Power Out seems low for FT8

Don_N5SKT

I have been running an Amp for a while but decided that running FT8 via the Amp is not required for what I do. So, I created a new FT8 generic profile (I was creating a profile per band but don't think it is necessary) and started working with it. With the Amp, the power out of the radio was dialed back to a few watts and and so I went in and created a new radio profile with all bands set to 100 on tx. However, with the power slider all the way to the right, I am getting between 70-80w out. I THINK it is a Windows issue between WSJT-X and DAX as there seems to be about a thousand mic controls in windows. I run into issues when I plug in my USB headset and find that I get no power out to the radio even though the TX is firing in DAX. I usually need to restart Smart SDR and DAX to correct the issues. Sometimes, I need to reboot the radio also. But that is 0 power out and when restored, I still and seeing 70-80w. TX gain in Dax is set to 50% and I leave it there. What other black magic is there in Windows? I created an FT8 MIC profile but it never worked. The Default profile does. BTW, from FRSTACk monitor, I see the power on an FT8 broadcast vary between 70-80w during the transmission like there is something wavering. The SWR and Ref power stays steady. Just the forward power is moving. I remember a year ago always getting 100W out when I set for FT8.

Mike-VA3MW

@Don_N5SKT

The first critical point is what does the Level Meter in SmartSDR show while transmitting? It should be about -5dbm.

Next, what is your supply voltage at the radio when under follow load? It should be 14V or higher. You can check this voltage using FRStack if you like with the Meters window.

Mike

WB2RRF

I was just going to ask a question re power on FT8 as well. I am new to Flex about 2weeks with a 6400 and all was great till last night. Power has dropped form full 100w to jumping/varying between 10 and 30w almost like a modulation signal on ssb would do. Level meter is unchanged where it has always been, didn't touch any other settings. Ran the radio into a dummy load and the same issue with and without ATU on. Tested on SSB and full power output (100w). The smartSDR for Mac software did crash when this happened last night. Rebooted the smartSDRmac and still having the same issue. The start up message when I rebooted the SDR program said version 2.0.15. Not sure if the power issues is related or there was some bug in a software upgrade. Any help would be appreciated. Have been loving my first 2week back on the air on FT8 and would like to figure out what to try to get operational again. Thanks Ray WB2RRF

Mike-VA3MW

If SSB works as it should but FT8 doesn't, then the problem points to the FT8 module or DAX path within SmartSDR for MAC. You may want to reach out to the developer of SmartSDR for MAC.

Based on the way you worded it, it does not sound like a radio/hardware issue.

WB2RRF

Thanks for getting back so fast. I did some more troubleshooting and believe it is a software issue with the OS version of SmartSDR. FT8 is working fine at full power if I run it off the iPad iOS version. So confirms its not the 6400! I have reached out to the developer.

Don_N5SKT

Mike,

I have an adjustable power supply that is currently set for 14.1V. When it transmits, it does drop low but only around 13.2 using the Alinco DM-43OT. I have just added an Astron 35M supply and I know, changing equipment when debugging is not the best thing to do but I got a good deal on the Astron ;)

Mike-VA3MW

You could set the Alinco to as high as 15V and test with it.

John KB4DU

depending on your setup there can be significant power loss between the ps and the flex. I target 13.8 volts at the flex when txing. Flex spec is 13.8 +- 15%, so 15.87 max.

Don_N5SKT

I am getting a pretty stead 90w with the Astron. Seems maybe it was the Alinco going weak?