenna output can be assigned a different Transmit Profile, which includes its own TX Band Settings Table. Forcing all power outputs on all bands to be the same would be a deletion of a feature enjoyed by many others -- for example, due to limitations in my antenna system, I must restrict power output on certain bands in order to keep other electronic devices in my home happy, or to avoid overheating elements of other antenna components.

    However, I would like the option to make a setting more or less "permanent" so that it is the same when I recall a particular Transmit Profile.

  • Mike-N1VE
    Mike-N1VE Member ✭✭

    Thanks Craig and Ken. What you do sounds reasonable, though a bit more complicated than I prefer. However, I will check out the Profiles manual and maybe it would be a good starting point for operating. Conditions and my selection of an antenna often requires that I either increase or reduce the output power, but as Ken wrote, it would make a good starting point.

  • Rick N0VT
    Rick N0VT Member ✭✭

    You also have the option to go into Settings ->Radio Setup in SSDR and set a hard power limit on the "TX" tab. Set it to whatever drive level you want to use with your amp and your radio won't exceed that power output no matter what else you do.

  • Mike-N1VE
    Mike-N1VE Member ✭✭

    Thanks Rick, but I work both barefoot and with an amplifier. Sometimes I run 100 watts, but generally with the amplifier I run less than 20 watts. I simply want each band to have the same power output at the same time.

  • Geoff AB6BT
    Geoff AB6BT Member ✭✭✭

    Readin the mail here...

    If you never change a the power setting of a transmit profile then Ken Well's answer is the solution.

    The caveat is that if you change the output power the profile will be overwritten.

    Seems good to me...

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