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 check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.
Need the latest SmartSDR and Power Genius Software?
SmartSDR v3.1.12 and the SmartSDR v3.1.12 Release Notes. | SmartSDR v2.6.2 and the SmartSDR v2.6.2 Release Notes.
SmartSDR v1.12.1 and the SmartSDR v1.12.1 Release Notes. | Power Genius XL Firmware v3.4.16. | Power Genius XL Utility v2.2.10.
SmartSDR v3.1.12 and the SmartSDR v3.1.12 Release Notes. | SmartSDR v2.6.2 and the SmartSDR v2.6.2 Release Notes.
SmartSDR v1.12.1 and the SmartSDR v1.12.1 Release Notes. | Power Genius XL Firmware v3.4.16. | Power Genius XL Utility v2.2.10.
DAX RX Gain After Changing AGC for Digital Operation
When running digital modes using FLDigi or similar programs I typically turn off AGC and move the AGC/Threshold slider fully to the right in SmartSDR. This 'redlines' the RX Gain indicator in the DAX Control Panel, suggesting a significant decrease in the RX Gain setting. Going back to voice modes requires the DAX Control Panel gain to be changed back to around 50%.
I would appreciate advice on how others are setting their AGC threshold for digital modes and whether they are then changing the RX Gain in the DAX control panel. Is the 'best-practice' for digital work to find the 'knee' in the noise level using the AGC slider, move the AGC slider all the way to the right, and/or turn AGC off? I looked through the forum history but could not find any comments that linked AGC operation back to the DAX control panel.
Thanks, Ron
K2RAS
I would appreciate advice on how others are setting their AGC threshold for digital modes and whether they are then changing the RX Gain in the DAX control panel. Is the 'best-practice' for digital work to find the 'knee' in the noise level using the AGC slider, move the AGC slider all the way to the right, and/or turn AGC off? I looked through the forum history but could not find any comments that linked AGC operation back to the DAX control panel.
Thanks, Ron
K2RAS
0
Leave a Comment
Categories
- 65 Community Topics
- 1.9K New Ideas
- 117 The Flea Market
- 5.3K Software
- 4.9K SmartSDR for Windows
- 35 SmartSDR for Maestro and M models
- 84 SmartSDR for Mac
- 143 SmartSDR for iOS
- 149 SmartSDR CAT
- 66 DAX
- 278 SmartSDR API
- 7K Radios and Accessories
- 5.8K FLEX-6000 Signature Series
- 553 Maestro
- 14 FlexControl
- 720 FLEX Series (Legacy) Radios
- 147 Power Genius Products
- 116 Power Genius XL Amplifier
- 10 Power Genius Utility
- 21 Tuner Genius
- 41 Shack Infrastructure
- 22 Networking
- 88 Remote Operation (SmartLink)
- 50 Contesting
- 127 Peripherals & Station Integration
- 61 Amateur Radio Interests
- 402 Third-Party Software
Answers
Just my way of doing it..
AL, K0VM
must just be me, but on CW, when i turn off AGC, and start digging for weak signals,somebody comes along and blows my headphones off my head! digital decoding software doesn't overload, or clip, or go into gain compression, so it doesn't need AGC?
would sure like to decode some more weak sigs, though, so will try the above suggestions.
73, w5xz, dan
Actually, George has a point. When I started this posting I just assumed that I should be setting the RX Gain in the DAX control panel back to a 'normal' level when I went back to voice mode. Since voice modes do not use DAX, I really should not worry about the DAX setting when running voice.
It is interesting that there is no consensus yet on how to set AGC for digital, so I was not missing something. I would be interested in Flex's opinion on the 'best practice'.
Ron'just sayin', as the kids say?
73, w5xz, dan
It depends on two factors; the receive bandwidth filter and band QRN / QSB conditions. It really helps to understand how AGC algorithm is implemented in the radio since it is a dual track AGC that works on both fast and slow increases in gain. I highly recommend reading the section on Noise Mitigation in the SmartSDR for Windows Software User's Guide.
In general, I do not want a stronger signal in my receive passband "capturing" the AGC where the audio gain will decrease, making weak signal reception more difficult. If I am using a narrow filter relative to the mode I am operating and the bandwidth of that filter is such that the probability of another strong signal entering the passband is low, then I use the Fast or Medium AGC and adjust the AGC-T to the point where I have maximum signal to noise (SNR) based on band conditions (see the section in the manual on how to do this).
If band conditions are fluctuating or I am using a wide RX filter, then I set the AGC to Slow or sometimes Off. Again if the AGC is set to Slow, I adjust the AGC-T for maximum SNR. If I use the Off setting, you have to be a little more careful. When AGC is off, it really isn't off. It means that a fixed amount of gain will be applied to both fast and slow increases in noise. I use these setting so that a strong signal in my passband does not capture the AGC and trigger an AF gain reduction.
After that, I adjust the DAX audio level with the DAX control panel. Most of the time I have plenty of adjustment room, and I can always change AGC-T up or down as needed.
73, Jay - NO5J
For psk 31 I use AGC off, slider set to 45 or so, usually i adjust agc based on waterfall in fldigi.
Fldigi I have viewer squelch set to 1.5 with Receive Squelch level set 1/4 from bottom
I found today that while working Feld **** that I needed to crank the agc slider to 90 or so to make out the information
Works as I expect it too.
73, Jay - NO5J