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I'm trying to complete my EMF assessment, so does anyone know what the duty cycle of VaraAC is?
This is an old thread, but perhaps of interest to those who need to complete an EMF assessment. There is an RSGB on-line calculator that shows ICNIRP 2020 and 1998 limits. The important part of the duty cycle relates to the percentage of transmit time in a 6 minute period on frequencies above 10 MHz. Averaged over 6 minutes, even a 100% duty mode, such as FM, would drop to 50% due to the TX/RX timing.
Note that on frequencies below 10 MHz (40m/80m, etc), the compliance distance is based on peak power, not on percentage of time transmitting in a 6 minute period. This is different for the ICNIRP 2020 Limits compared to the ICNIRP 1998 Limits. Try the calculator and you will see the effect, for example a half size G5RV with the lowest part of the antenna at 3.5 metres and 1KW of RF on 40m, as you change the duty cycle you will see the compliance distance change for the 1998, but not for the 2020.
Funny how physics varies depending on where you are located in the world too, equally you can opt to use the 1998, or the 2020 figures for our OFCOM, depending on which works out "safer" for your garden arrangement, what a crazy situation...
73 Dave G4AON
I'd like to hear about this also. So far I haven't seen transmission bursts > 6 seconds, but won't say so with certainty.
My reasons are different from yours. I'd like to know how much power I can safely drive my radio. It's rated at 50% with full carrier modes. With VarAC the full carrier bursts are brief so I can go above the 50% of the full power recommendation by Yaesu. Simply unsure how much higher.
My educated guess for your EMF assessment is it's well under 50% but highly variable. Don't depend my guess...