Output Power Less Than 100 Watts

Charlie

It seems that output power on all bands with my 6300 is between 75 and 78 watts into a dummy load.  I have the RF Power slider all the way to 100 watts. Is there another settings that I should check to be able to get out 100 watts or close to it?

K1UO Larry

Hi Charlie,   This was posted about a week ago and should explain what is going on at the moment with your 6300.  Hope it helps for now.

Regards

A few FLEX-6300 customers have mentioned that output power on CW is lower than the output power on SSB.  We have looked at several different radios and found that the power offset is typically 0.3 - 0.7dB lower with CW due to the different path that RF takes through the radio when operating QSK.  At most, this amounts to a roughly an 85W output when set to 100W (your mileage will vary).  15W difference sounds like a lot, but to keep this in perspective, an S-Unit is 6dB so this is only 1/10th of an S-Unit difference for a receiving station!  Nevertheless, we want to account for the difference so the radio is a full 100W output on CW as well.

When the radio was designed, it was assumed that there would not be an offset in the paths so the calibration difference was not accounted for along with the myriad of other calibrations in the radio (board losses, filter losses, PA gain variance, etc.).  It may be interesting to note that the difference is not a power loss (it is not power dissipated in the radio), but is a generation offset (less power is produced).  As a result of this discovery, we have updated the calibration algorithm which will offset the power for CW to overcome the difference.  The change has already been coded and tested and we will be releasing this as a point release software update in the next several weeks (this along with other fixes will first be tested by the Alpha team, etc).

Steve - N5AC, VP Engineering

• 337 Posts
• 194 Likes

Posted 1 week ago

Charlie

Thanks Larry,  I found that announcement after I posted the message.  That is exactly what is happening.  Glad Flex is aware of it and I am sure that a fix will be forthcoming.  I really like the 6300.  It take some getting use to it since this is my first sdr radio but it working well.

Ed, K0KC

In addition to Steve's calibration comments above, be sure that you have 13.8 volts at the radio end of the DC power cable when transmitting at full RF output. I have a 6700 and I imagine that the 6300 also uses PowerPole connectors which are difficult to get to with DMM probes. My solution was to push a couple of sewing needles into the PowePoles to  make contact with the radio end of the power cable and place the DMM leads on the needles for the DC measurement.

Also, I believe that the correct way to set the radio for maximum power is to active the Tune button and then drag the RF Power slider to 100%.

Ed, K0KC

Reggie-k6xr

I have same indication on my 6500. Peak reading Wattmeter says 100 watts actual output but 6500 indicates 20 watts lower than that on each band.

DrTeeth

Closest I have got to 100W on the scale with my 6300 with SSDR 1.4.0. is 85-90 into an antenna with 1:1 SWR. 13.8 v to the radio on receive.

KY6LA_Howard

@Guy

13.8V on receive is not a good measure of your transmit power voltage.

Your voltage on Transmit is important because with the higher XMT current draw any resistance means a voltage drop and less power

How is your wattmeter calibrated

Finally there was a bug in the power output of the 6300 that will be corrected in 1.4 Point release.

DrTeeth

Hi Howard, I use DDUtil to read the voltage. I assumed that the rig was to be supplied with 13.8v on receive, not on tx. If 13.8 is safe on tx and will not harm rig on rec, I'll try upping the voltage a tad. I know the other end of a QSO will not be able to tell if I radiate the extra power, but it would be nice to get the full rated output...every little bit helps. 73