Power level changing when sliding panadapter

  • 1
  • Problem
  • Updated 1 year ago
  • Not a Problem
Has anyone seen this before? It just started happening. I have my power level set to about 32 but when I start to slide the panadapter to the right it suddenly jumps to 100 without changing the transmit frequency , mode ,etc. When this happens the sound also cuts out completely. Notice the level change.

I can repeat the problem over and over on 12 meters and 17. On 12 it happens immediately but on 17 I have to slide a lot more before it does it.

Take a look at the attached video. Sorry about the bad resolution

Flex 6700   v1.10.16.174

Thanks
Pat

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Pat N6PAT

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Posted 1 year ago

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Tim - W4TME, Customer Experience Manager

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The construct of a "band" is defined by the panadapter, not the frequency of the slice. When the bandwidth or frequency range of the panadapter goes out of band, then the new band's persistence values take precedence. You have changed from a ham band to the default "GEN" band and certain values change, like max power level and the RF preamp settings, just to name a few. A full listing of band persistence values can be found in the SmartSDR Softwqre Users Guide.
(Edited)
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Pat N6PAT

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This is not a good thing at all. I am keeping the TX frequency the same and only sliding the panadapter to view the rest of the band. It definitely should not be changing the power levels on it's own. What if I had an ongoing SSB QSO as I slide the panadapter and suddenly the output doubled?  This could result in damaging equipment. My amp has a limit of 50 watts drive but does have overdrive protection. Many older amps do not.
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Tim - W4TME, Customer Experience Manager

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Set the max power value to 50W in the radio setup if this is your concern.  It is a global setting.
(Edited)
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Pat N6PAT

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That's what I'm doing but that becomes a pain when I run barefoot. For example, my amp does not cover 6 meters so I run 100 output from the Flex and bypass the amp.
I will have to change the global setting just to work 6 meters and have to remember to set it back when I'm done.

The bottom line is the radio should NEVER increase the power setting of the active TX slice unless you direct it to. There is no reason for the power to jump to 100 watts when you are just browsing non ham areas. 
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Tim - W4TME, Customer Experience Manager

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What you want to do is easily performed by creating a global profile for 6m and configure the transmit sub-profile characteristics for your 6m setup. It is a single mouse Mose click to operate 6m once it is setup.
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Pat N6PAT

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Tim, I cannot see why the radio should be allowed to change the power output on it's own when the active slice TX frequency , mode , antenna, etc. stays the same. Please explain to me why the power output or any other TX attributes should change by browsing a different portion of the panadapter without any slice modifications. That's like saying the volume on the TV show you're watching should change just because you started browsing the channel guide

Also, if the power was going to change for non ham bands then shouldn't it drop to zero instead of jumping to 100? 
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Tim - W4TME, Customer Experience Manager

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The TV example is not really 100% applicable because it only has one actual receiver and a tuner (channelized VFO).  The 6000s have multiple independent receivers that can be used simultaneously.

It works in this manner due to the way the 6000 direct sampled, multi-receiver radio is architected.  Think about this.  You have 8 slice receivers all over a 14 MHz wide spectrum.  What "band" is the radio in now?  What preselector is used?  What RF preamp setting is applicable? What bandwidth is used for mitigating periodic noise using the WNB?  These are all radio states that have to be maintained automatically by the radio for proper operation.

Is it the transmit slice?  Let's look at that.  What happens when you delete the slice that owns the transmitter ( a new one is not automatically created because the transmitter is always under positive user control)?  Now the radio is in a "bandless" state - that is not a good thing and the software has to prevent that from happening.  If you delete the pandapter, then the state of the band is moot.

In situations like this, what actually defines a band?  That was a question we asked ourselves very early on when architecting the radio.  Something fundamental in the radio has to define the construct of the band which is nothing more than a segment of bandwidth.  And based on the radio architecture, segments of bandwidth are by their very nature represented by a panadapter.  The RF spectrum processed by the FPGA is divided into multiple segments which become the panadapter once an FFT process is applied.  These are foundational components upon which slice receivers are defined.  Since a band is a foundational construct in the radio, it is only natural that it is defined by a panadapter.  Is it an ideal architecture,  no, but it makes doing a lot of other key processes in the radio more reliable and predictable. 

The 6000s are different radios and have different operational characteristics than legacy single transceiver radios.  Just like you would not spin the VFO when transmitting, you don't want to change the panadapter bandwidth (frequency range) so much that it goes out of band or the tune slice frequency either. 

Fortunately, you have at your disposal multiple panadapter resources. Rather than changing the bandwidth of the panadapter, create a new one if you want visibility into other parts of the spectrum.

And the power output does not drop to 0 outside of the ham bands because 6000s (sans 6300) have the ability to transmit out of the ham bands for government, commercial and MARS/CAP/SHARES purposes.
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Pat N6PAT

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"The TV example is not really 100% applicable because it only has one actual receiver and a tuner (channelized VFO).  The 6000s have multiple independent receivers that can be used simultaneously."

Tim, a RECEIVER should NEVER control the power output of the TRANSMITTER