AGC-T Sweet Spot

Butch · April 2021

I recently watched Tim's Youtube video titled Flex 6000 Receiver Tuning:

Excellent video. At the 39:00 point in the video Tim's talks about the AGC-T sweet spot setting, and for clarification shows a yellow dash line indicating a visual AGC-T reference.

It would be really slick if there was an on/off option in SmartSDR for such a yellow dashed line show up on the screen, for a second or two, as the operator adjusted their AGC-T control. This would give an interesting visual perspective between the noise floor and the AGC-T setting. Anyone else think this might be a useful feature to SmartSDR?

Butch

KF4HR

KD0RC · April 2021

Hi Butch, I agree!! Tim does a great job of explaining the AGC-T and his graphic makes you want that line in real-time. I don't know how hard it would be to implement. I am pretty sure it is not trivial to get the AGC gain level to reference the pan adapter noise floor level. Would probably depend on the selected bandwidth and panadapter display width and other factors that I don't understand.

I tried to come up with a formula where you look at the noise level on the panadapter and subtract 95 dB to get the AGC-T setting. I thought I really had something there but it does not work that way... I have learned to adjust it according to Tim's (strong) recommendation, and that really does work well.

BUT... If even an approximate line to get you in the ballpark could be implemented, I think that would be great.

John K3MA · April 2021

Yes it has been suggested on the forum many times and many years ago. I believe it even showed up on the feature request survey that Flex completed more than a year ago or maybe even two years ago. I don't remember clearly as it seems time moves slowly with anything Flex.

John K3MA

Al_NN4ZZ · April 2021

Here is a link to the idea to automate the AGC-T setting and also display the visual line. It is the number 1 most requested idea at 101 votes. It was submitted 7 years ago. Not sure if they look at the votes these days to prioritize enhancements but it may still eventually happen. Feel free to add more votes and comments it you would like to see this feature.

https://community.flexradio.com/discussion/6389202/option-to-automate-the-agc-t-setting/p1

Option to Automate the AGC-T setting

Al_NN4ZZ

Oct 10, 2014

Background
The AGC-T setting needs to be adjusted differently based on the band and current conditions that affect the noise floor. We often need to make adjustments on a regular and frequent basis.
This idea below was spurred by a request from Bill / K7UOP asking for a FlexLib feature to provide AGC-T values. His idea is to write an external program to set the AGC-T value based on the noise floor. It would set the AGC-T a specific amount based on the current noise floor. He wrote such a program for PowerSDR. Here is a link to his idea for reference:
https://community.flexradio.com/flexradio/topics/flexlib-agc-t-values-in-dbm

Idea to Automate the AGC-T setting
My idea is to take it one step further and add an option to incorporate this into SmartSDR. It would allow you to specify the amount above the noise floor you want and then it would automatically and dynamically keep the setting there.   Here are some notes and a mockup illustrating the changes to the GUI.

Features:
- retain ability to manually adjust the AGC-T by selecting "Manual" button.
- provide the ability to automatically and dynamically adjust the AGT-T by selecting the "Auto" button.
- Provide a slider for the auto setting to adjust from +0 dB to +25 dB.

Regards, Al / NN4ZZ
al (at) nn4zz (dot) com

Regards, Al / NN4ZZ

al (at) nn4zz (dot) com

6700 Win10 SSDR V2.4.10

Butch · April 2021

I could see where automating the AGC-T adjustment could easily lead to complaints about the automated adjustment being too tight or loose for personal preference.

Perhaps FRS will see fit to add the graphic representation of the AGC-T control in SSDR v4.0.

Butch KF4HR

WX7Y · April 2021

I agree with Butch, Look at what trouble the Profile Autosave has and does cause for MANY of us.

Al_NN4ZZ · April 2021

Hi Butch and Bret,

One major difference with the automated AGC-T feature is that it also includes a switch to use the current manual process as well. That is shown on the mockup, so there is nothing lost. And you can also elect to see the visual line showing the AGC-T setting or not. I included both as user selectable options in the request. I anticipated that there would be times or users that preferred the manual process.

By the way, I’m also in favor of the profile autosave ON/OFF switch and waiting for it before upgrading past 2.4.10.

Regards, Al / NN4ZZ

Lionel · April 2021

If not auto, maybe difficult to implement, how about a "suggestion" by a line across the spectrum scope? Then use it, or change to your preference. No auto/man switching. This may be an easier calculation to implement.

AGC-T Sweet Spot

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Option to Automate the AGC-T setting

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