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.

Output power control

Andrew - G0RVM
Andrew - G0RVM Member ✭✭
edited March 2020 in SmartSDR for Windows
The Power output slider on SSDR (2.6.1) is great and gives granular control over a 100W range (Flex-6600).  At a setting of 1 my SPE amplifier generates about 120W; at 2 it generates about 380W.  I would like to have increased granularity of control when using CW so a higher setting - perhaps 5 or 10 - results in 380W or thereabouts.  Put another way, I'd like to configure the upper limit of the SSDR Power output slider to a value - perhaps 50W - and distribute that across the entire range of the slider control.  Hope that makes sence.

I don’t think the upper limit of the SSDR Power control is configurable so the only way I can think to achieve greater control is to add an attenuator in the transmission line between the Flex and the amplifier.  The problem with this approach is that with a single antenna the transmit/recieve path is shared.  Thus the attenuator needs to be removed from the receive path, preferably automatically via transmit/receive switching.

Just wondering if I'm missing something? Perhaps SSDR can be configured differently?

Thanks,
Andrew
G0RVM

Answers

  • Jim Gilliam
    Jim Gilliam Member ✭✭
    edited January 2020

    Scaling the power output control to better tailor driving a linear amplifier is a great idea. Maybe it can be implemented in future updates.'

    Perhaps something like this:

    0-25
    0-50
    0-75
    0-100

    Jim, K6QE
  • ctate243
    ctate243 Member ✭✭
    edited January 2020
    "I don’t think the upper limit of the SSDR Power control is configurable "

    Settings >> Radio Setup >> TX tab >> Max power  Change 100 to your desired max output power.
  • Dwayne_AB6A
    Dwayne_AB6A Member ✭✭
    edited January 2020
    When I ordered my amp to match my 6600, I was able to specify the input range and chose 50W -> 1000W vs 5W -> 1000W and other options. Learning more about my amp, I found it is using the A1000-100-11X 10dB pad https://www.barryind.com/pdf/Attenuator/Power_Flange/A1000-100-11X.pdf to control input attenuation. Worst case (and a nice Sunday project) is a small circuit that incorporates a pad mounted to a heatsink together with a relay that will switch the pad inline/offline with PTT.

    Your amp may already have a pad installed in the transmit path but just the wrong one for your use case and it may be a quick swap to achieve the desired input range.
  • Andrew - G0RVM
    Andrew - G0RVM Member ✭✭
    edited January 2020
    I'm not in front of SSDR right now but I didn't think that re-scaled the Power output control just set an upper limit....
  • Andrew - G0RVM
    Andrew - G0RVM Member ✭✭
    edited January 2020
    Thanks Dwayne.  Yes, that is the design I was considering. :-)  I currently have an external 10dB attenuator that I was thinking of using if needed.  Cheers.
  • Dwayne_AB6A
    Dwayne_AB6A Member ✭✭
    edited January 2020
    The hard part is switching it in and out of the transmit path ;)
  • Andrew - G0RVM
    Andrew - G0RVM Member ✭✭
    edited March 2020
    Thought I’d just update this post to describe the hardware solution I now use as it seems to work well.  The scaling of the SSDR Power slider control remains a more elegant solution tho as the additional kit would not be required......A future version Flex?

    I inserted a DX Engineering DXE-RTR-2 and a 50W 10dB attenuator between the Flex 6600 and the SPE amplifier.  The RTR-2 splits the transmit and receive paths so the transmission path is: Flex ANT1 -> attenuator -> RTR-2 -> Amplifier -> Tx/Rx Ant and the receive path is Flex RXB IN <- RTR-2 <- Amplifier <- Tx/Rx Ant.

    A Flex Tx Relay output is connected to the RTR-2 to provide a T/R switch signal.  It should be possible to cascade the Tx Relay signal from the RTR-2 ACC PTT port to the amplifier but this doesn’t seem to work for me. Instead I use another Flex Tx Relay output to switch the amplifier.

    Hope that’s clear and maybe helps someone else.  ;-)

    Andrew
    G0RVM
  • Dwayne_AB6A
    Dwayne_AB6A Member ✭✭
    edited March 2020
    Nice ;) Did you poke around inside your amp to validate if there was the possibility of inserting a pad in the internal transmit path?
  • Andrew - G0RVM
    Andrew - G0RVM Member ✭✭
    edited March 2020
    Hi Dwayne.  No I didn't.  I took the lazy but expensive approach ;-)
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2020
    Power control scaling is not a feature of SmartSDR.

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.