Re: Checking SWR with BITx40
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This is the nature of SSB.? You can't get an accurate read on SSB because it's comes from removing one sideband and carrier from Amplitude Modulation.? So it modulates the amplitude (power) of the signal based on the input.??
You should get a antenna analyzer.? It will give you a picture of the whole range of the antenna and not just one specific frequency.? The Nano VNA is rediculous cheap.? Less than $25 now.??
On Sun, May 17, 2020, 22:46 Scott Skroch < sskroch@...> wrote: My son purchased a?BITx40 and we thought it would be a good idea to check the SWR of his home made antenna before transmitting too much.
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The problem we have run into is that his BITx40 only puts out a fraction of a Watt of power (.016 W) unless we are speaking into the microphone.? We are not able to use our?SWR bridge with?the?low power.
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1. Is this normal for a BITX40?
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2. Is there a standard way to increase the power to the antenna for these types of measurements?? (We could just set up a speaker next to the microphone to give consistent white noise input to the mic but this does not seem right.)?
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Voltage measurements were taken with a multimeter on the output leads of?a 50 Ohm dummy load.
1.05V without speaking into the microphone (1.05V)^2 / 50 Ohm *.707 = .016?W (RMS power)
18V Loudly speaking into the microphone (18V)^2 / 50 Ohm *.707 = 4.58 W (RMS power)
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Thanks,
Scott
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