Tuner Genius Power Meter much Lower than PGXL in Single Sideband

Joe Bales

I thought I had read a post recently about the PGXL and Tuner Genius showing large differences in output power in their respective utilities but searching I am not finding it.

My question is are any other users of the PGXL and the Tuner Genius noticing output power meters showing close to 50% lower on the Tuner Genius compared to the PGXL when in Single Sideband Mode? For example, if the PGXL shows 1000 watts the Tuner Genius shows 475-600 which I just did. It is like the PGXL is reading Peak and the Tuner Genius is reading Avg - -

When using CW both the PGXL and Tuner Genius output power meters are very close in power output - when using a constant carried mode like FT8 there are nearly identical on output power.

any thoughts?

K4JKB

Joe

Mike-VA3MW

Joe

There are many variables that will make this happen. What happens if you test on a dummy load?

This helps to explain why: https://www.arrl.org/files/file/Technology/tis/info/pdf/q1106037.pdf

Mike

Joe Bales

Hi Mike,

Same thing with a Dummy Load - This happens only in SSB mode - CW and Digital all is good and output readings are quite close.

Tim responded to my help desk ticket as follows:

"Yes, the power detection circuitry in the TGXL is not peak reading which explains the difference when using non-constant carrier modes, as you have observed. The PGXL does use a different power detection circuitry that does a better job at reading average power."

I meant to follow up on here yesterday but life happened.

thanks

Mike-VA3MW

Hi Joe

They are all calibrated when they leave the factory to a 50 Ohm resistive load.

If it is really off, please follow up with the support team to see why.

73

Joe Bales

I'm confused. I submitted a help desk ticket. Tim quickly responded and his comment I posted above. and he closed the ticket. Didn't I contact support via the help desk ticket Tim responded to?

it's been a long day I must be missing something?

can you discuss with Tim E. ? It appears I am getting conflicting information from two Flex employees.

Thanks

Mike-VA3MW

my bad... I missed that. That is what I get for answering stuff while on vacation. ;) My apologies.

So, the deal is monitoring/measuring SSB (Peak Envelope Power) is actually very complicated. 4O3A does the code for the Tuner Genius and FlexRadio engineeers did the PEP code for the Power Genius.

Dave, who wrote the code for the PGXL, spent a significant amount of time coming up with an algorithm that could calculate PEP without overloading the processor in the PGXL. In order to do it accurately, you have to measure the RF power hundreds of times a second. This is also why watt meters like the LP-100/700 are so darn good since they make the calculations accurately.

For the TGXL, I can only assume what their algorithm is like, but if you ask 4O30A, they might be able to comment as they own the entire solution. FRS is just the distributor. I also do not know if we share the code between the 2 units.

https://en.wikipedia.org/wiki/Peak_envelope_power

Joe Bales

Thanks Mike. Go enjoy your vacation. Thanks for taking the time. I will use PGXL metering for ssb

joe

k4jkb

David Decoons, wo2x

Hi Joe

I use a Relwpoat LP700 with four sensors on my station.

As you found out, the TG XL is accurate with constant carrier modes but not at PEP reading. That is why I have the LP700.

Also the LP100 is a very good peak reading meter and you can bridge the couplers so that whichever is receiving power will be displayed. Convenient for the PG XL outputs.

73

Dave wo2x