Changes to DAX TX Gain?

Jerry Gardner

Were changes made to the DAX TX Gain levels? I used to get 25 watts output in digital modes with the RF Power slider set to 100, but now I need to set TX Gain to 28 to get 25 watts.

Michael - N5TGL

I would check to see what DAX is set to, as the TX slider setting may have changed as a result of the update?

Tim - W4TME

We did a little tweaking with the TX audio chain in this release so there may have been some minor changes to the gain scale.

Jerry Gardner

It seems like the TX Gain control is a more linear control of output power than it used to be. This is good.

In the prior version, I had to pull the TX Gain slider down to 17 before output power started decreasing from 100 watts. Now when I pull the TX Gain slider down, power starts decreasing sooner and the level seems to match the output power more closely. Now, to get 25 watts output, I put the TX Gain at 25 or 26. Previously I had to pull it down to around 10.

Steve - M3SXA

I'm finding it a bit critical to move these sliders to get my 10 watts for digimodes slightest movement and I'm over... was running with a dummy load at one point and showed 40 watts moved the slider the smallest amount and went down to 25 not sure I like this feature... :-(
BUT.... apart from that well happy....

Michael - N5TGL

Don't use the dax slider to ADUST power, use the RF power slider. You'll get much better control.

Jerry Gardner

Steve,

It's better than it used to be. Before the latest version, the TX Gain slider in the DAX control panel was only effective in the lowest part of its range. With the RF Power slider set at 100, I had to pull the TX Gain slider down to 17 before power output started to drop below 100 watts at all, and any adjustments after that were very sensitive.

Another way to set output power in digital modes is to use the RF Power slider to set how many watts you want as output directly (e.g. set the slider to "10" for 10 watts output), and then use the DAX TX Gain slider to set the peak level to just under 0 dB in the transmit control panel.

I'm not sure which method results in a cleaner signal as I haven't had a chance to hook up my spectrum analyzer yet, but at lower power levels it probably doesn't much matter.

Steve - M3SXA

Hi Jerry it's just I got used to how it was, can't complain though all seemed To work just fine this afternoon but hopefully spend a bit more time over the weekend as we have a 'holiday' Monday to play....

Steve - M3SXA

Hi Mike, I'll try that way over the weekend or come and visit you for some lessons hi hi Can't wait for the nightshift to Finnish :-)